There's a new type of landslide affecting northern latitudes, and it could affect more areas as the planet continues to warm.

These landslides, called permafrost detachment slides, occur in areas with relatively thin permafrost and seem to be a long-term impact of wildfire in these environments, according to a paper published Sept. 23 in the journal Geophysical Research Letters. Such slides have not been observed in the region before and may be unprecedented over the past 10,000 years or more, said study leader Joseph Young, who completed the work as part of his doctoral degree at the University of Alberta.

"It has been stable, and then it just flipped a switch, essentially," Young told Live Science.

Young and his colleagues were doing field observations in Canada's Northwest Territories when they noticed large landslide scars in valleys that have long hosted stable permafrost, which is sediment that remains frozen year-round. They began using satellite imagery to map the changes and also conducted fieldwork, which revealed that the slides weren't standard melting permafrost.

"Typically with permafrost, everything just thaws and melts in a slurry and moves like a mud downslope," Young said. "But with these large landslides, we found blocks of frozen material in the debris."

Some of these blocks were 33 feet (10 meters) tall, the height of a two-story house. The researchers ran an electrical current through the ground to determine the depth of the permafrost on the slopes.

They focused on two slides. One, in the Johnson River Valley, took place in 2017 and moved more than 636 million cubic feet (18 million cubic meters) of soil and rock. The other, in the Redstone River Valley, moved almost 159 million cubic feet (4.5 million cubic meters) of debris in 2018. The smaller slide left a scar three-quarters of a mile (1.2 kilometers) long, while the larger one gouged nearly 2 miles (3.2 km) out of the hillside.

The researchers then used the data they'd collected to build a model of how these icy slides occurred. The permafrost in this area has been warming by about 0.54 degrees Fahrenheit (0.3 degrees Celsius) per decade since 1980, when monitoring began, and there were also severe wildfires nearby in 1995.

The researchers found that instead of a top-down melting process by which the permafrost thawed to a muddy slurry from above, the slides were instead caused by a combination of fire-related thaw and warming temperatures, leading to cracks near the top of the slopes. These cracks allowed the thaw to penetrate deeper, eventually melting the bottom of the permafrost layer. This propagation can take 20 years to penetrate 66 feet (20 m), which is exactly what happened in the Johnson River and Redstone River valleys.

"We had a fire in '95 and then 20 years later, we start to get a lot of these widespread disturbances," Young said.

The two large slides the researchers studied are among more than 150 in the area, Young said. The others are smaller, but they still typically move over 35 million cubic feet (1 million cubic meters) of land apiece. Canada's Northwest Territories are remote, so the permafrost detachment slides have yet to damage any infrastructure. But the two in the study did dam rivers, creating brand-new lakes and rapidly dumping sediment into the waterways downstream, Young said.

There are many other places in Canada and Alaska where the permafrost is 66 to 130 feet (20 to 40 m) deep and thus vulnerable to the same type of slide. This is especially true given the increasing intensity of wildfire at northern latitudes, Young said.

"This is almost a potential glimpse into the future of what we might be able to expect in these areas with changing forest fire dynamics," he said.

About 251 million years ago, volcanic eruptions wiped out most life on Earth. For about a million years, the Siberian Traps in Russia spewed huge clouds of carbon dioxide into the atmosphere, leading to the most severe extinction event in our planet's history.

Equatorial temperatures spiked, making much of the land too hot for life. Meanwhile, the oceans became acidic and most of the creatures in them suffocated from lack of oxygen. Known as the Permian-Triassic mass extinction or the "Great Dying," it ultimately destroyed more than 90% of ocean life and 70% of terrestrial species.

However, in a corner of what is now China, a refuge of pollen-producing plants avoided that fate and created an oasis for surviving animals. Research suggests that this was not the only place where plants were able to weather catastrophic climate change during the Great Dying, and that plants may have been better able to withstand the extinction event than other organisms.

"Plants do indeed sometimes have a lot of resilience because they can't move individually, and even as a population, they're not very good at moving," Chris Thomas, an ecologist and evolutionary biologist at the University of York in the U.K., told Live Science. As a result, many plants have evolved mechanisms to survive in place despite difficult conditions, he said.

As climate change raises global temperatures and throws ecosystems into upheaval, plants will need to draw once more upon this resilience. Many plant species have evolved unique adaptations that help them weather harsh conditions. Experts told Live Science that these adaptations — along with a hefty dose of luck — will now decide the difference between survival and extinction.

Growing with the flow

Unlike most animals, many plants have the ability to regenerate limbs — and those limbs can make them better able to adapt to new environment conditions. Plants in general have higher developmental plasticity than animals, which means that they have greater flexibility to change how their cells and tissues grow and develop.

"Many plants have what we call indeterminate growth and modular body plans," Amy Angert, a botanist at the University of British Columbia in Canada, told Live Science. Indeterminate growth means that an organism continues to grow and develop indefinitely throughout its lifespan.

"If we lost an arm, it would be gone forever. But on plants, if you cut off a branch, they can sprout new ones and those new ones can then receive signals from the current environment instead of being stuck with sort of developmental programs from the past environment."

For example, researchers found that resprouts on holm oak trees (Quercus ilex) are better able to cope with drought than those that had not resprouted.

And because buds can go dormant, many plant species can resprout after catastrophic events, such as fire. Cape Floristic Region in South Africa, for example, is the smallest of the world's six recognized floral kingdoms, and most of its plant species depend on fire — its plants resprout after fire and many of their seeds require fire to germinate.

Some plants, such as the Snow Gum (​​Eucalyptus pauciflora), have a thick layer of insulating bark to protect their buds, while others like stinging nettles (Urtica dioica) bury them underground in a "bud bank". The soil insulates the seed's buds from extreme heat and cold and protects most of the plant from life-threatening conditions. This widespread adaptation allows herbaceous plants to endure through the winter and plants with bulbs to hide their tissues from the ravages of fire.

Storing seeds for better times

Plants can also store seeds underground when times are difficult. Almost 350,000 plant species produce seeds. For most of these species, the seeds contain dormant tiny versions of the young plant, with all the structures that will turn into leaves and roots.

"Seeds can live essentially in stasis in the soil," Daniel Anstett, an evolutionary ecologist at Cornell University, told Live Science. "You can have the seed bank where certain seeds might come back, and there's access to the backward library of genetic information that many plants can ultimately draw upon."

Seed banks are a vital tool for resilience in many plant species. They create the opportunity for metabolically inactive individuals to reanimate when environmental conditions improve, according to a 2021 paper published in the journal Nature Communications. "When lucky, at least some of these individuals will awaken in the future when the environment is more conducive for growth and reproduction," the authors wrote.

Rapid evolution

Seedbanks can also be reservoirs of genetic diversity, which is integral to being able to adapt to new environments.

"The raw material for adaptation comes from genetic variation," said Angert. "Genetic variation is larger in large populations, and genetic variation can be shared between populations as the environment changes — if individuals can disperse successfully between them."

In a paper published in journal Science earlier this year, researchers, including Angert and Anstett, showed rapid evolution saved scarlet monkey flower (Erythranthe cardinalis) populations from prolonged drought in the U.S. and Mexico between 2010 and 2018.

"They can either grow really fast, flower and put out seeds before the fall drought takes effect, or they can grow much more slowly and bunker down,” Anstett explained.

The researchers sequenced the genomes of 55 scarlet monkeyflower populations to find areas within their genomes linked to coping with stress and drought. They tracked the populations and how they changed over the period. Some populations experienced rapid evolution to cope with the changing environment.

They found that, based on populations’ genetic diversity, they could predict whether a population would be able to survive the drought — even before it started.

While this is only one plant species, Anstett believes it could be true of other organisms too.

Flexible photosynthesis

Some plants are able to transform how they produce energy to endure a changing environment. This is what Zhen Xu, a paleobotanist at the University of Leeds in the U.K, thinks allowed some plant species to survive the Permian-Triassic mass extinction and might become increasingly important for plants in today's changing climate.

Plants use photosynthesis to convert carbon dioxide and water into sugars and oxygen, and use stomata, or small pores on their leaf surface, to regulate the amount of carbon dioxide entering the plant.

Many plants open their stomata during the day to let in CO₂ and release oxygen. Others use CAM photosynthesis, which stands for "Crassulacean acid metabolism," to close their stomata during the day and protect themselves from the heat. At night, they absorb CO₂ and transform it into an acid, which they store in their tissues to be used to make sugars during the day.

"CAM photosynthesis is very common in present day desert plants, like the cactus and succulents," Xu told Live Science. "It's a very smart way to escape from the high temperature or aridity during the daytime."

In a study published in journal Nature Ecology & Evolution earlier this year, Xu and colleagues showed that plants that used CAM photosynthesis had an advantage during the Permian-Triassic mass extinction.

They found that Lycophytes, or are ancient vascular plants, switched to CAM photosynthesis around the time of the mass extinction. "We think CAM photosynthesis may be the special strategy to survive" and allowed these plants to dominate after the mass extinction, Xu said.

Hopeful monsters

Some plants go to even more extreme lengths. During cataclysmic events, plants have turned into "hopeful monsters" to survive environmental upheaval, past research shows.

In nine separate events over the past 150 million years, many flowering plants duplicated their whole genome to give themselves a better chance of survival, according to research published in journal Cell earlier this year. The duplicate genome gives them more opportunities to evolve and adapt to challenging environmental conditions.

"We see clusterings of whole genome duplications in time, and every time it corresponds with a described, important geological event, whether it's a global cooling period, whether it's a global warming period, or whether there's an extinction event," study co-author Yves Van de Peer, a genome biologist at Ghent University in Belgium, told Live Science at the time.

Boils down to luck

Still, the survival of specific plant populations or species often boils down to luck, experts told Live Science.

Plants "essentially have this broad toolkit" but "some of the plants have some pathways, and other plants have others, and some have some traits, and some have others", Anstett said. Whether the particular tools they have will help depends on the conditions they face.

During the Triassic-Permian mass extinction, the plants in refugia in China (and elsewhere) were in the right place at the right time, with the right suite of potential adaptations at their disposal and enough genetic variety to tap into them.

The same holds true for modern-day species facing a changing climate and potential extinction. Angert said there are ways to make plant species "luckier" in the years ahead, such as connecting fragmented populations to increase genetic diversity, which increases the suite of potential tools at a plant species' disposal.

"The best thing we could do is to leave larger and better connected populations on the landscape," she said.

Anstett agreed. "If populations become really disconnected, then potentially we're eroding away whatever toolkit that these plants have to be able to adapt."

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Climate change is making Earth progressively rounder, new research finds.

The findings are a signal of human-caused climate change, however, and tracking the shape of the Earth can help reveal just how much impact people are having on its ice caps.

Our planet is not a perfect sphere. Because of its rotation, it is a bit flatter at the poles and bulges in the middle. But the new study reveals that Earth is getting rounder at an accelerated rate, largely due to shifts caused by the melting polar ice caps.

This finding applies only to the solid parts of the planet; the ocean continues to bulge outward at the equator.

The study, published Sept. 9 in the journal JGR Solid Earth, used direct measurements from the global navigation satellite system (GNSS) to track the planet's shape-shifting over time. This system provides direct measurements, but there are limits in how it can be used. For example, there are few GNSS stations near the North and South poles and few in remote oceans because they must be deployed on buoys.

Christoforos Kotsakis, a professor of geodesy at the Aristotle University of Thessaloniki in Greece, developed a new method for analyzing GNSS data to better capture the changes in the planet's surface. He found that the poles are rising and the equator's bulge has been shrinking, each by about 0.04 inch (1 millimeter) per year between 2011 to 2015. That's a small number, considering Earth's diameter at the equator is about 7,926 miles (12,756 kilometers). But that change is bigger than between 1997-2000, when Earth was becoming about 0.02 inch (0.5 mm) rounder per year. This means Earth's shape is rounding at 0.016 inch (0.4 mm) more per year with each decade that passes.

The shift is being driven by polar ice melt, which takes pressure off the Earth's crust and allows it to rise slowly, similar to how rising bread dough springs back after you press a finger into it, Kotsakis reported. Meanwhile, increased mass toward the equator puts pressure on the crust there, reducing its bulge. However, there's a catch: When considering the solid Earth and the ocean together, the planet is getting flatter by about 0.03 inches (0.8 mm) a year because the ocean is getting bulgier at the equator as water shifts away from the poles. This 'water weight' overwhelms the rounding happening in the rock below.

These shifts are also slowing Earth's rotation, other research has shown.

Researchers also track Earth's changing shape using measurements of its gravity field, which varies depending on the mass of particular regions. GNSS changes and gravity field measurements don't match up perfectly, Kotsakis found, which indicates that the planet's shape and gravity field aren't in perfect lockstep. However, the two methods can be used together to track the major effects of climate change, especially the melting of Greenland and Antarctica and the varying movements of ocean water.

This striking satellite snap shows the scorching land and sea surface temperatures that hit Southern Europe during one of the continent's record-breaking heat waves this summer.

The image was created using data from the Sea and Land Surface Temperature Radiometer (SLSTR) on board the European Space Agency's (ESA) Sentinel-3B satellite. It was selected for this week's edition of Earth from space by Simonetta Cheli, director of Earth observation programs at ESA and head of the European Space Research Institute (ESRIN) in Frascati, Italy.

Live Science recently visited Frascati to see ESRIN's newly operational Space HPC supercomputer and sat down with Cheli for an in-depth discussion about Earth observation. When asked about her favorite satellite image, Cheli highlighted this photo as one that caught her eye this year.

In the thermal image, dark reds highlight terrestrial temperatures in excess of 95 degrees Fahrenheit (35 degrees Celsius) across most of Spain and parts of France and Italy, while dark purple spots show highs above 104 F (40 C) across patches of Spain and North Africa. The image also reveals sea surface temperatures spiking across the Mediterranean Sea. (The colors in the image do not represent the same temperatures on land and sea. For example, orange indicates temperatures of around 86 F (30 C) on land but around 73 F, or 23 C, at sea.)

Cheli said that assessing how terrestrial and marine environments interact during extreme weather events is really important and that including both in the same image is the only way to appreciate the true scale of this heat wave: "You see the red in the sea, and you see the red on the land, and I think it gives the feeling of the heat wave that we've all been living through this summer," she said.

While many people may find such images related to human-caused climate change disheartening, Cheli sees it as a sign of hope that orbiting spacecraft can monitor otherwise-invisible changes to our planet's surface in such detail.

"It makes me feel that we can do a lot about it," she said. "It makes me feel that we have tools and certainly information capabilities to support, help and also raise awareness about this topic."

Cheli told Live Science that ESA's ability to monitor extreme weather events like this will only improve as the agency launches new-and-improved spacecraft into orbit. In September, ESA successfully launched Sentinel-3C, the successor to the spacecraft that snapped this image, which has already captured its first photos of Earth and will help study future heat waves in greater detail.

Europe's record-breaking summer

Between late May and mid-August, parts of Europe were hit by at least five separate heat waves, meaning temperatures stayed unusually high throughout the season. "We had, I would say, the hottest summer ever," Cheli said.

The peak heat occurred in June, when the average temperature for that month reached 69 F (20.7 C) — its highest in Western Europe's recorded history, according to the World Meteorological Organization. (This average includes nighttime temperatures, which is why it seems relatively low compared to other temperatures mentioned so far.)

Eight countries — Austria, Belarus, Czechia, Denmark, Germany, Hungary, Poland and Slovakia — recorded their highest land surface temperature of all time at various points throughout this summer, and several others had record temperatures for a specific month or region.

The extreme weather caused widespread droughts across the continent, some of which are still ongoing, and helped trigger several wildfires, including a series of particularly large blazes in France. Experts think the high temperatures resulted in at least 35,000 excess deaths across Europe, although the true number is expected to be much higher, according to The Guardian.

The heat waves were caused by "heat domes," which are pockets of high pressure in the atmosphere that trap warm air beneath them, like placing a lid on top of a boiling pot. These are also linked to higher sea surface temperatures.

The ongoing super El Niño began in May and has already led to record temperatures in the Pacific Ocean, but it did not contribute to the European heat waves, according to ESA. Instead, the record temperatures are a continuation of recent global warming trends.

However, El Niño could lead to more extreme weather this winter, in Europe and in North America.

See more Earth from space

Rising temperatures around the globe are contributing to a range of health risks, from infectious disease to food insecurity and wildfire smoke. Extreme heat is another major public health concern, as climate change drives up both average temperatures and the frequency of extremely hot days. This August was the world's hottest on record, and it drove upticks in heat-related emergency visits and deaths in various U.S. states.

Hotter weather is expected to pose dangerous health risks for millions, and pregnant people are especially vulnerable to its impacts, experts caution.

"Pregnant people are physiologically more vulnerable to heat," Dr. Susanna Esposito, a pediatrician at the University of Parma in Italy, told Live Science. "Climate adaptation should treat pregnant people as a priority population."

Extreme heat is linked to adverse birth outcomes that can be fatal for both mothers and newborns. Heat can also hinder fetuses' development, contributing to long-term health and cognitive effects.

Scientists and public health experts are working to identify the thresholds between safe and dangerous heat for maternal and prenatal health. As the planet warms, how will that affect the risks associated with pregnancy? And how can those risks be countered?

Low birth weight

When the body tries to cool down, blood moves to the extremities to dissipate heat through the skin's surface. Some studies suggest that, in a pregnant person, this may reduce blood flow to the placenta, which in turn reduces the organ's supply of oxygen and nutrients. This is thought to contribute to low birth weight, which is associated with a heightened risk of illness and death shortly after birth, as well as cognitive and mental-health challenges later in life.

Heat stress may also spike the body's levels of cortisol beyond what they should be in a healthy pregnancy, studies in lab animals suggest. This may expose developing fetuses to more cortisol than usual, affecting some aspects of development and functions of the placenta. This mechanism is not fully understood in humans yet, though.

That said, several studies in humans support the notion of a link between heat exposure and low birth weight. Mothers who were pregnant during a 2003 heat wave in France were more than twice as likely to have a baby of low birth weight than mothers whose pregnancies did not coincide with the extreme heat. The trend was especially strong when the heat wave hit during a person's first trimester.

In a study conducted in Arizona, hotter temperatures during the third trimester were also associated with lower birth weight, said study co-author Kristin Mickelson, a social-health psychologist who studies public health at the Arizona State University.

Preterm and early birth

Preterm delivery — before 37 weeks of gestation — is one of the most concerning health outcomes that's been linked to heat, Esposito told Live Science. The risk of neurological and developmental disabilities is higher in preterm babies than in full-term babies.

"If you're born preterm, you have a heightened risk of all sorts of adversities throughout infancy, but then also extending into childhood and even longer term," said Clara Heil, health researcher at Lund University in Sweden.

Severe heat may make preterm birth more likely. A review of 70 studies suggests that the chance of preterm birth is 16% higher when a multiday heat wave hits during the final weeks of pregnancy. Regarding average temperatures across an entire pregnancy, each additional 1.8 degrees Fahrenheit (1 degree Celsius) boosts the risk of preterm birth by 5%, the same review found.

High temperatures have also been tied to early births, which occur after 37 weeks of pregnancy but before 39 completed weeks. Early birth is associated with an increased risk of hospitalizations through childhood and slower neurologic development.

A study analyzing 56 million U.S. births across two decades suggested there was about 1 more early birth per 100,000 pregnancies on days with a maximum temperature above 90 F (32.2 C), compared to 60 to 70 F (15 to 21 C). Deliveries on hot days were typically about six days earlier than anticipated, but some were up to two weeks early.

With average temperatures continuing to rise, early and premature births could become more common. The United Nations predicts that the world is set to cross the 1.5 C (2.7 F) threshold of warming compared with pre-industrial levels, likely within the next five years, and we may even surpass the 2 C (3.6 F) threshold in that timeframe.

"We can probably expect to see these temperatures, or worse, in the upcoming years," Lizbeth Burgos Ochoa, statistician at Tilburg University in the Netherlands, told Live Science.

Preeclampsia, heart defects and other risks

Maternal heat exposure has also been associated with an increased risk of preeclampsia, a pregnancy complication related to blood pressure that can be fatal. In a 2011 study conducted in France, hotter temperatures during the first trimester were associated with a slightly increased risk of severe preeclampsia, although more research is needed to understand why.

Heat exposure has also been linked to other conditions of pregnancy, including gestational diabetes and hypertension, as well as increased emergency hospital admissions during pregnancy, overall.

Additional studies have highlighted potential risks for developing fetuses and newborns. For example, following a heat wave in Canada, the risk of a baby being born with critical heart defects was 6% higher, one study found. Babies with the highest risk had been exposed to temperatures of 86 F (30 C) or higher for at least 15 days during the first trimester of pregnancy.

Extreme heat waves may also raise the chance of stillbirth, according to a study conducted across six U.S. states. Four consecutive unusually hot days — exceeding the 97.5th percentile of temperature for a given county — in the last week of pregnancy was linked to a 3% increase in the risk of stillbirth.

These studies are observational, so they show links between heat and pregnancy outcomes but cannot directly show that the heat spurred the increased risks. They also don't take into account study participants' home environments or strategies for cooling off, so they don't provide a full picture of how much heat they were exposed to.

Caring for pregnant people and the next generation

Researchers are still working to understand what temperatures pregnant people should be most concerned about.

"It would be [helpful] to understand what level of heat becomes dangerous to women," Heil said. "Is there a threshold where it becomes difficult for the body to dissipate heat? And especially for the pregnant body, which is different from the non-pregnant body, to cope with that heat?"

Heil and her research team synthesized over 100 studies on heat and poor birth outcomes, such as stillbirth, preterm birth, placental abruption and preeclampsia. The studies varied considerably in that they covered different timeframes, focusing on just one trimester or all three, for instance. But in general, their results converged on a pattern: The risk of poor outcomes rose as temperatures hit about 87 F (30.5 C). At 102 F (39 C), the combined risk of poor outcomes rose by 20%.

This summer, daytime maximum temperatures in the continental U.S. averaged a record-breaking 88.6 F (31.4 C). The number of days per year over 105 F (35 C) is expected to triple in the U.S. by midcentury.

Heat's detrimental effects on birth outcomes are even more extreme for those with disadvantaged socioeconomic conditions, Burgos Ochoa noted. People with lower incomes are less likely to have air conditioning, and neighborhoods with a lower median income tend to have less green space, which contributes to trapped heat in their immediate surroundings. Expanding green spaces and adding bodies of water can help cool down neighborhoods and mitigate heat impacts on health, she said.

Heil's research team has developed a phone app for pregnant people and those who have recently given birth that forecasts the risk of heat stress and suggests actions to take to mitigate those risks, such as hydrating or changing clothing. Heil is hopeful that the app and similar early-warning systems can make a difference.

"Maternal health should be at the top [of our concerns], because it is about the next generation," Mickelson said. "If we don't take care of the mothers that are giving birth to the next generation, that's going to have long-term consequences down the road."

This article is for informational purposes only and is not meant to offer medical advice.

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When temperatures spike, California redwoods slow down photosynthesis, new research has found. This finding has serious implications for the long-term survival of the iconic trees in a warming world, and their role in storing carbon from the atmosphere.

California redwood (Sequoia sempervirens) forests are among the largest aboveground carbon stores on the planet. These towering trees are native to central and northern California, and evolved to take advantage of the region's historically mild weather. In recent decades, their range has contracted significantly. But climate change is threatening the health and function of these forests.

The region has seen significant warming in recent decades, and faces more frequent extreme heat days, with temperatures spiking above 100 degrees Fahrenheit (37 degrees Celsius). Now, in a new study, published Sept. 22 in the journal JGR Biogeosciences, a team of researchers has shown that California's renowned redwoods are struggling to photosynthesize in the heat.

Photosynthesis is the process used by plants, algae and some bacteria to turn sunlight into energy. It chemically converts carbon dioxide and water into sugars and oxygen.

"These trees adapted to grow in really temperate environments, so no one had really looked at the impact of heat on photosynthesis," study first author Lily Klinek, a doctoral candidate in the Plant Optics Lab at the University of California, Davis, told Live Science.

From 2022 to 2024, Klinek and colleagues measured how the leaves of redwoods in Garcia River Forest in Mendocino County responded to the heat. Once or twice a month, the researchers took three different California redwood leaf samples and measured their fluorescence and temperature.

A plant's molecules can use absorbed light in three ways: for photosynthesis, dissipated as heat, or reflected as light (florescence). Fluorescence is a proxy measurement to understand photosynthesis in the plant, Klinek said.

The researchers wrapped a fourth leaf in tinfoil for 20 minutes to put it in a state of "rest" before taking the same measurements. "When they're in a state of rest, we expose them to a pulse of light that’s in the wavelength they would use for photosynthesis to see what would be their maximum photosynthetic rate," Klinek said.

They found that on hot days, the leaves exposed to sunlight were up to 18 degrees Fahrenheit (10 degrees Celsius) hotter than the air temperature. "That's a huge difference and indicates that the leaves are stressed to the point where they can't thermoregulate effectively," Klinek said.

Many plants' leaves manage their temperature and photosynthesis by opening or closing their stomata, which are tiny pores on their surface. These stomata (from the Greek word for mouth) regulate the amount of carbon dioxide entering the plant, and how much oxygen and water vapor it releases. Lower carbon dioxide intake leads to reduced photosynthesis, meaning the plant has less energy.

The large differences between air and redwood leaf temperatures suggest that the leaves had closed their stomata to avoid losing water from evaporation during hot conditions and consequently overheated, Klinek said.

To further investigate the impact of heat on leaf physiology, the researchers took California redwood leaf samples back to the laboratory and exposed them to a range of temperatures while they were in water. Despite their access to water, the leaves still photosynthesized less as they got hotter, even though their stomata were open, Klinek said.

This shows that heat imposes direct limitations on redwood photosynthetical capacity, rather than indirectly decreasing that capacity by causing stomatal closure, the researchers wrote. The finding indicates that redwoods' ability to photosynthesise and store carbon will decrease as temperatures rise.

​​"It is not only stomatal closure that is causing reduced photosynthesis," Lucy Rowland, an ecologist at the University of Exeter in the U.K. who was not involved in the study, told Live Science in an email. "These trees are already suffering from the direct effects of heat on their photosynthetic systems."

The finding has serious implications for the future of redwoods and similar plants. "The points at which this damage becomes irreversible remains really poorly understood, but is something which is really essential to understand if we want to predict how our future climate is going to impact plants," she said.

The next step in Klinek's research is to move beyond leaf physiology to understand these thresholds on the trees and their ecosystems as a whole.

"We're not sure to what extent the effect that we saw is a reversible stress response and if they are sustaining damage from this constant stress," she said. Researchers need more data to "really get a better sense, beyond the leaf scale, how these ecosystems are responding to heat and drought," she added.

Some of the first people in North America lived through extreme climate change at the peak of the last ice age, a new study suggests.

Researchers studied ancient pollen locked in rocks at White Sands National Park in New Mexico, which houses an archaeological site thought to contain the oldest human footprints in the Americas. The researchers previously dated those footprints to around 21,000 to 23,000 years ago, though their age is the subject of some scientific debate because they are significantly older than other Indigenous sites in the Americas.

The new findings, published Wednesday (Oct. 14) in the journal Science Advances, suggest that humans kept using White Sands after temperatures warmed and thus saw the landscape undergo rapid changes during the coldest era of the last ice age, known as the Last Glacial Maximum (26,500 to 19,000 years ago).

"It's remarkable that early humans in the region were real-time witnesses to a rapidly changing environment discernible within a human lifetime — that is really food for thought," study co-author Kathleen Springer, a research geologist at the U.S. Geological Survey, said in a statement.

The White Sands footprints suggest that people from Asia reached the Americas via the region around the Bering Strait much earlier than scientists initially thought, challenging a long-held assumption that humans arrived on the continent around 13,000 years ago. While some scientists have disputed the methods used to date the footprints, evidence is building that they are around 23,000 years old.

White Sands contains footprints from various time periods, including footprints of a caregiver and a toddler who were there 10,000 years ago. Over thousands of years, people trudged across the New Mexico landscape alongside iconic ice age animals, including mammoths and giant ground sloths. The researchers have also discovered sled-like drag marks alongside ancient footprints at White Sands, providing evidence for a kind of travois — a wooden frame made from two poles bound together — that people likely would have used for transporting goods.

By looking at ancient pollen for the new study, researchers could deduce which plants grew across the millennia when humans lived in the area. The site's rock samples also contained waxes from plant leaves, membrane lipids from bacteria, and other organic molecules that helped the researchers better understand the environmental conditions of the time.

The analysis revealed that around 24,200 years ago, White Sands had a large lake and its surrounding mountains were coated in conifer trees (Pinus, Abies, and Picea). Then, over the next two millennia, temperatures rose, the lake began to shrink, and the conifer trees were replaced by oak trees (Quercus) and sagebrush, according to the statement.

"Throughout these periods of change, the people continued to visit and live in this area," study co-author Sally Reynolds, a paleoanthropologist at Bournemouth University in the U.K., said in the statement. "The sediments containing their footprints show us their environment changed significantly within individual human lifetimes."

The researchers speculated that people might have returned to White Sands at different times to benefit from the changing climate, with a shrinking lake potentially providing higher concentrations of animals and plants. However, while the footprints document that humans were present, they reveal little about their behavior.

"The footprints give us a snapshot of the people who lived there over 20,000 years ago," Reynolds said. "But they are not a continuous movie of their lives. They are individual frames — showing moments when humans, mud, water and chance came together."

The sea surface temperature in a key section of the central equatorial Pacific Ocean has now surpassed all previous temperatures on record for this region, exceeding 86 degrees Fahrenheit (30 degrees Celsius) for the first time, according to preliminary data released Monday (Oct. 5).

Specifically, these temperatures occurred in the Niño 3.4 region, located between 5 degrees north and 5 degrees south latitude, and 120 degrees west and 170 degrees west longitude. Researchers use this region to monitor the progression of El Niño, the warm phase of a multiyear natural climate pattern that's currently in full swing and steadily intensifying. But how significant is this new record, and could it be a harbinger of increasingly extreme El Niño events in the future?

At this time of the year, sea surface temperatures above 86 F are common in the western Pacific warm pool, a mass of water located northeast of Australia. But the Niño 3.4 region is nowhere near the warm pool and usually has much cooler temperatures. This latest data indicates "an exceptionally warm state for this part of the tropical Pacific," said Jin-Yi Yu, a professor of Earth system science at the University of California, Irvine.

"If the reported daily El Niño 3.4 temperature above 30°C is verified in the observational dataset, it would be an extraordinary record," Yu told Live Science in an email.

Other experts agreed. A Niño 3.4 sea surface temperature above 86 F is a "very significant" new record, Timothy Osborn, a professor of climate science and the director of the Climatic Research Unit at the University of East Anglia in the U.K., told Live Science in an email. Mat Collins, a professor of climate systems and the head of mathematics and statistics at the University of Exeter in the U.K., also called the temperature "very significant" in an email to Live Science.

But it's important to note that absolute temperature is not the standard way of measuring the strength of El Niño, Osborn said. Researchers usually assess El Niño intensity by comparing sea surface temperatures in the Niño 3.4 region with the average conditions there or with sea surface temperatures across the rest of the tropics, with the latter method removing a skew in the data caused by the climate-change-induced heating of oceans globally.

"On those measures, the current event is already close to being the strongest [El Niño] on record and will likely soon exceed previous records given that the event is forecast to strengthen further," Osborn said. "For some measures, it is already record-breaking for the time of year."

"Super" El Niño

El Niño events happen when warm water in the western tropical Pacific Ocean migrates eastward along the equator, toward South America. This boosts global temperatures, triggering heavy rainfall and floods in regions like East Africa, southern China, the southern U.S. and the Pacific coast of equatorial South America, while places such as Indonesia, the Philippines, southern Africa and northern South America experience drought.

"El Nino impacts are greatest across the tropics and in the lands around the Pacific Ocean," Osborn said. "An El Nino with record strength is very significant because it greatly disrupts the atmospheric circulation which controls the weather patterns including patterns of rainfall."

As of Oct. 6, the temperature anomaly in the Niño 3.4 region is 6 F (3.34 C) above average and rising. A typical El Niño increases Niño 3.4 temperatures by a maximum of 1.8 to 3.6 F (1 to 2 C) above average, so the current condition is "exceptionally large," Yu said. "This indicates that a very strong, or what is sometimes called a 'super,' El Niño is developing."

This year's El Niño is being amplified by human-driven global warming, which has increased background ocean temperatures. As a result, it's likely that sea surface temperatures in the Niño 3.4 region will keep rising over the coming weeks and peak in November or December, before declining again in 2027, Collins said.

"The Niño 3.4 anomaly is very likely to remain extremely large and may increase further," Yu said, echoing forecasters' suggestions that it could reach 7.2 F (4 C) by November.

A new kind of El Niño?

The world is on the brink of crossing a critical warming threshold, raising the question of whether the current conditions can be considered a new normal for future El Niños.

While it's likely that future El Niños will be more extreme than past ones, on average, not every El Niño will be record-breaking and as dramatic as the one unfolding now, because these events tend to be very variable, Collins said.

As climate change intensifies, the big worry is that certain regions will be primed for extreme conditions even before an El Niño strikes, Osborn said. For example, regions that are getting drier due to global warming could see catastrophic droughts if they overlap with areas that experience dryness during El Niño events. Likewise, places that are getting wetter could see worse deluges of rain and flooding if they coincide with areas with higher precipitation during El Niños. But that doesn't necessarily mean extreme El Niños are the new normal, he said.

Instead, the location and duration of El Niño events may be transforming, Yu suggested. "In research by my group and collaborators, we have documented changes not only in El Niño intensity, but also in where the warming occurs and how long events persist," he said.

Yu and his colleagues helped to introduce the idea that we are seeing the emergence of two distinct types of El Niño: the eastern Pacific El Niño and the central Pacific El Niño. "Many El Niño events in the earlier observational record were dominated by warming in the eastern tropical Pacific, whereas Central Pacific El Niño events became much more prominent in recent decades," he explained, adding that El Niños have also been lasting longer.

Global warming may be creating a new kind of El Niño by strengthening atmosphere-ocean interactions in the subtropical Pacific, Yu said. If these interactions combine with processes in the equatorial Pacific, where eastern Pacific El Niños emerge, they might trigger unusually strong events with extreme heating in the central Pacific.

"That provides a physical reason to take the possibility of more frequent extreme El Niño events in a warmer climate seriously," Yu said. "But I would distinguish that from saying that every El Niño will become progressively stronger."

Earth's life-support systems are in peril — and they're getting worse — but although the window for action is closing, we still have a chance to give our planet a sustainable future, a new report finds.

The report, called "Planetary Health Check 2026," was written by more than 60 scientists and assessed the state of interconnected natural systems, or planetary boundaries, upon which Earth's stability and resilience depend. When these boundaries are crossed, researchers say there's an increasing risk of serious and irreversible harm.

According to the report, seven of the nine identified planetary boundaries have already been breached, including climate change, ocean acidification and biosphere integrity. Niklas Kitzmann, lead editor of the report, likened assessing these planetary boundaries to giving Earth a blood test — and getting alarming results.

"If you had a patient with a blood test that looks like this, you would send them to the ICU right away," Kitzmann, a researcher in the Planetary Boundaries Science Lab at the Potsdam Institute for Climate Impact Research in Germany, which publishes the report, told Live Science.

Specific ecosystems highlighted in the report include the Amazon rainforest, which is in danger of passing a devastating tipping point, and the seafloor, which is being damaged by bottom trawling and faces the developing threat of deep-sea mining. There's also plenty on extreme weather events fueled by climate change, as well as forever chemicals, species loss and more. However, the authors believe we can still heal our ailing planet if we act fast.

"We still have a window to turn this around, but we do have to start bending the curves on emissions and on nature degradation within the next few years," Kitzmann said. "We're rapidly running out of time."

Planetary health check

The Planetary Boundaries Science Lab publishes a Planetary Health Check around this time each year, coinciding with Climate Week. The 2026 edition isn't marked by significant boundary changes as it was last year, but it finds that the state of the breached boundaries continues to worsen.

In 2025, ocean acidity levels became so high that a research team concluded that ocean acidification had become the seventh — and most recent — planetary boundary to be breached. The other six breached boundaries are freshwater change, land system change, climate change, modification of biogeochemical flows, introduction of novel entities, and change in biosphere integrity. The remaining two boundaries — stratospheric ozone depletion and increase in atmospheric aerosol loading — remain at safe levels, at least globally, according to the report.

The researchers essentially have a traffic light system for assessing the risk to planetary boundaries, with green representing a safe operating space; yellow/orange representing a breach and an increasing risk, with the system no longer considered within safe limits; and red representing the danger zone, with a likely risk of severe, irreversible damage. These categories are designed to account for uncertainty, but there's inherent uncertainty baked into assessments of complex natural systems.

Of the breached boundaries, ocean acidification, freshwater change and land system change sit in the increasing risk category, while climate change, modification of biogeochemical flows, introduction of novel entities and change in biosphere integrity are in the danger zone, according to the report.

Boundaries in the danger zone

One of the report's key takeaways is that all of the planetary breaches are now becoming increasingly apparent. Kitzmann said the researchers are seeing extreme events like heat waves increase in frequency and severity all over the world. He also noted that they've seen consequences such as glacial loss, marine heat waves and severe coral bleaching.

"The Earth is sending us her invoices for the breaching of these planetary boundaries," Kitzmann said.

Although much of the report was gloomy, Kitzmann stressed that there's still hope. He argued that positive momentum is building in the renewable energy transition, especially as the costs of solar power technology decrease, and that there's more social awareness and international treaties that protect oceans and land.

"It's not enough yet, it's not sufficient, but we shouldn't think that this is a completely unsolvable problem," Kitzmann said. "It is very much in the process of being solved, and we just need to step on the accelerator right now and make sure that these solutions that we have get implemented as quickly as we possibly can."

The ongoing El Niño is breaching the "super" threshold as Earth crosses into unprecedented climate territory.

El Niño, officially underway as of June 11, is a climate pattern that's injecting extra heat into our already-warming world, threatening disruptive weather across the globe and a humanitarian crisis in some regions.

While El Niño is part of a natural multiyear climate cycle, scientists have noticed that it has been rapidly strengthening like never before, intensified by human-driven climate change, and putting stressed natural systems under extra strain.

In a new update this week, the National Oceanic and Atmospheric Administration's (NOAA) Climate Prediction Center continues to forecast a 75% chance that this El Niño event will be stronger than any previous El Niño since 1950, the earliest year from which NOAA has data to make historical comparisons. Furthermore, this El Niño appears to be going "super" ‪—‬ something that has been expected for weeks.

Weekly NOAA data from the eastern Pacific's El Niño region reveal that sea surface temperatures have reached 3.8 degrees Fahrenheit (2.1 degrees Celsius) above average, hitting the more than 3.6 F (2 C) threshold for a very strong or "super" event. Strictly speaking, NOAA uses three-month averages to categorize strength, as weekly data is more prone to temporary anomalies. But the latest data once again signals where this El Niño is heading, with NOAA forecasting a more than 90% chance of a very strong event emerging in the fall and winter.

How will El Niño impact the U.S.?

During El Niño, warmer waters gather east of the equatorial Pacific, forcing the jet stream south. The patterns associated with El Niño bring exceptionally stormy winter weather and a higher chance of rain and snow across California and Southern states, with Northern states experiencing fewer storms and a milder winter, according to the Climate Prediction Center. El Niño can also increase the risk of high-tide flooding, particularly on the West Coast, according to NOAA.

However, as with climate change in general, El Niño doesn't have the same impacts on all regions. Furthermore, while a more intense El Niño typically increases the certainty of expected impacts, they are not guaranteed.

The last "super" El Niño happened in 2015 and 2016. Associated impacts included a historic hurricane season in the central North Pacific and record drought in the Caribbean, according to Climate.gov. Before that, the last El Niño to go super was in 1997 and 1998. That winter was marked by a variety of extreme weather events, including flooding in the Southeast, an ice storm in the Northeast and tornadoes in Florida, according to a report by the National Climatic Data Center.

Already this year, tropical storms in Hawaii have been attributed to El Niño, with warming in the waters where storms typically form there, CNN reported. Meanwhile, the strengthening of El Niño in the Pacific appears to have left the Atlantic unusually calm. Ars Technica reported that the Atlantic hurricane season passed its traditional peak without a tropical storm or hurricane in what is becoming a historic period of quiet.

What is El Niño?

El Niño affects the whole planet, but it begins with unusually warm waters in the eastern tropical Pacific Ocean. NOAA recognizes El Niño conditions when these waters are at least 0.9 F (0.5 C) warmer than average, while wind, surface pressure and rainfall in the region are also consistent with El Niño conditions. An El Niño is then categorized based on its strength, from weak to very strong. Very strong El Niños (above 3.6 F, or 2 C, warmer than average) are nicknamed "super" El Niños, though this isn't a scientific term.

The European Centre for Medium-Range Weather Forecasts' El Niño models suggest that temperatures are sailing past the 2 C threshold and will exceed 6.3 F (3.5 C) by the end of the year. On Sept. 20, the daily El Niño temperature was 5.5 F (3.06 C), according to The Climate Brink. But while this year's El Niño is certainly supercharged, there's still uncertainty about its impacts.

El Niño forecast

On Sept. 3, the World Meteorological Organization (WMO) released a fresh set of El Niño warnings along with a Global Seasonal Climate Update, which the WMO said offers a more refined picture of expected conditions in the coming months.

"For September-November 2026, WMO multi-model forecasts indicate an increased likelihood of above-normal temperatures across almost all land areas, alongside rainfall patterns showing a pronounced and classic atmospheric response to the strong Pacific El Niño," WMO representatives wrote in a statement.

In other words, much of the world is likely to be hotter than normal, while some areas will experience more rainfall and others will see less. The most severe El Niño impacts will likely be felt outside North America.

Liz Stephens, a professor in climate risks and resilience at the University of Reading in the U.K., recently noted that the Indian monsoon season had seen less rainfall than normal and that satellite data revealed that parts of East Africa, Central America and Southeast Asia are experiencing record-dry conditions. The human impact of such weather can be devastating.

"During the large El Niño event of 1997/1998 the associated flooding in Somalia killed over 2000 people," Stephens said in a statement released Sept. 3. "With a bigger El Niño event on the way, and global temperatures now 0.7°C [1.26 F] higher and capable of holding even more moisture as a result of climate change, scientists are concerned that there is potential for even more severe flooding."

The massive Nepal-Tibet flood on Aug. 26 showed just how devastating glacier-related disasters can be. As of Sept. 16, the event killed at least 1,400 people, with more than 6,000 people still missing.

The Himalayas, with their steep slopes studded with rapidly melting glaciers, are high risk, but areas across much of the world carry the risk of glacier-related disasters, including one tropical region that is at particular risk, experts told Live Science.

"Slope failure from glacier shrinkage is occurring everywhere," Mark Carey, a professor of environmental studies and geography and director of The Glacier Lab at the University of Oregon, told Live Science in an email.

Nepal-Tibet flood

The recent Nepal-Tibet disaster unfolded when a large mass of bedrock and glacial ice detached from the mountainside. The ice and rock accelerated rapidly, reaching speeds of 500 feet per second (150 meters per second) as it dropped 6,500 feet (2,000 meters) directly into the Lhende River in Tibet, according to the Stimson Center think tank in Washington, D.C.

The rock, ice and water that then raced rapidly downstream eroded the riverbanks and collected debris and water along the way.

Carey noted that this disaster was exacerbated by a combination of factors.

"This particular event in Nepal-China was so profound because of the scale of the landslide, the quantity of water in the flood, the speed of the flood, and the number of people, communities, public works/infrastructure in the flood path," he said. "There was also little warning."

Risks in the High Mountains Asia

The Himalayas and the wider High Mountains Asia — an area that includes parts of China, Afghanistan, Nepal, India, Pakistan, Bhutan, Kazakhstan, Uzbekistan, Kyrgyzstan, and Tajikistan — are among the major epicenters for future glacier-related disasters, experts said. More than 9 million people in this region are at risk from glacial outbursts — when a lake bursts through or overtops its dam and drains rapidly — a 2023 Nature study found.

The region is nicknamed the "third pole" because it has the third-highest amount of ice in the world, after the Arctic and Antarctica.

Compounding this, any water, ice or debris can be channeled down the steep slopes into narrow valleys, meaning water and material can move quickly and travel huge distances, potentially inundating the downstream valleys where many people live.

For instance, in the recent Nepal glacial collapse, the resulting flood caused damage more than 60 miles (100 kilometers) away. The 2025 collapse of Birch glacier in Switzerland, by comparison ‪—‬ in which rock and ice also detached from a slope and destroyed the village of Blatten —‬ traveled just 2.6 miles (4.2 km).

The Himalayas are also among the most seismically active places on Earth, and glaciers are frequently weakened by tremors, which can trigger avalanches, glacial lake outburst floods or glacial collapse.

The Himalayas are also warming twice as fast as the global average, reducing ice cover and increasing meltwater. "Permafrost and glacier cover help stabilize mountain slopes," Carey said. "They hold the rock in place." So as glaciers melt, the mountain slopes become more prone to avalanches.

Glacial meltwater can also act as a lubricant as it seeps into the bed of the glacier, which, in turn, can facilitate sliding, Bethan Davies, a professor of glaciology at Newcastle University in the U.K., told Live Science in an email.

The region's large population makes the geographic hazards there riskier, she added.

And with some of the biggest dams in the world going up in seismically active regions of the Himalayas and the Tibetan Plateau, new hazards are being introduced, Live Science previously reported.

A planet-wide risk

But another region on the other side of the world is also at very high risk of glacier-related disasters. Peru has 68% of the planet's tropical glaciers and has experienced disasters for decades, experts told Live Science.

"In Peru in 1970, 6,000 people died when an earthquake shook loose part of the glacier and rock on Mount Huascarán," Carey said. "The same slope had failed in 1962, causing a massive rock-ice landslide that buried the community of Ranrahirca, killing about 2,000 people in an event similar to the one recently in Nepal-China."

The Cordillera Blanca portion of the Andes in Peru is considered a particular hazard as a result of glacial lakes that are rapidly expanding due to glacial melt, fueled by increased temperatures driven by climate change. One such lake, called Lake Palococha, sits above the town of Huaraz, which is home to about 130,000 people. All told, experts have identified 528 lakes in Peru that are at risk of overflowing, with 58 considered "very high risk" due to their proximity to populations.

This threat spans the Andes. A 2023 study in the journal Nature noted that the number of glacial lakes in the Andes has risen by 93% in the past two decades — much more than the 37% increase in the High Mountains Asia.

In Europe, the Alps and cold regions like Scandinavia are potential hotspots for glacier-related disasters. Europe is warming faster than the global average.

In North America, meanwhile, Alaska is at risk for landslides and lake outbursts as glaciers collapse and retreat. Although many of the at-risk glaciers aren't in highly populated areas, there's a risk that glacial lakes could burst their banks and inundate the state's Suicide Basin, which frequently drains into and floods Juneau, Carey noted.

Glaciers or glacier-related landslides can also crash into the sea. "All areas with glaciers and all coastal areas where tsunami-like waves from a glacier collapse could inundate them," are at risk, Carey said.

How to reduce the risks

Better monitoring of glaciers and their lakes in at-risk regions can help mitigate the risks in the short and medium term, experts told Live Science.

The impact of good monitoring was evident last year in Blatten.

"The Birch Glacier was well monitored, and when it started to show signs of movement, the village below was evacuated," Davies said. Just one person — a 64-year-old shepherd who was outside the evacuation zone — died.

However, the Himalayas are a vast region with many potential hazards, and local authorities do not have the resources to establish and run giant monitoring networks, experts said. Nor do local authorities typically have access to expensive rescue equipment, like helicopters that can quickly evacuate people who would otherwise be trapped, Carey said.

Carey noted that when a potential hazard is identified, authorities can take other steps, such as draining a swollen lake to try reducing the risk.

In Peru, over 70 years, for example, authorities "drained 34 glacial lakes over those decades, no doubt saving tens of thousands of lives," he said.

But disasters can still occur even with monitoring, draining and scientific assessment.

"Everyone, including me, had thought that engineering works to stabilize and contain Lake 513 [in Peru] back in the 1990s had secured it," Carey said."We were all wrong."

Despite all that work, in 2010, a giant avalanche generated a 82-foot-tall (25 m) tsunami that overtopped the lake's dam and flooded homes and nearby farmland.

In the long term, slowing global warming is the most sweeping way to reduce the risk of glacial collapse.

"Stronger climate action may prevent a worsening and increasing destabilisation of these high mountain environments," Davies said.

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In the summer of 2008, New York City lowered the threshold for activating its emergency heat plan.

The city had historically relied on the National Weather Service threshold of a heat index of 105 F (40.6 C), but they noticed that people were getting heat stroke at lower temperatures.

As part of a wider effort, they changed the alert threshold: it would trigger if the temperature reached 100 F (37.8 C) for a day, or 95 F (35 C) for two days in a row. When the threshold was reached, city officials conducted targeted outreach, including to vulnerable groups, like homeless people; alerted residents on their phones; launched measures to protect the power and water supply; and opened cooling centers.

Lowering this threshold correlated with a more than 50% reduction in hospitalizations for heat stroke and related illnesses on hot days.

New York's case study offers one of the clearest examples of an intervention that worked to protect people from deadly heat.

As the planet warms, we will need to find more of these solutions. The consensus among scientists is that the most effective way to avoid the worst health outcomes of climate change is to slow warming by reducing carbon emissions. Limiting warming to 1.5 degrees Celsius (2.2 degrees Fahrenheit), for instance, would mean 11,600 fewer deaths due to wildfire smoke exposure in the U.S. annually, compared with warming of 5.4 F (3 C).

But even if we rapidly reduce emissions, climate change will have wide-ranging effects on our health

So what measures actually work to protect people's health? Live Science reviewed dozens of studies and talked with 19 climate and health experts at universities and health and climate associations, to identify the most promising solutions to two of the biggest climate-related threats: extreme heat and wildfire smoke.

Some interventions have demonstrated a reduction in deaths or disease at the population level, while others have used modeling to predict health impacts or rely on proxy measures.

"The strongest evidence is where these approaches reduce illness, hospital visits or death," said Charles Leonard, an associate professor of epidemiology at the University of Pennsylvania, told Live Science, "not just heat exposure, pollution levels or other intermediate markers."

Most solutions do not offer the level of clarity of the New York example, however. Many reduce temperatures or alter human physiology in ways that are likely to decrease the number of heat-related deaths or cases of illness. But a deeper examination reveals limited evidence that many seemingly intuitive interventions, such as cooling centers, are effective on a societal level.

For both heat and wildfire smoke exposure, we analyzed the evidence to see which interventions have actually worked.

Extreme heat

Air conditioning and heat pumps

Evidence grade: Strong

One of the most common interventions for managing indoor temperatures is the use of mechanical systems with refrigerants, such as air conditioning or heat pumps.

Air conditioning has been tied to reduced hospital admissions in California and reduced heat-related deaths at Texas prisons. During a heat wave in Portugal, patients admitted to an AC-supported hospital had a 40% lower risk of dying than those in wards without AC. It is a clear way to impact health outcomes.

But AC can't be the whole solution.

"One of the most important lessons emerging from heat adaptation research is that no single intervention is sufficient on its own," said Shweta Arya, senior project manager for smart surfaces at the American Public Health Association's Center for Climate, Health and Equity, which leads the association's work on health and climate action.

While 90% of U.S. households used AC in 2020, the latest year for which energy survey data is available, it's not a cure-all. It is vulnerable to power outages, and it contributes to outdoor warming via added electricity demand and heat expelled from vents.

Additionally, just because people have AC doesn't mean they can afford to use it. This is known as the "heat or eat" dilemma: analysis of US household data have consistently shown families limit food purchases and take on debt to pay AC-linked energy bills.

"In many cases, the primary barrier to stay[ing] cool indoors is not access to cooling equipment but the ability to pay monthly energy bills," Pilar Botana Martinez, a research scientist at Boston University's Department of Environmental Health, told Live Science.

Shade, rest and hydration outdoors

Evidence grade: Strong

Staying indoors to avoid the heat is one way to reduce the health impacts of climate change, "but this is not a practical solution for everyone, especially those doing demanding jobs in very hot warehouses, on construction sites, in agricultural fields," Barrak Alahmad, director of the Occupational Health and Climate Change Program at Harvard University, told Live Science.

Nearly one-third of U.S. employees — mostly men — have regular outdoor exposure as part of their job.

Some of the strongest evidence for strategies for keeping them safe on the job comes from studies of sugarcane workers in Central America, Alahmad said. A nongovernmental organization called La Isla Network has rolled out a strategy in which workplaces incorporate mandated rest, shade, hydration and sanitation breaks.

In data collected over six years, La Isla Network has shown that this strategy improves health by reducing negative outcomes such as heat-related kidney failure. Similar reductions in heat-related illnesses have been seen in California; Texas; and Guangzhou, China, when such measures have been implemented. And although these interventions have some training and supply costs, they increase productivity, the data shows, which makes them an easier sell for companies.

"The aim is to build systems that reduce risk and harm, increase productivity and provide a return on investment so that these efforts just become business as usual," Jason Glaser, CEO of La Isla Network, told Live Science.

Passive cooling

Evidence grade: Intermediate

Passive cooling reduces indoor temperatures without mechanical devices like AC. These strategies include modern technologies, such as reflective surfaces and roofs that reflect more sunlight and thus keep buildings cooler; shade structures and urban greenery; and traditional techniques, like courtyards, shades and ventilation.

"These are often low-cost material choices that can make a big difference in the safety and comfort inside a building and have a proven track record of performance [in lowering temperature]," said Kurt Shickman, senior fellow at the WRI Ross Center for Sustainable Cities.

These passive technologies also make AC more efficient, thus reducing costs and lowering demand for electricity on peak power days, Shickman said.

The evidence suggests cool roofs work at scale. A 2019 California modeling study predicted that state-wide adoption of this technology would halve the number of people exposed to heat wave conditions by 2050, while a 2024 study in London that modeled cool-roof deployment predicted that the technology could reduce heat-related deaths by up to 32% during heat waves.

Green spaces can also reduce heat exposure. In dense cities in Southeast Asia, the introduction of green infrastructure, such as trees lining streets and additional bodies of water, has been shown to reduce air temperatures by up to 4.7 F (2.6 C) and surface temperatures by 19.8 F (11 C).

Those interventions won't work everywhere, though, in part because strategies that reduce deaths from heat could worsen those from cold, and cold-related deaths are four times more common globally, a 2025 study found. So places that have both cold snaps and heat waves will need to think about those trade-offs before implementing such strategies.

City-wide heat warning systems

Evidence grade: Strong

Heat warning systems have been proposed to reduce heat exposure. There is evidence that some existing systems, such as New York City's, work to reduce death or hospitalization. But whether these systems are effective depends on how they're implemented.

"Effective systems do far more than issue a temperature alert" based on forecast high-heat events, Arya told Live Science ‪—‬ an idea other experts echoed. Instead, they trigger coordinated actions, such as reaching out to vulnerable populations, extending utility protections, and coordinating with healthcare systems for surges in the number of patients.

It's difficult to test such plans in controlled experiments, but researchers try by comparing a city before and after an intervention, or by finding comparable cities or regions that did or didn't implement a heat plan and assessing the plan's effectiveness. These "natural experiments" offer a comparison without having an alternative universe as a control group. Academics using such methods concluded in 2025 that heat exposure prevention plans led to a 25% reduction in deaths attributable to extreme heat across Europe.

Personalized alerts

Evidence grade: Strong

While most warning systems trigger when temperatures cross a threshold that's considered dangerous for an average person, Shickman said, "[i]n reality, people experiencing the same air temperature will have very different responses to it."

One solution could be to individualize attention. Shickman pointed to a pilot program by insurance company Emblem Health in New York, in which a trained artificial intelligence (AI) agent supported 17,000 people with personalized advice targeted to those with complex health or social issues. The intervention halved hospital admissions compared with a control group that didn't take part.

"We can go a step further and use technology to shift from generic, passive warnings to proactive ones that address individuals' needs," he explained.

Cooling centers

Evidence grade: Weak

A common strategy implemented during heat waves is the use of cooling centers — dedicated public spaces like libraries, schools, religious buildings or commercial locations where cooler air (often via air conditioning) offers respite.

Despite extensive adoption across the U.S. and internationally, there is very limited evidence that cooling centers reduce deaths or hospitalizations from heat exposure — likely because they're not visited much.

For example, a 2024 study into Virginia's cooling centers questioned the state's existing strategy because communities that had cooling centers also had higher numbers of heat-related illnesses. Surveying the field, a 2025 review from the National Bureau of Economic Research questioned "whether those who can most benefit from reduced heat exposure can or are willing to access cooling centers, and whether travel to centers can actually increase heat exposure relative to staying at home."

Wildfire smoke

Wildfire smoke is full of fine particulate matter known as PM_2.5. These particles are 30 times smaller than the diameter of an average human hair and can penetrate deep into the lungs and the bloodstream, thereby increasing the risk of ailments such as heart attacks, asthma attacks and adverse pregnancy outcomes.

PM_2.5 pollution contributes to tens of thousands of excess deaths every year in the U.S. And research suggests that wildfire smoke emissions could increase by 262% to 482% by 2055, depending on the level of carbon emissions.

Here's what has been shown to work against this threat.

Commercial air filtration

Evidence grade: Intermediate

Data repeatedly shows that air filtration — whether through commercial HVAC systems or even a fan with a filter taped to it — reduces indoor PM_2.5 exposure.

"For wildfire smoke, an important adaptation is cleaner indoor air, as simple as that may sound," Leonard said.

Staying indoors protects individuals from the worst PM_2.5 exposure. But a 2021 California study that used 1,400 air quality sensors showed that on days with nearby wildfires, smoke found its way into households, tripling PM_2.5 compared with days without fires.

Putting newer-grade filters (MERV 16 or higher) on commercial systems, however, can reduce PM_2.5 indoors by 81%, studies found. Similarly, portable air filters have been shown to reduce PM2.5 exposure in Montana offices, Seattle homes and Singapore apartments.

However, what's still unclear is the extent to which air filtration will reduce deaths or hospitalizations related to wildfire smoke. This is because we don't know whether interventions that make air cleaner in perfect conditions scale up; people may not replace their air filters, or they may use the portable ones only some of the time, for example.

Modeling of some air filtration measures, however, suggests that they could prevent 11% to 63% of the hospital admissions and 7% to 39% of wildfire-linked deaths.

Masks for outdoor smoke exposure

Evidence grade: Intermediate

Many people, including those who work in construction and other outdoor jobs, must venture outside during smoky days, and they need information and tools to protect themselves, said Gillian Capper, program manager at the American Public Health Association's Center for Climate, Health and Equity.

For example, these measures include "distributing N95 respirators and requiring smoke protection plans for outdoor workers," she said.

Modeling studies show that N95 respirators can reduce exposure to wildfire smoke by 90%, and a modeling exercise that used data from 2012 wildfires in Washington state showed that these masks decrease smoke-linked hospitalizations by up to 30%, compared with a group that did not use masks.

Land management

Evidence grade: Intermediate

The evidence to support a reduction in wildfires through land management is mixed. The idea is that by thinning forests, harvesting trees, clearing underbrush and doing prescribed burns to prevent unplanned conflagrations, we can reduce the risk of massive, uncontrolled wildfires.

"Reducing fuels today may help avoid larger, more severe fires and associated smoke impacts in the future," Micah Hahn, an associate professor of environmental health at the University of Alaska Anchorage, told Live Science. "But relatively little research has directly measured those downstream health benefits."

A 2022 modeling exercise led by U.S. Forest Service scientists compared four forest management scenarios ‪—‬ including actions such as forest thinning and prescribed burning — in the Lake Tahoe basin over the next century. It found that these measures reduced PM_2.5 particle levels as well as smoke-related illness and death, compared with fire suppression on its own. It also modeled the health impacts for one year (2039) and found reduced health costs tied to such management.

But the benefits plateaued with more land burns. Research from the southeastern U.S. shows that management can become a large source of PM_2.5.

Still, prescribed burns have an advantage over a spontaneously erupting wildfire, experts said. "With prescribed burning, one distinct difference is the ability to plan for smoke," Heidi Huber-Stearns, director of the Center for Wildfire Smoke Research and Practice at the University of Oregon, told Live Science, and to "know when and where it will likely affect communities as compared to the unpredictability of wildfires."

Smoke alerts

In theory, fire alerts, which use high-resolution air-quality data, could reduce smoke exposure, Laura Kate Bender, vice president of nationwide advocacy and public policy at the American Lung Association, told Live Science. Alerts would be paired with tailored guidance to notify people of dangerous smoke levels and to tell them when to take action.

Because these alerts are a fairly new idea, however, there's little data showing that such programs would reduce smoke exposure or related hospitalizations and deaths. That said, there’s evidence from other fields: a 2012 World Bank modeling exercise calculated that weather data and early warnings saved nearly 800 lives per year in Europe, and could save a further 23,000 in the Global South if systems were upgraded.

"The hurricane warnings are good examples to follow, as people do act on these early warnings", Kai Chen, faculty director at the Yale Center on Climate Change and Health, told Live Science.

Ultimately, the researchers we spoke with agreed that we need more data, which requires funding for further studies into which interventions are effective and can be scaled.

"We've put a lot of effort into understanding the impacts of climate change and related exposures," Alahmad said. "But there comes a point where we need to move from studying the impacts to looking at interventions and solutions and see what actually works out there."

How we evaluated studies

We categorized evidence as strong, intermediate, or weak. Here's the criteria we used to assess them.

Strong: Data shows a reduction in disease, hospitalization or death at a population level. Data comes from either randomized trials or quasi-experimental protocols. Sample sizes are robust enough to show a clinically meaningful effect.

Intermediate: Data shows an improvement in an intermediate proxy measure, such as temperature or particulate matter concentrations, which has been tied to negative health outcomes, and/or data relies on modeling to show improved health outcomes at the population-level.

Weak: Limited data exists, or the data that does exist does not show a strong protective effect.

Burning up — How can we adapt to a warming world?

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The Amazon, Earth's largest tropical rainforest, could be on the brink of an irreversible change as the ongoing El Niño strengthens its grip on our climate.

El Niño is the warm phase of a multiyear natural climate cycle that is often marked by rising global temperatures and disruptive weather. This time, scientists monitoring the event are warning that climate change has helped supercharge it to likely the strongest ever recorded.

As temperature records are breached and the risk of a humanitarian crisis looms, already stressed natural systems are coming under unprecedented strain. The Amazon is one such system. Having suffered severe degradation in recent decades, some fear that a historic El Niño could launch a devastating drought that may help force the Amazon beyond a tipping point — transforming the verdant rainforest and vital store of the planet's carbon into savannah.

To get to grips with this looming catastrophe, Live Science spoke to Bernardo Flores, a Brazilian ecologist who studies the Amazon and has been sounding the alarm about its fate.

Patrick Pester: How could a strengthening El Niño impact the Amazon?

Bernardo Flores: We have a very high confidence that it is already a strong El Niño and that it will be very strong, possibly the strongest one on record. This is very concerning because during past decades we saw a few very strong El Niños — not as strong as this one, probably — and the consequences were very dramatic, and they became increasingly dramatic.

The Amazon becomes drier during El Niño, and then you have conditions for forest fires. You can have different types of fires, but forest fires are those that penetrate and spread through the moist forest, which is rarely flammable. And during these years, you can have thousands of kilometers of burnt forest that were not disturbed before.

We expect that these burnt areas will increase, possibly exponentially. There will be an acceleration, and that's a sign of a tipping point.

PP: Could a historic El Niño push the Amazon beyond a tipping point this year or next year?

BR: One of the things that makes the Amazon resilient is the existence of Indigenous people and local communities protecting the forest and managing the forest. But there is an increasing territorial expansion of organized crime syndicates involved in illegal activities that destroy the ecosystem. They're spreading ignition sources through these remote forests and competing for these territories with the local and Indigenous peoples. They bring violence, and then through violence, people die, people lose livelihoods, and become increasingly less capable of living in that area.

If you add to that these droughts, fires and water and food insecurity caused by these El Niños, then you increase the risk that these regions will be abandoned and become easier for organized crime groups to occupy through methods that involve destruction and fires. So, the tipping point of the Amazon has these mechanisms. You have climate change and El Niño that are disturbances in the climate, but you also have shifts from local and Indigenous management and governance to low governance and destructive organized crime activities, and the spread of wildfires that become increasingly large and recurrent.

Through a model, we pinpointed that with 1.5 degrees [Celsius, or 2.7 degrees Fahrenheit] of global warming, which is what we have now basically, and 22% of deforestation accumulated across the Amazon, there could be a tipping point. Then you have lost so much forest that you lose so much rain that the system becomes trapped in the self-degrading drought-fire loop. But this is not considering all the forest degradation that has occurred over the past decades, which is accumulating. At least 40% of the Amazon has been estimated to be degraded.

I have been saying that we could cross a tipping point. So, the message is we have to be very careful and take precautions to avoid wildfires. This is a very concerning and critical moment to focus on wildfires.

PP: In your recent paper, you and your colleagues wrote that the Amazon could undergo a "near systemwide transition" with global warming of 1.5 C to 1.9 C and deforestation of 22% to 28%. Most people now think the Paris Agreement's goal of keeping warming below 1.5 C is dead, so if the degradation is now at 40%, do you think this transition can be avoided, realistically?

BR: Yes. The tipping point is not a collapse. It is just a point beyond which the feedbacks change. The feedbacks that were previously keeping the Amazon resilient, they weaken, and other feedbacks that make the system self degrade gain strength. So, it means that when you cross the tipping point, it becomes more difficult to avoid, but it's not impossible.

The Amazon is a huge system. Forests, trees, they have long lives, so the dynamics are relatively slow. The collapse of the Amazon, if we did nothing, could take 100 years, centuries; we don't know. But this means that we have a few decades to act. In the next 10 years, we [need to] invest heavily in large-scale reforestation where rainforests have been cleared and degraded; restore the capacity of these forests to pump moisture into the atmosphere; and also shift the economic activities in the region to legal ones and strengthen the local people's capacity to persist and govern the landscape. Also, shift the economies of the region into more sustainable ones — not based on clearing for cattle and soy; but based on forest products, agroforestry, medicine, lots of industries that can be developed through forest products.

There are several issues being debated, but there is huge potential to shift. Even within a capitalist economic system, we could do that. Forest restoration will take 20, 30 years, but the time for that is now. And also to control organized crime. That's probably the most difficult thing; more difficult than shifting the whole economy.

PP: What's the difference between how the organized crime groups are approaching the landscape and how the local people are managing it?

BR: The local people and Indigenous peoples have been there for thousands of years. They know the forest in so much detail. They have empirical experience of hundreds of El Niños. Of course, the climate is changing, so they are dealing with conditions that are new to everyone, including them, but they have more capacity to adapt because they identify the changes. They have huge potential to help us deal with climate change. They manage the ecosystem in ways that the forest becomes more abundant in food; the forest becomes more resilient.

Organized crime comes from outside with the intention just to extract and destroy, and the methods are based on violence. They involve people working in illegal mining, for instance, and illegal logging and land grabbing. And then there's laundering of ecological assets. So, there's timber laundering. They do this with minerals also. When they occupy a region, a territory, the lives of people in the rural areas and Indigenous territory become much more violent and much more degrading. These regions are remote, so it's difficult. We can have control of these territories, but it depends on lots of international cooperation because they involve politicians. There are very powerful people who are involved with the organized crime system, and they also have a lot of economic power because they have this very diverse economic approach through different activities, legal and illegal, in the urban and rural areas. They accumulate all this wealth and capacity to invest in machines, for instance, in guns.

Ten years ago, we would work in remote parts of the Amazon, and it was fine. These weren't dangerous places. Now I have a colleague who goes to work, and they are in a river in a canoe with local people, and suddenly a fast boat approaches with very powerful engines, and there are five or six men with machine guns wanting to know what they are doing there. This is something that is increasingly more common, and it didn't exist before. To me, that's the most challenging problem to address.

PP: I mean, it sounds challenging. What gives you hope this can be overturned?

BR: I tend to be optimistic, and I have hope because I know how it can be done. It depends on results from elections; it depends on people becoming more aware, but because I work with tipping points, I know how tipping points occur in social systems and behavior. Suddenly, people can understand the importance of something, and then they support ideas. I believe that we are moving towards such tipping points. I don't know how late [we'll be], or what will be lost, but at some point we're going to have to react.

Editor's note: This interview has been edited and condensed for clarity.

Climate change is often discussed in terms of rising temperatures, extreme weather and environmental loss. But there's another consequence that can be harder to see: The impact on our mental health.

In this exclusive video, we explore how heat exposure influences mental state, drawing on research by Kim Meidenbauer, a neuroscientist at Washington State University who studies the effect of heat on emotion and behavior.

Editor's Note: This text was updated at 12:30 p.m. EDT to correct the spelling of Kim Meidenbauer's name.

Burning up: How can we adapt to a warming world?

As the planet warms, our environment will be transformed, but so will our bodies. This video is part of a series where we investigate the health impacts of climate change, focusing on heat, air quality, food and infection risk. We also evaluate the promising solutions that could help us adapt to our warmer future.

Weakening Atlantic Ocean currents could cripple agriculture in some of the world's major breadbaskets, threatening global food security and raising the price of basic commodities, new research finds.

The study, which hasn't been peer-reviewed yet, investigated how a roughly 60% decline in the Atlantic Meridional Overturning Circulation (AMOC) would impact global food production. The AMOC is a system of ocean currents that regulates the global climate and brings heat from the tropics to the Northern Hemisphere.

However, the system is currently the weakest it's been in more than 1,000 years, having lost 10% to 20% of its strength due to climate change, estimates show.

In the new study, researchers used a computer model to simulate the AMOC's future decline. They modeled 100 years of change, assuming 3.6 degrees Fahrenheit (2 degrees Celsius) of warming above preindustrial levels. The team forced an AMOC slowdown over the first 50 years in one simulation but didn't modify the circulation in a second experiment, which enabled them to compare the world with and without an AMOC failure.

The model's outcomes mirrored the results of previous studies, showing broad cooling in the Northern Hemisphere and a southward shift of the belt of clouds and rain that encircles the globe near the equator. As in past studies, these effects were irreversible on human timescales, said study co-author Michael Hinge, a senior economist at the nonprofit Alliance to Feed the Earth in Disasters (ALLFED).

"Once the damage is inflicted, it stays there," Hinge told Live Science, adding that in the 50 years after the peak rate of AMOC slowdown in the model, the circulation weakened by an extra 20%. The study was posted on ALLFED's website July 7.

An agricultural "shock"

Hinge and his colleagues ran three models to look at the most common varieties of wheat, maize and rice, layering these models on top of the AMOC simulations. They found that global yields for these crops decreased by 5.3% by the 50-year mark, once the AMOC had weakened substantially.

"Lots of these effects manifest earlier, so it's a moving target," Hinge said.

He added that the results were based on a single warming scenario that was run once and used monthly rather than daily data, so they should be interpreted as a proof of concept. "We've set up a pipeline that is ready to take pretty much any AMOC scenario that can generate high-resolution climate data and see what it implies for crops," Hinge said.

While there was a 5.3% decrease overall, that global metric concealed huge differences between regions. For example, countries like Germany and Ukraine lost up to 19% of their cereal yields due to sudden, sharp cooling, while Canada showed a 12% decline in production for the same reason.

"Scandinavia, the United Kingdom and Canada are particularly exposed," Hinge said, "but there are many other [vulnerable] locations, some of which may be surprising even to the people who are living there."

For instance, the model produced a "very nasty brown splodge" of reduced precipitation over India, Pakistan and big parts of China, he said. Iran, Sudan and Eritrea, which are already water-stressed countries, also exhibited severe declines in rainfall, indicating that a portion of the agriculture there may not survive an AMOC collapse.

The 5.3% result also hides variability among years, Hinge said, because it's an average. So there may be years when global cereal losses reach 10% or more, which would bump up food prices, in part because countries might stockpile crops instead of trading them.

Global response

The regional effects of an AMOC slowdown would interact with climate change, triggering unpredictable outcomes. In particular, maladaptation — taking actions that end up backfiring — is a worry, Hinge said.

"You're preparing and setting up for much hotter temperatures or trying to develop areas for these temperatures and the trends you're seeing, and suddenly you see something different," he said. "That may cause an even larger compounding effect [on agriculture]."

The findings build on prior research led by Paul Ritchie, a climate scientist at the University of Exeter in the U.K., whose team explored the effects of an AMOC collapse on agriculture in Great Britain. That study, published in 2020, had similar limitations as the new one, so it's best to interpret both papers as a suggestion of what might happen rather than a precise forecast, Ritchie told Live Science in an email.

"I think the new study is valuable in showing the potential scale and geographic distribution of the initial agricultural shock," said Ritchie, who was not involved in the latest work. "What that would ultimately mean for food production and food security is more uncertain, because there are many possible responses by farmers, markets and governments." For that reason, the regional predictions may be more informative than the 5.3% global average, he said.

Average food prices worldwide could rise by 17% to 40% if the AMOC weakens to the extent it did in the model, the study predicts. The level of increase depends on how countries respond to the shock and their degree of preparedness, as well as on whether agriculture can be sustainably expanded in places like the African Sahel (the semi-arid zone directly south of the Sahara Desert) and Brazil, the analysis suggests.

The U.S. would not be spared from this price jump, and the model indicated that the country could see crop losses of about 3% for domestic wheat and corn. This loss would likely impact other foods that rely on cereal inputs, like meat, Hinge said. "The variety of foods available in the stores may well diminish for periods," he added.

An AMOC collapse would fundamentally deepen the need for countries to trade with each other, because some regions — such as the Indian subcontinent, China, Iran, Russia, Ukraine and Canada — could endure this giant shift only if they imported more food, Hinge said.

"Should countries turn inwards and start to restrict exports in an effort to ensure access for their own citizens first, or deal with the uncertainty, or offset concerns, then this will massively magnify the effects of AMOC," he said.

If governments behave as they have during past shocks, such as the 2008 financial crisis and the COVID-19 pandemic, they may restrict trade and start stockpiling food if and when the effects of AMOC weakening begin to show, Hinge predicted. The researchers hope their work and future modeling can help people understand the need to take swift, effective action if a collapse were to occur, he said.

Currently, "if that warning light starts flashing, we're not sure what to do with it," Hinge said. "There are no easy answers here; an AMOC [collapse] would be deeply catastrophic."

To the untrained eye, Xiaoyu Shan's lab bench looked like a home gardening experiment gone bad: dishes filled with dirt — some that looked like mud pies and others that were bone-dry — and not a plant to be seen.

But those dishes held a warning. The dirt that Shan, a postdoctoral research associate in biology and biological engineering at Caltech, was studying contained soil microbes. And those soil microbes were exhibiting a concerning propensity: In dried-out soil, they were evolving to become more antibiotic resistant.

The study describing those findings, published in March, systematically showed that drought conditions could fuel the evolution of antibiotic-resistant bacteria. Most of this resistance is driven by humans' misuse of antibiotics, which spurs bacteria to evolve genes that help them ward off the drugs. But the Caltech study raised a new worry: As many places face increased drought conditions, climate change itself could act as a selective pressure that could supercharge the evolution of these drug-resistant superbugs.

"We can expect to have more resistant bacteria being selected for in certain places around the globe," said Dianne Newman, a Caltech microbiologist and co-author of the study.

Increased antibiotic resistance is just one way that climate change is likely to put new populations at risk of multiple types of infections.

And this increased disease burden will coincide with climate change scrambling supply chains, eroding nutrition and stressing our health in other ways.

"No individual metric really does justice to the overall risk and health and well-being of these multiple stressors being exacerbated all at once and compounding each other," said Marina Romanello, a principal research fellow at the Institute of Global Health at University College London.

Warm-weather disease

In the small mountain town of Bailey, Colorado, which lies at an elevation of 7,740 feet (2,360 meters), May often brings snowstorms that can blanket the ground in white even as the sun starts to bake the plains at lower elevations. But on Memorial Day 2026, the forest floor was dry and ticks quested their way along blades of grass, seeking a blood meal.

A mild winter in most of the country means ticks — and the diseases they carry — are a rising concern. In April, the Centers for Disease Control and Prevention (CDC) reported that emergency department visits for tick bites were at their highest for that month since 2017. That trend isn't a one-off, according to the CDC; as temperatures rise, insects and arthropods can survive longer in the year and farther north.

As a result, vector-borne illnesses such as Lyme disease (spread by black-legged ticks in the Ixodes genus) and West Nile virus (spread by mosquitoes) will become more common in increasingly northerly locations. Already, alpha-gal syndrome, which is not an infection but is transmitted by the Lone Star tick (Amblyomma americanum) and causes an incurable allergy to red meat, is also seeing a dramatic rise as the species expands its range across the Northeast. Positive tests for antibodies to the alpha-gal molecule have increased by 100 times between 2013 and 2024.

Right now, almost half a million people are treated for Lyme disease each year, and the CDC records more than 8,000 cases of other tick-borne diseases annually across the country. It's not clear how this will change as the climate warms. One 2022 study found major increases in Lyme disease only at levels of warming of 6.3 to 9.9 degrees Fahrenheit (3.5 to 5.5 degrees Celsius) by 2100, but that much warming that fast is now considered an implausible scenario. However, the researchers saw a huge amount of uncertainty in the numbers, given the number of variables that affect whether a spreading tick population will transmit more disease, such as how often people go outside or what steps they take to avoid tick bites. Tick-borne illnesses are likely also underreported, so even the true number of illnesses transmitted each year right now is unknown.

But ticks are responsible for spreading 90% of all vector-borne diseases in the U.S., so any trends in the suite of illnesses spread by ticks are likely to affect thousands to tens of thousands of people.

An even more ubiquitous bloodsucker, the mosquito, currently spreads only a few diseases in the U.S. The most common and most serious is West Nile virus, which mosquitoes catch from feeding on infected birds. As of Sept. 8, 504 cases of West Nile virus had been reported in the U.S. in 2026, with 363 of them affecting the central nervous system. And because fewer than 1% of West Nile cases progress to the central nervous system, those numbers likely represent a dramatic underreporting of milder cases, which can cause months of fatigue in some people, in addition to acute flu-like symptoms, such as fever, headache and body aches.

Mosquito-borne illnesses like West Nile are expected to spread more quickly in warming temperatures. Heat helps mosquitoes stick around longer during the year, much like it does for ticks. It also speeds up the transmission and replication of the virus inside the mosquito, since the insects are cold-blooded and thus their metabolism is ruled by the weather.

"Except for places that are already really, really warm, we should expect that the replication rate of the virus inside the mosquito will speed up," said John Drake, director of the Center for the Ecology of Infectious Diseases at the University of Georgia. "That shortens the generation time, and that means we expect there to be more transmission."

Even though mosquitos love water, climate-related drought could ironically nearly triple the number of human West Nile cases in the U.S. over the next 30 years from around 2,000 reported cases (according to CDC data) to between 5,000 and 6,000. That's likely because in drier conditions, more mosquitoes are infected, possibly because birds, the intermediate host of the virus, either congregate more closely with mosquitoes around water sources or breed less readily in drought, meaning the fraction of birds that carry the virus is higher than in more water-abundant times.

Mosquito-borne diseases long ago eradicated from the U.S. could also resurge with warming temperatures. The southeastern United States will become more prone to malaria and dengue fever transmission under all levels of warming; summer 2026 saw more than 40 locally-acquired cases of dengue fever in Florida. Public health surveillance and disease-control measures have largely stopped those transmission chains, but the likelihood is that society will have to pour more money into beating these diseases back again in future decades. For example, there are malaria vaccines approved for children, but currently, they are recommended only in areas where the illnesses are endemic. If malaria were commonly found in the southern U.S., millions of Americans might need vaccines, including susceptible adults.

"If we were to get endemic diseases like those in the U.S. again, it could become a huge burden and it could be quite costly," Drake said.

Disaster and disease

Flooding is another factor that's exacerbating vector-borne disease under climate change. As climate change worsens, extreme weather events will, too. Because warm air can hold more moisture, many areas will see increased episodes of heavy rainfall and hurricanes will become more intense.

"Flooding creates habitat for these mosquitoes," Drake said.

Disasters also spur the spread of other diseases that are usually quite rare in the U.S., such as leptospirosis, a bacterial infection that spreads from animals to humans via animal urine. Floodwaters may be contaminated by the bodies of drowned animals; in 2022, after Hurricane Fiora hit Puerto Rico, leptospirosis cases leapt by a factor of 3.6 to over 10 cases a week.

After Hurricanes Matthew and Florence in 2016 and 2018, respectively, North Carolina saw an 11% increase in emergency department visits for gastrointestinal illnesses. Black and American Indian residents were the most affected, likely because discrimination over generations has disproportionately pushed Black Americans and Native Americans to less desirable, more flood-prone land, the researchers found.

Cycles of precipitation, drought and subsequent dust storms can spur the spread of Valley fever, a fungal respiratory disease that causes an estimated 700 to 1,100 deaths per year, mostly in the U.S. Southwest. Valley fever is already on the rise, with cases in Arizona, one of the hotspots for the disease, doubling from about 64 cases per 100,000 people in 2005 to 145 cases per 100,000 people in 2022. As the West warms and dries, Valley fever is likely to spread from its stronghold in the Southwest and become endemic in Idaho, Wyoming, Montana, Nebraska, South Dakota and North Dakota, putting millions more people at risk.

The infectious disease risk from natural disasters tends to stack on top of other health problems stemming from these catastrophes. Flooded buildings can harbor mold that can worsen allergies, asthma and other respiratory illnesses. When major storms cause power loss, people turn to generators for electricity, which release pollutants linked to asthma. Though it's often hard to track the effects of these disasters, one study found that flooded regions after Tropical Storm Imelda in Texas in 2019 saw 10% more emergency department visits for asthma than nonflooded regions did.

Moreover, the threat to life and livelihood from these disasters can cause mental health conditions, such as post-traumatic stress disorder, Romanello said. The problems compound on each other, she said; already, she has heard reports from Africa about malaria outbreaks, fed by warming, and health workers struggling to reach the affected regions because flooding, also exacerbated by warming, has washed out roads.

"What is the most concerning aspect is that all of that is happening together, so we're seeing all of this risk being exacerbated at once," she said.

Antibiotic resistance on the rise

As Newman and Shan's work shows, as spots around the U.S. face new infection risks, existing treatments may become less effective. Their work showed that drought concentrated the natural antibiotics that bacteria make in the soil, making it harder for bacteria susceptible to the compounds to survive. As a result, the microbes with genes for antibiotic resistance did better. The problem for human health is that bacteria are very good at gene swapping, so these soil microbes can easily pass their antibiotic resistance superpowers to bacteria that infect people, their research showed.

"Gardening, breathing dust ‪—‬ that's how it happens," Newman said of human and soil bacteria coming into contact. "We are constantly encountering bacteria in our environment."

The researchers found an association between drought and antibiotic resistance reported by hospitals.

They aren't the only ones. A recent study on Salmonella, a bacterium that causes about 1.35 million cases of food poisoning each year in the U.S. alone, found that temperature and rainfall promote antibiotic resistance in this microbe. "Globally, climate change was linked to about a 10% increase in Salmonella resistance gene abundance," said study first author Zhen-Chao Zhou, an ecology researcher at the Chinese Academy of Sciences in Beijing. Other microbes show similar effects.

Meanwhile, warmer conditions help bacteria grow faster, adapt to stress and swap resistance genes, Zhou said, while drought concentrates them in limited water sources where they mingle freely. Climate-change-induced flooding can then, in theory, spread the resistant genes far and wide.

Combating the compounding risks requires both public health and climate mitigation approaches, experts say. Not only does the world need to cut greenhouse gas emissions, but people also need to use antibiotics more carefully, Zhou said; improve sanitation practices, such as sewage management, around the world so that antibiotic-resistant strains don't spread as easily; strengthen food safety; and expand disease surveillance. The public also needs to understand that climate change is a health issue, Romanello said.

"When we talk about tackling greenhouse gas emissions," she said, "what we're talking about is a sustainable livable future with healthy economies."

Burning up — How can we adapt to a warming world?

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In this excerpt from "The Carbon Wave" (MIT Press, 2026), author Leah Stokes, an associate professor of environmental politics at the University of California, Santa Barbara, looks at a hopeful moment in U.S. politics when climate change took center stage: when Rep. Alexandria Ocasio-Cortez and Sen. Ed Markey ramped up calls for a "Green New Deal."

In September 2017, a still­-unknown Alexandria Ocasio-­Cortez watched as Hurricane Maria devastated Puerto Rico. Electricity went down for months. Like thousands of Puerto Ricans, her grandfather died in the storm's aftermath. She could see how climate change was hitting her community harder than others.

And it wasn't just Ocasio-­Cortez's community: the year before, she'd traveled to Standing Rock, North Dakota, to see firsthand how the fossil fuel industry was harming Indigenous people. It was mere weeks after the 2016 election, and the resistance to Trump had found its center in a makeshift camp along the Missouri River. People had united to oppose an oil pipeline.

Serendipitously, the day after Ocasio-­Cortez left the protest, a progressive organization reached out to ask her to run for Congress. Moved by the activists at Standing Rock, she said yes. In 2018, she ran a long-­shot primary campaign in a Bronx district occupied by a ten-­term congressman in House leadership. Her platform included an idea that some had bandied about before, but no one had developed in earnest: a Green New Deal. As she told journalists that summer, "The Green New Deal we are proposing will be similar in scale to the mobilization efforts seen in World War II or the Marshall Plan. We must again invest in the development, manufacturing, deployment, and distribution of energy, but this time green energy." In June, she won the primary. Her election signaled the beginning of a broader shift: climate change was back on the political agenda.

That fall, the world's leading climate science organization, the Intergovernmental Panel on Climate Change —­ often called the IPCC —­ released a short report concluding that limiting warming to 1.5°C would require emissions to fall by almost half by 2030. The news ricocheted around the world, with headlines like "We Have 12 Years to Limit Climate Catastrophe." In my own neighborhood, someone printed a copy and stuck it in the free lending library, labeling it "important reading." The report changed how many people thought about the problem: it wasn't something we could deal with in 50 years; it was something we had to deal with today.

In the November 2018 midterm elections, two years into the first Trump administration, Democrats won big, paving the way for Nancy Pelosi to return as Speaker of the House after eight years as the minority leader. Days later, a group of young activists from the Sunrise Movement staged a sit-in at her office. Their bright yellow and­ black signs read "We have 12 years. What’s your plan?" referencing that scientific report.

Newly elected Representative Ocasio-­Cortez joined the action that day. She told the organizers they needed a clear ask and encouraged them to call for a Green New Deal. The idea broke through, sparking widespread coverage across the country. It was a new, hopeful vision for climate policy. These young people were not just talking about the climate disasters we needed to avoid —­ they were explaining how investments in clean energy could create good jobs. They were showing us the better world we could build together. If we only tried.

I watched these developments unfold in DC from my office by the Pacific Ocean and wanted to be a part of it. I wouldn't have to wait long. The Green New Deal held a force like gravity, pulling people into its orbit. By chance, I met some of the people tied to Ocasio-­Cortez at a conference and was invited to an early gathering to develop the idea into more detailed policy. By then, she'd released a framework for the plan with Senator Ed Markey of Massachusetts.

The meeting was held in March 2019, at a hip hotel in DC's Adams Morgan neighborhood, miles away from the Capitol. A wide swath of people were invited: youth activists, environmental justice leaders, political organizers, think tank wonks, and a few academics like me. It was a contentious meeting that opened with a protest, revealing fissures in the movement that would eventually grow into large cracks. Some people believed that frontline communities facing the greatest pollution burdens were not being adequately consulted or invited to participate in the event. At the time, I didn't understand these dynamics between the climate and environmental justice movements. I was just a political science professor trying to understand how I could make my work more practical and help get a climate law passed if we got the chance.

It was at that event that I met Varshini Prakash, the executive director of the Sunrise Movement. I’d seen her photo many times, standing in the middle of Pelosi's office with her dark red jacket over a black­ and yellow T-­shirt, surrounded by young people sitting on the floor. Four months had passed since the sit-­in, and Varshini had ricocheted to the center of the climate movement. But she was also a recent college grad in her mid-­twenties, feeling a heavy burden from the climate crisis and the work involved in fighting it. At one point during the meeting, she spoke frankly about the stress that was on her and other young activists and cried. I found her vulnerability moving.

The fact was, Varshini had already changed history. She'd given me, and millions of others, a sense of hope and possibility. It was her actions, alongside all the other organizers in the Sunrise Movement, that brought us together in that first DC convening, and in countless other meetings to come. She inspired me to believe that I could do something bigger if I tried.

Too often, the way we think about cause and effect is simplistic. We're fed a linear model that favors the immediate. One person is responsible for their own carbon footprint. One person only has one vote. One person can only do so much. From this perspective, standing against more than a century of fossil fuels running through the heart of our society, it can feel like there's nothing we could do to shake the system loose. We're too small. Mere drops. But drops in the ocean can make waves.

Excerpted from The Carbon Wave: A Story of Democracy, Parenthood, and the Race to Protect Our Planet by Leah C. Stokes. Reprinted with permission from The MIT Press. Copyright 2026.

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Two distinct climate regimes that could trigger runaway methane emissions are emerging in Siberia due to Arctic warming, new research suggests.

While western Siberia is becoming wetter in response to rising heat and moisture transported from the North Atlantic Ocean, eastern Siberia is getting drier and more prone to wildfires, a study published Aug. 6 in the journal Science finds. The Yenisei River (also spelled Yenisey) in central Russia delineates the separate environmental states — referred to as regimes because they describe specific types of climates — on each side of the basin, the study authors said.

Between 2010 and 2023, methane emissions from Siberia rose by 5% per year, with western Siberia releasing methane mainly via microbial activity in thawing soils and eastern Siberia discharging the powerful greenhouse gas through biomass burning, the results showed.

"Given the observed increases in permafrost thaw, wetland activity, and wildfire occurrence, an increase in methane emissions was expected," study co-author Paul Palmer, a professor in the School of Geosciences at the University of Edinburgh, told Live Science in an email. "What is surprising is how large and sustained the increase appears to be."

Annual methane emissions grew by about 13.2 million tons (12 million metric tons) over the study period, almost mirroring the rate of increase in methane emissions from wetlands worldwide. Although Siberia currently makes up only about 5% of global methane emissions, the region is becoming one of the fastest-growing natural methane sources on the planet, Palmer said.

In their study, Palmer and his colleagues integrated satellite observations with near-surface measurements to map methane emissions from Siberia over time. Instead of adding up individual methane sources on the ground, the researchers used a modeling method known as a methane flux inversion system, which helped them limit the uncertainty in their estimates to roughly 10%.

Siberia is vast, remote, sparsely instrumented and currently inaccessible for many scientists due to the Russia-Ukraine war, making it hard to monitor methane consistently by any means other than satellites. Although satellites rely on sunlight, of which Siberia gets very little in the winter, most methane emissions are thought to occur in the spring and summer, when Siberia gets more sunlight, Palmer said.

The results of the study show that Arctic warming amplifies methane emissions via distinct pathways in western and eastern Siberia because the regions are influenced by different climate patterns. The researchers also used climate models to predict future methane emissions from Siberia and found that additional warming could unleash millions of tons of greenhouse gases stored in forests and permafrost, which would further accelerate the warming trend.

In western Siberia, methane is released mainly from permafrost, or ground that has stayed frozen for at least two consecutive years. Siberia holds 46% of the Northern Hemisphere's permafrost, and this icy sediment traps vast amounts of carbon that have accumulated for thousands of years, Palmer said.

Western Siberia is influenced by the Scandinavian pattern of atmospheric circulation, a climate connection that consists of a main circulation center over Scandinavia and opposing weaker centers over Western Europe and eastern Russia. Global warming makes the Scandinavian pattern transport more warmth and moisture to western Siberia from the North Atlantic. Together with soaring temperatures in western Siberia itself, this triggers extensive permafrost thaw and unlocks carbon that microbes can convert into methane.

Conversely, eastern Siberia is influenced by a climate pattern known as the Arctic Oscillation, which causes atmospheric air pressure to "seesaw" between the Arctic and the Northern Hemisphere's middle latitudes. Climate change affects the Arctic Oscillation, leading to persistent high-pressure systems that intensify heat waves, reduce cloud cover and promote wildfires in eastern Siberia, Palmer said.

The climate models showed that methane emissions will increase with temperature rise and that the increase could become steeper the hotter the world gets, triggering a feedback loop.

"Eastern Siberia appears to be the main driver of the projected increase because it is warming faster than western Siberia and has seen a sharp rise in extreme wildfires," Palmer said. "Whether that trend continues will depend on how much vegetation remains available to burn, but there is also evidence that fires may be accelerating permafrost thaw and the release of methane from previously frozen ground."

However, the rise in methane emissions reported in the study is small relative to global and projected future emissions, especially if wildfires are already destabilizing eastern Siberia's permafrost, Palmer said.

"Siberia's vast permafrost carbon store is a sleeping giant," he said. "Continued warming risks waking up a much larger source of greenhouse gases."

Large patches of open water were visible just 37 miles (60 kilometers) from the North Pole on Aug. 29, a NASA satellite image shows. Although this doesn't necessarily mean that Arctic ice is worse off this year than the past few years, the image reveals how severely climate change is affecting the region, experts say.

The image is from the NASA Worldview satellite photo browsing tool and was shared last week on the blog Arctic News. The patches are "quite striking," but it's not the first time that water has encroached upon Arctic ice in this way, said Julienne Stroeve, a professor of polar observation and modeling at University College London.

"We can see open water at times at the North Pole but I don't think it's ever been this extensive," Stroeve told Live Science in an email. For instance, the central Arctic Ocean and regions north of 80 degrees north latitude, an imaginary line that crosses Canada's Ellesmere Island and Spitsbergen in Norway, were highly fragmented in early September 2016.

The time of year is one reason water is now visible in this region, said Zachary Labe, a climate scientist at Climate Central, a nonprofit news organization that analyzes and reports on the climate. "By the end of summer, the sea ice generally becomes more fragmented, with areas of open water appearing more widespread between pieces of sea ice," Labe told Live Science in an email.

This means that local weather conditions and ocean currents can create large gaps between ice floes, Labe said. For example, strong winds can push ice fragments together or pull them apart, leading areas of water to widen or close within hours or days.

"Individual satellite images from around the North Pole in just the last two weeks show dramatic changes in the amount and location of visible open water," he noted.

The current extent of Arctic sea ice isn't particularly low when compared with record-setting years, but that's now very changeable due to the diffuseness of the ice, Stroeve said. "Winds could change and compress the ice into a more compact ice cover leading to sudden drops in total extent," she said.

There is no specific distance from the North Pole at which open water should normally stop, because Arctic conditions can vary substantially from year to year, Labe said. However, the summer ice has become thinner and more fragile in recent years, so open water is consistently reaching closer to the North Pole than it did before.

"To me, this image doesn't necessarily show that conditions are dramatically worse this year compared to other recent years," Labe said. "Instead, it represents a worrying snapshot of a very different Arctic Ocean than only a few decades ago and one that is quickly changing over time."

The Arctic is warming nearly four times faster than the global average. Some of the northernmost regions that have historically boasted expansive, thick and persistent ice at the end of summer now have young, brittle ice floes instead, Labe said.

"The broader implications of more open water across the Arctic Ocean are wide-ranging, from changes in local weather and ocean conditions to impacts on marine ecosystems and greater coastal risks like erosion and flooding for Arctic communities," he said.

Scientists expect that sea ice will start to refreeze by mid- to late September, closing at least some of the gaps.

With only a couple of months to go before the harvest season for winter wheat in Colorado, the crop faced a whiplash: After a warm, dry winter, a cold snap plunged the plants into freezing weather for 12 hours, and temperatures soared to nearly 90 degrees Fahrenheit (32.2 degrees Celsius) two days later. When the final harvest numbers were tallied in July, 73% of the crops were in poor or very poor condition. According to early estimates by Colorado Wheat, 2026's winter wheat crop was the smallest in the state since 1965.

Pick a crop, any crop, and you'll hear a similar story: Extreme weather and climate change are rocking the food supply. The warming climate makes food less nutritious, threatens crop survival, and triggers tipping points that would upend farming as we know it.

The impacts will be felt most intensely in less-developed regions of the world, where many people can't afford imported food and climate-related famines and nutritional scarcity are already happening.

But the U.S. is facing big changes to its food systems too, and no one is immune. Humans have overcome looming agricultural disasters before, but experts say the challenge should not be underestimated.

"There are real food security and nutrition concerns," said Andrew Hultgren, an environmental economist at the University of Illinois, Urbana-Champaign, "especially under these high-warming futures."

Food is becoming less nutritious

As the planet warms, food crops are expected to become less nutritious. That's because, due to plant biology that's not yet fully understood, crops grown under higher levels of carbon dioxide are deficient in zinc, protein, magnesium, iron and other micronutrients. Crops are already less nutritious than they were in the 1950s, but this is partly due to breeding decisions that prioritize yield over nutrition. The carbon dioxide deficiencies will exacerbate this nutrition decline.

The global monthly average concentration of carbon dioxide in the atmosphere is now over 420 parts per million (ppm), well over the preindustrial average of 280 ppm. By the end of the century, those levels will increase to at least 550 ppm in all but the most optimistic scenarios.

That will mean an additional 175 million people will be zinc deficient and an additional 122 million people will be protein deficient by 2050, a 2018 study found. Zinc deficiency has consequences for immune and skin health and may lead to poor growth in childhood; protein deficiency can also cause stunted growth as well as fatigue, muscle weakness and stress fractures. Those figures account only for the effects of carbon dioxide. A cascade of climate shifts and extreme weather may also affect the number of nutrients (and calories) available to the world.

The threats are myriad: Rising sea levels may inundate farmland and lead to saltier soil in coastal regions where, for example, rice farming is common. Soil salinity can make it impossible to grow crops in some regions. Droughts, heat waves, storms or temperature swings like those seen in Colorado this year might take out certain crops in particular places, leading to year-by-year price spikes or shortages. In the U.S., the results might look a lot like the recent egg shortages triggered by bird flu; temporarily empty shelves, price spikes, or even restrictions on the amount a customer can purchase in a visit for an affected food.

Climate shifts that harm pollinators and fuel the spread and introduction of plant pathogens such as harmful fungi will also likely reduce crop yields.

Areas that depend on the ocean for food are also facing steep challenges, due to both ocean acidification and the degradation of coral reef ecosystems, which are sources of food for many coastal communities and form much of the base of food chains for the larger fish people eat.

Hotter weather also affects food safety, said Christopher Golden, a professor of nutrition and public health at the Harvard T.H. Chan School of Public Health.

"Increasing sea temperature and increasing sedimentation within seas could lead to harmful algal blooms or increasing food poisoning events from temperature-related food spoilage," Golden said. Algal blooms can contaminate shellfish like oysters or scallops with neurotoxins that can sicken and kill people who eat them. Food spoilage is a concern in regions such as Madagascar, where catches are brought ashore and readied for consumption in the open air.

Meanwhile, fish may move poleward to avoid the hottest sea temperatures, leaving the most vulnerable regions ‪—‬ such as Southeast Asia, the Caribbean, Africa, Central America and the Pacific ‪—‬ with fewer fish in their waters. How bad this looks depends on the extent of the climate swings, with research suggesting that without any mitigation, fishers could see their catches decline by 58% to 92% off small islands in the Pacific and by 70% to 86% in Southeast Asia. This would drive food insecurity and malnutrition in those regions. The U.S. will likely face impacts too, as most of its seafood is imported from subtropical or tropical waters elsewhere.

There may be shifts in trade networks that lessen the blow for U.S. consumers, Golden said, but it's hard to predict. Some possibilities include "price shifts or trade shifts that lead to changing dietary patterns or more shelf-stable and heavily processed items that we know aren't good for your health," he said. In other words, less fresh-caught snapper and more potted meats.

Changing foods on the table

Individual producers are adapting, sometimes in ways that may not be immediately obvious to consumers. "Climate change is bad in that it's a slow-moving wave," said Elizabeth Wolkovich, a professor of forestry at the University of British Columbia. "You don't really notice that it's shifting underneath you and that the apple you eat isn't the apple your granddaughter will eat."

On that note, growers in the Pacific Northwest and U.S. Northeast will face challenges getting apples to lunch boxes around the world. Fewer cold days and more extreme-heat days will likely reduce apple yields by affecting how and when trees go dormant and bloom. Because it takes five or more years to establish fruiting trees in new regions, this could mean a reduced apple supply and higher prices.

Today's smooth arabica coffee (Coffea arabica) varieties may get harder to find and more expensive as climate change forces coffee growers out of many of the places they used to farm and droughts reduce supply. Earthier, more bitter robusta coffee beans (Coffea canephora) do better in warming temperatures, but even those beans could struggle with increasing seasonal variability caused by climate change.

Climate has already shifted wines in favor of less-acidic and higher-alcohol varieties, Wolkovich said, but it's happened slowly enough that, unless you're a connoisseur, you may not have noticed. Wine lovers can expect more changes: Wolkovich has found that the varieties of wine grapes that growers can produce will shift with climate change. Wildfires in grape-growing regions like California can also produce an unpleasant acrid and smoky flavor in wine.

And it's not just flavors that will be affected. U.S. dairy cattle breeds originated in cool and cloudy Northern Europe, and their milk output goes down as temperatures climb. Such heat stress reduced annual milk yield by an average of 1% a year between 2012 and 2016 alone, and heat-related losses are expected to balloon by 30% by 2050.

Americans have long been drinking less milk from the glass, but their demand for yogurt and cheese is rising, said Jared Hutchins, an assistant professor of agricultural and consumer economics at the University of Illinois Urbana-Champaign and first author of the study on milk yield. Those products depend heavily on the fat and protein content in milk, which is the first thing to drop when cattle are hot. "Fat and protein are what deliver the cultured dairy products that are in high demand," Hutchins told Live Science.

The story repeats itself across agricultural products, Hultgren said. "For each degree of that global temperature rise, caloric output [from crops] drops by 120 kilocalories or U.S. calories per person per day," he said, "which is about 4.5% of a person's daily recommended caloric intake."

That calculation, published by Hultgren and his colleagues in the journal Nature in 2025, already accounted for adaptations that farmers can make to reduce crop losses. Without those adaptations, the number would be over 30% higher, he said.

Reductions in available calories will translate to food shortages in vulnerable places, such as the Horn of Africa or India, said Marina Romanello, executive director of a multinational research project that tracks the impacts of climate on health at University College London. In North America, "it would feel like inflation," Hultgren said ‪—‬ yet another factor driving up grocery prices.

Worst-case scenarios

For farmers, the year-by-year uncertainty of climate change is a problem. Will this year bring drought? Will there be a sudden storm or flood that will wash away the spring crop? Should they take a risk on a new heat-resistant plant or agricultural technique?

Similar uncertainty haunts the long-term forecast. Climate tipping points can lead to sudden, irreversible changes in the system. For agriculture, one of the scariest tipping points is the potential collapse of the Atlantic Meridional Overturning Circulation (AMOC). This pattern of ocean currents brings warm surface water north from the equator and circulates cold water south, warming Northern Europe and the northern parts of North America and cooling the Southern Hemisphere.

If this current were to collapse, northwestern Europe would cool dramatically, with studies suggesting that London could see temperature lows of minus 4 F (minus 20 C) ‪— ‬colder than the city's lowest temperatures on record. Precipitation would decline across Europe, leading to drought. Meanwhile, in the Amazon, the wet season could become the dry season and vice versa, said René van Westen, a climate researcher at Utrecht University in the Netherlands who has studied the impacts of an AMOC collapse.

On the other hand, if the AMOC doesn't collapse, London is expected to warm by 4.9 F (2.7 C) and see 15% to 18% more precipitation, depending on the season. The uncertainty in these predictions makes preparations difficult. There is still a lot of controversy over whether the AMOC will collapse and, if so, when. Should farmers plan for England to become increasingly toasty, or should they expect it to be plunged into a little ice age?

AMOC-related changes will take decades to centuries to unfold, even with a total collapse, van Westen told Live Science. But even so, they would require a total rewriting of agriculture in Europe and the northeastern U.S. "It will be very challenging to adapt to such a scenario," he said.

That doesn't mean a collapse of the world food system is inevitable. Farmers are already adapting to the early impacts of climate change by scaling back water-hungry crops in drought years and, in some places, testing new, heat-resistant varieties of crops in an attempt to stem the losses.

And humans have overcome looming disaster in agriculture before: In the 1950s and 1960s, new varieties of rice and wheat, along with the availability of synthetic nitrogen fertilizers, spurred the "Green Revolution," tripling the world's yield of cereal crops while expanding farmland by only 30%. Similar innovations could limit hunger even as the world warms.

But the biggest way to mitigate these impacts is the most obvious one. While Hultgren and his colleagues found that adaptation could cut caloric losses under climate change by 30%, mitigating warming by reducing emissions today could slash them by half. Similarly, the AMOC is on a path toward weakening, van Westen said, but as long as humans slow the pace of climate change, the current can recover.

"If you are cutting your emissions," van Westen said, "you can lower your risk."

Burning up — How can we adapt to a warming world?

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China's solar power capacity has overtaken coal for the first time, marking a major milestone in the country's rapid expansion of renewable energy.

China had about 1,288 gigawatts (GW) of installed solar capacity at the end of July, compared with 1,285 GW of coal-fired capacity, according to figures from the country's energy administration reported by the South China Morning Post.

The milestone could have major implications for global efforts to tackle climate change: China is the world's largest annual greenhouse gas emitter, accounting for around 30% of global planet-warming emissions. If its rapid expansion of renewable energy begins to displace coal-fired power ‪—‬ one of the country's primary sources of greenhouse gas emissions ‪—‬ the impact could extend well beyond Chinese borders.

"China reaching around 1,288 GW of installed solar capacity, marginally overtaking coal, is a major milestone," Matthew Davies, UNESCO chair in sustainable energy technologies and a professor of chemical engineering at Swansea University in the U.K., told Live Science.

However, installed capacity doesn't necessarily equate to actual electricity generation. "Solar only generates when sunlight is available, whereas coal plants can run for much longer periods, so solar still supplies a much smaller share of China's electricity than coal," Davies said.

In other words, China has more solar capacity than coal capacity, but coal remains far more important when it comes to the amount of electricity actually delivered to the grid.

Between January and July this year, Chinese solar power output rose 15.5% compared to the same time period in 2025. Over those seven months, it reached 802.4 TWh, which is around 13% of the country's total electricity consumption.

"I would see this as a structural turning point, not the point at which solar has replaced coal," Davies said. "The key question is whether renewable generation can grow fast enough not only to meet rising electricity demand but to push coal generation down in absolute terms. Given the scale of China's power system, sustained reductions in coal use could have a major impact on global CO₂ emissions."

To do that, China will need to do more than build solar farms. One of the biggest challenges will be integrating all of the new renewable power into the electricity system.

"Installing solar is only part of the transition; grids, transmission, storage and demand flexibility all need to keep pace so that renewable electricity can actually be used," Davies said.

This transition toward solar panels will also make renewable energy more accessible around the world, as China's enormous manufacturing capacity will help drive down the global cost of solar panels. However, Davies said the next phase of the transition is to ensure the whole solar production process is sustainable. "We need to think about where technologies are made, where materials come from, how long they last, and how they are reused or recycled," he said.

Solar panel manufacturing involves raw material extraction, processing, manufacture, transport and installation, so it has an initial carbon footprint. High energy requirement for polysilicon production is a considerable factor as it uses coal-fired power plants. But, this is offset by the electricity they generate.

There is also a case for expanding local and regional manufacturing, Davies noted. Doing so could strengthen supply chains, create local skills and economic value, and make the global energy transition more resilient and equitable. That could be particularly important for expanding access to electricity in parts of the world where reliable power remains limited.

"The global energy transition is not only about replacing fossil fuels in existing electricity systems; it is also about enabling people who still lack reliable electricity to gain access to clean, affordable power," Davies said. "Ultimately, success is not simply about installing more solar panels. It is about building a clean-energy system that is affordable, sustainable, resilient and accessible globally."

Yellow fever is appearing in regions that haven't seen cases of the disease in years, largely as a result of climate change.

Historically, the virus ravaged cities across the Americas, Europe and Africa, until a vaccine was introduced in 1937 and its range shrunk significantly. But now, as climate change creates favorable conditions for virus-carrying mosquitoes, scientists are seeing outbreaks in unexpected areas.

"Yellow fever is a highly deadly disease," Dr. Joelle Ivy Rosser, an infectious-disease researcher at Stanford University, told Live Science, "so any environmental pressures that increase the likelihood of future yellow fever virus outbreaks … is highly concerning."

How is climate change contributing to this pattern, and could it get worse in the future?

How rising temperatures impact yellow fever

Yellow fever is a mosquito-borne disease caused by the Orthoflavivirus flavi virus, better known as yellow fever virus (YFV). The infection causes fever, muscle aches, headaches and vomiting. About 15% of cases become severe, with patients showing jaundiced skin and eyes, bleeding from the mouth, eyes, nose and stomach, or organ failure.

Devastating yellow fever epidemics spread in the 17th to 19th centuries, before the development of a vaccine. Nowadays, an estimated 31,000 to 82,000 yellow fever deaths occur each year; severe cases have an estimated fatality rate of 20% to 50%.

Most yellow fever infections are a result of spillover from nonhuman primates; mosquitoes bite monkeys that carry the virus, such as howler monkeys, and then the infected mosquitoes bite humans. Several types of mosquitoes carry the virus, but the species Aedes aegypti is the main vector for yellow fever in cities, where high population density can make outbreaks especially severe.

Although there is an effective vaccine for yellow fever, cases have been on the rise in the past three decades. This led the World Health Organization (WHO) to set out a strategy in 2017 for eliminating yellow fever epidemics by 2026 through outbreak prevention and containment.

Climate-change-driven warming and extreme weather events may have heightened yellow fever risk over the past few decades, experts say. Rising temperatures make mosquitoes bite more because heat makes their metabolisms more active, said Dr. Seth Judson, an infectious-disease physician-scientist at UCLA. Warming also cuts down the virus's extrinsic incubation period, meaning the time it takes for the virus to replicate in a newly infected mosquito and then get passed on to another person, he told Live Science.

Weather patterns and deforestation

Changing weather patterns play a role, too. In 2017-2018, Brazil saw its first yellow fever outbreak in a city in almost a century. That outbreak, primarily in Belo Horizonte and São Paulo, was likely a result of drought, according to one study.

While heavy rainfall creates a breeding ground for mosquitoes, in this case, drought pushed forest-based mosquitoes — as well as YFV carriers like marmosets and howler monkeys — closer to cities as the animals searched for water. Drier conditions can also prompt dehydrated mosquitoes to bite more as they search for fluids, study co-author Jamie Caldwell, a disease ecologist at Princeton University, told Live Science.

"Extremes of weather in either direction" — very wet or very dry — "can exacerbate mosquito-borne disease transmission," Rosser said.

Parts of Africa and South America that were considered low-risk for yellow fever have already been seeing new outbreaks, Judson said, so maps of yellow-fever-affected areas have had to be updated. In research that's been released as a preprint but not peer-reviewed yet, Judson found that yellow fever is reemerging in an area of the Colombian Andes where it hadn't been reported since 1940.

Experts are paying particular attention to the edges of cities, where urban centers meet the forest. The risk of yellow fever transmission from monkeys to humans via mosquitoes is rising at these edges due to both climate change and deforestation.

"Humans are expanding the agricultural frontier and encroaching on forests where yellow fever mosquitoes … are found," Gabriel Parra-Henao, a biologist with the WHO, told Live Science in an email. "[This] results in more people being exposed to their bites."

Similar patterns have been seen with other mosquito-borne infections, such as malaria.

Could yellow fever return to the U.S.?

Climate change is expected to bring yellow fever to new areas. One study predicts that, under the most severe climate change scenario, nearly a billion people could face their first exposure to the mosquitoes that can carry YFV in the next century. While that worst-case scenario may not be the most likely, the mosquitoes' ranges are still expected to expand under less-severe conditions.

Europe is predicted to face the largest increase in exposure to Ae. aegypti mosquitoes compared to the rest of the world, and the U.S. and Canada are predicted to see increases too. In the U.S., the mosquito species already lives in a number of states, including Florida, Mississippi, Arizona and New Mexico. However, warming would increase the chances of mosquitoes surviving in locations further north, such as Philadelphia and New York, which suffered major yellow fever outbreaks in the past. One model predicts Ae. aegypti could spread as far north as Chicago by 2050.

Although the mosquito lives in the U.S. already, yellow fever cases are exceedingly rare within the country because the virus is not present in local populations. That's because of an international campaign that the U.S. spearheaded in the 20th century, which involved researching YFV, eradicating mosquito breeding grounds, and vaccinating people widely.

"If yellow fever virus reestablished itself in our local Aedes aegypti population, then that would be very concerning," Rosser said.

One way yellow fever could return to the U.S. would be via people carrying the virus home with them after traveling to regions where the disease regularly circulates. Local mosquitoes could then catch the virus by biting those infected people, and then pass it on to others.

For local transmission to take hold, "there needs to be significant numbers of infections [passed to locals], and infections among travelers," Judson said. "But … it's in the realm of possibility."

With climate change driving resurgences of yellow fever in more places, and more regions of the U.S. becoming hospitable to the mosquitoes, that reintroduction scenario may become more likely. But some scientists think that even if North American cities saw yellow fever outbreaks, the outcome would likely not be devastating. Infrastructure in wealthier cities could be the difference between a disaster and a manageable health concern.

"There's access to medicines and vaccines; we pipe water to our homes, so we don't have standing water around," Caldwell said. "So it is a concern, but it's never going to be the next COVID."

Other experts noted that diligent surveillance of yellow fever infections can help public health officials prepare. In places where yellow fever is circulating in forest primates, forest conservation can limit contact among humans, wildlife and the mosquitoes that spread diseases among them. It's also crucial to make vaccines widely accessible to people who live in the virus's endemic regions and to travelers who visit those regions.

The WHO's yellow fever campaign is set to conclude at the end of this year, and its next steps are unclear. There's ongoing discussion of what comes next, Judson said, with questions about whether the control of yellow fever outbreaks will rely more on national strategies than on international coordination via the WHO.

Whatever happens, this is a time for heightened awareness of the virus, Judson said.

"We think of yellow fever as this historic disease," he said. "I think many people don't realize that we're still seeing significant yellow fever outbreaks. … It's really important to be aware of the risks and think about how we prepare for that."

This article is for informational purposes only and is not meant to offer medical advice.

Earth's temperatures are steadily rising, with the past decade experiencing all 10 of the warmest years on record. As heat waves become more frequent and intense, concerns are growing about how this heat could impact people's health.

Higher temperatures can have serious effects on the human body, including dehydration, heat exhaustion and heatstroke. But extreme heat can also drive up the rates of heart attack and strokes due to ill health.

In a Live Science poll, we asked our readers how concerned they are about rising temperatures affecting their health and fitness, daily activities and the safety of their community. Over 170 people responded to the poll, which was published Aug. 26, with 67% of readers voting "Yes, I'm very worried about how extreme heat is affecting everyone around the world."

The comments from readers also reflected their concerns. One commenter wrote, "Too much of humanity is unaware that the Earth is a single organism. Everything is connected. El niño may begin off South America but its effects are eventually felt everywhere. There is only one ocean."

Another reader mentioned the daily challenges caused by the rising temperatures, saying, "I've been trying to make walking around the block of my neighborhood a regular thing, but when it gets too hot (and more precisely too humid) I prefer staying inside my house where I can be comforted by the AC."

So what do you think? After reading these responses, are you also worried about extreme heat? Let us know in the comments.

Climate change is making El Niño stronger and more dangerous than ever before, scientists warn.

In a new study, researchers have revealed that El Niño events have become nearly 40% stronger over the past four decades than they were in the preindustrial era.

The finding comes as the world is in the grips of a historic "super" El Niño. While daily average sea surface temperatures soar to unprecedented highs, forecasters have become almost certain that the 2026 to 2027 El Niño will be an all-time record event.

"We don't see a time in the past where El Niños have been as strong as today, and we show that the strength of El Niño changes in parallel with the warming of global temperature," study first author Julia Cole, a professor and chair of the Department of Earth and Environmental Sciences at the University of Michigan, said in a statement. "Our findings tell us that the big El Niño events of the last 40 years are not normal in the context of the last thousand years."

El Niño events occur every two to seven years as part of the Pacific Ocean's El Niño-Southern Oscillation (ENSO) natural climate cycle. The ENSO cycle flips between the warmer El Niño phase and the cooler La Niña phase, with neutral periods in between.

El Niño periods bring elevated sea surface temperatures in the central and eastern Pacific, thereby weakening or reversing trade winds and strongly disrupting global temperatures and rainfall patterns. Earth's last El Niño ran from June 2023 to April 2024, delivering an injection of heat to our already warming world that made 2024 the hottest year on record.

The impacts of El Niño periods can be profound, with studies linking the events to famine in Europe, civil wars in tropical regions, and droughts, floods and forest fires around the world.

Climate scientists have long suspected a link between the growing intensity of recent El Niño events and global warming. But sparse instrumental records and significant variability in the natural climate pattern has made it difficult to say so for certain.

So in the new study published Aug. 27 in the journal Science, researchers investigated whether climate change has been boosting the severity of recent El Niño events. The team analyzed 13 ancient and modern corals taken from close to the events' epicenter — the Pacific Ocean's Galápagos Islands.

By analyzing the temperature-sensitive chemistry of the coral samples, the scientists discovered a millennium-spanning pattern of lower intensity El Niño events being gradually superseded by ones of increased strength after humanity's widespread adoption of fossil fuels in the 19th century. Using climate simulations, the researchers ruled out the possibility that natural causes, such as volcanic eruptions or solar variability, could have caused this shift.

"We kept adding records thinking well, this is going to get more complicated, but it really didn't," Cole said. "This is such a clear story."

The prospect of El Niño and climate change feeding back into each other is troubling, the researchers said, especially as the climate pattern has the potential to drive persistent shifts in major ecosystems such as the Amazon rainforest.

"El Niño is a really big source of climate extremes, and so if it's getting stronger, the impacts are getting stronger. Impacts like droughts, floods, wildfire and food insecurity," Cole said.

In the short term, the combination of climate change and El Niño could bring significant strain to our warming planet.

"The question is not whether the current El Niño is going to happen, but how bad is it going to be, and how bad will the impacts be?" Cole said. "This event is superimposed on global warming, and it's likely to supercharge the temperature increase that we would normally see from greenhouse gases."

The findings further underscore the urgent need to mitigate further global warming, Cole noted.

"No country has the resources to be fully protected from these impacts. This is one more reason we need to move away from fossil fuels, the root cause of the problem," Cole said.

As wildfires raged through Ontario, Canada in mid-July, millions of people in the Midwest and on the East Coast found themselves under a shroud of yellow skies, darkened by smoke from the infernos. The air quality index in Grand Rapids, Michigan hit 616 on July 16, breaking the previous record for the city of 350; any number over 301 indicates hazardous, emergency conditions.

Smoke events like this are only likely to worsen in the coming decades: Wildfires are one of the most imminent impacts of climate change.

Not only do the flames themselves directly threaten lives, but the smoke can trigger heart attacks, asthma attacks and premature births, as well as worsen heart disease or lung ailments such as chronic obstructive pulmonary disease (COPD). And those effects can spread as insidiously as smoke travels.

A 2025 study found that the record-breaking 2023 Canadian wildfire season may have shortened the lives of 87,000 people exposed to the smoke plumes worldwide. Another 2025 study found that wildfire smoke contributed to 41,380 excess deaths per year in the U.S. between 2011 and 2020 and that the number will rise to 71,420 excess deaths by 2050 if global temperatures rise 5 to 8.3 degrees Fahrenheit (2.8 to 4.6 degrees Celsius) by the end of the century.

In North America, the health impacts of this extra fire are likely to be significant. Wildfire season is getting longer and more intense in the West and Southwest, while regions not historically prone to wildfires will need to deal with the impacts of smoke plumes that can travel thousands of miles.

"Wildfire smoke is the fastest-growing environmental threat [to health] in the U.S.," said Marshall Burke, a professor of global environmental policy at Stanford University who was the senior author of the study predicting the grim rise in excess deaths. "It's just changing so rapidly."

Longer fire season, bigger blazes

Even a rapid drop in greenhouse gas emissions wouldn't fully mitigate the growing risk of wildfires. Because these gases persist in the atmosphere for decades, a more fire-friendly future is already locked in.

"No one foresees changes in the near future, at least, that are going to result in decreases in wildfire," said Mary M. Johnson, a principal research scientist in environmental health at the Harvard T.H. Chan School of Public Health. Wildfires are "predicted to increase in size, intensity and frequency."

Global data suggests that without climate change mitigation, fires will increase in all vegetation types by the end of the 21st century. Even if warming is held to 2.2 F (1.5 C) over pre-industrial temperatures ‪—‬ an increasingly challenging goal to meet ‪—‬ fires outside of tropical latitudes will become more frequent.

In the U.S., the picture is bleak. Between 1984 and 2015, the number of large wildfires in the U.S. West doubled, according to the National Oceanic and Atmospheric Administration (NOAA). The seasonality of fire is also shifting. A February 2026 study published in the journal Geophysical Research Letters found that climate change is nudging fire season in the boreal forests of Alaska and Canada forward as winter snow vanishes earlier, leaving spring vegetation dry and ripe to burn. In the U.S. West, on the other hand, fire season is stretching later because of summer drought.

"It's about dryness," GRL study senior author Hongliang Zhang, an air quality researcher at China's Fudan University, told Live Science.

Climate change warms the atmosphere, and a warmer atmosphere can hold more water. But changes in precipitation patterns can still lead to increased dryness and drought, Zhang said. With climate change weighing the scales toward more intense bouts of rainfall, a particular location could see more precipitation but still experience a simultaneous increase in dry or drought periods, he added.

Zhang and his colleagues found that under a scenario in which temperatures rise by about 7.9 F (4.4 C) by 2100 — a high-emission scenario in which we do little to curb carbon output — fire season would move forward by about a week in Canadian and Alaskan forests, with some of the northernmost regions of Canada and Alaska seeing shifts of up to 23 days. California, with its Mediterranean-like climate, would experience a peak burning shift later in the season. In the Southwest, fire season under this scenario would start a week later but end more than a month later than it does now.

How wildfire smoke is poisoning the air

All of this spells bad news for human health in the U.S. More frequent and intense fires will fuel dramatic increases in air pollution. For instance, a 2020 study suggests that particulate smoke pollution levels will double or triple in the Pacific Northwest and Northern California under unmitigated warming by the end of the century. And even though the West is the U.S. region most prone to fire, wildfire smoke pollution won't stay there. Instead, it will travel across the country, worsening air quality on the East Coast and in the Midwest, Burke and his colleagues found. Depending on the level of warming, smoke emissions will increase 262% to 482% between 2046 and 2055 compared to 2011 to 2020, the researchers found.

Climate change also brings an uptick in severe weather, including winds, Johnson told Live Science. More wind means smoke can travel many thousands of miles. For example, the smoke from the 2023 Canadian wildfires reached Europe and Asia, and that trend is likely to worsen.

"There really isn't any place in the world now where you can say, 'I'm not going to be exposed to smoke,'" she said.

When wildlands burn, they produce PM2.5, a fine particulate matter that is small enough to slip into the bloodstream. Epidemiological studies have linked exposure to PM2.5 to a range of health issues, including dementia, kidney disease and lung cancer. The particles increase oxidative stress on cells in lab dishes, induce cell death, and cause DNA damage that can lead to cancerous mutations, among other impacts.

The damage is evident during big fires. For instance, exposure to wildfire smoke raises the risk of heart attack, stroke and other cardiovascular emergencies, according to a study of California emergency department visits during the 2015 wildfire season. Cumulative exposure over time, however, is how wildfire smoke causes the most deaths. Between 2006 and 2020, PM2.5 from wildfire smoke exposure was responsible for an average of 24,100 deaths per year in the United States, a study published in the journal Science Advances in February found. Smoke exposure worsened the death rate for every health condition studied, with neurological disease deaths rising most significantly.

Wildfire smoke may also fuel premature births. Just a week of wildfire smoke exposure raised the risk of preterm birth by 3.4%, a 2022 study found — and in a world where smoke exposure could span weeks, that could translate to a significant uptick in the rate of premature birth. Other studies tell a similar story: a 2024 study found risk of premature birth rises with every incremental increase in exposure to PM2.5 from wildfires during pregnancy. And a 2025 study found that preterm birth risk increased in the U.S. West with smoke exposure, regardless of whether that exposure was measured by high-smoke days, exposure to 4-day waves of smoke, or by the concentration of particulate matter in the air.

Wildfire smoke may also affect cognition: A 2022 study found that cumulative exposure to wildfire smoke over the school year was linked to slightly lower test scores for elementary and middle schoolers. And research using data from cognitive brain-training apps has also shown that performance on a cognitive task declines on high smoke days in adults. Over the long term, PM2.5 exposure from wildfires is linked to dementia risk.

Toxic cocktail

Researchers are still working to understand why wildfire smoke is so dangerous to the body. Smoke can contain a toxic stew of ingredients, especially when homes and buildings burn. Air testing after the 2025 Palisades fire in Los Angeles found high levels of silver and chromium-6 nanoparticles, the latter of which are carcinogenic.

Johnson and her team have found that smoke exposure leads to epigenetic changes associated with the immune system.‪‬ In other words, the person's DNA doesn't change, but the way it's translated into building proteins and cells in the immune system shifts. And epigenetic shifts can be passed along to the next generation. One shift is a decline in regulatory T cells, immune cells that help the body tolerate itself and harmless allergens. The immune changes probably play a role in why wildfire smoke exacerbates chronic diseases, Johnson said.

More smoke days can also affect health indirectly, by keeping people from going outdoors. In California, the heaviest smoke days actually have fewer emergency department visits overall, Burke said. On the smokiest days, when the air is noticeably hazy and may even smell like a campfire, emergency department visits for asthma-related reasons rise, but visits related to injuries or car accidents decline even more, probably because everyone is staying home. That may sound like a net benefit, but if forced quarantines happen repeatedly, they can worsen physical and mental health over time, making people more sedentary or less able to socialize.

"It's keeping people from doing things they would otherwise love to do," Burke said.

On the flip side, emergency department visits rise on days when the Air Quality Index indicates a moderate risk or a risk to sensitive groups.On these days, the air may not seem noticeably bad, and people may go out without realizing the amount of pollution they are inhaling until they start to feel ill.

"That's really consistent with this broader air pollution literature that, especially recently, has shown there is no safe exposure level to air pollution," Burke said.

With an increasingly wildfire-friendly climate in its future, Americans will be less healthy. There are ways to reduce the impact, however. Burke and his team have found that controlled burns put off less pollution than wildfires, while reducing the fuel load that turns wildland fires into smoke-churning infernos. An investment in managing fuels could ultimately be an investment in improving the country's health.

"It is within our power to correct that problem," Burke said.

This article is for informational purposes only and is not meant to offer medical advice.

Burning up — How can we adapt to a warming world?

Earth is getting hotter, and people across the world are starting to feel the effects. The past decade includes all 10 of the warmest years on record, and 2024 was the hottest year ever measured. As temperatures continue to rise and heat waves become more frequent and intense, that heat could severely impact people's health.

Extreme heat can affect the body in serious ways, such as dehydration and heat exhaustion, and it can lead to more severe conditions, like heatstroke or an increased strain on the heart and lungs.

How worried are you about these health effects as our planet heats up? Are rising temperatures changing the way you think about your health and fitness, daily activities, or the safety of your family and community? Answer our poll, and let us know what you think in the comments below.

Global ocean temperatures have reached a record high as El Niño injects extra heat into our already-warming world.

On Saturday (Aug. 22), the daily global average sea surface temperature (SST) was hotter than at any time since records began in 1979, according to the European Union's Copernicus Climate Change Service.

"This record is another clear signal of an ocean under growing stress," Samantha Burgess, the strategic lead for climate at Copernicus, said in a statement. "El Niño is adding heat to the system, but it is doing so on top of decades of human-driven warming. As ocean temperatures continue to rise, the risks to marine ecosystems and coastal communities also increase."

Human activities are driving global warming through the widespread and continued burning of fossil fuels, along with other activities that emit carbon dioxide (CO₂) and other greenhouse gases into the atmosphere. These gases trap heat by absorbing radiation.

Now, El Niño, officially underway as of June 11, is temporarily piling on additional warming. El Niño is the warm phase of a multiyear natural climate pattern, marked by unusually warm waters in the Pacific Ocean. The pattern typically boosts global temperatures and fuels disruptive weather, but this time, the conditions appear to be supercharged.

Researchers have warned that we're on the cusp of a likely historic super El Niño, with the potential to bring about a humanitarian crisis and possibly push an already-stressed climate ecosystem across a critical threshold.

A new record

Copernicus estimates global SST using satellites with temperature-measuring sensors. These showed that the SST hit 21.1 degrees Celsius (69.98 degrees Fahrenheit) Saturday, surpassing the previous high of 21.09 C (69.96 F), recorded in 2024 — the hottest overall year on record. The 2024 records were fueled by Earth's last El Niño, which was on the cusp of the "super" threshold, so not as extreme as what's forecast this time.

The latest SST is particularly eye-catching because it's unusual to have a record daily high so late in the year. The hottest daily temperatures are typically recorded in March and April, after the Southern Hemisphere's summer, Copernicus representatives wrote in the statement.

Copernicus representatives noted that the record is consistent with long-term warming and the emergence of an extreme El Niño event. The new data is also in line with what Copernicus has documented in recent months. Both June and July saw record-high average SSTs for their respective months. The rising temperatures highlight that our ocean is "under unprecedented strain," the statement noted.

A warming ocean means increased sea level rise and a higher risk of marine heat waves, according to Copernicus. Rising sea levels threaten coastal communities around the world. Meanwhile, the warmer waters harm coral reefs and other key marine ecosystems, which, in turn, affects food webs and the people who depend on these systems. Ocean warming also influences our weather systems and fuels global warming, which causes more ocean warming.

Super El Niño

El Niño conditions are still ramping up, and we won't know their full extent until later this year and next year. However, the National Oceanic and Atmospheric Administration's Climate Prediction Center forecasts a more than 90% likelihood of very strong El Niño conditions emerging in the fall and winter.

Last week, the U.K.'s Met Office announced that this year's El Niño will be the largest in living memory and likely the biggest since the 19th century.

"We should be clear that this is an unprecedented event," Adam Scaife, head of long-range forecasting at the Met Office, said in an Aug. 21 statement. "I have never seen an El Niño signal this intense in our forecasts."

A strong El Niño doesn't guarantee more severe weather or other impacts, but the risks are higher with a stronger event. The Met Office noted that the summer monsoon season in India, which is one of the regional weather patterns affected by El Niño, is already experiencing "well below" normal levels of rainfall.

In the U.S., El Niño often brings warmer winters to Northern states, while Southern states are more likely to experience stormier weather. However, every El Niño is unique.

Atlantic Ocean currents that regulate the global climate can adapt to rising temperatures, but the sheer pace of warming may cause the catastrophic collapse of these currents in the next few decades, a new study suggests.

Climate models show that when global temperatures rise slowly due to small year-over-year increases in atmospheric carbon dioxide (CO₂), evaporation and sea ice feedbacks maintain Atlantic currents' strength at temperatures exceeding 9 degrees Fahrenheit (5 degrees Celsius) of warming above preindustrial levels. By contrast, a rapid rise in global temperatures driven by yearly greenhouse gas emissions equal to or higher than today's may trigger a tipping point at just 3.6 F (2 C) of warming, researchers found.

"Under slow warming, the entire ocean, from the surface down to its deepest layers, has time to gradually reorganise and adapt to the changing conditions," study co-author Henk Dijkstra, a professor of dynamical oceanography at Utrecht University in the Netherlands, said in a statement. "Under faster warming, the ocean simply can't keep up."

The study investigated how different rates of climate change could affect the stability of the Atlantic Meridional Overturning Circulation (AMOC), a giant network of ocean currents that includes the Gulf Stream and carries heat to the Northern Hemisphere. An unstable AMOC could make the climate in some regions unrecognizable in the long term. Specifically, slower currents could unleash freezing weather in parts of Europe, exacerbate sea level rise along the U.S. East Coast, and trigger droughts around the equator, previous research has shown.

Previous research suggests that the AMOC is at its weakest in more than 1,000 years and might grind to a halt if global warming reaches a certain threshold, which scientists calculate could be around 7.2 F (4 C) above preindustrial levels. However, the new study hints that there is more to the story than a single number.

The AMOC is vulnerable to global warming because the circulation relies on surface waters in the North Atlantic sinking to form bottom currents that propel the system. Surface waters sink if they are denser — typically, colder and saltier — than the layers underneath. But rising heat in the North Atlantic is warming surface waters, and Arctic meltwater is reducing their salt concentration, so these essential bottom currents are forming less reliably than they were before.

Dijkstra and his colleagues conducted model experiments known as CO₂ ramp simulations, in which it is possible to simulate increases in atmospheric CO₂ levels over time. The researchers worked with state-of-the-art climate models to perform one slow CO₂ ramp, where CO₂ levels increased by 0.5 particles per million (ppm) per year, and two fast CO₂ ramps, where levels rose by 2.5 ppm and 5 ppm per year, respectively.

The slow CO₂ ramp simulated a much slower increase than the current rise in atmospheric CO₂, which is between 2.4 and 2.5 ppm per year.

"We deliberately looked at a scenario that is much slower than what we're experiencing today," study co-author Reyk Bӧrner, a physical oceanographer at Utrecht University, said in the statement. "That allowed us to isolate the effect of the warming rate alone, independent of how warm it eventually gets."

The results were published Aug. 13 in the journal Nature Climate Change. They suggest that the pace of warming, rather than the extra heat on its own, will determine whether the AMOC persists under climate change. In the slow CO₂ ramp experiment, the AMOC remained strong until up to 9.9 F (5.5 C) of warming. In the faster CO₂ ramps, the AMOC collapsed when warming reached 3.6 F.

Slow warming allows the AMOC to adapt to changing conditions through two mechanisms, the researchers found. First, gradually rising temperatures may cause more evaporation in the North Atlantic Ocean, removing fresh water and concentrating salt in the surface layers, which makes it easier for them to sink. Second, the North Atlantic would take up less Arctic meltwater in a warmer world, because most of the ice would have already melted. Smaller freshwater inputs would allow the system to regulate itself, but the key is that these changes must happen slowly, according to the study.

The research has implications for climate policy, as current targets and risk assessments are based on temperature thresholds. Policy agendas should also consider the rate of warming, the researchers argued in the statement.

Additionally, it's important to note that climate strategies involving a temporary overshoot — meaning we temporarily exceed a warming target before dialing temperatures down again with technologies such as carbon capture — can trigger irreversible tipping points in the AMOC and other Earth systems, study first author René van Westen, a physical oceanographer at Utrecht University, said in the statement.

"A tipping point inducing an AMOC collapse could already be triggered during such a temporary overshoot," van Westen said. "Once that happens, it can't simply be undone."

The new study shows that an AMOC collapse can be avoided if we slow the pace of global warming, but the exact limit is still unclear, Jenny Mecking, a research scientist at the National Oceanography Centre in the U.K. who was not involved in the study, told Live Science in an email.

"While this study alone is not enough to establish bounds on the rate of CO₂ change to prevent AMOC collapse, it highlights the importance of considering the rate of CO₂ increase alongside the level of global warming when investigating earth system responses to climate change," Mecking said.

Editor's note: This article was updated at 5:00 a.m. ET on Sept. 4 to clarify that the AMOC did not collapse in the slow CO₂ ramp experiment.

Despite being one of the remotest places on Earth, more than 100,000 people journey to Antarctica every year. And within the next few years, the number of tourists flocking to the continent each summer could reach 450,000. That's far fewer people than visit the Great Barrier Reef or Grand Canyon National Park, but Antarctic tourism comes with a colossal carbon footprint — and the frozen continent is a particularly vulnerable place.

A study published online July 8 in the journal Annals of Tourism Research reveals the impacts of Antarctic tourism from the perspectives of 25 former guides who, year after year, took visitors on cruise ships to some of the most remote locations on Earth. What these guides witnessed eventually made them quit, the study and an accompanying article in The Conversation show.

To find out exactly what drove the tour guides to leave their roles and whether such individual choices make a difference to Antarctica's overall condition, Live Science spoke with two of the study's authors: social anthropologist Zdenka Sokolickova and polar tourism researcher Liz Cooper, who both work at the University of Groningen in the Netherlands. Sokolickova and Cooper divided the interviews between them, speaking with 14 male guides and 11 female guides about their experiences. Together, those conversations shone a light on the reality of Antarctic cruises and the huge emotional toll of quitting a dream job.

Sascha Pare: How did you get the idea to interview former Antarctic tour guides?

Zdenka Sokolickova: We both started to work as postdocs on this project. We started with interviewing current Antarctic tour guides, because we wanted to know more about the industry, and about how they felt about the tourism development. The industry is booming; it's growing rapidly. And with more vessels, more tour operators and more people wanting to go and visit on a guided tour, there is also a bigger need for guides. So more people are accepted into the industry, and that comes with consequences; for example, the industry might need to lower the standards for qualifications, or there are safety risks coming with people who have less experience.

But we also heard that, at the same time, some tour guides are leaving the industry. We felt that it could be interesting to get to talk to these quitters, because they are likely critical and without vested interests in the industry, since they have deliberately left. We posted ads or calls for participants on closed Facebook groups, because we also know that the polar-guiding identity is quite strong and people tend to stay connected to the community, at least digitally or virtually. Within six days, we had 30 sign-ups. It went really fast, which kind of confirmed that there is a need within the community to voice some concerns.

Liz Cooper: We were also motivated to do this study because, generally speaking, tourism research usually incorporates the voices of people who are connected to the industry. It's not so common to see the voices of people who have removed themselves from the industry or refuse to engage with the tourism industry.

Antarctic tourism is, on a global level, a small industry. Around 120,000 people per year go to Antarctica [as of 2025/2026]. But the really interesting thing about Antarctic tourism is, of course, that this is the most remote place on Earth that you can visit as a tourist. This means also that it's the most carbon-intensive form of tourism that you can engage in on Earth. And, of course, it's an extremely fragile place, as well. So you have enormous global environmental impacts from the emissions from long-haul flights and from cruise ships, and then you have wildlife populations and a very fragile ecosystem there that is easily pitched out of balance. We also don't know very much about how tourism impacts the ecosystem in Antarctica either. We do know that it's bad, but we don't really know how bad. It's, in those terms, a risky practice, I would say.

SP: Did the former guides mention specific events that contributed to, or propelled, their decision to leave the industry?

ZS: In the "Mind the gaps" paper [the Annals of Tourism Research study published July 8], we speak about these tipping points that can be external or internal. External means that something in the outer world happens that makes you realize that you cannot continue like this any longer. We had quite strong accounts of that happening, like the cruise ship breaking the sea ice for the sake of the guests' experience so that they could land on the ice, for example, and observe wildlife or get to a place.

Many of these former Antarctic tour guides were polar tour guides, meaning that they also worked in the Arctic. For some of them, this decision happened through experiencing both Arctic and Antarctic tourism, so some of these tipping points happened in the Arctic. But we still felt it's relevant for our analysis, because polar tourism is connected, even though geographically, these are separated regions. We had a very strong account of something that happened in the Arctic, where the cruise ship hit a whale, even though the tour guide saw it and he was trying to communicate that. But there is a hierarchy in the chain of command that he couldn't break. He ran to the bridge and told off the captain, and then, after that incident, he quit.

There was a story about someone finding a little penguin chick in a boot hole. Normally, when you're trampling over snow in Antarctica, you're wearing these snowshoes — boots — and you're supposed to cover up the holes when you're leaving the place. But, obviously, not everyone does that. And so this person found a little chick that was struggling and couldn't climb up the boot hole. That also was a tipping point; it was the moment when that person realized, "I don't want to participate in this any longer, because if I weren't here, this little creature would have died."

LC: The most striking story that I remember was a participant who was talking about how the ship that they were working on sometimes would try and find a place on the sea ice to land, so that they can get the guests out walking on the sea ice. Not all companies do this, but some do. And then, they have to put the gangway down onto the ice so that people can walk directly out onto it. This piece of ice that they had chosen was apparently too thin, or too unstable or something. Where the gangway was connected to the ice, the ice kept breaking, so the ship kept having to move farther into this ice floe to get a secure holding.

On this piece of ice, the participant remembers that there were penguins with their chicks. And penguin chicks, when they're born, have fluffy down feathers, which are not waterproof, so they can't swim until these feathers have molted and they grow waterproof feathers. What this participant recalled was that, as the ship was moving in to get a hold on the ice, it broke this ice floe into many parts. Penguin chicks became isolated on smaller ice floes. Our participant remembered thinking, "That chick is not going to shed its down feather before this small ice floe melts." Essentially, our participant came to the conclusion that these chicks wouldn't make it.

SP: Emotionally, how easy was it for these guides to quit their jobs?

ZS: For some people, it was more difficult internally, emotionally, to make that decision, and for others, it was easier. We think that for those who were more environmentally concerned, it was, maybe a bit counterintuitively, more difficult to take that decision. Now we could speculate [about why]: Was that bond with the place stronger? Also, the emotions that were felt upon quitting were very mixed, I would say. It was a mixture of both feeling angry and feeling sad with feeling relieved — a "weight lifted," as someone put it.

But it definitely was, for many people, a struggle that took a long time in terms of years — from when you realize that your values actually cannot reconcile with what you engage in; through you realizing that there is a radical solution to that, and that you cannot muddle through or find alternative justifications; to deciding to quit; and still from there, to actually quitting. There is a path to walk. You can have decided, but you still can be doing the job, not feeling good about that.

SP: Has it been easy for these people to find new jobs that are more aligned with their values?

LC: We found that many of those who had quit primarily for environmental reasons and had gone through this particularly difficult decision-making process then made it their life objective, or aim, to do something good for the environment. We have a group of participants who actually moved into environmentally focused jobs. We have somebody who went on to set up an environmental NGO [nongovernmental organization]; we have somebody who went on to fight wildfires; various sustainability positions. It was, for some of the participants, not just a difficult and life-changing decision in the sense that it was hard to do but also because it changed the trajectory of their lives into becoming somebody who's more actively pro-environmental in the world.

SP: Did any of them regret their decision to quit?

ZS: Many of them did, until this day. Since it was a difficult decision to make and to act upon, it still triggers emotions, and people still think back. Yes, some of them do resent and regret and wish it was less environmentally harmful and wish they still could be having that dream job.

SP: Did any of the former guides reflect on the effectiveness of their decision, given that someone else could have potentially replaced them in their job the very next day?

LC: Yes. As I recall, many of our participants actually didn't really believe that their decision would make an impact in the overall environmental state of Antarctica. I don't agree with that. But there was a general feeling that, "OK, my individual choice isn't going to make a difference in the grand scheme of things" — also because, like you say, they expect that they will just be replaced, and probably replaced by somebody who's less environmentally concerned than them and might engage with Antarctic tourism practices in a less environmentally responsible way, which actually might make things worse. But in those cases, the decision to leave was basically mainly based on this internal conflict — this uneasiness that got so monumental that they couldn't live anymore doing this job.

What we do in the paper, now on a bit more of an academic level, is we argue that even though, yes, a single choice of an individual really makes an incremental change to the enormous problem of the climate crisis, these decisions [can be framed as] high-impact, pro-environmental behaviors. Because when you look at other individual behaviors that people are encouraged to do in their lives to reduce their carbon footprint, reduction of long-haul flying is one of the most impactful things you can do. And these guides were traveling several times per year — long-haul, back and forth — to South America, and then on cruise ships a lot, which are also carbon-intensive. Their reduction in their carbon footprint by making that choice has been massive. Even though they were feeling personally like maybe they weren't making that much of a difference, I do think that their choices have made a big difference.

SP: Was there anything in the interviews that surprised you?

ZS: Several of them said that they felt alone when they were going through this process of deciding and after [they quit]. They said that the fact that we asked for their opinions and their stories made them feel that they're actually part of a bigger community of people. It made me feel like we're actually responding to a need that exists in the field and that these people actually want to be heard. They want their concerns to be public, but they maybe had feared repercussions, or had even faced some repercussions, when they were being critical while still working in the industry.

SP: Did your interviews touch on other popular destinations where tourism may be doing more harm than good? I'm thinking, for example, of the Galápagos Islands and "last-chance" tourism in the Arctic.

ZS: They actually did. Some of the participants who quit in Antarctica still guide in the Arctic. So what we often heard was this juxtaposition, or comparing what it's like to be guiding in Antarctica and in the Arctic. The often-repeated argument, which I resonate with, is that in the Arctic, there are human communities. If it's their desire to choose this tourism path, tourism can be benefiting the human communities. In Antarctica, there are no permanent human settlements, and the nonhuman Indigenous inhabitants of Antarctica have no voice. Who asks the penguins, or the krill, or the orcas whether they want tourism there? If we could ask them, they would probably say no. Also, many of the guides live either in Northern Europe or North America, so the travel is shorter to the Arctic. It just makes more sense for them to stay in the business up there and quit in the South.

I actually did have one guide who also had experience from Bali, for example, and other regions in Southeast Asia. There, the reflections were actually around how destructive tourism can be in Indigenous regions, where people have no say and they don't benefit from tourism; they're just being "consumed" as a resource, as a sightseeing item, basically. That person quit cruise guiding overall, because they felt it was destructive.

LC: We also had a few people who, in their life after the decision, still worked in tourism but deliberately only in very local tourism. They, for example, set up a kayaking company in the local area where they lived, because they're still passionate about showing people beautiful places and connecting people with nature, but they simply couldn't reconcile taking people so far to create that connection with nature.

SP: Having done this work, what do you think people should consider when booking their next vacation?

LC: I would like people to properly research the impacts and consider, if the impact is significant, whether they really need to go or whether they can go in a low-impact way. For example, can you take the train instead of a plane? And if you have to take a plane, do you really have to go?

ZS: Several of the tour guides actually said they wished people asked themselves, "Why am I going to this place?" If it's just to tick off the seventh continent or the 75th country, or if it's just to show off on social media that you have a selfie from the Antarctic continent, then it's not worth this enormous carbon footprint.

If it's to feel a connection with nature and be away from the urban, hectic life, you definitely do not need to go to a place that is this remote. Perhaps you have a place where you can feel that connection with nature just a couple of kilometers away.

If it's this lifelong dream, I don't feel entitled to say, "You shouldn't go," because for those people, it really plays a big role in their lives. But the "bucket listers," as the guides often called them — the guides felt like these people actually don't belong, and maybe even they don't deserve this beauty and this breathtaking fragility, to be consumed and to be forgotten the next month, when another intercontinental holiday is happening.

This interview has been condensed and edited lightly for clarity.

Brazil is home to some of the world's largest aquifers, yet many of those groundwater stores — which provide 55% of the country's water — have shrunk so much over the past 25 years that they face irreversible damage. This groundwater depletion has been caused by drought, increased water evaporation due to climate change, and pumping for human consumption, new research suggests.

Most of the world's soybeans, sugarcane, oranges and coffee — as well as a big proportion of the world's cotton and corn — are grown in the areas with the most depleted aquifers, so the dwindling groundwater supply could have ripple effects for food markets around the world, including in the U.S.

The depleted aquifers may also collapse river systems that produce hydroelectric power for Brazil, forcing the country to turn to coal or biomass for electricity, experts told Live Science.

Groundwater declines probably won't lessen total agricultural production in the next 10 to 20 years. "The concern is what happens if these trends persist for several decades," study first author Augusto Getirana, a researcher in the Hydrological Sciences Laboratory at NASA's Goddard Space Flight Center, told Live Science in an email. "Brazil is one of the world's major breadbaskets, so its water security has consequences well beyond the country itself."

A clear geographical contrast

Brazil holds the world's largest renewable freshwater reserves by country, mostly thanks to the Amazon Basin and its rainforest ecosystem. However, compared with countries like the U.S. and India, which have thousands of groundwater measuring sites, Brazil's network of monitoring wells is extremely sparse. Therefore, for the study, Getirana and his colleagues trained artificial intelligence (AI) models to fill in the gaps in the data.

The researchers fed the models measurements from 398 monitoring wells, satellite data showing tiny shifts in gravity resulting from groundwater changes, and information about the geology and land cover in different areas, among other datasets. AI reconstructed monthly groundwater level changes between 2002 and 2023 across different aquifers in Brazil at a resolution of about 6 miles (10 kilometers), Getirana said.

"We then reconstructed groundwater levels to estimate aquifer recharge — how much water reaches and replenishes the groundwater system — throughout the country," he explained.

The results, which were published June 3 in the journal Science Advances, showed severe, persistent groundwater losses in parts of central, northeastern and southeastern Brazil — including portions of the São Francisco, Paraná, Southeast Atlantic and East Atlantic basins, which together cover 760,000 square miles (1.97 million square kilometers), or about 23%, of Brazil's land area.

Some of Brazil's most critical aquifers went years with no recharge. By contrast, the Amazon Basin and parts of southern Brazil showed either no change or localized groundwater gains attributable to shifts in rainfall and natural climate variations, Getirana said.

"There is no single trend for the entire country," he said. "We found a clear geographical contrast."

Climate change is the culprit

The study didn't attribute groundwater changes to specific pressures, but it is clear from the data that climate shifts played a major role in the observed patterns, Getirana said. Several of the sharpest declines in aquifers came after prolonged droughts and major climate events, such as an El Niño cycle between 2015 and 2016.

Due to patchy monitoring, it is difficult to untangle and quantify the impacts of agriculture, industry and households on groundwater levels. However, the results revealed a substantial overlap between groundwater losses and areas with intense irrigation, urban and industrial demands, mining, land conversion and high well density, Getirana said.

"The most scientifically defensible interpretation is therefore that climate creates the underlying water deficit, while extraction and land-use changes are probably amplifying its magnitude and duration in heavily used regions," he said.

Javier Tomasella, an environmental scientist and hydrologist at Brazil's National Institute for Space Research who was not involved in the study, agreed that the main cause of aquifer depletion in Brazil is climate change.

"Droughts are lasting longer and becoming more intense in Brazil, and this is affecting most of the country, particularly the central area and the Northeast of the country," Tomasella told Live Science. Harsher droughts reduce groundwater recharge and create a higher demand for water, meaning people extract more from aquifers during dry spells. "This is why the impact in irrigated areas is much higher," he said.

The findings suggest that if droughts intensify over the next few decades, major agricultural regions in Brazil could run out of water to grow certain crops. Groundwater provides a buffer when rainfall and surface water resources become unreliable, especially for agriculture and municipal water supply, Getirana said.

The worry isn't so much that aquifers will dry up completely but rather that water levels will drop so low that it will become too expensive to pump water compared with the returns from producing crops.

"This is the same type of progression already observed in intensively exploited aquifers such as the High Plains and [Central] Valley systems in the United States and aquifers in northern India and Bangladesh," Getirana said. "The water does not necessarily disappear overnight; it progressively becomes harder, less reliable and more expensive to access."

Supply-chain risks

Farmers will likely adapt to smaller water supplies by switching water-intensive crops, such as soybeans, to less-thirsty ones, such as corn and wheat, Tomasella said. Some may do this during the dry season to save water, as is already common in regions such as northern Paraná that have a "double-crop" system. But if current market conditions hold, farmers' decisions about what to grow will ultimately depend on how much money they can make from crops while covering extra irrigation costs, he said.

The total production of mostly rain-fed crops like soybeans and corn likely won't be affected any time soon, but the balance of these crops may change, Tomasella said. Conversely, the total production of irrigated crops such as coffee, sugarcane and oranges may decline, "but that depends on how droughts will evolve in the next two decades," he said.

Countries that rely on food imports from Brazil might experience supply disruptions, but the scale of these is hard to predict. The most-exposed country is probably China, because it imports roughly 80% of its soybeans from Brazil, Getirana said. The U.S. and Europe may see declines in imports of coffee, sugar and oranges, while Asia and the Middle East could be affected through cotton and corn, he added.

"The United States alone relies heavily on Brazil for coffee and orange-juice imports," Getirana said.

Assuming market conditions don't change, it's unlikely there will be a decrease in Brazilian beef production, because demand for beef is so high, Tomasella said. If anything, he said, beef production will increase, because Brazilian farmers haven't yet maximized the number of cattle per acre of pasture. However, cattle do emit huge amounts of methane, which is a powerful greenhouse gas, he added.

Ripple effects

The study has implications beyond agricultural impacts, because aquifers are connected to river systems. Groundwater declines could cause rivers to dry up, and this would hit Brazil's hydropower network, which supplies 60% of the country's electricity, Tomasella said.

The alternative to hydropower is burning fossil fuels and biomass to produce electricity, he said. This comes with huge carbon dioxide emissions, which would worsen climate change and further amplify Brazil's water issues.

In the short term, groundwater losses are more likely to affect drinking-water supplies in big Brazilian cities like Rio de Janeiro and São Paulo than they are to impact agriculture, Tomasella noted.

"If droughts intensify, it might reach a point where you have to make very tough decisions," he said. "The real question is, 'Is this the new normal?' If this is the new normal, then we are in very deep trouble."

Losing mature trees from a neighborhood may be a matter of life and death, a new study suggests.

The research, published Aug. 5 in the journal GeoHealth, tracked tree canopy cover and mortality across Chicago neighborhoods over 11 years. It found that it wasn't the number of trees in a neighborhood that was most strongly linked to residents' survival — it was whether the overall tree canopy was shrinking or growing from one year to the next.

Neighborhoods that kept losing tree cover tended to see death rates climb, especially in the hottest parts of the city, while neighborhoods that kept gaining canopy saw death rates fall.

The study can't say for certain that losing trees is what spiked death rates; it only shows the two trends moving together. But the finding adds to growing evidence that urban tree cover plays an outsized role in protecting people from extreme heat as the planet warms. Trees cool city blocks by shading pavement and buildings and releasing water vapor that lowers the surrounding air temperatures.

The new study's finding is less about discovering trees are good for people's health — scientists have suspected that for years — and more about how the researchers tracked it, said Vivek Shandas, a professor of urban studies and planning at Portland State University who wasn't involved in the work.

Much of the past work linking tree canopy to mortality relied on a single snapshot of a neighborhood's greenery, including a 2022 analysis of heat-related mortality tied to tree cover across dozens of U.S. cities. In this new study, researchers followed how canopy actually changed year to year, and it was that change rather than the raw number of trees that tracked with mortality.

The finding "reinforces what we've found in other cities," Shandas, who studies heat exposure and tree canopy loss in the U.S., told Live Science in an email. "Across 33 U.S. cities, nearly three-quarters were losing greenery, and the hottest neighborhoods were generally losing more — or gaining less — than cooler neighborhoods."

The effect size in the new study was notable: each year-over-year percentage-point increase in canopy was tied to roughly a 10% drop in mortality, with the greatest reductions in cardiovascular, respiratory and mental health-related deaths.

To reach their conclusion, the researchers combined annual satellite measurements of tree canopy for every Chicago census tract from 2011 through 2021 with more than 220,000 death records from state and city health departments. They built statistical models that controlled for factors like summer temperature, air pollution, income and residential segregation, which past studies show are tied to higher levels of mortality.

The team then grouped neighborhoods by their degree of canopy cover, and teased out how the heat and mortality data related to that metric. That helped them pinpoint where the effects of canopy loss or gain were strongest.

It's a rigorous design, Shandas said, but like any observational study it has limits: it can show canopy loss and mortality moving together, not prove that one causes the other. Plus, satellite measurements can miss newly planted trees and thus underestimate canopy cover, whereas finer-resolution tools could potentially pick up young, small-canopied trees that coarser satellite data misses.

It's still not entirely clear why tree cover seems to help, although the data suggest that the shade provided by trees isn't the whole story. That's because canopy loss was tied to higher death rates from a range of conditions, not only those strongly related to heat.

Geographically, the patterns highlighted in the study echoed Chicago's history of disinvestment. The South Side and West Side saw the sharpest canopy losses, hottest summers and highest mortality rates, despite sometimes starting with above-average tree cover. Lakefront neighborhoods stayed cooler by contrast, with lower mortality.

Study co-author Harrison Garcia, a Northwestern medical student, said the project began with a walking tour of sparsely treed Chicago blocks. "I noticed how much more exhausting it felt to walk through areas with little tree cover compared to nearby blocks lined with mature trees," he said in a statement.

The team modeled a hypothetical citywide canopy increase of 0.03% a year — roughly matching Chicago's current pace of planting 14,000 trees annually — and estimated it would prevent about 105 deaths per year, thanks to canopy growth.

Shandas said that figure is best read as a useful estimate of scale rather than a precise promise, since it comes from a statistical model rather than a count of trees planted and lives actually saved. He added that a newly planted tree doesn't deliver a mature tree's shade overnight, and prior research in Portland found planted trees were tied to greater reductions in human mortality as those trees aged.

This pattern, Shandas said, only reinforces the study's central point that protecting existing, mature trees may matter more than planting new ones.

Forecasters are warning that the ongoing El Niño is likely to become supercharged in the coming months and inject potentially unprecedented heat into our already warming world.

El Niño is the warm phase of a multiyear natural climate pattern, but models suggest this year's cycle will be exceptionally intense. Super El Niño conditions could contribute to temperature extremes until next year, but scientists are warning that it may also pose longer-term threats.

Jong-Seong Kug, a professor in the Department of Earth and Environmental Sciences at Seoul National University in South Korea, uses observational data and artificial intelligence to model El Niño events.

Kug has found that super El Niño events can drive sudden, dramatic and even irreversible climate regime shifts. Live Science spoke with Kug to learn more about climate regime shifts and the long-term threats posed by this year's ongoing El Niño.

Patrick Pester: Last year, you published a study that found super El Niño events significantly increase the likelihood of potentially irreversible climate regime shifts. With a super El Niño now looking very likely, how concerned should we be?

Jong-Seong Kug: We should be concerned but not alarmist, because our study does not suggest that every super El Niño inevitably causes a climate regime shift. Rather, a super El Niño can push an already-stressed climate ecosystem across a critical threshold. If a system is near a critical threshold, then strong forcing can induce irreversible change.

Current forecasts indicate a very strong El Niño is increasingly likely later this year. We need to watch vulnerable regions closely, particularly those that are already experiencing severe warming, drying, ecosystem degradation or ocean stress.

PP: What kind of climate regime shift do you fear most?

J-S K: I am particularly concerned about the persistent shift in major ecosystems, such as the Amazon rainforest moving toward a much drier and degraded state. You know, a long time ago the Amazon was a savannah area, so we are now approaching this kind of tipping point. Also, in the Amazon, this drying can weaken [or] even reverse the forest's role as a carbon sink.

The Amazon is a carbon sink, but imagine it becomes drier and drier, and there's some die-back of the forest. Now, [carbon] sink becomes source. This could amplify global warming long after an El Niño event.

PP: Is there anything we can do to mitigate the threat of extreme climate and weather events in the coming months?

J-S K: We cannot stop El Niño. But we can greatly reduce its human impact or ecosystem impact. Governments should use precision forecasts to strengthen our heat health plan, water and food management and flood and wildfire preparedness. In the long term, a rapid reduction in greenhouse gas emissions remains essential because every additional degree of warming increases this possibility that an extreme natural event will trigger lasting damage.

PP: Do you think a reduction in greenhouse gas emissions is likely, given where we are now?

J-S K: I don't think so. It's very difficult.

PP: So, where does that leave us?

J-S K: I don't know. There are some additional techniques we may use at a critical point. Have you heard about climate engineering? Like stratospheric aerosol injection [reflecting solar radiation back into space]. If we cannot do anything, then we have to choose that kind of technology. I don't want this kind of situation, but maybe in the near future we have to decide.

There are two kinds of climate engineering. One is carbon mitigation, just direct air capture [taking carbon out of the atmosphere]. That is a safe way. The other is solar energy management. We can deflect more solar energy from the surface.

So, the easiest way is just to inject an aerosol into the stratosphere; then this aerosol reflects solar radiation, and then global temperatures will decrease. It's like a volcano: After a big eruption of a volcano, the global mean temperature drops by about 0.6 degrees [Celsius, or 1 degree Fahrenheit] because there is volcano aerosol [in the atmosphere]. Instead of volcano aerosol, artificially we can inject aerosol into the stratosphere. Then global temperature can easily decrease.

But there are many side effects. Some we already know, but some we don't know. Like climate inequality. If we artificially decrease temperatures, then some countries will have a drought or a flood. And then how will we compensate?

Obviously, if you want some kind of climate mitigation, we need a kind of consensus across the countries.

PP: Is there anything else you'd like to add that we haven't covered?

J-S K: This year, super El Niño is developing in an already exceptionally warm climate. We are already seeing widespread heat waves this year, so we cannot attribute every individual event to this El Niño. But El Niño will intensify toward the end of this year, so it is likely to further increase the risk of extreme events in many regions, so we need to prepare.

Editor's note: This interview has been edited and condensed for clarity.

Climate change's impacts are being felt everywhere, from health and food security to extreme weather, sea level rise and collapsing ecosystems. World leaders have been slow to adapt to the warnings, despite an ever-growing body of evidence showing the compounding risks of greenhouse gas emissions.

But despite fossil fuels remaining the world's primary source of energy and emissions continuing to rise, there are changes afoot.

In his book "Despite it All" (Granta, 2026), author and journalist Fred Pearce looks at the shifts that have taken place over the last 40 years, highlighting how far humanity has come in the green transition. He believes this progress gives us reason to hope that we can eventually overcome the challenges we face today.

Pearce spoke with Live Science about his book, which has been shortlisted for the 2026 Royal Society Trivedi Science Book Prize.

Hannah Osborne: There are a lot of positive environmental stories throughout the book, including those that aren't necessarily being told. Do you think that there is a growing appetite for positive climate news now? And will it help us?

Fred Pearce: I detect a kind of desire to be told something other than it's all hopeless and there's nothing we can do. Some people are therefore saying, "Well, what can I do?" And they're very sort of personal stories about how they can contribute. But also people who think more, if you like, strategically: What can the world do, what can governments do, what, how can we influence that?

I try not to write what I think people want to read. I try to write what I want to say. And it seems to me that we do so many things so badly, whether it's managing our resources or water or handling forests or the climate, or pollution or whatever. We do things so badly that there is a great deal of scope for doing things a lot better. So, we need optimists and we need pessimists. We need pessimists to point out the problems. We need optimists to come up with some solutions or suggest where [there are] half open doors that we can push open.

I wrote this book in that kind of spirit to say "Look, yes, things are bad, yes, I'm not denying that they're bad, but there's an awful lot that we can do about it and in some cases are doing about it." That then divides into whether we're talking about human activity, our technical solutions to climate change. Tech fixes are good, not bad, which is something that can be a hard sell in the environment community sometimes, so I want to stress that.

I went to the Earth Summit 30 years ago where they agreed [upon] the original climate change convention. Back then they said we [need to] prevent dangerous climate change, but they really didn't know much about how to do it. Wind turbines were just, you know, a few masts on a hill in California. Nobody was dealing much in solar power because it was just so expensive. It had been developed for powering satellites and electric cars. Nobody was talking about [it].

We have made quite a lot of progress and it's not fast enough and CO₂ emissions are stable, they're not going down. We need to do a hell of a lot more and we may have passed climate tipping points. I'm not denying any of that, but rather than throwing up our hands or saying it's hopeless, let's get on with the tech, let's also recognize that nature is very good at recovering. You destroy a forest, a rainforest, it doesn't mean that it's destroyed forever. It will, given the chance, come back if we give it room. So let's give forests room to recover.

In large parts of the world it's already happening — in Europe, even in North America. Agricultural land is being abandoned, and when it's abandoned nature comes back and not necessarily in the sort of ways that we might think. But nature does come back, stuff regrows. We can see how evolution is being kickstarted, if you like, by the chaos that we're creating. That's not to say we shouldn't stop creating the chaos, but we can see how nature recovers.

These are things that we can recognize and respond to; giving nature room to recover, rewilding projects, therefore I'm all in favor of [them]. We're not rewilding where we're trying to garden nature to get back to some sort of perfected past, a pristine system where we thought that everything was great — pre-industrial revolution or before Europeans arrived in North America or whatever it might be. But, we can give nature room to evolve and adapt and change. We can see that nature's doing that all the time, with or without climate change and with or without humans. Nature is constantly, if you like, remaking itself.

I'm not saying nature always comes back in ways that we approve of. Let's recognize the distinction between our sort of slightly romanticized idea of what nature should be and what nature actually is.

HO: You talk about rewilding and letting nature take its course, but how do humans fit in with this? Can we adapt our own perceptions of what nature is allowed and what's not?

FP: I think we can probably forget about what's allowed and what's not. Nature will do what it wants to do. We pride ourselves on our ability to garden nature in a way, or manage ecosystems. We're not really very good at it. Nature will very often take over and do what it wants to do.

Some of the world's biggest rewilding projects have gone quite badly wrong because we haven't quite thought it through. The one I'm thinking of really is the large project in the Netherlands where they're trying to sort of recreate ancient European ecosystems and they ended up with mass deaths of animals because their conception of the ecosystem didn't quite figure out. They then largely abandoned the project because they didn't like to see large numbers of animals dying.

A hardline rewilder would say let nature take its course. I see the case for that, and often I would support that, but we have our own sensibilities and our own concerns and we are living in a world where we are very much in charge of what's going on. So while I'm in favor of standing back and letting nature take its course, we have our own sensibilities, and it's not wrong for us to want to intervene sometimes.

HO: There's a chapter on human population and fertility rates, and how this is very much a climate change story as well. We're now seeing a lot of the rhetoric around this, and rights being stripped back and taken away. What's it like for you, having seen the changes from the UN International Conference on Population in Mexico in the 80s, to Cairo in the 90s to now?

FP: It's an extraordinary story. I've been working on these issues for 40 years now so I've seen a number of changes. Some of the changes I've seen are how technical fixes somehow became a reality when they seemed very distant a while ago.

But our perceptions change too on many things. We are, in many ways, more attuned to environmental issues now than we were 30 or 40 years ago. One of the big changes that I've seen is the notion of the population bomb, which for much of the 20th century was seen as the number one issue. People would say, "Well, there's no point in fixing the climate, there's no point in reducing our pollution because there are more and more people on the planet, and we're kind of doomed for that reason."

Well, it hasn't [happened]. When I went to my first international conference, which was the UN Population Conference in Mexico City in 1984, that was all the rage. They gave the UN Population prize to the mastermind of China's one child policy, which — in terms of human rights and what I would regard as acceptable human behavior — was dreadful. But such was the concern about population issues that they wanted to give a prize to the operator of that program.

A lot has changed. A feminist agenda, if I could put it that way, and I would say that approvingly, has taken over in reproductive politics. I saw it at a UN population conference in Cairo in 1994, 10 years after the Mexico event, that we need to assert reproductive rights. Many environmentalists said that's a cop out. It was all "it's feminist perspective, but it's dooming us."

Well, it didn't, because what we found was that by and large, women wanted to have smaller families because their children got to grow up. Medical improvements meant that you didn't have to have four or five children to secure the next generation. Two would usually do, sometimes you just wanted one. Women wanted to have lives outside the home. The population people seemed to be a bit surprised by that.

The environmental agenda was a very male-dominated one for a long time. So that came as a bit of a surprise, but the net result is that we've halved our fertility rates. They're more or less down to replacement levels [of reproduction] now globally.

I'm not just talking about Europe or North America. I'm talking about almost everywhere except Africa, and African levels have come down. Sometimes they're coming down to super low levels, so that people are now talking about not having enough babies and how we can encourage people to have babies. There are parts of the world where we're down to one child per woman and even a bit less.

My argument is that we need to carry on. Not take a sort of Elon Musk approach [or] send the women back to the home and [do] reproduction and that's what their job is. We need to complete the feminist revolution so that women have more rights, can make better choices, and indeed couples can make more and better choices about the family size that they want. We can arrange things so that it is possible to have children and a career, or make it easier to do that, and at that point probably reproduction levels will come back up.

What I'm really saying is that the agenda is now vastly different from what it was as recently as the 1980s and, and into the 1990s. The population bomb is being defused, to put it simply, there's a residual momentum effect which means that our numbers will carry on going up a bit. Sure, that creates strains on the planet, but we're not now talking about double the world population every 30 years, which is what was being talked about back in the mid 20th century. It's tailing off.

We now have, if you like, a consumption bomb more than a population bomb. The global issue is consumption in the rich world, and that's what's stressing the planet now — not too many babies in poor parts of the world.

HO: Inequality between the super rich and people in developing countries is becoming more and more stark. How do we bridge the gap to make sure there's a reasonable living standard for regular people without a huge cost to the environment?

FP: The truth is, and the numbers have been done by a number of different people, a reasonable standard of living for everybody on the planet is perfectly feasible without destroying the planet.

We need to do some things better, we need to have better technology, but for me, right up there with climate change is an issue of global inequality. When I was young, it was taken [that] inequalities were diminishing and it was taken almost as read that they would carry on diminishing, and a lot of aid policies were directed towards that. That's kind of disappeared since the sort of Reaganomics of the 1980s, all the changes in the finance system and perhaps the fall of the Berlin Wall, which meant that the sort of socialist or, or equality-based agendas collapsed politically.

We're now finding increased inequality, and that, it seems to me, is a threat to the lives of millions and billions of humans, but also to global stability and our ability perhaps to manage.

Serious global issues like climate change and many others are all undermined by the political stresses and economic stresses created by rising inequality. I see them going together.

It's also clear that it's important to level up, but also level down from the obscene riches that we see among a small number of individuals, who seem to be accumulating a greater share of the world's wealth, whether we're talking about dollars or natural resources.

HO: You have a whole chapter on renewables and how they're outpacing fossil fuels. They're the cheaper alternative. How do you see the political opposition to clean energy panning out over the next five to 10 years?

FP: It's fizzling out. It's a weird political backlash and yes, any big social trend or economic trend, they all have backlashes and it feels to me like this is it. What we see in the real world is that the U.S. — not just the U.S., but principally the U.S. — are in a state of near denial about climate and they're wanting to go back to fossil fuels.

In the rest of the world, if you look at it in terms of geopolitics of [the] U.S. versus China, then the U.S. is pushing this rather old agenda of fossil fuels, and China is absolutely going to reap the benefits in many, many ways in its drive towards renewables. China has been a really bad story in the past with its coal burning — and it's still building a few coal-fired power stations. But the really big story is how China has been principally responsible for bringing down the costs of renewable energy, particularly solar power.

You can now go to the most remote corners of rural Africa and you find people putting up their solar panels to recharge car batteries so that they can run their lights in the evening or whatever it is. And then you've got megacities operating using increasing amounts of solar power. India is getting on the bandwagon as well. It's got the fastest growing solar energy economy in the world.

In the real world, renewable [energy] is mostly cheaper than fossil fuels. It is also quicker to install, you don't have to build a huge power station, you can do it in bits and pieces, bolt bits on.

Yes, there are grid issues and they need to be addressed, and there are limits on operating. There are challenges, but renewables are just growing so fast, and it is growing so fast because it is so cheap.

And it's become so cheap, to put it very simply, because the Chinese 20 or 30 years ago decided this is what's going to happen. While everybody else was sort of talking about it and fussing about it and doing it in research labs, the Chinese kind of got to grips with it. I remember back in the 1990s talking about people who were going into China and coming back and telling me stories about how the Chinese are really serious about renewable energy. To be honest, I didn't quite believe them, but they were right, and 30 years on, the world is living with the benefits. That's true whether you're talking about Europe or rural Africa or big cities in Asia or wherever. It's coming.

There will be different solutions in different places and there are undoubtedly things that are harder to do than, you know, running our national grids on renewable energy, which is becoming really quite easy and something that everybody wants to do. The cement industries, fertilizers perhaps, some of these industries will take some more technical innovation. But it's happening, these are technical fixes that are working in the real world. Will we do it in time? Well, we're a bit late on the case, but we are on the case.

HO: We're now seeing a massive rise in AI data centers as well. Is this bad tech, shall we say?

FP: It's a serious issue. Partly because they're growing so fast — they can't just plug into the grid because the grid really can't deliver, so these companies are developing their own energy systems. Even in the U.S. they are very often renewable systems because they're cheaper. If you've got a data center out in Texas, then you're going to use wind power or solar power because it's cheaper and you're in control of it.

I suppose we reach a point where [we have to decide], do we want to reduce our use of energy or have almost as much energy as we want, but just green it and green it very fast. It is true that if all the renewable investment is going into electricity for data centers, that leaves less investment for other sectors of the economy, so I'm sure there are trade-offs, and I'm not saying that we should embrace data centers. But they can be a driving force for adoption of different forms of energy, renewable energy, and for perhaps changes in the grid systems as well.

I think we can have both. I think we need to have both because we're probably not going to stop the data engines, so we've got to find ways of greening them. There are issues and there are challenges ahead, and I don't want to diminish any of those, but you know, let's, let's be hopeful.

The title of the book uses the word hopeful rather than optimist because I don't want to sound Panglossian, but I do want to inject some hope.

HO: When you started writing the book, what did you hope people would take from it, and did that change after you'd finished?

FP: Well it kind of evolved. It began as an idea to sort of [be a] retrospective of my reporting, and then the publisher said, "Well, the story changes rather a lot along the way, so rather than just showcasing your reporting over 40 years, why don't you showcase the change, and be hopeful in the context of how things have changed over the last 40 years?"

That was [the] kind of starting point, and we sharpened up on it, as we went along it did become "Despite It All" and you know, the title is important, and not diminishing the "All." There's a lot of bad stuff out there, but despite it all we can have hope and we can find, develop and demand solutions.

HO: Did you find anything during the process of writing the book that surprised you?

FP: As I say, it started as a sort of retrospective project and going through it, [there were places I went years ago] and it did look bad, then I checked up on what had happened over the intervening years and suddenly things looked a lot better.

I went to Alaska and saw how the conflicts over managing caribou herds and the huge migrations that go on and it felt like that was doomed. I was talking to people who were hunting the animals and they were trying to protect them because they wanted to hunt them, therefore they wanted them still to be there, which is kind of counterintuitive for many environmentalists, but you know, they were the best defenders of the caribou because they ate them.

But it felt doomed, and yet 20 years later I checked out the numbers and the population of that herd has doubled and tripled. So stuff does happen and I suppose my surprise was how much good change I found when I looked into it further. Maybe that's me being better at looking for good news stories. I've written quite a lot of "bad news" books over the years and done a lot of "bad news" journalism over the years, so I certainly don't discount that. But if you step back and you think, well did good stuff happen? Well, yeah, sometimes it did.

The bison herds are coming back on the plains of parts of North America, if you go to Montana. The ranches are disappearing and big areas are being set aside for bison, and I've been seeing how farmland in parts of southern and eastern Europe has been abandoned over the years. It's not necessarily good news that we're abandoning farmland, but again, the way that nature comes back and woodlands are growing, there are more forests in Europe than there have been for probably centuries.

There's a lot of bad stuff to say. But it does seem to me that we have to not just cling onto, but embrace good stuff and try [to] take it forward.

Something I really hadn't thought about till I went back was what were the big issues in the 1980s, 1970s when I started out. Well, all our industrial rivers in Britain were filthy. Now our industrial rivers are relatively clean. It's our agricultural rivers that are filthy, so, I mean, there's been a big change there.

Nobody has to talk much about the ozone layer now. That was the number one issue in the mid 1980s, and the absolutely terrifying prospect if we hadn't fixed that. But it's been fixed.

We banned the chemicals that were doing it.

Remember acid rain, lead in petrol. They were hot topics, headline news, part of the rise of the environmental agenda in the 1980s — and they're the ones that we don't have to talk about anymore.

Now we're talking about climate change. I think there are other things coming up. I think the issue of nitrogen pollution is a fast growing one, and we need technical solutions to that.

The green revolution of crops, the high-yielding crops, which got us out of a cycle of ever worsening hunger and famines in the mid 20 century. That was a solution which created new problems. Those crops grew very well, but they required large amounts of inputs, including water, and water is now a growing issue — finding enough irrigation water, but also fertilizer and other agrichemicals. We're now reaping some of the bad effects of that, and we need to solve that. Scientists I know are working on, if you like, high-yielding crops that don't require so much fertilizer and don't require so much water.

It's doable because as I think I said at the start, we do a lot of things really very badly, but that does give us a lot of scope to do things a lot better, so let's get on with it.

This interview has been condensed and edited lightly for clarity.

Biodiversity loss has been recognized as a threat to global stability for decades. The decline in overall diversity of species on our planet, either through extinction or a fall in abundance, can culminate in ecosystem collapse.

But in this excerpt from "Despite it All" (Granta, 2026), author and journalist Fred Pearce looks at the remarkable resilience of nature. If we can put aside our notions of what should and shouldn't be in a given environment and leave nature to adapt and thrive, we may begin to see the gains needed to support a healthy biosphere.

"Despite it All" has been shortlisted for the 2026 Royal Society Trivedi Science Book Prize.

If we are serious about rewilding, then we need to accept that it will take its own course.

Often invasive species are just the first stage of an ecological resurgence. They are the first movers, and their infestations are short-lived. In time, diversity usually returns — even if it's not always the same diversity as was there before. We should recognize that. We need to be as adaptable as nature itself, and jettison our more romantic notions about biodiversity and pristine environments.

So do many oldschool ecologists, says Chris Thomas, an ecologist at the University of York. They too often simply ignore any bits of nature that do not meet their expectations of what "should" be present. "The establishment of successful species in new locations is commonly interpreted as further evidence that the Earth's system is departing from a more desirable state," he told me.

So when biodiversity assessments are conducted, "alien" species lurking in the undergrowth are simply not counted. As outsiders, they are deemed not to belong to the ecosystem they inhabit. Thomas says that, in Britain, official records show biodiversity in decline, even though, if we add all losses and all gains together, "it is unequivocally true that the total number of species in Britain is increasing."

Most of the gains — the weeds, pests and alien species — are kept off the biodiversity books. This amounts to an ecological catch-22. Biodiversity can only ever decrease, as new species are seen as inimical to the local environment, and each year millions of pounds, dollars and euros are being spent to eliminate them.

Of course, it sometimes makes practical sense to eradicate invaders. I don't say we shouldn't try to keep out pests that cause short-term ecological mayhem and economic damage. But if we choose to get rid of new species, we can't then hold up our hands in horror at declining biodiversity. And besides, ecologically as much as socially, migrants can stir things up to good effect. They interact with other species — eating or being eaten, pollinating, and rotting after death to nurture new organisms.

We should embrace novel ecosystems that contain both what we regard as native species and the feral, opportunistic interlopers that find their new environment congenial. In his book about weeds, British naturalist Richard Mabey celebrated what he called these "outlaw plants" and showed how they have had a hand in shaping not only our landscape but our civilization, becoming crops, medicines and sources of beauty and creative inspiration.

It is easy to be nostalgic about past ecosystems as a golden age. But what we imagine to be the perfect ecological state — a supposedly natural order of things that often gets called "the balance of nature" — was mostly itself a passing phase. Nature is always moving on. And more often than we realize, humans have had a hand in what we now like to regard as natural.

Environmental scientist Erle Ellis, who runs the Anthroecology Lab of the University of Maryland, argues persuasively that most of the planet has been heavily influenced by human activity for thousands of years, including places such as the Amazon that we often think of as untouched. We have, in effect, long lived on a "used planet," and humans and nature have not historically been at odds. The most biodiverse places are often those where people have lived the longest. By constantly tending the land, past civilizations created ever-changing mosaics of habitats where more species thrived than in places with less human interference.

So, we should be careful not to let our reverence for the pristine blind us to the environmental potential of today's wastelands, backwoods, abandoned fields, scrublands and no-go areas. In a Good Anthropocene we are likely to need more of them.

There is a final reason for believing that nature is equipped for recovery from almost anything we can throw at it. The apparent chaos of the Anthropocene is turbocharging evolution itself. Every perturbation of our environment creates an opportunity for existing species to adapt or for new ones to evolve, says Chris Thomas.

I first met Thomas in 2004, when he had just published an influential paper warning that climate change could wipe out a quarter of the world's species this century. He called it "terrifying." It was headline news. Two decades later, he has not changed that forecast, but he has added an important rider. Despite the coming extinction holocaust, he told me, "the Anthropocene could raise biological diversity."

His research is showing that evolution in the twenty-first century is speeding up to fill the gaps left by the extinctions — delivering new and better-adapted species. "The seeds of recovery are already visible," he told me. "Genes are jumping around. New species are beginning to emerge." Rob Dunn, an ecologist at North Carolina State University, agrees. In his book "A Natural History of the Future," he says that this evolutionary spurt is happening fastest in urban landscapes, where species are adapting to city life with almost as much alacrity as newly arrived humans.

This urban ecological renaissance resembles the story of the finches on the Galápagos archipelago, which Charles Darwin observed to have evolved different beaks to match the food on the different islands. In modern cities, house mice have evolved to produce saliva with a chemical make-up better able to digest the carbohydrates available in urban food; cockroaches and bedbugs have developed resistance to pesticides and even learned to avoid sugar-impregnated bait; London's pigeons have learned to commute on the Underground. We have clothes moths and carpet beetles.

Such natural innovations may not always be cuddly, but they do show that nature is on the prowl in the Anthropocene. So where is biodiversity headed? It is undeniable that most species of plants and animals are currently in numerical decline in a human-centric world.

This global disturbance is favouring some generalists — so-called superspecies — that can occupy a wide range of habitats, displacing local, rare and specialist species. Locally, however, biodiversity has sometimes increased substantially, especially in the rich kaleidoscopes of gardens, parks, toxic brownfield sites, roadside verges and so on that humanity has helped create.

Such places may become crucibles for a biodiversity rebound. Understanding this reality should change how we do conservation. We should not abandon nature to its fate. Some of our favourite species will pass into history unless we act to save them, and I'd vote for action any day. But it does mean embracing rather than rejecting the processes of change. Change in the Anthropocene is good. We should be grateful that nature is finding a way.

This is an extract from Despite it All by Fred Pearce, published by Granta.

While millions around the world grappled with extreme heat this month, a research station in Antarctica recorded Earth's coldest temperature since 2012.

The high-altitude research station, named Concordia, logged a low of minus 119.4 degrees Fahrenheit (minus 84.1 degrees Celsius) on July 18, according to data from the station.

Concordia is located in the interior of the Antarctic continent, which is currently in the dead of winter with no sunlight. Temperatures at the station regularly fall below minus 112 F (minus 80 C) this time of year ‪—‬ so the new reading isn't unprecedented, but it's still significant.

"Even here, where extreme cold is expected, temperatures below minus 84 C are remarkable and highlight how variable Antarctic weather can still be," Gabriele Carugati, the station leader at Concordia for Italy's National Antarctic Research Program (PNRA), told Live Science over a video call from the station.

The French Polar Institute Paul-Émile Victor, which runs Concordia with the PNRA, sent Live Science raw data from July 18, which showed the temperature dropping to minus 84.1 C twice, at 6:25 a.m. and 6:34 a.m. local time.

The extreme chill at Concordia stands in sharp contrast to the sweltering heat that many countries are currently experiencing. North America and Europe have been battling heat waves this summer, with Western Europe recording the hottest June on record. Meanwhile, wildfires are raging in Canada, the U.S., France, Spain and other countries.

Globally, average temperatures are going up as humans pump more heat-trapping greenhouse gases into the atmosphere. However, Earth's weather systems are complex, and climate change doesn't mean that everywhere gets hotter all of the time.

"Climate change describes the long-term global trends, while individual weather events can still [bring] exceptional cold," Carugati said. "Antarctica is influenced by complex atmospheric processes, so an extreme low temperature at one location does not contradict the broader picture of global warming."

"Astronauts of ice"

Concordia is considered the most remote and extreme research station in the world. Built on top of a 10,800-foot-thick (3,300 meters) ice cap, the station is used for a variety of purposes, including seismic observations, astronomy and the modeling of Earth's past climates, according to the French Polar Institute Paul-Émile Victor.

"Concordia is a special place because it sits at over 3,200 meters [10,500 feet] above sea level on the Antarctic Plateau, and more than 1,000 kilometers [600 miles] from the coast," Carugati said. "During winter, there is no sunlight for months, the atmosphere is extremely dry and stable, and under clear skies, heat continuously escapes to space because there are no clouds, allowing temperatures to fall to extraordinary levels."

Concordia's environment is so harsh and isolated that the station is also used to improve our understanding of the physical, mental and social challenges astronauts experience in space. Carugati noted that the only person at the station who is not researching the environment is a European Space Agency biomedical doctor, who is studying the researchers who work there, nicknamed "astronauts of ice."

Planes can't fly to Concordia once winter sets in, and it's around 370 miles (600 kilometers) from the nearest research station. That technically makes crews more isolated than astronauts on the International Space Station, which orbits about 250 miles (400 km) above Earth, according to the European Space Agency.

What is the coldest temperature ever recorded?

The coldest temperature ever recorded at Concordia was minus 120.5 F (minus 84.7 C), logged in the winter of 2010, according to the Italian Antarctic Meteo-Climatological Observatory. However, another high-altitude research station in East Antarctica has the all-time record for the coldest temperature ever recorded on Earth. Russia's Vostok weather station, the nearest station to Concordia, recorded a temp of minus 128.6 F (minus 89.2 C) in July 1983, according to the World Meteorological Organization.

Satellite data suggests that temperatures can drop as low as minus 144 F (98 C) in East Antarctica, according to a 2018 study published in the journal Geophysical Research Letters. However, even though Antarctica is the coldest and driest continent, it's not immune to global warming.

Major glaciers and the ice sheet they support are at risk in West Antarctica, with the Antarctic Peninsula — which extends out of the western side of the continent — experiencing the most rapid warming. A study published in February in the journal Frontiers in Environmental Science found that decisions made on greenhouse gas emissions today will determine how much the peninsula will change in the coming centuries, with sea ice, ice shelves and glaciers, along with the penguins that live on them, at risk of disappearing.

Concordia sits on the largest ice sheet on Earth. This sheet in East Antarctica is more stable than the smaller sheet of West Antarctica, but it is still vulnerable to rising temperatures. An unprecedented Antarctic winter heat wave in March 2024 saw temperatures near Concordia rise to a record high of 15.1 F (minus 9.4 C) ‪—‬ about 32 F (18 C) warmer than the previous March maximum. This East Antarctic heat wave was amplified by global warming, according to a study published in April in the journal npj Climate and Atmospheric Science.

Earth recently entered an El Niño, the warm phase of a multiyear natural climate pattern, which could bring unprecedented temperature extremes to an already-warming world. Carbon Brief, a U.K. based outlet that reports on climate news and policy, has predicted that 2026 is likely to be the second-warmest year on record, behind 2024, with the intensifying El Niño increasing the likelihood that 2027 will be the warmest year ever recorded.

For now, at Concordia, the researchers are continuing their work in the blistering cold of Antarctica's winter. Carugati noted that the latest extreme-temperature data will inform forecasts and long-term climate monitoring.

"Extreme observations like this help scientists better understand atmospheric processes and improve the climate models," he said.

Runoff from Greenland's rapidly melting ice sheet could severely disrupt currents in the Atlantic Ocean that regulate the global climate, researchers say. But the fresh water won't trigger the complete and irreversible collapse of the circulation that some research predicts, a new study suggests.

By 2100, Greenland meltwater could cause a reduction in the strength of the Atlantic Meridional Overturning Circulation (AMOC) equivalent to an additional 10% to 20% on top of the weakening that many scientists already expect for this huge system of currents, researchers found.

Previous research suggests the AMOC, which moves heat from the tropics to the Northern Hemisphere and cold water back south toward Antarctica, is at its weakest in more than 1,000 years due to Arctic ice melt and soaring ocean temperatures. Models indicate that the circulation will continue to weaken for decades to come, potentially unleashing freezing weather in Northwest Europe, additional sea-level rise along the U.S. East Coast and droughts around the equator.

The new study revealed that by 2300, Greenland's ice sheet could cause a whopping 40% of AMOC weakening on top of the declines projected by some climate models if we continue to cook the planet. The results highlight the effects on the AMOC of a growing freshwater pulse from Greenland that most climate models currently don't take into account, the authors said.

"By the year 2100, yes, we have something, but the greatest fraction is what we add later," study co-author Jost von Hardenberg, a professor in the Department of Environment, Land and Infrastructure Engineering at the Polytechnic University of Turin in Italy, told Live Science.

Meltwater from the Arctic and Greenland slows the AMOC by preventing the formation of deep currents in the North Atlantic that drive the circulation south toward Antarctica. Deep currents form when masses of cold, salty water sink to the seabed, but inputs of fresh water and rising water temperatures are blocking this step by diluting and warming surface waters.

While Arctic meltwater is commonly integrated into climate simulations, researchers have been slower to include runoff from the Greenland ice sheet in models, partly because this runoff may not be as disruptive as Arctic meltwater on shorter timescales, von Hardenberg said.

"In order to represent correctly the Greenland melt, you need a specific, dynamic model for the Greenland ice sheet. It's nice to have, but it requires a lot of resources to develop," von Hardenberg said

The Community Ice Sheet Model version 2 (CESM2) is one of the few available simulations of the Greenland ice sheet. For the study, von Hardenberg and his colleagues used a global climate model called EC-Earth3, which does not include the Greenland ice sheet. The team added the ice sheet from CESM2 to explore how it might affect the AMOC over the next few centuries. Adding the ice sheet separately enabled them to compare AMOC weakening with and without Greenland, clearly revealing the impact of the ice sheet on the AMOC's strength.

The results, published June 19 in the journal Science Advances, suggest the Greenland ice sheet will have a big influence on Atlantic ocean currents, especially after 2100.

"Greenland starts really melting strongly only after that date," von Hardenberg said. "If you go farther in our simulation — we go up to the year 2300 — that is also when this meltwater really becomes extremely strong."

Yet unlike other studies that show the AMOC collapsing irreversibly under climate change, in this model, the circulation recovered once the team switched off the meltwater or dialed down greenhouse gas emissions. Both the simulations that didn't include the Greenland ice sheet and those that did had similar results, recovering partially when the meltwater was turned off and fully when greenhouse gas emissions were stopped.

The recovery in the model suggests that the AMOC is more stable than previously thought and doesn't suddenly flip from an active state into a collapsed one, von Hardenberg said. "It's consistent with a strong weakening, but not a shutdown," he said.

Overall, the findings show that it is important to include the Greenland ice sheet in climate models — something von Hardenberg and his colleagues are planning to do in the next version of the EC-Earth3 model.

"It's really something which is worthwhile doing to better constrain the uncertainty of these future simulations," von Hardenberg said. "If we have a larger set of models which include this component, we will be in a better position to try to answer the question, 'How much do we expect AMOC to decrease in different scenarios?'"

Other experts agreed that integrating the Greenland ice sheet in climate models will increase the accuracy of AMOC predictions.

"What makes the study particularly interesting is that it directly tests a process that has often been highlighted as an important source of uncertainty in future AMOC projections," said Jonathan Baker, a senior climate scientist at the Met Office in the U.K. who was not involved in the study.

The results are consistent with previous research showing that Greenland meltwater causes additional AMOC weakening, but whether the system could collapse is still uncertain, given that the team used only one model, Baker told Live Science in an email. "Repeating these experiments across a wider range of models will be important to assess how robust the findings are," he said.

Nicholas Foukal, an assistant professor at the University of Georgia's Skidaway Institute of Oceanography who was not involved in the study, said he doesn't think the use of a single model limits the analysis.

"I think this result is robust and I am glad to see the authors come to this conclusion in such a high-resolution and realistic coupled climate model," Foukal told Live Science in an email. "This finding also agrees with other modeling results that require immense amounts of fresh water, much more fresh water than is available on Greenland, to cause irreversible change in the AMOC."

However, a third expert said the model used in the study is unrealistic, because its parameters make the AMOC more resilient than those of other models. Therefore, the study should be replicated in other models to draw unbiased conclusions.

"While the experiment reported is interesting, its outcomes are neither surprising nor should be interpreted as exemplary for the whole model ensemble," Sybren Drijfhout, a professor of physical oceanography at the University of Southampton in the U.K., told Live Science in an email.

Researchers should investigate the impact of the Greenland ice sheet on the AMOC further, von Hardenberg said. "It would be interesting in the future to check it [the AMOC's recovery with Greenland meltwater] with other models, but of course it's encouraging to see it in one case," he added.

Extreme coastal flooding events are occurring far more frequently in our warming world than ever before, threatening countless communities that will only become more vulnerable as climate change intensifies.

A recent study found that once-in-a-century flooding events now strike on our planet about once a decade. The study, published June 10 in the journal Nature Climate Change, also found that human-driven climate change has quadrupled the frequency of coastal sea level extremes since 1900.

The findings were released alongside another study by a separate team, published in the journal Science Advances, that found human-caused sea level rise was clearly measurable at 97% of sites sampled around the world, and was responsible for around 58% of the observed daily extreme water level exceedances between 2000 and 2018. In other words, human activities are the primary drivers behind sea level extremes — which include storm surges, high tides and rising sea level anomalies.

As the ocean's potential to devastate coastal communities surges, Live Science spoke with Sönke Dangendorf, lead author of the Nature Climate Change study, to learn more about what's to come. Here's what he had to say.

Patrick Pester: How do you separate human-driven sea level rise from natural forces?

Sönke Dangendorf: The absolute basis for doing these kinds of investigations is to work with observations, but observations are unfortunately sparse. We have a few more than 100 tide gauges [distributed worldwide] that offer long, century-scale records of sea level change since the early 20th century. We see that sea levels are changing at those locations, but we cannot tell a whole lot about what is happening elsewhere. So, what we can do is use the same climate models that we use to produce future projections of sea level change.

If you compare observations with the models, then the models need to be able to reproduce what the observations have shown. That was the first step we did, and indeed we proved in this study that the climate models are capable of reproducing observed climate. The nice thing with climate models then is that if you are able to reproduce what has been observed, you can start doing experiments. For instance, you can keep greenhouse gases constant in the modeling and then assess the influence of natural climate variability on the changes that we have observed. That's what we did in the study.

We found that we have seen already a 12-fold increase on average globally in what used to be a once-in-100-year event in 1900. And when we do these forcing experiments, we have also seen that anthropogenic forcing [human-driven change], in particular since the 1970s, has become the dominant force.

PP: What does this mean for coastal communities around the world?

SD: A couple of centimeters of sea level rise doesn't sound like a whole lot in theory, but if you live along the coast, it hits you much harder than you might think. Just an example: I used to live along the U.S. East Coast in Norfolk, Virginia. The community was built along the water, and they used to be fine in the 1950s and 1960s; they wouldn't see flooding at all, or maybe just once every five or six years. But due to sea level rise, what happens now is that high tide leads to flooding. You see flooded streets, and that affects your commute, so people increasingly cannot make it to work.

It affects your daily life suddenly. And then it makes it very hard for you and your coastal community because you have increasing insurance costs — the accumulated costs of these events can easily be as much as a major hurricane making landfall. So, this is a daily experience that many people already have, and it's a direct impact of sea level rise.

With respect to what we assessed in these more extreme events, people may absorb a once-in-a-100-year event once in their lifetime. They may experience something like a Storm Sandy, and they may be able to recover from that, but if you think about recovering from that basically every eight years — the frequency of these events nowadays compared to 1900 — that's of course way more difficult and not feasible for many people.

PP: What can we do?

SD: We can adapt. The silver lining here is that we have shown humans are the dominant forcing factor behind these changes. That's the silver lining because it means if we react, we can do something about it.

The reaction to changes in climate is often delayed, so we have sea level rise that we are already committed to. For instance, if you look into projections, they all agree with respect to what happens until around 2060, independently of how much greenhouse gases are emitted. There's no way around that. We could stop emitting greenhouse gases today, and we would still experience it. So, we need to adapt to that sea level rise, but if we mitigate climate change, if we stop emitting greenhouse gases, then we can avoid dangerous sea level rise, and that's very important.

PP: What will the world look like in 2060 with the committed sea level rise?

SD: According to the last IPCC [Intergovernmental Panel on Climate Change] report, what used to be a once-in-a-100-year event in the present day will occur annually at 19% to 31% of tide gauge locations by 2050. So, at about a quarter of the locations, you will experience these once-in-a-100-year events annually, and that is something that is just mind-blowing.

The changes are happening much quicker in low-latitude locations. The reason is that in the tropics you typically have a less variable climate. You don't have these massive swings all the time. For instance, in the North Sea, we have a storm season, and we have huge tide ranges. We are already adapted to pretty massive changes of multiple meters, so a couple of centimeters of sea level rise do not play out that hard, but in the tropics, where it's more calm, it makes a huge difference.

As an analogy, think about two hurdle runners. You have one hurdle runner that's compared to the tropics; he jumps very consistently but always below the hurdle, so he never makes it over. Then you have another hurdle runner that's the North Sea type of guy. His jumps are very variable. Sometimes he's very high and makes it over that hurdle, but very often he also jumps very low. Now think about lowering that hurdle, which is comparable to increasing sea levels. Suddenly, that hurdle runner who is very consistent makes it over all of the time, while the guy from the North Sea may jump over the hurdle a couple more times, but he also still has the very extreme lows. So, the constant jumper is way more sensitive to these changes.

Editor's note: This interview has been edited and condensed for clarity.

Tropical forests draw down and store large quantities of CO₂ from the atmosphere. The Amazon rainforest in South America, for example, stores approximately 123 billion tonnes of carbon — more than is stored in any other terrestrial ecosystem in the world. But these forests are facing a critical challenge.

Research from 2023, which was carried out by me and more than 100 colleagues, found that tropical forests in South America are vulnerable to climate extremes. We determined that during an El Niño event, the warm phase of a natural fluctuation in the Earth's climate system, South American tropical forests may fail to act as a carbon sink.

This finding becomes even more alarming when we consider the increasing frequency and intensity of El Niño events. There have been twice as many "very strong" El Niños in the last 60 years as there were in the 60 years before that. And the US National Oceanic and Atmospheric Administration has recently confirmed that such an El Niño is currently underway.

Tropical forests absorb CO₂ through the process of photosynthesis and convert it into biomass. However, the balance between photosynthesis and respiration is delicate and depends on two factors: temperature and water availability.

In hotter and drier conditions, plants close the pores of their leaves to avoid water loss. But closing them effectively cuts off a plant's fuel supply because it is through these pores they absorb CO₂. This starves plants of the carbon needed for photosynthesis and to grow.

During El Niño years, which are characterized by high temperature anomalies, prolonged climate stress leads to reduced forest growth and increased tree mortality. The effects of this are felt for decades as carbon is released back into the atmosphere when the dead trees decompose.

Our findings revealed that during the 2015-2016 El Niño, when temperatures on land were at least a degree higher on average than usual conditions, some of South America's tropical forests effectively stopped absorbing carbon. This raises concerns about the possible impact of the current El Niño on the Amazon and global climate.

In our research, we measured over half a million trees across six South American countries over a period of more than 30 years, using tape measures to track their growth. These trees belonged to over 4,000 different species. We used this data to calculate precise estimates of the amount of carbon stored as a forest's aboveground biomass.

We found that the vulnerability of these forests to El Niño conditions was closely linked to their baseline climate. While we tend to assume that rainforests are all hot, wet and biodiverse ecosystems, seasonal drought is a reality for many tropical forests. Conditions in regions at the edge of the Amazon rainforest, for example, tend to be particularly hot and dry.

Our findings revealed that drier forests at the edge of the Amazon, where trees regularly endure periods of limited water availability, were especially susceptible to extreme El Niño conditions. On average, a 0.5°C increase in temperature caused these forests to lose 0.5% of their aboveground carbon.

Larger trees suffered the most. While tree mortality rates increased from 1.8% to 3% per year during the El Niño in South American tropical forests as a whole, mortality rates effectively doubled for medium (classified as over 20cm in diameter) and large trees.

The fact that larger trees with less dense wood died at much higher rates compared to small trees and those with high wood density points strongly to hydraulic failure, when intense atmospheric moisture demand snaps the tension in the tree's internal water column rather than slow carbon starvation.

These results suggest that adaption to seasonal drought may not be sufficient to protect tropical forests from extreme events. Climate extremes are possibly already pushing forests at the edges of the Amazon beyond their capacity to adapt, causing catastrophic carbon losses.

A looming threat

Scientists have warned that 2026 may again be the warmest year on record. Heightening the alarm further is the severity of the current El Niño. Never before has an an El Niño begun when oceans are already so warm and air temperatures so high.

On top of this is the fact that, over the past three decades, the edges of the Amazon have experienced some of the highest temperatures and most rapid warming the tropics have ever seen. The structural integrity of a forest is compromised when a major climate anomaly occurs before it has recovered from recent, multi-year stress.

These compounding factors mean that we risk witnessing tree and carbon losses on scales not yet seen.

Tropical forests are invaluable assets in the fight against climate change. But South American tropical forests, a once-reliable carbon sink, are vulnerable to intensifying heat and drought. There is a risk these essential ecological allies stop acting as a carbon sink as extreme climate conditions become the norm.

Preserving tropical forests is thus essential. Their ability to continue acting as carbon sinks hinges on efforts to protect them and a collective commitment to limit global temperature rise. The Amazon's future depends on this, and so does ours.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Rainforest quiz: Can you sort Earth's largest rainforests from biggest to smallest?

For decades, cities have been designed around "gray infrastructure." Roads move people. Bridges connect communities. Water systems protect public health. These systems are governed by engineering standards because society recognizes that safety cannot depend on good intentions alone.

Urban nature deserves the same recognition.

In June, a heat wave gripped Europe, breaking temperature records across the continent. In France, officials reported over 2,000 excess deaths. In the U.K., hospitals declared critical incidents and machinery and IT systems failed. In the U.S., a heat dome over the Midwest and East Coast disrupted Fourth of July celebrations, with at least 25 heat-related deaths over Independence Day weekend.

Cities are being tested by a warming climate. Yet one of our most effective forms of climate infrastructure is being lost — not because it does not work but because we still do not treat it as infrastructure.

My view is simple: Urban nature ‪—‬ including street trees, parks, wetlands and other urban green spaces ‪—‬ should be categorized and managed as essential infrastructure, with minimum standards for its protection, quality and long-term maintenance. Just as we regulate roads, bridges and drinking water, we need standards that ensure all urban residents benefit from healthy and thriving urban nature. Without such standards, cities will become hotter, less resilient and increasingly unequal as climate change accelerates.

Scientific research shows that urban trees and green spaces cool cities during heat waves, reduce flooding by absorbing stormwater, improve air quality, store carbon, support biodiversity, and improve both physical and mental health. During extreme heat, neighborhoods with mature tree canopies can be several degrees cooler than nearby streets dominated by concrete and asphalt. Those few degrees can mean the difference between manageable discomfort and dangerous heat exposure, particularly for older adults, children and people with existing health conditions.

But while the science is strong, our governance is not.

Cities enthusiastically announce ambitious tree-planting campaigns, biodiversity strategies and new greening targets. These initiatives are valuable, but they often focus on what is easy to count rather than what truly matters. Planting a tree is not the same as growing a healthy urban forest. Creating a park does not guarantee biodiversity. A green roof delivers little value if it fails during drought.

The real measure of success is whether urban nature continues providing benefits decades after trees are planted and established.

This is where cities are still falling short.

Unlike buildings or transport systems, urban nature rarely operates under consistent minimum standards. Many cities have no requirements for minimum tree canopy cover, adequate rooting space, soil quality, biodiversity targets, long-term maintenance or even whether newly planted trees survive. As a result, access to nature depends heavily on where people live. Wealthier neighborhoods often enjoy mature tree canopy and high-quality parks, while disadvantaged communities experience hotter streets, fewer green spaces and greater exposure to climate risks.

That is not simply an environmental issue. It is a public health issue, a climate adaptation issue, and an issue of social equity.

The solution is not simply to plant more trees. It is to establish urban nature standards that recognize nature as essential infrastructure.

These standards would not prescribe the same solution for every city. Instead, they would establish minimum expectations based on scientific evidence. They could include targets for accessible green space, minimum tree canopy cover, sufficient soil volume for healthy tree growth, biodiversity outcomes, long-term maintenance funding and routine monitoring to ensure that urban nature continues delivering benefits to communities.

Importantly, these standards should focus on outcomes rather than simple planting targets. Counting how many trees are planted tells us little about whether cities are becoming more resilient. Measuring survival, canopy development, ecosystem health and equitable access provides a much better picture of whether investments in urban nature are actually returning dividends.

Some critics argue that cities cannot afford stronger standards for urban nature. Municipal budgets are already stretched by housing, transport and aging infrastructure. But this argument overlooks a fundamental reality: We already spend enormous sums responding to the consequences of extreme heat, flooding, poor air quality and declining public health. Healthy urban ecosystems help reduce these costs while delivering multiple benefits simultaneously.