Eight U.S. East Coast cities are at high or very high risk of "extreme" flood damage based on current scenarios, with New York and New Orleans facing some of the greatest dangers, a new study finds.

New York could see the highest number of people affected by flooding: 50% of New York City's population ‪—‬ around 4.4 million people ‪—‬ and 47% of its buildings are currently at high risk of exposure to extreme flood damage if a major flood occurs, according to a flood risk assessment published Wednesday (April 22) in the journal Science Advances.

New Orleans faces the greatest relative risk, with 98% of its population ‪—‬ about 375,000 people ‪—‬ and 99% of its infrastructure at high risk of being exposed to extreme damage, according to the study.

The other six cities mentioned in the report are Houston; Miami; Norfolk, Virginia; Charleston, South Carolina; Jacksonville, Florida; and Mobile, Alabama.

The heightened threat and damage levels these cities face result from their low elevation, high population density, poor drainage, building height, rainfall and proximity to water. The study authors urged policymakers to work with local stakeholders to mitigate flood risk using nature-based solutions alongside structures like floodgates, levees and dikes.

"Such policies should restrict further urban development in high-risk zones while promoting the systematic incorporation of nature-based solutions," the authors wrote.

Flood risk

Flooding is the most expensive natural disaster in the U.S., costing billions a year. By 2050, sea levels along the contiguous U.S. coastline are projected to rise by up to 1 foot (0.3 meters), and flooding following hurricanes is also increasing along the East Coast due to climate change.

With around 30% of counties along the U.S. Gulf and Atlantic coasts at high flood risk, it's essential to understand which measures will prevent flood damage most effectively, the authors wrote in the study.

The researchers used machine learning to assess flood risk along the U.S. East Coast, using historical flood damage data from the Federal Emergency Management Agency. This data is of visual, bird's-eye-view damage to properties associated with recent major flooding events, including Hurricane Isaac in 2012 and Hurricane Irma in 2017. The study classified properties that were fully destroyed as "extreme flood damage."

The team then compiled data on 16 flood risk factors and developed a flood risk map, using these risk factors to predict exposure to flood damage The flood risk factors included natural hazards, such as distance from the water and elevation; exposure factors, such as population density; and the vulnerability of the population, such as the percentage of people living in poverty.

Based on these factors, the model produced a "flood risk index" of probability scores ranging from "very low" to "very high" risk. The coastal cities at the highest risk of floods leading to extreme flood damage could then be estimated. The team calculated the number of people and buildings that would be exposed to this damage.

The results showed that New York City and New Orleans share the "grim reality" of being "major flood-risk cities," the authors wrote in the study. Almost 4.4 million people in New York City and over 215,000 buildings could face extreme flood damage. Over 98% of New Orleans' population and buildings face similar damage.

Houston and Mobile, Alabama, are also at high risk of extreme flood damage, so, along with New York and New Orleans, these cities demand "prioritized attention from policy-makers," the authors wrote in the study.

The authors noted several ways to potentially reduce flood damage. For example, parking lots built with impermeable concrete should be replaced with grass tiles to allow the soil to soak up the water, and wetlands and river floodplains should be restored and linked to drainage systems like gutters to support the fast removal of water from cities.

This intriguing astronaut photo shows off the contrasting colors of five ephemeral lakes that emerged around the edges of a giant salt pan after a major flooding event in southwest Africa.

The kaleidoscopic scene occurred in the northwest corner of the Etosha Pan — Africa's largest salt flat, or mineral pan, which covers around 1,800 square miles (4,730 square kilometers) in northern Namibia. The name Etosha roughly translates to "Great White Place" in an Indigenous Namibian language, and the ghostly expanse is located roughly 250 miles (400 kilometers) from the country's capital, Windhoek.

The satellite photo shows a snaking pair of ephemeral rivers that drain into the Etosha Pan: the Ekuma River (left) and the Oshigambo River (right). These winding waterways are surrounded by roughly a dozen bowl-like depressions that occasionally fill with water when the rivers sporadically flood their banks.

When the image was taken, both rivers had recently flooded due to heavy rains in the region, causing around half of these pale depressions to fill with water. The rest of the lakes remained empty and are the same pale hue as the rest of the Etosha Pan.

The contrasting colors of the newly filled lakes — which include yellow, green, brown, red and pink — are likely the result of different species of algae that bloomed within their shallow waters, according to NASA's Earth Observatory. (For scale, the green lake is around 4 miles (6.5 km) long at its widest point.)

The Etosha Pan likely formed around 10 million years ago and has been a freshwater lake for most of that time. But around 16,000 years ago, toward the end of the last ice age, tectonic activity diverted one of the major rivers that fed into the lake, causing it to dry out.

As the water slowly evaporated, it left behind a thick layer of minerals, which covered the lake bed. Most of the pan's surface is covered by honeycomb-like hexagonal structures that are common among salt flats across the globe.

During flooding events, a thin layer of water can briefly lie within the pan, transforming it back into a shallow lake. However, this rarely happens, even when its rivers flood.

The last time a majority of the pan flooded was in 2006, which was also captured from space by ISS astronauts.

Wildlife haven

Despite the Etosha Pan's extreme dryness and salinity, which make it largely inhospitable to life, the area surrounding the ancient lake is covered with rich grassland and woodland.

This diverse ecosystem is protected as part of Etosha National Park, which covers 8,900 square miles (23,000 square km), and is home to a variety of animals, including lions, giraffes, zebras, hyenas, impalas, elephants, rhinos, springboks, wildebeests and ostriches, according to iNaturalist.

The salt flats themselves are also an important breeding site for flamingos, and up to 1 million of the pink birds congregate there at a time, according to the Etosha National Park website.

If you look closely at the astronaut photo, you can see the park's northern fence running across the image from left to right — just above the green lake and bisecting the red and pink lakes. This 10-foot-tall (3 meters) barrier stops the park's animals from wandering outside the woodlands where they could be targeted by poachers, according to the Earth Observatory.

See more Earth from space

Many of the world's biggest river deltas — including the Nile, Amazon and Ganges — are sinking faster than global sea levels are rising, a new study shows.

This means subsidence is becoming the main driver of land loss, coastal flooding and saltwater intrusion at river deltas — surpassing the impacts of sea-level rise from climate change. Researchers also found that groundwater extraction is the biggest cause of subsidence at deltas globally, with urban expansion and declines in rivers' sediment loads contributing to the overall sinking trend.

Deltas are facing a "double burden" of sea-level rise and sinking land that increases the risk of catastrophic flooding and displacement for millions of people in some of the world's biggest cities, the study's authors warn.

"To our knowledge, this is the most comprehensive, high-resolution, delta-wide assessment of contemporary land subsidence ever conducted at the global scale," co-author Manoochehr Shirzaei, an associate professor of geophysics and remote sensing at Virginia Tech, told Live Science in an email. "Across the deltas we analyzed, groundwater storage change emerged as the single most influential anthropogenic factor explaining subsidence patterns in many systems."

Shirzaei and his colleagues used data from the Sentinel-1 satellite to examine subsidence at 40 of the world's largest river deltas between 2014 and 2023. Sentinel-1 captures changes in ground elevation resulting from subsidence, as well as sediment deposition and erosion, according to the study, which was published Wednesday (Jan. 14) in the journal Nature.

Of the 40 deltas, 18 had average annual subsidence rates greater than the current rate of global sea-level rise, which is about 0.16 inches (4 millimeters) per year.

Zooming in, the researchers found that every studied river delta except the Rio Grande Delta was in some places sinking faster than global sea levels are rising. In 38 deltas, more than 50% of the delta area sank during the study period, and in 19 of them — including the Mississippi Delta, the Nile Delta and the Ganges-Brahmaputra Delta — more than 90% of the delta area had subsided.

The worst-affected deltas in the study were the Chao Phraya Delta in Thailand, the Brantas Delta in Indonesia and the Yellow River Delta in China. These showed average sinking rates of about 0.3 inches (8 mm) per year — double the rate of global sea level rise.

Two main points arose from the study, Shirzaei said. "First, land subsidence often exceeds sea-level rise as the dominant driver of relative sea-level rise in river deltas today, meaning that many coastal risks are increasing faster than climate-only projections suggest. Second, there is a profound mismatch between risk and capacity: the deltas sinking fastest are often in regions with the least resources to respond."

River deltas are home to between 350 million and 500 million people around the world. They host 10 of the world's 34 megacities, along with vital infrastructure such as ports, meaning the impacts of subsidence and sea-level rise — such as shoreline retreat and more frequent floods — are immense.

And these huge populations are themselves a driver of subsidence, because cities pile enormous weight onto the land, compressing the soil. Huge populations typically also require massive amounts of water, which exacerbates groundwater pumping. This causes further compaction of the soil.

"In rapidly urbanizing deltas, urban growth can substantially exacerbate land sinking," Shirzaei said. However, groundwater extraction for all purposes, including agriculture and industry, remains the biggest cause of subsidence at deltas, he said. "Groundwater pumping is a well-known local driver of subsidence, but what stood out was how consistently dominant it appears at the global scale, even when compared alongside other major anthropogenic pressures."

Another cause of subsidence is a reduction in the amount of sediment that rivers flush into the ocean due to dams and other river-control strategies. Sediment delivery can offset subsidence and sea-level rise to some extent, but human modifications to natural river flow have disturbed this balance. For example, about 1,900 square miles (5,000 square kilometers) of land has been lost in the Mississippi River Delta since 1932 due to the combined effects of dams, levees and erosion.

The main drivers of subsidence at river deltas are human-made, which presents an opportunity for intervention, Shirzaei said. "One of the most important messages of the study is that subsidence is often manageable," he said.

Alongside efforts to limit climate change, countries should consider reducing groundwater extraction and replenishing aquifers with floodwater or treated wastewater, Shirzaei said. Controlled flooding and sediment diversions can help increase sediment deposition. And restricting heavy infrastructure in the areas most prone to subsidence could also help slow subsidence, he said.

"When combined with flood protection and climate adaptation, these measures can significantly reduce long-term risk," he said.

Caroline Muller looks at clouds differently than most people. Where others may see puffy marshmallows, wispy cotton candy or thunderous gray objects storming overhead, Muller sees fluids flowing through the sky. She visualizes how air rises and falls, warms and cools, and spirals and swirls to form clouds and create storms.

But the urgency with which Muller, a climate scientist at the Institute of Science and Technology Austria in Klosterneuburg, considers such atmospheric puzzles has surged in recent years. As our planet swelters with global warming, storms are becoming more intense, sometimes dumping two or even three times more rain than expected. Such was the case in Bahía Blanca, Argentina, in March 2025: Almost half the city’s yearly average rainfall fell in less than 12 hours, causing deadly floods.

Atmospheric scientists have long used computer simulations to track how the dynamics of air and moisture might produce varieties of storms. But existing models hadn’t fully explained the emergence of these fiercer storms. A roughly 200-year-old theory describes how warmer air holds more moisture than cooler air: an extra 7 percent for every degree Celsius of warming. But in models and weather observations, climate scientists have seen rainfall events far exceeding this expected increase. And those storms can lead to severe flooding when heavy rain falls on already saturated soils or follows humid heatwaves.

Clouds, and the way that they cluster, could help explain what’s going on.

A growing body of research, set in motion by Muller over a decade ago, is revealing several small-scale processes that climate models had previously overlooked. These processes influence how clouds form, congregate and persist in ways that may amplify heavy downpours and fuel larger, long-lasting storms. Clouds have an “internal life,” Muller says, “that can strengthen them or may help them stay alive longer.”

Other scientists need more convincing, because the computer simulations researchers use to study clouds reduce planet Earth to its simplest and smoothest form, retaining its essential physics but otherwise barely resembling the real world.

Now, though, a deeper understanding beckons. Higher-resolution global climate models can finally simulate clouds and the destructive storms they form on a planetary scale — giving scientists a more realistic picture. By better understanding clouds, researchers hope to improve their predictions of extreme rainfall, especially in the tropics where some of the most ferocious thunderstorms hit and where future rainfall projections are the most uncertain.

First clues to clumping clouds

All clouds form in moist, rising air. A mountain can propel air upwards; so, too, can a cold front. Clouds can also form through a process known as convection: the overturning of air in the atmosphere that starts when sunlight, warm land or balmy water heats air from below. As warm air rises, it cools, condensing the water vapor it carried upwards into raindrops. This condensation process also releases heat, which fuels churning storms.

But clouds remain one of the weakest links in climate models. That’s because the global climate models scientists use to simulate scenarios of future warming are far too coarse to capture the updrafts that give rise to clouds or to describe how they swirl in a storm — let alone to explain the microphysical processes controlling how much rain falls from them to Earth.

To try to resolve this problem, Muller and other like-minded scientists turned to simpler simulations of Earth’s climate that are able to model convection. In these artificial worlds, each the shape of a shallow box typically a few hundred kilometers across and tens of kilometers deep, the researchers tinkered with replica atmospheres to see if they could figure out how clouds behaved under different conditions.

Intriguingly, when researchers ran these models, the clouds spontaneously clumped together, even though the models had none of the features that usually push clouds together — no mountains, no wind, no Earthly spin or seasonal variations in sunlight. “Nobody knew why this was happening,” says Daniel Hernández Deckers, an atmospheric scientist at the National University of Colombia in Bogotá.

In 2012, Muller discovered a first clue: a process known as radiative cooling. The Sun’s heat that bounces off Earth’s surface radiates back into space, and where there are few clouds, more of that radiation escapes — cooling the air. The cool spots set up atmospheric flows that drive air toward cloudier regions — trapping more heat and forming more clouds. A follow-up study in 2018 showed that in these simulations, radiative cooling accelerated the formation of tropical cyclones. “That made us realize that to understand clouds, you have to look at the neighborhood as well — outside clouds,” Muller says.

Once scientists started looking not just outside clouds, but also underneath them and at their edges, they found other small-scale processes that help to explain why clouds flock together. The various processes, described by Muller and colleagues in the Annual Review of Fluid Mechanics, all bring or hold together pockets of warm, moist air so more clouds form in already-cloudy regions. These small-scale processes hadn’t been understood much before because they are often obscured by larger weather patterns.

Hernández Deckers has been studying one of the processes, called entrainment — the turbulent mixing of air at the edges of clouds. Most climate models represent clouds as a steady plume of rising air, but in reality “clouds are like a cauliflower,” he says. “You have a lot of turbulence, and you have these bubbles [of air] inside the clouds.” This mixing at the edges affects how clouds evolve and thunderstorms develop; it can weaken or strengthen storms in various ways, but, like radiative cooling, it encourages more clouds to form as a clump in regions that are already moist.

Such processes are likely to be most important in storms in Earth’s tropical regions, where there’s the most uncertainty about future rainfall. (That’s why Hernández Deckers, Muller and others tend to focus their studies there.) The tropics lack the cold fronts, jet streams and spiraling high- and low-pressure systems that dominate air flows at higher latitudes.

Supercharging heavy rains

There are other microscopic processes happening inside clouds that affect extreme rainfall, especially on shorter timescales. Moisture matters: Condensed droplets falling through moist, cloudy air don’t evaporate as much on their descent, so more water falls to the ground. Temperature matters too: When clouds form in warmer atmospheres, they produce less snow and more rain. Since raindrops fall faster than snowflakes, they evaporate less on their descent — producing, once again, more rain.

These factors also help explain why more rain can get squeezed from a cloud than the 7 percent rise per degree of warming predicted by the 200-year-old theory. “Essentially you get an extra kick … in our simulations, it was almost a doubling,” says Martin Singh, a climate scientist at Monash University in Melbourne, Australia.

Cloud clustering adds to this effect by holding warm, moist air together, so more rain droplets fall. One study by Muller and her collaborators found that clumping clouds intensify short-duration rainfall extremes by 30 to 70 percent, largely because raindrops evaporate less inside sodden clouds.

Other research, including a study led by Jiawei Bao, a postdoctoral researcher in Muller’s group, has likewise found that the microphysical processes going on inside clouds have a strong influence over fast, heavy downpours. These sudden downpours are intensifying much faster with climate change than protracted deluges, and often cause flash flooding.

The future of extreme rainfall

Scientists who study the clumping of clouds want to know how that behavior will change as the planet heats up — and what that will mean for incidences of heavy rainfall and flooding.

Some models suggest that clouds (and the convection that gives rise to them) will clump together more with global warming — and produce more rainfall extremes that often far exceed what theory predicts. But other simulations suggest that clouds will congregate less. “There seems to be still possibly a range of answers,” says Allison Wing, a climate scientist at Florida State University in Tallahassee who has compared various models.

Scientists are beginning to try to reconcile some of these inconsistencies using powerful types of computer simulations called global storm-resolving models. These can capture the fine structures of clouds, thunderstorms and cyclones while also simulating the global climate. They bring a 50-fold leap in realism beyond the global climate models scientists generally use — but demand 30,000 times more computational power.

Using one such model in a paper published in 2024, Bao, Muller and their collaborators found that clouds in the tropics congregated more as temperatures increased — leading to less frequent storms but ones that were larger, lasted longer and, over the course of a day, dumped more rain than expected from theory.

But that work relied on just one model and simulated conditions from around one future timepoint — the year 2070. Scientists need to run longer simulations using more storm-resolving models, Bao says, but very few research teams can afford to run them. They are so computationally intensive that they are typically run at large centralized hubs, and scientists occasionally host “hackathons” to crunch through and share data.

Researchers also need more real-world observations to get at some of the biggest unknowns about clouds. Although a flurry of recent studies using satellite data linked the clustering of clouds to heavier rainfall in the tropics, there are large data gaps in many tropical regions. This weakens climate projections and leaves many countries ill-prepared. In June of 2025, floods and landslides in Venezuela and Colombia swept away buildings and killed at least a dozen people, but scientists don’t know what factors worsened these storms because the data are so paltry. “Nobody really knows, still, what triggered this,” Hernández Deckers says.

New, granular data are on their way. Wing is analyzing rainfall measurements from a German research vessel that traversed the tropical Atlantic Ocean for six weeks in 2024. The ship’s radar mapped clusters of convection associated with the storms it passed through, so the work should help researchers see how clouds organize over vast tracts of the ocean.

And an even more global view is on the horizon. The European Space Agency plans to launch two satellites in 2029 that will measure, among other things, near-surface winds that ruffle Earth’s oceans and skim mountaintops. Perhaps, scientists hope, the data these satellites beam back will finally provide a better grasp of clumping clouds and the heaviest rains that fall from them.

Research and interviews for this article were partly supported through a journalism residency funded by the Institute of Science & Technology Austria (ISTA). ISTA had no input into the story.

This article originally appeared in Knowable Magazine, a nonprofit publication dedicated to making scientific knowledge accessible to all. Sign up for Knowable Magazine’s newsletter.

A Hurricane Watch is up for the south coast of Haiti and a Tropical Storm Watch for Jamaica as newly-formed Tropical Storm Melissa chugs west across the central Caribbean. Melissa is gathering strength over near-record-warm Caribbean waters untouched by any hurricane or tropical storm so far this year, and as of 2 p.m. EDT Tuesday, was located in the central Caribbean about 305 miles (490 kilometers) south of Port-au-Prince, Haiti. Melissa's top sustained winds were already 50 mph (85 km/hr), and the storm was predicted by the National Hurricane Center to reach hurricane strength by Saturday. Melissa was moving just north of due west at around 14 mph (22 km/hr).

The many possibilities for Melissa's future over the next few days include multiple days of torrential rain over some of the Caribbean's most flood-vulnerable places. Disastrous flooding and mudslides are an increasing threat for Haiti, as well as across the southern Dominican Republic. Because of high wind shear from the placement of the subtropical jet stream from Florida eastward through the Bahamas, Melissa is not expected to pose any threat to the continental United States for at least the next week, and ensemble models indicate only a remote chance that the storm could end up far enough northwest to affect Florida.

Melissa is the 13th named storm of the 2025 Atlantic season, forming just four days before the average arrival of the season's 13th named storm — October 25 (across the period 1991-2020).

Near-record-warm Caribbean waters will fuel Melissa's growth

Although we're near the tail end of the Atlantic hurricane season, the Caribbean is where you'd most expect to see a named storm develop in mid-to-late October, since wind shear farther to the north has typically become too strong for tropical cyclones. At this point in the year, the Caribbean's waters haven't usually cooled too much from their seasonal peak, while the wind shear that so often makes the Caribbean a "graveyard" for incipient tropical systems has typically lessened.

This week, Melissa will traverse some of the warmest waters ever recorded this late in the season anywhere in the Atlantic basin. Averaged across the Caribbean, sea surface temperature was at least 0.5 degree Celsius (0.9°F) warmer as of Sunday, October 19, than in any year on that date except 2023 and 2024, as analyzed by the University of Arizona's Kim Wood.

Human-caused climate change has made the current warmth in the central Caribbean an incredible 500 to 800 times more likely to occur, according to Climate Central's Climate Shift Index (see Fig. 2).

Where will Melissa head?

If Melissa were to follow the initial forecast from the National Hurricane Center issued at 11 a.m. EDT Tuesday, it would slow to a crawl just south of Haiti into the weekend (and perhaps beyond) while still gathering strength — a recipe for potentially devastating floods and mudslides over southern Hispaniola. Poverty, governmental instability, and deforestation have left Haiti extremely vulnerable to the kind of disaster Melissa could inflict.

That said, forecast models have been far from unanimous on Melissa's future (see Fig. 3 below). Part of the problem is that the storm lacked a well-defined center until Tuesday. Now that Melissa is a bona fide tropical storm, we may well see an increasing amount of model agreement. However, it appears steering currents will be weak, and slow-moving storms can be problematic for even the best forecast models.

Through early Tuesday, the European model continued to favor a slow westward track, with most of the European model ensemble members keeping the system in the Caribbean through at least next Monday, October 27 (left side of Fig. 3), though a substantial minority bring Melissa toward western Haiti. The GFS (American) model (right side of Fig. 3) has been just as insistent that Melissa will make a northward turn and leave the Caribbean, but its ensemble members differ starkly on the timing and location of that turn. The Google DeepMind AI-based model, which has been a top performer on track this year, also leans toward an eventual northward turn but again with sharp variations among ensemble members on its timing and location.

Intensity forecast for Melissa

Steady strengthening appears to be a safe bet for Melissa over the next several days. The storm is embedded in an uncommonly moist atmosphere: mid-level relative humidity will be climbing from 70-75 percent on Tuesday to as high as 80 percent by Wednesday. Wind shear was a moderate 10-20 knots on Tuesday afternoon, and is expected to remain moderate to high for a couple of days. High pressure at upper levels is predicted to build over the Caribbean toward this weekend, which would favor strengthening.

As well as unusually warm surface waters, the Caribbean has ample oceanic heat extending to a substantial depth right now, so even a slow-moving Melissa is unlikely to be greatly hindered by churning up cooler subsurface water. NHC was not predicting Melissa would rapidly intensify over the next five days, but the 18Z Tuesday SHIPS model forecast called for a 12% chance of rapid intensification of 35 mph in 24 hours, and a 25% for rapid intensification by 75 mph in 72 hours. That would put Melissa at category 3 strength on Friday afternoon, with 125 mph winds.

If the forecast scenario of an "M" storm in October cruising into the Caribbean, stalling, and turning north as a major hurricane seems familiar to you, it should: this outcome would be remarkably similar to what we saw with Matthew in 2016.bmcnoldy.blogspot.com/2025/10/meli...#Melissa

— @bmcnoldy.bsky.social (@bmcnoldy.bsky.social.bsky.social) 2025-10-23T12:03:13.447Z

The dangers of late-season hurricanes in the Caribbean

Slow-moving, late-season systems that gain strength in the Caribbean can cause immense trouble. In early October 2016, Hurricane Matthew moved north over far western Haiti as a Category 4 hurricane, dumping more than 20 inches (500 mm) of rain over much of far eastern Cuba and southwestern Haiti and pummeling the Bahamas and several other islands. Matthew took 731 lives and caused more than $16 billion in damage (2016 USD).

Just over 20 years ago, Hurricane Wilma strengthened with astonishing speed into a Category 5 monster in the northwest Caribbean. On October 18-19, 2005, Wilma set two all-time records for the Atlantic basin for rapid intensification, as the storm deepened from 975 to 892 millibars (hPa) in 12 hours and from 979 to 882 mb in 24 hours — the latter making Wilma the strongest hurricane by central pressure in Atlantic history. Wilma also set a record for the largest 24-hour increase in top sustained winds, going from 75 to 175 mph. Wilma struck Mexico's Yucatan Peninsula as a strong Cat 4 storm and raced northeast to strike southwest Florida on October 24 at Cat 3 strength. Wilma led to 52 deaths and caused $26.5 billion in damage (2005 USD).

Near the end of October 1998, former Category 5 Hurricane Mitch dumped mammoth amounts of rain over Guatemala, Nicaragua, and Honduras (30 to 40 inches, or 750-1000 millimeters, in many areas) even as it decelerated and weakened, coming onshore at Cat 1 strength. Flooding and landslides caused some $6 billion in damage (1998 USD) and caused more than 11,000 confirmed fatalities, with another 11,000 missing people unaccounted for. Mitch was the deadliest Atlantic hurricane of the satellite-monitoring era (i.e., since the 1960s), and perhaps since the Great Hurricane of 1780.

This article was originally published by Yale Climate Connections.

Flash floods like the one that swept down the Guadalupe River in Texas on July 4, 2025, can be highly unpredictable. While there are sophisticated flood prediction models and different types of warning systems in some places, effective flood protection requires extensive preparedness and awareness.

It also requires an understanding of how people receive, interpret and act on risk information and warnings. Technology can be part of the solution, but ultimately people are the critical element in any response.

As researchers who study emergency communications, we have found that simply providing people with technical information and data is often not enough to effectively communicate the danger and prompt them to act.

The human element

One of us, Keri Stephens, has led teams studying flood risk communication. They found that people who have experienced a flood are more aware of the risks. Conversely, groups that have not lived through floods typically don't understanding various flood risks such as storm surges and flash floods. And while first responders often engage in table-top exercises and drills — very important for their readiness to respond — there are only a few examples of entire communities actively participating in warning drills.

Messages used to communicate flood risk also matter, but people need to receive them. To that end, Keri's teams have worked with the Texas Water Development Board to develop resources that help local flood officials sort through and prioritize information about a flood hazard so they can share what is most valuable with their local communities.

The commonly used "Turn Around Don't Drown" message, while valuable, may not resonate equally with all groups. Newly developed and tested messages such as "Keep Your Car High and Dry" appeal specifically to young adults who typically feel invincible but don't want their prized vehicles damaged. While more research is needed, this is an example of progress in understanding an important aspect of flood communication: how recipients of the information make decisions.

Related: Texas flood devastation revealed in before-and-after satellite images

Interviews conducted by researchers often include responses along these lines: "Another flash flood warning. We get these all the time. It's never about flooding where I am." This common refrain reveals a fundamental challenge in flood communication. When people hear "flood warning," they often think of different things, and interpretations can vary depending on a person's proximity to the flooding event.

Some people equate flood warnings with streamflow gauges and sensors that monitor water levels — the technical infrastructure that triggers alerts when rivers exceed certain thresholds. Others think of mobile phone alerts, county- or geographic-specific notification systems, or even sirens.

Beyond technologies and digital communication, warnings still come through informal networks in many communities. Emergency managers directly coordinate with and share information with major businesses and organizations, saying, "Hey, John, be sure you have somebody up tonight watching the National Weather Service alerts and rivers."

This human-centered approach, similar to neighborhood-level systems we have studied in Japan, can provide direct confirmation that warnings have been received. This is something mass media and mobile systems cannot guarantee, especially during infrastructure failures such as power and cell tower outages.

Effective messages

Research shows that effective warning messages need to include five critical components: a clear hazard description, location-specific information, actionable guidance, timing cues and a credible source. The Federal Emergency Management Agency's integrated public alert and warning system message design dashboard assists authorities in rapidly drafting effective messages.

This warning system, known as IPAWS, provides nationwide infrastructure for wireless emergency alerts and Emergency Alert System messages. While powerful, IPAWS has limitations − not all emergency managers are trained to use it, and messages may extend beyond intended geographic areas. Also, many older mobile devices lack the latest capabilities, so they may not receive the most complete messages when they are sent.

Hyperlocal community opt-in systems can complement IPAWS by allowing residents to register for targeted notifications. These systems, which can be run by communities or local agencies, face their own challenges. People must know they exist, be willing to share phone numbers, and remember to update their information. Social media platforms add another communication channel, with emergency managers increasingly using social media to share updates, though these primarily reach only certain demographics, and not everyone checks social media regularly.

The key is redundancy through multiple communication channels. Research has found that multiple warnings are needed for people to develop a sense of urgency, and the most effective strategy is simple: Tell another person what's going on. Interpersonal networks help ensure the message is delivered and can prompt actions. As former Natural Hazards Center Director Dennis Mileti observed: The wireless emergency alerts system "is fast. Mama is faster."

Warning fatigue

Professionals from the National Weather Service, FEMA and the Federal Communications Commission, along with researchers, are increasingly concerned about warning fatigue — when people tune out warnings because they receive too many of them.

However, there is limited empirical data about how and when people experience warning fatigue — or about its impact.

This creates a double bind: Officials have an obligation to warn people at risk, yet frequent warnings can desensitize recipients. More research is needed to determine the behavioral implications of and differences between warnings that people perceive as irrelevant to their immediate geographic area versus those that genuinely don't apply to them. This distinction becomes especially critical when people might drive into flooded areas outside their immediate vicinity.

The key to effective emergency communication is to develop messages that resonate with specific audiences and build community networks that complement technological systems. We are now studying how to do this effectively in the United States and internationally. It's also important to apply behavioral insights to the design of every level of communication warning systems. And it's important to remember to test not just the technology but the entire end-to-end system, from threat identification to community response.

Finally, maintaining true redundancy across multiple communication channels is an important strategy when trying to reach as many people as possible. Technology supports human decision-making, but it doesn't replace it.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

New satellite images have captured the trail of devastation left in the wake of Texas' deadly flash floods earlier this week.

The flooding, which began in the early hours of Friday (July 4), has been catastrophic, with 121 people reported to have died and at least 150 people still missing, at the time of writing.

Most of the deaths have occurred in Kerr County, where extreme rainfall caused the Guadalupe River to swell and burst its banks.

Space technology company Maxar Technologies has released satellite images that show the Guadalupe River before and after the flooding. Click on the right of the images below to see how the landscape changed as a result of the floods.

Related: Why were the Texas flash floods so catastrophic?

These images show the Ingram Dam, located in Kerr County, before and after the devastating floods. The first image was taken in July 2022, while the second was taken on Tuesday (July 8). Last Friday, water levels in the river rose by more than 26 feet (8 meters) in just 45 minutes.

These two satellite images show vegetation along the Guadalupe River before and after the flooding. The first image was taken in June 2023, while the second was taken on July 8. Much of the vegetation visible in the first image has been washed out in the second.

These before-and-after photos from along Texas State Highway 39 illustrate some of the catastrophic damage the waters caused. In the second image, taken after the flooding on July 8, homes just above the highway have been swept away.

These floods are the deadliest inland flooding in the U.S. since 1976, when the Big Thompson Canyon flood killed 144 people in Colorado, The Associated Press reported.

These before-and-after shots show how the river expanded and swept through trees, causing many to tumble down. The first satellite image was taken in June 2023, while the second was taken on July 8. Many trees have either fallen or are completely missing in the second image.

In the early hours on Friday (July 4), a large storm dropped about a foot of water in just a few hours over the Texas Hill Country. In 45 minutes, the water ran down the region's slopes into the Guadalupe River, which rose by more than 26 feet (8 meters) and burst its banks. In Kerr County, the deluge of water swept away people, homes and infrastructure and, as of July 8, more than 100 people have died.

So what caused such catastrophic flooding?

First off, the area is prone to flash flooding. In fact, Texas leads the U.S. in deaths due to flood. This is partially because of its hilly terrain and semiarid soil, which does not absorb much moisture, Hatim Sharif, a professor of civil and environmental engineering at the University of Texas, San Antonio, wrote for The Conversation. "The water sheets off quickly and the shallow creeks can rise fast."

What is flash flooding, and why was it so bad in Texas?

Flash floods are a special type of flood "usually characterized by raging torrents after heavy rains that rip through river beds, urban streets, or mountain canyons sweeping everything before them," according to the National Weather Service. They can occur within minutes or a few hours of excessive rainfall.

Texas is no stranger to flooding, and this particular area is known as "Flash Flooding Alley," Daniel Swain, a climate scientist at UCLA, told Live Science. "All the ingredients were in place for a potentially extreme rainfall," he said.

The major driver of these floods was the sheer quantity of water, Swain said. "An extraordinarily persistent torrential thunderstorm just sat over the same watershed for several hours and slowly propagated down that watershed in the direction of the flood wave."

Related: Climate change made April's catastrophic floods worse, report finds

The remnants of Tropical Storm Barry, which hit near Mexico last week, had already added moisture and instability into the atmosphere. Then, an easterly wind blew this saturated air inland, forcing the warm atmospheric air upward as it moved toward Texas. That air "rises into thunderstorms producing torrential rainfall, with very extreme rainfall rates on the order of two or three inches per hour and this is sustained over hours," Swain said.

In Texas, that created an extreme flash flood localized on one river system.

Can scientists predict flash floods?

While meteorologists can identify conditions that tend to fuel flash floods and regions that are prone to them, predicting exactly where and when one is likely to occur is very difficult, one expert told Live Science.

"It is very difficult to predict intense rainfall and flash flooding," said Jess Neumann, a geographer who specializes in flood risk management at the University of Reading in the U.K. "There is always uncertainty in a forecast in terms of the exact amount of rain that will fall, where precisely it will fall, and how that water will behave and move across the land once it reaches the ground."

In this case, the National Weather Service did issue a flash flood warning at 1:26 a.m. local time on Friday, and posted a follow-up emergency flash flood warning on X at 4:06 a.m.

Some pundits have suggested that recent mass layoffs at the National Oceanic and Atmospheric Administration, which runs the National Weather Service, may have hindered surveillance efforts ahead of these events. For example, KXAN reported that the warning coordination meteorologist at the National Weather Service Austin/San Antonio office, took early retirement in the wake of the NOAA funding cuts. The office is responsible for the areas most affected by the flash flood.

However, Swain said that the predictions from the office were as good as could be expected. “The real failure here was in the communication of that forecast and the failure of local authorities to have a plan of action and to put it into place to keep people safe,” he said.

Will flash flooding get worse in future?

As the climate warms, scientists warn that extreme rainfall events — such as the one that led to the Texas flash flood — will become more common. A warmer atmosphere can hold more water vapor, which will eventually fall to Earth as precipitation.

A fundamental law of thermodynamics known as the Clausius-Clapeyron equation, which describes the relationship between temperature and vapor pressure, predicts that for every degree Celsius that the atmosphere's temperature rises, its water-vapor-carrying capacity will increase by about 7%.

However, it might be even worse for flash flooding, Swain said. "When you talk about the very most extreme rain events — and, in particular, the very most extreme thunderstorm downpours — they increase at an even faster rate that is close to double that."

There are many places in the US, including several in southeastern states, which have a heightened flash flood risk due to their hilly geography and proximity to the Gulf of Mexico.

“When you have immediate proximity to an exceptionally warm body of water, occasional storm systems that push air rapidly upslope and unstable atmospheres that can occur, you can see these sorts of events,” said Swain. “The number of places where this at least is occasionally relevant is quite widespread.”

The risk of flooding events along the U.S. Northeast coast has doubled since 2005. Now, scientists have discovered that up to 50% of these events occurred because key Atlantic ocean currents are slowing down.

In a new study, researchers found that a considerable portion of the increase in flood risk was linked to the deceleration of the Atlantic Meridional Overturning Circulation (AMOC) — a giant network of ocean currents in the Atlantic Ocean that includes the Gulf Stream and brings heat to the Northern Hemisphere.

The AMOC relies on surface waters that have traveled north from the Southern Hemisphere sinking in the North Atlantic. Once they reach the seabed, these waters can ride back south on bottom currents. But climate change is blocking the sinking step by releasing meltwater from the Arctic and Greenland Ice Sheet into the North Atlantic. This dilutes the salt concentration and reduces the density of surface waters, keeping them at the top of the water column.

"Our results clearly show that AMOC weakening has contributed to above-average sea level rise and more frequent flooding along the U.S. Northeast coast over recent years," study lead author Liping Zhang, a project scientist at the National Oceanic and Atmospheric Administration (NOAA)'s Geophysical Fluid Dynamics Laboratory, told Live Science.

The East Coast as a whole is extremely vulnerable to sea level rise and flooding from climate change, but the Northeast coast is a hotspot when it comes to these impacts, Zhang said. That's mainly because weak circulation in the Atlantic Ocean redistributes heat to regions like the Northeast coast, which causes the water there to swell, she said.

Related: 'We don't really consider it low probability anymore': Collapse of key Atlantic current could have catastrophic impacts, says oceanographer Stefan Rahmstorf

"Global warming actually has two effects [on sea levels]," she said. "One is the melting of ice caps, which is adding water mass from the land to the ocean, and the other is through thermal expansion, which is when water gets warm and starts expanding."

Areas of the ocean that receive the most heat, and therefore undergo more thermal expansion, are likely to experience more rapid sea level rise. "From dynamics, we can see that the AMOC has the strongest [sea level rise] effect on the U.S. Northeast coast," Zhang said, "so that's why we focused on this region."

The aim of the new study was to explore the impact of a "moderate" AMOC decline on sea levels and flooding frequency along the Northeast coast. A moderate decline is consistent with climate modeling and direct observations over the past 20 years, Zhang said, so the research is a realistic picture of the AMOC's contribution to the recent increase in sea levels and flooding.

The researchers first used a global climate model to simulate large-scale atmospheric and ocean dynamics. They then fed this model sea level data for the Northeast coast from 1912 through 2022, "to force the model to be consistent with observations," Zhang said. Next, the scientists increased the resolution of the ocean component in the model, enabling them to focus on coastal regions. The last step was a statistical analysis to tease out the likely contributions of the AMOC from those of global warming more generally, Zhang explained.

The results indicated that the AMOC has played a major role in boosting sea levels and flooding risk along the Northeast coast over the past two decades.

Twenty years ago, people living on the Northeast coast could expect around five days of flooding per year, but that has recently increased to 10 days per year, Zhang said. Weakening of the AMOC may be responsible for 20% to 50% of this increase — a substantial contribution when compared to the influence of the global warming trend, the researchers wrote in the study.

The model predicted that AMOC-driven sea level rise and flooding frequency will continue to increase over the next three years but then stabilize and reach a plateau as the AMOC itself stabilizes, albeit in a weak state. The model's prediction of an increase in flooding is backed by a mountain of research, but the flattening out of sea level rise and flooding risk may not happen in reality, Zhang said.

That's because the model used in the study accounted for the effect of thermal expansion on sea levels but did not incorporate ice melt, Zhang said. "In the real world, if we add the risk of melting ice caps, we might see flooding risk continue to go up," she said.

Despite the limitations of the study, Zhang thinks the results can help policymakers plan for the future. "I think the two to three-year predictions will provide critical information for long-term decisions — for example, infrastructure planning, land use and financial planning," she said.

The results were published Friday (May 16) in the journal Science Advances.

All of the biggest cities in the United States are sinking into the ground in places, new satellite data reveal — and 34 million people are affected. However, some cities are sinking faster and over a much larger area than others.

A study found that Houston is the fastest-sinking city, with some areas dropping at a rate of 0.4 inches (10 millimeters) per year, while most major cities have localized zones where the land is sinking faster than 0.2 inches (5 mm).

Cities are sinking for a variety of reasons, but the most common cause is groundwater extraction. The sinking is a problem because it increases the risk of flooding and threatens buildings and other infrastructure, according to the study, published Thursday (May 8) in the journal Nature Cities.

To address the sinking, the researchers suggested measures like flood mitigation, retrofitting vulnerable structures and limiting building in areas at greatest risk.

"As opposed to just saying it's a problem, we can respond, address, mitigate, adapt," study lead author Leonard Ohenhen, a researcher at Columbia University's Columbia Climate School, said in a statement. "We have to move to solutions."

Related: Parts of San Francisco and Los Angeles are sinking into the sea — meaning sea-level rise will be even worse

Land subsidence is often associated with coastal areas, where a combination of sinking land and rising sea levels can potentially drown cities like New Orleans and San Francisco in water. However, land subsidence isn't just limited to coastlines and can cause problems across the U.S., according to the study.

The new research explored land subsidence in the country's 28 most populous cities, which all had populations exceeding 600,000 people. The researchers used remote sensing data collected by the European Space Agency's Sentinel-1 satellites to create high-resolution maps of vertical land motion.

The maps revealed that in all 28 cities, there was sinking in at least some parts of each city — a minimum of 20% of the urban area. Twenty five of the 28 cities had at least 65% of their area sinking. In the case of Houston, Dallas, Fort Worth, Chicago, Columbus, Detroit, Denver, New York, Indianapolis, and Charlotte, the sinking covered 98% of the city.

Houston, Dallas and Fort Worth had the highest proportion of areas (more than 70%) sinking at a rate of 0.1 inches (3 mm) per year. Houston was the worst affected, with 43% of its land sinking more than 5 mm per year and 12% sinking at 10 mm per year, according to the study.

Why are the cities sinking?

Land subsides due to both natural and human-driven factors. The ground is never truly static, with geological processes keeping us constantly on the move. In cities like New York and Nashville, the ground is adjusting to the loss of massive ice sheets that weighed it down during the last ice age around 16,000 years ago. This process, called glacial isostatic adjustment, causes land to rise and fall as it returns to its original pre-ice age shape.

However, despite these natural processes, humans are still the biggest contributors to sinking urban land, according to the study. The researchers said that 80% of the urban land subsidence is associated with groundwater extraction. Pumping groundwater can have a variety of knock-on effects. For example, removing water from aquifers with fine-grained sediments creates spaces between those sediments, which can then collapse and compact the earth below, pulling the surface down. In Texas, this problem is exacerbated by the pumping of oil and gas, according to the statement.

The researchers noted that sinking problems could be further exacerbated by climate change. As the planet heats up, droughts will likely create greater demand for groundwater and drive more extraction. Furthermore, the threat of flooding is likely to grow as climate change increases the frequency and intensity of extreme weather, according to the study.

Another problem is that cities are still growing, which means more people will live on subsiding land, and therefore there will be more demand for groundwater and more strain on infrastructure. The study found that vertical land motion has already put 29,000 buildings in high damage risk areas.

"As cities continue to grow, we will see more cities expand into subsiding regions," Ohenhen said. "Over time, this subsidence can produce stresses on infrastructure that will go past their safety limit."

Climate change intensified the catastrophic floods that swept through several U.S. states at the beginning of April, a new report has found.

At least 15 people have died as a result of the flooding, which devastated states like Tennessee, Arkansas and Kentucky between April 2 and 6. The southern Midwest and parts of the southeastern U.S. also experienced multiple rounds of tornadoes at the same time, which killed at least 9 people.

Now, researchers have studied how climate change may have played a role in the historic flooding and extreme weather. They estimated that human-caused climate change increased the likelihood of the flooding by about 40% and increased their intensity by about 9%, according to a report by World Weather Attribution (WWA), which studies how climate change influences extreme weather events.

However, it's still difficult for scientists to quantify our impact on global weather, and the researchers noted their estimates were conservative due to discrepancies between different climate models. The report also highlighted that an effective emergency response prevented what could have been an even larger catastrophe.

Related: Kids born today are going to grow up in a hellscape, grim climate study finds

The historic flooding came in the wake of extreme rainfall. These rains came when a high-pressure system over the East Coast and southeastern U.S. clashed with a low-pressure system to the west, and the boundary between these two systems stalled, so the rainfall kept hitting the same area. At the same time, the jet stream carried moisture into the region from the eastern Pacific as surface moisture came in from the Gulf of Mexico.

To estimate the degree to which climate change increased the likelihood and intensity of the flooding, the researchers analyzed historical data in the central Mississippi River valley alongside the rainfall data from April. The team found that both regional weather trends and enhanced sea surface temperatures led to more moisture being available when the rains fell, according to the report.

For example, the report highlighted the role of climate change in the increased moisture coming in from the Gulf of Mexico. Sea surface temperatures are increasing with global warming, and the team found that higher temperatures led to higher rates of evaporation in the Gulf of Mexico, which increased the amount of moisture available when the rains fell over the U.S.

Scientists are still teasing out the degree to which human activity has influenced any given extreme weather event, but it's clear we're causing the planet to heat up through burning fossil fuels and other activities. When the researchers just looked at overall warming, they concluded that an extreme rainfall event like the one in April is expected to occur every 90 to 240 years, based on current conditions, but it would be much rarer if the climate were 2.3 degrees Fahrenheit (1.3 degrees Celsius) cooler. This amount of warming made the event between two and five times more likely with 13% to 26% more intensity, based on the report estimates.

World leaders signed the Paris Agreement in 2015, which was an international treaty that promised to limit global warming to preferably below 2.7 F (1.5 C) and well below 3.6 F (2 C). Earth is now consistently above that target, with April representing the 21st out of the last 22 months to breach the preferred 2.7 F limit, according to the European Union's Copernicus Climate Change Service.

The authors of the report warned that we're heading for 4.7 F (2.6 C) by the end of the current century. Climate models predict that extreme rainfall will become more frequent and intense in certain regions as the world continues to warm.

At those levels of warming, such extreme rainfall events will likely double in frequency and be 7% more intense, according to the report.

A congested atmospheric pattern known as an "omega block" has brought extreme downpours and thunderstorms to parts of the U.S. over the past week, with flood warnings issued Wednesday (May 7) for the southern coasts of Texas, Louisiana and Mississippi.

Abnormally wet and windy weather struck New England Saturday (May 3), The Washington Post reported, and storms rolled over the Rocky Mountains and southern Great Plains Monday (May 5) through Wednesday. While many Eastern, Southern and Western states have experienced adverse weather due to the omega block, conditions in the north-central U.S. have remained mild and clear due to the location of the block.

But what, exactly, is an omega block? And how might it affect weather conditions in the coming days?

An omega block is an atmospheric phenomenon in which a blob of high-pressure air remains trapped between two blobs of low-pressure air for a prolonged period. This sandwich configuration forces weather fronts that usually bring rain from west to east to move up and around the high-pressure area, forming an upside-down U shape that resembles the Greek letter omega. Because weather fronts bring moisture, the ground beneath the two low-pressure areas receives abundant rainfall, but the ground beneath the high-pressure area stays dry.

Related: La Niña is dead — what that means for this year's hurricanes and weather

"In meteorology, blocks are types of pressure patterns that upset the usual eastward progression of our weather," the U.K. Met Office explained in a YouTube video. "The blocks can remain in position for several days, which will lead areas under them to have similar weather for a prolonged period of time."

Currently, a blob of high-pressure air is hovering over the north-central U.S., leading to settled weather conditions and relatively warm temperatures there. By contrast, the East, the West and parts of the South are sitting beneath two blobs of low-pressure air, meaning they are experiencing downpours, thunderstorms and cooler temperatures this week. Omega blocks move very slowly, so these contrasting conditions could last until the weekend and perhaps beyond, meteorologists say.

The role of the jet stream

Omega blocks occur when the jet stream — a fast-flowing air current that usually moves from west to east at an altitude of 5 to 7 miles (8 to 11 kilometers) above Earth's surface — starts to meander like a river. Strong winds within the jet stream may buckle and loop, slowing the current and making areas of low-pressure air closer to Earth's surface migrate unpredictably.

When these migrations happen, the jet stream can steer areas of low-pressure air around an area of high pressure, triggering an omega block. In general, low-pressure air leads to unsettled, cool weather conditions, while high-pressure air leads to more settled and milder conditions.

According to the U.K. Met Office video, a weak jet stream can also lead to another type of block — a "diffluent block" —where a blob of high-pressure air stagnates to the north of a blob of low-pressure air. As with omega blocks, the exact positioning of the high- and low-pressure blobs within a diffluent block determines the type of weather observed at Earth's surface.

Omega and diffluent blocks are most common in the spring but both can persist for several months around midsummer or midwinter, according to the Met Office.

Current forecasts

The current omega block is unlikely to budge before this weekend, and it could stay stuck even longer, an expert told USA Today.

Brian Hurley, a senior meteorologist with the National Weather Service's Weather Prediction Center, told the newspaper that although a temporary breakdown of the omega block could potentially occur, the atmospheric pattern would likely reinstate itself before the weekend and then persist through next week.

It's unclear when the omega block will break down for good, as it would require the jet stream to start flowing smoothly from west to east again, Hurley said. However, "we're not really seeing that now," he said.

There's also a remote chance that a second omega block could appear this week, according to The Washington Post, which would lock in yet more unruly weather.

On Oct. 29, 2012, Superstorm Sandy unleashed a 14-foot (4 meters) wall of seawater into New York City. Regionally, the storm killed 147 people, inflicted $50 billion in damage, and opened a window into the future.

By mid-century, flooding like this could become routine.

While the Statue of Liberty may not be submerged, low-lying places like Ellis Island could be underwater. By 2100, sea-level rise alone could approach Sandy's 2012 high water mark. The NYC Panel on Climate Change (NPCC) predicts up to 2.5 feet (0.76 m) of local sea-level rise by the 2050s and 9.5 feet (3 m) by 2100.

However, new evidence from Earth's past suggests these dire scenarios may be likely — and perhaps even conservative predictions.

Around 2.6 million years ago, the planet descended into the Quaternary, a period of alternating glacial-interglacial cycles that occurred roughly every 100,000 years. These cycles, driven partly by the planet's eccentric wobbles, tweak the amount of solar radiation reaching Earth. During cold (glacial) cycles, ice sheets sprawled across Antarctica, Greenland and North America, locking away water and lowering sea levels. In warmer (interglacial) times, the ice retreated and oceans rose.

The key to understanding today's rising seas may lie in the Last Interglacial (129,000 to 116,000 years ago), when global temperatures peaked at 1.8 to 3.6 degrees Fahrenheit (1 to 2 degrees Celsius) above preindustrial levels. Considering we're currently 2.7 F (1.5 C) above preindustrial levels, the Last Interglacial could presage changes in the coming decades as human-caused warming continues.

Related: Atlantic ocean currents are weakening — and it could make the climate in some regions unrecognizable

For years, researchers believed North America's Laurentide Ice Sheet disappeared very early in the Last Interglacial. But new evidence suggests the Laurentide lingered thousands of years after that. If true, this fundamentally alters our understanding of where and how quickly ice melted back then.

New models suggest that if the Laurentide persisted, Antarctica likely melted more — and more rapidly — than previously thought. And that has worrying implications for future sea levels.

"We all want to understand how small Antarctica's ice sheet became the last time Earth reached similar temperatures," Roger Creel, a geophysicist at Woods Hole Oceanographic Institution in Massachusetts who studies sea-level change, told Live Science. "Sea-level projections may be too low if Antarctic melt was underestimated."

Sea-level-rise projections

Global seas have risen a little less than 1 foot (0.25 m) since 1880. With the rate doubling since 2006, another quarter meter is all but certain by 2100. But that's likely an underestimate, as scientists expect accelerating polar melt.

The problem is pinning down how much the poles will melt.

Projecting sea levels is similar to forecasting a storm's path: We are trying to predict the future from past data. Unlike with a modern storm, however, very few of our sea-level records are definitive.

Direct measurements — taken from tide gauges and satellite data — capture just a blink of geologic time. The Liverpool tide gauge, one of the longest-running records, spans just 300 years, or 0.01% of the Quaternary. Predicting the future based only on direct measurements, then, is a bit like guessing a novel's ending from just the first few chapters.

Further back in time, the record gets murkier. Ancient glaciers obliterated much of the physical evidence that could help explain past climate changes. Where direct evidence survives — say, in ice cores or rubble piles — dating can be challenging. What's left is a patchwork of clues — fossils, sediments and ancient shorelines — that scientists piece together like detectives.

Patchwork of evidence

One person deciphering these ancient clues is Andrea Dutton, a University of Wisconsin-Madison geologist.

Far from Antarctica, jagged limestone scarps rise from the turquoise waters of the Caribbean. Beginning about 129,000 years ago, ice melted, seas swelled, and reefs grew to chase the sun. These reefs preserve evidence of sea-level fluctuations like mosquitoes in amber. Receding waters marooned these fossilized reefs on land, leaving them for researchers like Dutton to study.

Dutton has spent years tracking coral growth-and-death cycles to untangle how seas rose and fell during the Last Interglacial. Researchers still debate how high or fast seas rose, with estimates ranging from 6.5 to 33 feet (2 to 10 m) above present levels.

Dutton's work has taken her across the globe, and what she's found is perplexing. In the Caribbean, for example, sea levels peaked multiple times, whereas Chilean shores show no such patterns.

The public generally imagines uniform sea-level rise — a meter in Vancouver, a meter in Sydney. But that uniform rise "is a figment of our imagination," Dutton told Live Science.

In fact, deciphering ancient sea levels is maddeningly complex. That's partly because land surfaces aren't static, either. For instance, Dutton recalled researchers cataloging fossil corals in Papua New Guinea, only to find their study site uplifted by a sudden earthquake, which jumbled the geological record of historic sea levels. Aside from shifting coastlines, gravitational forces can distribute water unequally across the planet.

"That's why it's so important to look at many sites," Dutton said. "They all have different stories, yet clearly one thing must have happened in terms of global sea level."

Researchers initially attributed mysterious sea-level shifts — multiple peaks in some regions and falls in others — mainly to the melting and regrowing of Greenland and Antarctica during the Last Interglacial. But the idea of ice sheets regrowing when temperatures remained high never sat right with some. When evidence emerged from deep in the North Atlantic showing the Laurentide persisted, researchers needed a new model.

The lingering Laurentide

Creel set out to explain these mysterious sea-level patterns as part of his doctoral dissertation work under Jacqueline Austermann at Columbia's Lamont-Doherty Earth Observatory. Perched on rock once polished by the Laurentide Ice Sheet, the campus overlooks the Hudson River from a safe elevation above encroaching seas.

The Laurentide remains central to the big question: How high and fast will seas rise again?

Creel frames it like an accountant. Scientists typically budget interglacial sea levels from known suspects: ocean thermal expansion, Greenland, Antarctica and mountain glaciers. But the Laurentide adds a new line to the ledger.

For Creel and Austermann, timing is everything. "Antarctica is probably more vulnerable than we thought," Creel said. "If the Laurentide lasted longer, it may have masked how much Antarctica melted."

Once sprawling across 5 million square miles (13 million square kilometers) with ice up to 10,000 feet (3,000 m) thick, the Laurentide carved the Hudson River Valley and Great Lakes, growing and shrinking through ice ages. Today, evidence of it lingers in overgrown rubble piles and other topographic oddities. "The Laurentide is gone but not forgotten," Creel said.

For years, some scientists suspected a long-lived Laurentide, but hard evidence was scarce. That changed in 2022, when researchers studying North Atlantic sediment cores found signs of an enormous ice dam collapse 125,000 years ago — implying large amounts of North American ice.

A month later, a lead isotope study revealed the Laurentide lasted until around 122,000 years ago — well after temperatures rose during the Last Interglacial. And a 2023 study suggested this pattern wasn't unusual; sediments dropped from icebergs indicated the Laurentide melted only briefly and infrequently across multiple Quaternary interglacials.

To balance the books, Creel and Austermann fit together scattered and seemingly contradictory pieces of evidence — ice cores, fossils, sediments and geophysical properties — into a cohesive narrative.

A key element, they found in a study published late last year, was a process called isostatic adjustment. Ice sheets press down on the land; when they melt, the ground rebounds, altering Earth's rotation and gravity.

"It's like sitting on a cheap mattress," said Natasha Barlow, a paleoceanographer at the University of Leeds in the U.K. who was not involved in the study. "It sinks under your weight, and the other end rises — just like how ice compresses the Earth. When it melts, the 'mattress' rebounds, affecting sea levels differently depending on where you are."

Researchers already knew this process occurred, but the revised model's implications are striking: Antarctica experienced "rapid and drastic" ice loss early in the Last Interglacial — outpacing Greenland's melt — which caused the Antarctic crust to rise, sloshing water north. That raised sea levels in the Caribbean and other regions but caused them to fall near Antarctica. The process continued, lifting and dropping local seas differently in the global North versus the South.

"It was like a competition between the poles," Dutton said.

The model connected many puzzling data points, including the persistent Laurentide Ice Sheet and the confusing sea-level patterns of the Last Interglacial, Barlow said.

These findings help explain ancient sea-level puzzles, but they also hint at what's coming. If Antarctica melts faster than expected, places like New York will bear the brunt. While global seas may rise 6 feet (2 m) by 2100, New York could see a 10-foot (3 m) rise.

"For many years, we've said it's all about Greenland and Antarctica," Barlow told Live Science. "But the evidence over the last five years says, 'Hold on a second. Maybe the Laurentide persisted longer than we thought.' This is the first study seriously considering its influence at this level. If we're going to calibrate our models for the future, we need to think about this."

All eyes on West Antarctica

Because most of Antarctica's ice lurks below sea level, it is more vulnerable to melt than Greenland's land-based ice — precariously so in West Antarctica.

In 1978, glaciologist John Mercer warned that rising carbon dioxide levels could trigger the collapse of the West Antarctic Ice Sheet, causing 15 feet (5 m) of sea-level rise and the "submergence of low-lying areas." His claims, which initially drew accusations of alarmism, now appear eerily prescient.

Whether seas rise slowly or exponentially depends on carbon dioxide emissions and ice sheet behavior.

In the past decade, researchers have coalesced around the idea that marine ice sheet instability (MISI) may lead to considerable West Antarctic melt. In MISI, warm water melts ice along Antarctica’s coast, causing the grounding line — the ice's contact with the seafloor — to retreat. As the grounding line retreats inland, ice flows faster and more icebergs break into the ocean, accelerating ice loss in a self-reinforcing cycle. MISI, other ice retreat processes, and high-emission scenarios underpin the Intergovernmental Panel on Climate Change's (IPCC) worst-case predictions.

Mathieu Morlighem, a Dartmouth glaciologist who studies ice sheet physics, believes MISI may be inevitable.

"In all our simulations, West Antarctica collapses," Morlighem told Live Science, referring to model projections over the next few centuries. West Antarctica alone could contribute over 10 feet to global sea levels.

Evidence from the Last Interglacial also supports the modern observations that West Antarctica is especially prone to melt. Sediment and ice core studies published in 2021 and 2023 suggest West Antarctic ice melted or thinned significantly during the last warm period. Another 2023 study found octopus populations around West Antarctica interbred during the Last Interglacial, which would have been unlikely with an intact ice sheet.

Combined with data about the Laurentide, the emerging picture suggests West Antarctica melted significantly in the Last Interglacial and may do so again over the next several decades.

From the past comes the future

If recent findings hold up and significant West Antarctic melt is imminent, even our gloomiest predictions may be optimistic.

In the IPCC's "high impact, low probability" 2100 scenario, sprawling and vibrant low-lying areas — including the Jersey Shore; Manhattan's East Village and Financial District; the Rockaways; Coney Island; Red Hook, Brooklyn; and parts of Staten Island — would be perpetually submerged.

New York already experiences "sunny day flooding," but storm surges would magnify the damage. The NPCC concluded that, by the 2080s, rising sea levels alone — without any changes in storm frequency or intensity — could make today's "once-in-a-century" coastal floods happen twice as often, or even 10 to 15 times more frequently.

"I can't dunk. But if I raise the court a foot, my chances are better. Boost sea level, and you're looking at the potential for much greater flooding risk," Daniel Bader, a climate scientist at Lamont-Doherty and an NPCC member, told Live Science.

And the new insights from the Last Interglacial could lend weight to this scenario, which was once dismissed as extreme.

Still, several experts cautioned against drawing too many lessons from the past. Ancient clues are scattered, dates are imprecise, and the drivers of warming were vastly different then. Yet some experts told Live Science they believe the IPCC's worst-case models are, if anything, too conservative.

Unlike warm periods driven by natural processes, today's warming feels more dire, Dutton said. "Today we're forcing both [natural and human-induced warming] simultaneously," she explained. "Greenhouse gas concentrations are heating both poles at the same time." Warming during the Last Interglacial, by contrast, was likely focused more on the Northern Hemisphere.

For Klaus Jacob, a Columbia University geophysicist and climate mitigation expert, whether the worst-case scenarios are likely is beside the point. The possibility demands action: "Would you board a plane with a 10% likelihood of crashing?" Jacob said.

Jacob envisioned three possible responses: protection, with barriers like those that defend the Netherlands but failed catastrophically in New Orleans during Hurricane Katrina; adaptation, such as using stilts, abandoning ground floors, and embracing Venetian-style boat transport; and relocation.

New York only began earnest reflections after Superstorm Sandy but remains mired in bureaucratic inertia, Jacob said. Coastal defenses are stopgaps, he argued; the real solution is managed retreat. In other words: "Get the hell out."

That means moving to higher elevations, and potentially abandoning entire low-lying regions along the U.S. East Coast, Gulf Coast and swaths of Asia. And if the retreat isn't managed?

"It's chaos," Jacob told Live Science. "Chaotic retreat."

This story is part of The 89 Percent Project, an initiative of the global journalism collaboration Covering Climate Now.

The central U.S. could experience historic flash flooding this week as torrential rains and thunderstorms repeatedly strike the same areas, forecasters have announced.

Weather website AccuWeather has warned of the potential for a 1-in-1,000-year flood across northeastern Arkansas to western Kentucky, with the worst-hit areas to receive the equivalent of four months' worth of rain in just five days. In some cases, this will fall on areas that could be vulnerable to flooding, having already received a great deal of rainfall in recent months.

"We're concerned about the risk of life-threatening and historic flash flooding, which could evolve into a major river flooding event," Jonathan Porter, chief meteorologist at AccuWeather, said in a statement. "Dangerous situations can escalate to life-threatening emergencies in a matter of seconds with a flash flooding threat as serious as this."

Heavy rain is expected to fall from Wednesday night (April 2) through Sunday (April 6), leading to widespread flash flooding, particularly in the Lower Ohio Valley, Mid-South, and Arkansas, according to the National Weather Service.

Related: Giant, near-perfect cloud ring appears in the middle of the Pacific Ocean — Earth from space

The rain is flowing into the central U.S. from the tropics on an atmospheric river — a long, thin region of the atmosphere that transports heat and water vapor. The movement of water is expected to slow down and effectively stall between now and the weekend, resulting in a massive deluge of rain in the same few areas.

"A big area of high pressure off the coast of the Southeast U.S. will funnel moisture from the Caribbean and Gulf into parts of the central U.S.," Porter said. "The weather pattern will look like a traffic jam in the atmosphere, with repeating thunderstorms and downpours over the same areas. This is a recipe for big flooding problems."

Parts of Arkansas, Missouri, Tennessee, Illinois, Indiana and Kentucky are all expected to receive up to 1.5 feet (0.5 meter) of rain between Wednesday and Saturday (April 5), AccuWeather reported. Some of these same regions have already battled deadly flooding this year, particularly Kentucky, where flooding led to the deaths of at least 24 people in February.

Forecasters anticipate that the rains will ease off over the weekend, but rivers may continue to rise into next week. Porter noted that people in the affected areas should be prepared to make for higher ground.

"Relentless rainfall will cause problems along creeks, streams, and low-lying flood-prone areas first before evolving into a river flooding problem as all of the water tries to flow downstream," Porter said. "Be ready to move quickly to higher ground."

The historic Egyptian city of Alexandria is crumbling due to rising sea levels, scientists have found.

Over the past decade, the rate at which buildings have collapsed along the ancient city's seafront has increased from around one per year to as many as 40 per year, according to a study published Feb. 12 in the journal Earth's Future.

In the past 20 years, 280 buildings in this 2,300-year-old port city — known for being the birthplace of Cleopatra and the ancient home of the famed Library of Alexandria — have collapsed due to coastal erosion, and 7,000 more are at risk of collapsing in the future, according to the paper. Between 2014 and 2020 alone, 86 buildings completely crumbled, and 201 partially collapsed across the city, resulting in 85 deaths.

"The true cost of this loss extends far beyond bricks and mortar," study co-author Essam Heggy, a water scientist at the University of Southern California's Viterbi School of Engineering, said in a statement. "We are witnessing the gradual disappearance of historic coastal cities, with Alexandria sounding the alarm. What once seemed like distant climate risks are now a present reality."

The crumbling of coastal buildings results from sea level rise and the subsequent intrusion of seawater into the ground under the city. As saltwater creeps farther inland due to rising sea levels, it increases groundwater levels beneath buildings and other infrastructure and erodes the soil. This can lead the ground to sink, which makes buildings unstable and at risk of collapse. Additionally, saltwater corrodes the steel reinforcements of building foundations, further weakening the structures.

Average global sea levels have risen by between 8 and 9 inches (20 to 23 centimeters) since 1880, with a 4-inch (10 cm) rise since 1993 alone, according to the National Oceanic and Atmospheric Administration (NOAA). If nothing is done to curb climate change, U.S. sea levels could rise by as much as 7.2 feet (2.2 meters) by 2100 compared with the levels seen in 2000.

Low-lying cites face the highest risk of erosion and flooding due to sea level rise, especially those along the U.S. East Coast, West Coast and Gulf Coast, according to NASA.

"Our study challenges the common misconception that we'll only need to worry when sea levels rise by a meter," Heggy said. "However, what we're showing here is that coastlines globally, especially Mediterranean coastlines similar to California's, are already changing and causing building collapses at an unprecedented rate."

In the study, the researchers mapped collapsed buildings around Alexandria between 2001 and 2021, and compared satellite images from between 1974 and 2021 with maps of the city from 1887, 1959 and 2001 to determine sea level rise. Using this data, they determined that Alexandria has seen its coastline move inland by tens of meters over the past few decades, with some regions experiencing up to 79 to 118 feet (24 to 36 m) of soil erosion per year.

The researchers also analyzed chemical isotopes in the soils to determine the degree of soil erosion.

"Our isotope analysis revealed that buildings are collapsing from the bottom up, as seawater intrusion erodes foundations and weakens the soil," study co-author Ibrahim Saleh, a soil radiation scientist at Alexandria University, said in the statement. "It isn't the buildings themselves, but the ground underneath them that's being affected."

The researchers suggest several ways that Alexandria could prepare for the oncoming onslaught of seawater. These steps include building sand dunes and other barriers along the coast, elevating buildings, and relocating people who live in the highest-risk areas.

"Historic cities like Alexandria, which represent the cradle of cultural exchange, innovation and history, are crucial for safeguarding our shared human heritage," Heggy said. "As climate change accelerates sea level rise and coastal erosion, protecting them isn't just about saving buildings; it's about preserving who we are."

Another powerful winter storm hit the eastern U.S. over the weekend, causing widespread floods in Kentucky and leaving a number of people dead.

The storm killed at least nine people in Kentucky and one person in Georgia. However, officials expect the death toll to rise as rescue efforts continue this week, the weather website AccuWeather reported.

Kentucky governor Andy Beshear announced on Sunday (Feb. 16) that most of the state's deaths came from cars getting stuck in high water, The Associated Press (AP) reported.

"So folks, stay off the roads right now and stay alive," Beshear said, via AP. "This is the search and rescue phase, and I am very proud of all the Kentuckians that are out there responding, putting their lives on the line."

Since the storm began on Saturday (Feb. 15), more than 1,000 people have been rescued across Kentucky, but hundreds more are still stranded, AP reported. Beshear warned that more flooding was expected in the coming days, AccuWeather reported.

Related: Florida's snowfall record smashed as historic storm blasts Gulf Coast

The flooding is linked to a storm moving eastward across the country, while moisture is pulled up from the Gulf of Mexico.

The National Weather Service warned in a social media post on Friday (Feb. 14) that repeating rounds of heavy rainfall on Friday night and Saturday was going to bring a high risk of life-threatening floods to Kentucky.

Western Kentucky and Tennessee were at particularly high risk of flooding because the ground in the region was already soaked from previous stormy weather, exacerbating the threat posed by increased rainfall from the latest storm, AccuWeather reported.

Rescuers used boats to reach some stranded individuals as photographs on social media revealed roads, cars and parts of buildings submerged in water.

The flooding caused counties in several of the affected states to declare a state of emergency over the weekend. For example, parts of Tennessee's Obion County went into a state of emergency after a river embankment failed and flooded the small town of Rives, AP reported. Rives is still in a state of emergency, at the time of writing.

"There will be mandatory evacuations in effect for the residents in Rives due to the rising water, no electricity, and freezing temperatures creating a life-threatening situation," Obion County mayor Steve Carr said in a statement on Sunday, via AP.

The U.S. will continue to be pummeled by stormy weather this week as forecasters predict a blast of Arctic air will bring record-breaking cold to the central states between Tuesday (Feb. 18) and Thursday (Feb. 20). The northern Plains will experience wind chills between -30 degrees Fahrenheit (-34 degrees Celsius) and -60 F (-52 C), while below zero wind chills are expected to reach as far southern Texas, Arkansas, western Tennessee and Kentucky, according to a National Weather Service forecast.

This eerie satellite image shows a golden river of potentially toxic waste winding across the countryside after a deadly disaster at a diamond mine in South Africa.

On Sept. 11, 2022, a dam at a diamond mine in Jagersfontein suddenly collapsed, releasing a deluge of mining waste, known as tailings, which swept through the outskirts of the town and into the surrounding countryside, according to NASA's Earth Observatory.

The disaster killed at least three people and injured around 40 others, Bloomberg reported at the time. The flooding also destroyed dozens of houses, damaged cell phone towers, shut down roads, temporarily polluted drinking water and washed away hundreds of sheep, Reuters reported.

In the photo, you can see the collapsed section in the south wall of the dam. From there, the tailings flowed down the hillside in a massive, 1-mile-wide (1.6 kilometers) wave that eventually funneled into the nearby Wolwas Dam before spilling over into the adjoining Prosesspruit river.

Another aerial image of the site taken the day before the disaster (see below) helps show the scale of the torrent that was unleashed.

Related: See all the best images of Earth from space

In total, the dried tailings covered around 10 square miles (26 square kilometers) of farmland. Parts of the Prosesspruit also appear to have widened, suggesting that the torrent of mining waste may have eroded away the river's banks, according to the Earth Observatory.

It is unclear if any of the tailings remain in the area, but experts initially predicted that the dried waste would quickly crumble and either be blown away by wind or washed away by rain.

Toxic gold

Tailings are a muddy mix of dust, crushed rock, water and other byproducts left over from mining, according to Earthworks, a U.S.-based non-profit organization that supports communities impacted by mining and fossil fuel extraction.

The surplus slurry often contains trace quantities of metals, such as copper, mercury, cadmium and zinc, as well as other compounds, including petroleum, sulfuric acid and cyanide, according to Earthworks. This concoction makes the mixture appear gold when viewed from above, but also makes it potentially lethal to animals.

The diamond mine, once the deepest hand-excavated hole in the world, was also damaged from the flooding and has not reopened since the disaster. It is not clear if it ever will.

The mine produced two of the world's eight largest diamonds — the Excelsior Diamond and the Reitz Diamond, also known as the Golden Jubilee Diamond, according to the Cape Town Diamond Museum.

When the cosmos' first stars exploded in spectacular supernovas, they may have unleashed enormous amounts of water that flooded the early universe — and potentially made life possible just millions of years after the Big Bang, new simulations suggest.

However, this theory clashes with our current understanding of cosmic evolution and will be extremely difficult to prove.

Water is one of the most abundant compounds in the universe, according to NASA. Aside from Earth, astronomers have found water in several places throughout the solar system, including scattered above and below the surface of Mars, inside the ice caps of Mercury, surrounding the shells of comets and buried in underground oceans on several major moons. Outside our cosmic neighborhood, researchers have also detected water on distant exoplanets and within massive clouds of interstellar gas that permeate the Milky Way.

Until now, scientists assumed that all this water gradually built up over billions of years as hydrogen, the most abundant element in the universe, combined with oxygen that has been forged in the hearts of stars and expelled via supernovas. But in the new study, uploaded Jan. 9 to the preprint server arXiv, researchers simulated the explosive deaths of giant, short-lived early stars — which each had a mass equivalent to around 200 suns — and found that they could create the conditions needed for water to take shape.

The water from these stellar explosions would likely have formed at the hearts of dense clouds of hydrogen, oxygen and other elements left behind by stars. It may have had concentrations up to 30 times higher than the water seen floating in interstellar space within the Milky Way, the researchers wrote in the study, which has not been peer-reviewed yet.

Related: Could a supernova ever destroy Earth?

If correct, the new findings would have big implications for scientists' understanding of galaxy evolution and extraterrestrial life.

"Besides revealing that a primary ingredient for life was already in place in the universe between 100 million and 200 million years after the Big Bang, our simulations show that water was likely a key constituent of the first galaxies," the researchers wrote.

Early cosmic uncertainty

One of the biggest issues with the new study is that scientists have never directly observed one of the early stars that the researchers are modeling, known as population III stars. Instead, researchers have only indirectly observed a few of these stellar trailblazers by analyzing the stars that were birthed from their remains, so it's still not certain what they were really like.

If there was abundant water in the early universe, it would also suggest that the cosmos should have accumulated much more water than we currently see in our surroundings.

One explanation for this that has been posited by other scientists is that the universe underwent a drying-out period during which large quantities of water were lost, according to Universe Today. However, it is unclear what the cause of this event could have been.

"There is also the fact that while water formed early, ionization and other astrophysical processes may have broken up many of these molecules," Universe Today reported, meaning that the water from the first supernovas may have been short-lived.

Although water is a key ingredient for life on Earth, there is also no guarantee that its presence in the early universe would have made extraterrestrial life more likely.

For the first time, global warming exceeded 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels in 2024, new data has shown. That makes 2024 the hottest year on record.

Earth's average temperature in 2024 was around 2.9 F (1.6 C) above pre-industrial levels as greenhouse gas emissions hit an all-time high, according to the European Commission's Copernicus Climate Service.

And the effects of climate breakdown, and the human suffering it causes, are already evident — in unprecedented heatwaves, storms, droughts, floods and wildfires witnessed around the world.

"We are now teetering on the edge of passing the 1.5ºC level defined in the Paris Agreement and the average of the last two years is already above this level," Samantha Burgess, strategic lead for climate at the European Centre for Medium-Range Weather Forecasts (ECMWF), said in a statement. "These high global temperatures, coupled with record global atmospheric water vapour levels in 2024, meant unprecedented heatwaves and heavy rainfall events, causing misery for millions of people."

Global warming of 2 C (3.6 F) is considered an important threshold, as warming beyond this greatly increases the likelihood of devastating and irreversible climate breakdown. This includes the collapse of most of the Greenland and West Antarctic ice sheets, extreme heat waves, severe droughts, water stress, and extreme weather across large parts of the globe.

Related: The most important and shocking climate stories of 2024

Around 200 countries pledged to limit global temperature rises to 1.5 C or under in the 2015 Paris Agreement. As this target refers to an average taken over more than two decades, today's news doesn't mean the agreement is defunct, but it does make meeting the target perilously uncertain.

"There's an extremely high likelihood that we will overshoot the long-term average of 1.5 C and the Paris Agreement limit," Burgess said at a news conference on Thursday (Jan 9.).

Last year's record temperatures can be partly explained by El Niño, a climate cycle lasting between 9-12 months that causes waters in the eastern tropical Pacific to grow warmer than usual, affecting global weather patterns.

However, following El Niño's end in April 2024, temperatures did not return to their previous averages — sparking debate among scientists about whether other weather patterns, cuts to shipping pollution, or reductions in cloud cover could be driving the apparent acceleration in global warming.

"Not every year is going to break records, but the long-term trend is clear," Gavin Schmidt, director of NASA's Goddard Institute for Space Studies (GISS) in New York, said in a statement. "We're already seeing the impact in extreme rainfall, heat waves, and increased flood risk, which are going to keep getting worse as long as emissions continue."

It's too early to say what this means for 2025. Global sea surface temperatures, which hit a record high in 2024, appear to now be cooling to more typical levels. And La Niña, El Niño's cooler counterpart, has developed in the equatorial Pacific Ocean, which should reduce temperatures further.

"All of the internationally produced global temperature datasets show that 2024 was the hottest year since records began in 1850," Carlo Buontempo, Director of the Copernicus Climate Change Service, said in the statement. "Humanity is in charge of its own destiny but how we respond to the climate challenge should be based on evidence. The future is in our hands — swift and decisive action can still alter the trajectory of our future climate."

The most important Earth news in 2024 was undoubtedly the most depressing: Climate change wreaked havoc around the globe, indirectly causing flooding, drought, wildfires and other extreme weather events.

This year is on track to become the warmest year since records began and the first year that global temperatures have been 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels.

In May, levels of carbon dioxide (CO2) in the atmosphere — as measured from the National Oceanic and Atmospheric Administration's Mauna Loa Observatory — reached a record high of 426.90 parts per million. "Not only is CO2 now at the highest level in millions of years, it is also rising faster than ever," Ralph Keeling, director of the Scripps CO2 Program, said in a statement at the time. Global carbon emissions from fossil fuels also reached a new record high.

All that warming has had disastrous impacts on weather around the globe. The year started with one of the strongest El Niño events on record. That led to a devastating hurricane season that culminated in the deadliest storm to hit the continental U.S. in decades. El Niño also fueled a severe drought in the Amazon. This prolonged drought made the rainforest "more flammable" — an impact that led to the worst wildfire season in nearly 20 years.

And in Spain, torrential rain led to flash floods that killed over 200 people. Scientists also linked this dramatic weather event to climate change.

Climate change devastation edging closer

But some of the scariest news about the planet isn't what happened this year but rather what could occur if we don't stop spewing carbon into the atmosphere. A study published in June suggested ecological tipping points — such as the collapse of the Greenland Ice Sheet and the transformation of the Amazon rainforest into savanna — could be reached in just 15 years if climate change isn't controlled.

In October, scientists penned an open letter warning about the risk posed by the collapse of a key Atlantic current. In it, researchers urged policymakers to address the threat posed by the weakening Atlantic Meridional Overturning Circulation (AMOC) — a giant ocean conveyor belt that transports heat to the Northern Hemisphere, and the breakdown of which could cause temperatures across Europe to plummet.

We've also been warned that we're facing a global water crisis due in part to climate change and chronic mismanagement of resources. "For the first time in human history, we are pushing the global water cycle out of balance," Johan Rockström, director of the Potsdam Institute for Climate Impact Research and co-chair of the Global Commission on the Economics of Water, which produced the report, said in a statement. "Precipitation, the source of all freshwater, can no longer be relied upon due to human caused climate and land use change, undermining the basis for human wellbeing and the global economy."

Still, it's not too late to avert some of the worst of these futures. Michael Mann, presidential distinguished professor and director of the Center for Science, Sustainability and the Media at the University of Pennsylvania, believes it's not too late to stop the worst effects of climate change. "We [climate scientists] have, in some ways, failed to communicate that we can still avert catastrophic climate change," he wrote for Live Science in November.

"We actually decide how bad the climate crisis will get. There is still time to preserve our 'fragile moment,' but the window of opportunity is narrowing. There is urgency in reducing carbon emissions. But there is also still agency on our part in acting."

A strange weather phenomenon known as a DANA has caused catastrophic flash flooding in Valencia, Spain, this week. More than 155 people have died and dozens remain missing in what meteorologists are calling one of the worst natural disasters in recent memory.

On Tuesday (Oct. 29), some areas received the equivalent of a year's worth of rainfall in just a few hours, triggering massive floods that devastated entire towns and left thousands of people stranded. In some areas, rainfall reached up to 20 inches of rainfall (500 liters per square meter).

The cause of this disastrous weather is a phenomenon that forms in the Mediterranean called a Depresión Aislada en Niveles Altos (DANA),a Spanish phrase that translates to isolated depression at high levels. It was the most severe DANA recorded in the 21st century, comparable to the catastrophic "Pantanada de Tous" in 1982, according to Spain's State Meteorological Agency (Aemet).

What is a DANA?

DANAs are intensified versions of what's known as a "cold drop," which occurs when a mass of warm air collides with a stagnant mass of cold air at an altitude of around 29,500 feet (9,000 meters).

In the upper atmosphere, there is a very strong wind current that surrounds Earth like a belt. Sometimes, this current begins to oscillate, appearing more like a snake than a belt. When this happens, the oscillation can get "stuck," enabling the mass of cold air to remain in one place. On this occasion, it happened over southeast Spain.

A DANA occurs when this cold air meets very warm air near the surface, especially above the warm waters of the Mediterranean. This combination creates a significant temperature difference between the different layers of the atmosphere, which in turn causes the warm air to rise easily and become saturated with water vapor.

If this temperature contrast is combined with humidity and energy from the Mediterranean, which is very warm after the summer months, the result is heavy storms and torrential rain.

"The winds may not be as violent as those of a hurricane, but in terms of rainfall and intensity, they can even surpass them. These events can cause material damage and loss of life as significant as those of an average hurricane," Jorge Olcina, director of the Climatology Laboratory at the University of Alicante, told Live Science.

Iago Pérez, a geoscientist at the University of Oxford, described DANAs as one of the most dangerous meteorological phenomena in Spain, noting that "they release enormous quantities of water in a very short time."

DANAs form only over Spain, but similar weather patterns, called extratropical cyclones, form in the Atlantic off Uruguay and Argentina, the researchers said.

On Oct. 29, the DANA hovered over the same area for more than 12 hours, making it the most intense day of the weather event — which is expected to continue with less intensity until Sunday (Nov. 3).

DANAs use warm water as "fuel," meteorologist Mar Gómez told Live Science.

The DANA encountered water temperatures around 72 degrees Fahrenheit (22 degrees Celsius) off the coast of Valencia, while the usual temperature for this time of year is around 70 F (21 C). That difference may seem small, but it is enough to supply the storm system with extra energy. This can "trigger a cascade of rainfall in a very short period," Olcina said."These rains can be characterized as monsoonal."

What does climate change have to do with it?

Gómez and Olcina agree that the severity of this week's DANA is directly related to climate change. Pérez, however, thinks pinning the phenomenon on global warming requires deeper analysis.

The Mediterranean Sea is one of the marine basins that has warmed the most in recent decades. It acts as a "transmission belt for humidity and energy," Olcina said. Since the 1980s, the average temperature of the Mediterranean has increased by 2.7 F (1.5 C) — almost double the rise in air temperature in the region over the same period. "Since 2020, summers on the Iberian Peninsula have seen record temperatures, and this year, sea surface temperatures have exceeded 84.2 F [29 C]" Olcina said.

This warming has altered the timing of DANAs, as the Mediterranean now begins to heat up in May and retains that warmth through November. In comparison, during the 1980s and 1990s, this phenomenon generally occurred in September and October. Currently, an estimated 15% to 20% more DANAs form each year compared with six decades ago.

For researchers, this episode offers important lessons, beginning with the need to improve early warning communication protocols.

"When there are fatalities, it means that something has gone wrong. Communication and anticipation of these events must be enhanced," Gómez stated.

Climate change will likely fuel more frequent intense and exceptional precipitation events. This underscores the urgent need to adapt prevention and protection systems and to restructure vulnerable areas to reduce risks associated with an increasingly extreme climate, Olcina said.

Of all the hazards that hurricanes bring, storm surge is the greatest threat to life and property along the coast. It can sweep homes off their foundations, flood riverside communities miles inland, and break up dunes and levees that normally protect coastal areas against storms.

As a hurricane reaches the coast, it pushes a huge volume of ocean water ashore. This is what we call storm surge.

This surge appears as a gradual rise in the water level as the storm approaches. Depending on the size and track of the hurricane, storm surge flooding can last for several hours. It then recedes after the storm passes.

Water level heights during a hurricane can reach 20 feet or more above normal sea level. With powerful waves on top of it, a hurricane's storm surge can cause catastrophic damage.

Related: How strong can hurricanes get?

What determines how high storm surge gets?

Storm surge begins over the open ocean. The strong winds of a hurricane push the ocean waters around and cause water to pile up under the storm. The low air pressure of the storm also plays a small role in lifting the water level. The height and extent of this pile of water depend on the strength and size of the hurricane.

As this pile of water moves toward the coast, other factors can change its height and extent.

The depth of the sea floor is one factor.

If a coastal area has a sea floor that gently slopes away from the coastline, it's more likely to see a higher storm surge than an area with a steeper drop-off. Gentle slopes along the Louisiana and Texas coasts have contributed to some devastating storm surges. Hurricane Katrina's surge in 2005 broke levees and flooded New Orleans. Hurricane Ike's 15- to 17-foot storm surge and waves swept hundreds of homes off Texas' Bolivar Peninsula in 2008. Both were large, powerful storms that hit in vulnerable locations.

The shape of the coastline can also shape the surge. When storm surge enters a bay or river, the geography of the land can act as a funnel, sending the water even higher.

Other factors that shape storm surge

Ocean tides — caused by the gravity of the moon and sun — can also strengthen or weaken the impact of storm surge. So, it's important to know the timing of the local tides compared to the hurricane landfall.

At high tide, the water is already at an elevated height. If landfall happens at high tide, the storm surge will cause even higher water levels and bring more water further inland. The Carolinas saw those effects when Hurricane Isaias hit at close to high tide on Aug. 3, 2020. Isaias brought a storm surge of about 4 feet at Myrtle Beach, South Carolina, but the water level was more than 10 feet above normal.

Sea level rise is another growing concern that influences storm surge.

As water warms, it expands, and that has slowly raised sea level over the past century as global temperatures have risen. Freshwater from melting of ice sheets and glaciers also adds to sea level rise. Together, they elevate the background ocean height. When a hurricane arrives, the higher ocean means storm surge can bring water further inland, to a more dangerous and widespread effect.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Editor's note: This is a developing story that will be updated as Hurricane Milton approaches Florida.

Another catastrophic hurricane is barrelling towards Florida's Gulf Coast just 10 days after Hurricane Helene left at least 230 people dead and thousands of homes flooded across the Southeast.

Hurricane Milton, currently churning its way eastward from the western Gulf of Mexico, strengthened from a tropical storm into a Category 1 hurricane on Sunday (Oct. 6) night, according to the National Weather Service. By mid-morning Monday, it had exploded into a Category 4 hurricane with sustained winds of at least 150 miles per hour (241 km/h). As of 2 p.m. EDT, it had swelled into a Category 5 storm with sustained winds near 175 mph (280 km/h) and even higher gusts, according to the National Hurricane Center.

Officials forecast that the hurricane will maintain most of its intensity before it makes landfall in or near the Tampa Bay area on Tuesday night (Oct. 8) or Wednesday morning. Milton's winds will bring yet another deadly storm surge to Florida's west coast as the region still reels from Helene.

The appearance of the hurricane has prompted renewed evacuation orders across Florida. Republican Governor Ron DeSantis declared a state of emergency for 35 counties on Saturday, according to a statement from his office.

"I highly encourage you to evacuate," Kevin Guthrie, the executive director of the Florida Division of Emergency Management, said at a news conference on Sunday night. "We are preparing … for the largest evacuation that we have seen, most likely since 2017, [for] Hurricane Irma."

Related: We may need a new 'Category 6' hurricane level for winds over 192 mph, study suggests

In 2017, 6.8 million people evacuated their homes in advance of Irma, which killed more than 130 people across Florida and the Caribbean, according to the Federal Emergency Management Agency.

When it hits, Milton is likely to be particularly dangerous because it's landing on a region already devastated from a glancing blow by Helene. Helene was a Category 4 hurricane when it made landfall late on Sept. 26 — but even though Tampa Bay didn't sustain a direct hit, the area experienced storm surges up to eight feet (2.4 meters) high.

Milton is gaining strength rapidly because of its small pinhole eye, which has a maximum wind radius of 11 miles (18 km), compared to Helene’s 60 miles (97 km). Hurricanes with smaller eyes tend to be more powerful as they dissipate energy slower and spin faster.

"This is the most impactful storm we have faced, much stronger than Hurricane Helene," St. Petersburg Mayor Ken Welch said at a news conference. "We already will be rebuilding for years because of Hurricane Helene, and that will be exacerbated by the impacts of this storm."

"Remember, Hurricane Helene was 100 miles [161 km] away from us [in St. Pete], moving in a different direction," Welch added. "This is a powerful Category 2 or 3 hurricane headed directly for us," he said at the time. Since then, the storm has grown.

Hurricanes grow from a thin layer of warm ocean water that evaporates and rises to form storm clouds. The warmer the ocean is, the more energy the system gets, accelerating the formation process so that violent storms can rapidly take shape. This is why hurricane season occurs from June to November and why the most powerful storms in the Atlantic usually occur between August and September, when ocean temperatures peak.

Climate change has made extremely active Atlantic hurricane seasons much more likely than they were in the 1980s. Since March 2023, average sea surface temperatures around the world have hit record-shattering highs, giving storms like Milton and Helene an extra boost before they make landfall.

"Milton is the 3rd Atlantic storm to become a major hurricane since September 26 (Helene, Kirk)," Philip Klotzbach, a meteorologist at Colorado State University, wrote on X. "This is the most on record for the Atlantic between September 26 - October 7, breaking the old record of 2 set in 1893, 1941 and 1959."

Milan's marble facades and narrow, stone-paved streets look elegant and timeless. But all of that stone emits heat and does nothing to absorb rain, and temperatures and flooding in the posh Italian city are only predicted to increase in the coming decades.

In Jakarta, black floodwaters already rush into homes every winter along the Indonesian city's many rivers. That water is filled with sewage and harbors disease, but many people can't afford to move. Soon, climate change will put more of Jakarta — and many other low-lying cities — below sea level.

And in arid San Diego, water is already treated like a precious commodity. As drought increases in the coming years, protecting this resource will become even more important.

Human-caused climate change is transforming weather patterns and shifting ecosystems around the globe. In some places, climate change means too much water; in others, it causes drought. Global action is needed to curb fossil fuel use, slow the rise in temperatures and prevent the worst impacts of human-driven climate change. But significant warming is already baked in.

Cities will have to respond, and some are already taking bold steps. Milan is planting millions of trees. Indonesia is moving its capital city. And San Diego is recycling wastewater back into city taps — one of the first major cities to do so.

Each of these three cities offers a different roadmap for climate adaptation that has lessons for other places around the world. And while no single approach will be a silver bullet, each offers a hopeful vision of how we can learn to live and thrive on a warming planet.

In Milan, for example, the city is working to plant trees throughout the city, rather than just focusing on the wealthiest areas.

"I think it stands out as a successful role model that other cities can learn from," Matilda van den Bosch, a researcher with the European Forest Institute, told Live Science.

Milan: A forest in the city

Like many cities, Milan is a "heat island": Temperatures there are 7 to 14 degrees Fahrenheit (4 to 8 degrees Celsius) hotter than in surrounding rural areas. This is because buildings, roads and other infrastructure absorb and reemit heat from the sun better than forests and bodies of water do. And climate modeling predicts things will only get worse, with temperatures in the city rising by up to 4.1 F ( 2.3 C) by 2050.

To address this threat, the city has launched a public-private partnership called ForestaMi — or Forest for Milan — that aims to plant 3 million trees and bushes by 2030. As of 2024, it had planted more than 610,000 trees and bushes. The tree-planting initiative is part of a larger climate plan that Milan hopes will help it keep local warming below 3.6 F (2 C) by 2050.

In the urban planning world, planting trees is a popular climate mitigation strategy. Trees and other vegetation bring down temperatures by offering shade, absorbing and diffusing heat better than cobblestones and pavement, and releasing moisture into the air. Increasing tree canopies over European cities could save thousands of lives by blunting the impact of urban heat waves, according to a 2023 study in the journal The Lancet.

But planting trees may have other benefits, too. Replacing pavement with soil can help cities absorb more rainwater and reduce flooding. That will prove essential in Milan, which climate modeling predicts will face more torrential rain in the coming decades.

But tree planting has limitations. In July 2023, a sudden hailstorm hit Milan, downing 5,000 trees in just 15 minutes, city council member Elena Grandi told Live Science in an email. While storms like this are rare in Milan, Grandi noted, the city will face more river flooding and drought in the future, meaning it will need a mix of trees that can withstand such conditions.

"We have learned that it is necessary to plan urban green spaces in a different way, planting varieties more resistant to storms or to extreme temperature and water scarcity," Grandi said.

Jakarta: Mass relocation

Jakarta, a megacity roughly eight times larger than Milan, faces both too little and too much water. Sea level rise is already a crisis in low-lying Jakarta, a swampy city that is crisscrossed by 13 rivers.

Jakarta was built during the Dutch colonial era around a series of canals that never quite contained those rivers. Since 1990, Jakarta's population has more than doubled, further straining the city's infrastructure. Because Jakarta cannot provide enough piped water to its residents, owners of both high-rise condos and informal shacks dig illegal wells to pump groundwater, said Deden Rukmana, a professor and expert on Indonesia's urban planning at the University of Texas at Arlington, told Live Science.

This overpumping helped make the city one of the fastest-sinking areas in the world; some places are dipping 4 inches (10 centimeters) per year. Coastal flooding forces people out of their homes, and at current rates, 95% of the city's coastal district is estimated to be underwater by 2050.

And the risks are not confined to the coast. The combined effects of sea level rise and groundwater depletion will put the entire city below sea level by 2100, modeling predicts. Rising seas also mean that salt water will contaminate the city's freshwater supply.

To buy some time, Jakarta's city planners are already building and reinforcing dikes and estuaries closer to the shore. As a next step, they envision building a cluster of 17 islands shaped like a giant bird. Together, those islands would create an 80-foot-tall (24 meters), 25-mile-wide (40 kilometers) seawall and an artificial lagoon that planners hope will help buffer the city from tidal flooding.

But researchers warn that even a huge seawall won't prevent flooding if overpumping continues to drive subsidence inland. Efforts to relocate water-guzzling industries and to promote development in areas that are less prone to flooding are helping on that front, Rukmana said.

To stay above sea level, Indonesia's primary city will need to crack down on illegal wells and create alternate water sources, which could take years, Rukmana said. The city could also work to refill aquifers, as Tokyo has done.

But there is another step that could relieve pressure on Jakarta's groundwater: mass relocation. In 2019, Indonesia announced plans to move its capital from Jakarta to a new city called Nusantara, on the island of Borneo. The first civil servants are expected to move there in September 2024.

Like similar relocations in Brazil and Nigeria, Rukmana said, the project aims to relocate a colonial-era capital to a more central location within the country.

"Without any intervention, people will still move to Jakarta," Rukmana said. Nusantara won't change that right away, but it could have an impact over time. When Nusantara is built, the goal is that 10,000 civil servants will have their jobs relocated, he said.

Of course, relocating doesn't always go as planned. In 1999, Malaysia moved its prime minister's office from Kuala Lumpur to nearby Putrajaya, also due to water issues. Over the past two decades, its population has increased to 100,000 — but that number is less than one-fifth of the total population envisioned. Rukmana said building a new city from scratch is a big risk but one that could pay off for Indonesia if it provides a new source of development for the country.

So far, Nusantara is mostly just cleared land. But planners envision a smart city built around public transportation, walkable neighborhoods and electrification, with robust digital tools for management — a far cry from Jakarta's congested traffic, air pollution and overcrowding.

Indonesia recently partnered with the United Nations to get input from people living in Argo Mulyo, an existing village that will be incorporated into Nusantara's footprint.

Nusantara also has tree-planting goals, which are arguably even more ambitious than Milan's. The new city will be located on land that was previously used for industrial agriculture; it aims to reforest 204,000 acres (83,000 hectares) of rainforest. At the city's current planting densities, that would be the equivalent of tens of millions of trees.

So far, however, experts say those efforts are falling short, Mongabay reported. Non-native trees, such as Eucalyptus, are being planted instead of local rainforest species, and a phased approach may be needed to account for the area's damaged soil. For example, "pioneer" tree species may need to be planted first, followed by typical rainforest species, to replicate natural forest processes.

Nusantara city leaders say they are working on a master plan to address these challenges. In the long run, however, Jakarta still needs to address its own problems, Rukmana said.

San Diego: No-waste wastewater

While low-lying Jakarta struggles with flooding, arid San Diego faces drought. The California city, which gets less than 12 inches (30 cm) of rainfall a year, is predicted to experience hotter temperatures and less-predictable rain as climate change worsens.

But San Diego is in a better place than many cities because its climate adaptation actually began decades ago. When California faced a drought in 1990, San Diego's water supplier, the Metropolitan Water District of Southern California, temporarily cut the city's water supply by half.

"The political leaders in San Diego said, 'We just can't have this; we need to create our own water independence,'" Jeff Stephenson, now the director of water resources for the San Diego County Water Authority, told Live Science.

At that point, they began rolling out a low-flow-toilet initiative to reduce household water consumption that inspired similar efforts around the country. But San Diego was just getting started.

Over the past 30 years, the city has pulled just about every lever available to reduce demand. Low-flow toilets were followed by low-water landscaping and a water conservation partnership with inland agricultural areas.

Since it started conservation efforts, San Diego County has successfully halved its per capita water use and reduced its reliance on water from Los Angeles by even more. But water conservation on its own isn't enough. "You can't conserve your way completely out of a drought," Stephenson said. "You're still going to need water."

So, the water authority built and raised dams for more water storage and lined canals to prevent water from seeping away en route from the Colorado River. It built pumps to move water north within San Diego County, partly in case of droughts.

And San Diego also moved to beef up its local water supply. Because the city's plentiful ocean water makes up for its lack of groundwater, San Diego invested in the nation's largest desalination plant, which currently supplies around 10% of the region's water.

After three decades of work, plus a couple of wet winters, San Diego now has water to spare. It's even planning to lease some of its Colorado River supply to nearby cities.

And facing the likelihood of more climate-driven drought, the city is still aiming to do more. For that, San Diego is again looking to toilets for inspiration. Over the next decade, the city of San Diego and two suburbs plan to recycle wastewater back into city taps. It goes beyond gray water — not-quite-drinkable water that's used for landscaping, or indirect reuse, which mixes wastewater into other reservoirs first. Instead, San Diego wants to send purified wastewater directly back into the city's potable water supply. This is a new approach in California.

That level of purification may sound daunting, but when planners ran the numbers, it was cheaper than other waste upgrades, Stephenson said. San Diego County expects 18% of its water to come from recycled water by 2045.

All of these changes took political will. They also required substantial resources: San Diego benefits from a stable population, plenty of funding and efficient government systems, which many cities worldwide lack.

And for San Diego — as well as Milan, Jakarta and Nusantara — one moonshot project will not be a silver bullet for avoiding climate impacts.

Stephenson encouraged cities to use a variety of approaches — and to stick it out. Change happens one step at a time. "It's a slow process," he said, but as in San Diego, the results eventually come.

Editor's Note: This story was updated on Tuesday, Sept. 24 at 9:30 a.m. EDT to update Deden Rukmana's affiliation after a recent move and to correct the name of the water authority that supplies San Diego's water; it is the Metropolitan Water District of Southern California, not Los Angeles. The article was also updated to clarify that San Diego's water recycling project goes beyond indirect reuse.

Severe turbulence, record rainfall, killer heatwaves and raging wildfires to name but a few: is it just me, or is "Is Earth's weather getting weirder?" The answer? Yes. Well, sort of. 

These weather events have happened in the past, but the problem is nowadays they're happening more frequently and to a far greater extent. 

What's causing this uptick in "global weirding" and is there anything we can do about it? Space.com spoke with a leading climate scientist Katharine Hayhoe to learn more about this strange surge in weird weather events and what it means for us.

Related: 'The last 12 months have broken records like never before': Earth exceeds 1.5 C warming every month for entire year

It's no secret that Earth's climate has changed dramatically over its 4.5 billion-year history. Nature has seen both warmer and colder conditions before. But it is the current rate of change that is putting the living world at risk.

"Each of us, wherever we live, are experiencing the impacts of climate change today," climate scientist Katharine Hayhoe told Space.com in an interview. 

Some of us might not even be aware of the impacts climate change is having on our everyday lives. From how more extreme weather events are causing home insurance rates to rise, or how our food is becoming less nutritious and drinking water more scarce, whether we like it or not, we are all affected by climate change.

One significant direct effect of climate change is the upturn of extreme weather events that put lives at risk and have a huge economic impact. Extreme weather events attributable to climate change cost the world $143 billion USD per year, the majority of which (63%) is due to loss of human lives, according to a research paper published in the Journal Nature in 2023. 

But just how is Earth's weather getting weirder?

Heat waves

Let's begin with one of the more obvious effects of climate change: heat waves. As the world gets warmer, heat waves are not only becoming more frequent but also much more intense. 

The recent heat wave along the U.S. West Coast saw Las Vegas hit its all-time temperature record of 120 degrees Fahrenheit (49 degrees Celsius). Approximately 36 million people were exposed to an excessive warning during the extreme heatwave with temperatures running as much as 20 degrees above average for this time of year.

In Saudi Arabia, over 1,300 people died during the annual Hajj pilgrimage that coincided with an exceptional heatwave. Temperatures of 125 degrees Fahrenheit (52 degrees Celsius) were reported at the Grand Mosque in Mecca, according to the BBC. Greece has just experienced the earliest heatwave recorded in the country, and several tourists died, including British TV and radio presenter Michael Mosley. Meanwhile, northern India is reeling from the most severe heat waves it has ever seen with reported temperatures of 120 degrees Fahrenheit (49 degrees Celsius). Summers in India are notoriously hot and humid, but this year's heat waves have been longer, more intense and far more frequent, according to the BBC. 

Heat waves occur when a high-pressure atmospheric system moves in and pushes warm air down toward the ground. The trouble we are currently facing is that the high-pressure systems are being reinforced as the planet warms, catalyzing a vicious cycle. 

"The warmer it is, the stronger the high-pressure system, and the stronger the high-pressure system, the warmer it is," Hayhoe explained. 

Heavy rainfall and flash floods

Another by-product of a warmer world is that a warmer atmosphere holds more water vapor. Wherever moisture-laden air passes over land or converges into a storm system, it can produce more severe precipitation, for example, heavier rain and snow storms.

Atmospheric rivers are one of the big players when it comes to heavy precipitation events. An atmospheric river is a river of moisture in the sky. When one of these approaches a mountain, the air is forced to rise. As it does, the air cools and the water condenses and falls out as rain.

"So what's happening is atmospheric rivers are getting stronger and bigger because they're picking up a lot more water vapor. After all, the warmer it is, the more water evaporates from the ocean." Hayhoe continued.

During the 2023/2024 fall and winter seasons, rainfall in the U.K. and Ireland was about 20% heavier due to human-induced climate change, according to the World Weather Attribution.

This year, downpours and floods have already wreaked havoc around the world, and it doesn't look like stopping anytime soon. In May a catastrophic flood struck Afghanistan, killing over 300 people in the provinces of Baghlan, Takhar and Badakhshan. In June, heavy rain swept across Switzerland, France and Italy causing landslides and torrential floods, at least seven people are reported to have been killed. In India, Nepal and Bangladesh large-scale flooding is not uncommon during the monsoon season but this year's abnormally early heavy rainfall has killed more than 40 people so far.

Hurricanes, typhoons and cyclones

Hurricanes and typhoons are a type of weather phenomenon known as tropical cyclones. Tropical cyclone is an overarching term used to describe a rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters and has closed low-level circulation, according to the National Oceanic and Atmospheric Administration (NOAA). Once wind speeds reach 74 miles per hour or higher, a tropical cyclone is classified as a hurricane, typhoon or tropical cyclone depending on where the storm originates. The term hurricane is used in the North Atlantic, central North Pacific, and eastern North Pacific. The term typhoon is used for a disturbance in the Northwest Pacific, while the generic tropical cyclone term is used in the South Pacific and Indian Ocean. 

No matter their name, these storms are unique in that they're powered by warm ocean water. 

The planet's oceans are particularly vulnerable to climate change and our warming world. "90% of the extra heat being trapped inside the climate system is going into the ocean, not the atmosphere," Hayhoe explained. This means that there is a lot of energy to power stronger storms. As such, a far greater proportion of named storms are further intensifying and developing into hurricanes, typhoons and tropical cyclones. 

"The storms are not only there intensifying faster, they're moving more slowly. So they're sitting over you for longer and they're dumping much more rain," Hayhoe continued. 

Hurricane Harvey, which hit the U.S. in 2017, was the first significant hurricane to hit the U.S. where scientists could calculate how much of an effect climate change had on the event. Scientists found that climate change made the rainfall over Houston, Texas, during the hurricane event, three times more likely and 15% more intense.  

Wildfires

Another significant effect of climate change is a rise in how often severe wildfires occur. Wildfires have destroyed over 1.7 million acres of land during the first three months of 2024 in the U.S. alone, according to the Independent.

Though a majority of wildfires in heavily populated areas like the U.S. are due to accidental human ignition, they are exacerbated by climate change, specifically hotter, drier weather. 

"Imagine that you accidentally drop a match into a pile of green wet wood. What happens? Not much, imagine if there's snow around the wood, nothing happens" Hayhoe explains "Now imagine you drop that match into a pile of bone dry wood that's been baking in extreme heat for weeks, and even months," Hayhoe continues.

"That's why we see that the area burned by wildfires and the number of large wildfires is increasing."

Wildfire seasons are also coming earlier and lasting longer. For example, this year's wildfire season in Canada began in February, just like it did last year. In the past, however, it wouldn't start until March.

Last year (2023), Canada witnessed a fire season like no other, with approximately 45 million acres burned by over 6,500 fires. To put this into perspective, the total area burned in 2023 was eight times higher than the 40-year average, according to a report by the BBC.

Unfortunately, this devastating scenario will become more common due to climate change.

Unlike U.S. wildfires, most of the wildfires in the northern forests, like the ones observed in Canada, are caused by lightning strikes, not humans. Scientists predict an increase in lightning frequency by 11-31% for every degree of global warming, according to the BBC's report. This is because warmer air can hold more moisture, about 7% more moisture per 1.8 degrees Fahrenheit (1 degree Celsius) of warming. As moisture is a key ingredient in thunderstorm development, the more moisture in the air, the higher the chance of thunderstorms and accompanying lightning strikes.

Air turbulence

In May 2024, a Singapore Airlines flight encountered a severe bout of turbulence which left one person dead from a suspected heart attack and several others badly injured. The same month, a Qatar Airways flight from Doha to Ireland endured strong turbulence over Turkey, leaving 12 people injured. In July 2024, dozens were injured after an Air Europa flight was hit by severe turbulence; the flight from Spain to Uruguay had to make an emerging landing in Brazil. 

A bit of turbulence is par for the course for air travelers. But a recent uptick in severe incidents has left people wondering whether climate change is to blame. 

It's a difficult one to pin directly onto climate change but there is evidence to support that it could be increasing the risk of turbulence, according to the BBC.

Two main types of air turbulence affect air travel, one is from thunderstorms and the other is called "clear air" turbulence.

Turbulence caused by thunderstorms is likely to increase because the frequency of thunderstorms is increasing due to climate change, as previously discussed. But this type of turbulence is less problematic for pilots, as it is linked to storms and therefore easier to predict. 

The other type, "clear air" turbulence, also called "invisible turbulence" is highly unpredictable and is one of the largest causes of weather-related aviation incidents. It is expected to worsen with climate change, and under specific climate change scenarios, it could become four times more frequent by 2050 compared to historical levels.

All hope is not lost

"Wherever we look around the world, we see that these weather events are getting supersized by climate change, and they're putting us all at risk," Hayhoe explains.

Though it may be hard to find any positives in a sea of negative climate change news, rest assured that the tides are changing. People are increasingly recognizing the impacts and severity of climate change. However, it remains uncertain if this awareness is spreading quickly enough. What is clear is that we all share responsibility for climate change and can take steps to mitigate it.

Without action, there is no hope. 

What you can do to help

If you're like me and often feel overwhelmed by the negative effects of climate change while also thinking "How can I help, I'm just one person?" Hayhoe has laid out a great list of how individuals can help catalyze change for the better and feel like they are making a difference. 

• Start a conversation about why it matters, and what people can do. "That's why I do my newsletter every week," Hayhoe explains. Every week Hayhoe provides a clear-eyed and hopeful look at climate science and solutions. 
•  Join a climate action group. Don't be alone, join one in your town, in your city, at your school, at your church, wherever it is. And if you don't have one, think about setting one up, Friends of the Earth have some useful tips on how to start.  
• Consider where you keep your money. "Where we bank, the credit card we use, where we have our pension or retirement, if it's invested in fossil fuels, it's perpetuating the system," Hayhoe explains. We should be looking at banks that invest in clean energy and environmentally friendly enterprises like clean energy, that way we are actively contributing towards a better world with our own money.  
• Spark ideas for change wherever you work or wherever you go to school. "That's using your voice specifically, saying why don't we do this together as a business or an organization?" Hayhoe says. 
• Hold politicians accountable. Hayhoe explains that this doesn't only mean voting but also using your voice to tell them why it matters. "Studies have shown that politicians consistently underestimate how concerned their constituents are because they don't hear from them enough," says Hayhoe. 
• Reduce your personal footprint. The environmental charity World Wildlife Fund has some useful resources on how you can reduce your carbon footprint, from changing the way you travel to what you eat.  

Originally posted on Space.com.

This 2020 satellite image shows tea-like "blackwater" bleeding into the sea from South Carolina's Winyah Bay around two weeks after Hurricane Sally made landfall and triggered widespread flash flooding.

Winyah Bay is a coastal estuary that's located near Georgetown, South Carolina, and flows into the Atlantic Ocean. It is fed by four blackwater rivers: the Waccamaw River, the Pee Dee River, the Black River and the Sampit River, all of which run through eastern South Carolina.

Blackwater rivers flow through swamps, wetlands, forests and other ecosystems that are rich with decaying vegetation. As it breaks down, this rotting vegetation releases chemicals such as tannin, phenol and humic acid, which stain the water brown — similar to brewing tea, according to NASA's Earth Observatory.

The staining material is known as colored dissolved organic matter (CDOM). After heavy rains, the floodwater gathers more CDOM and feeds into nearby rivers, before being washed into Winyah Bay and then flushed into the ocean.

Related: 12 amazing images of Earth from space

On Sept. 16, 2020, Hurricane Sally made landfall in Alabama with max winds of around 110 mph (177 km/h). The Category 2 storm dumped up to 30 inches (76 centimeters) of rain across Florida, Alabama, Georgia, South Carolina and Louisiana, triggering flash flooding in most of those states, according to a National Weather Service report.

On Oct. 1 (the day this photo was taken), monitoring stations in Winyah Bay revealed that the levels of CDOM in the estuary were more than 50% higher than average for that date. Most of the CDOM ended up in the ocean, according to NASA's Earth Observatory.

Increased CDOM levels in the ocean mean that less blue light can penetrate deep into the water column. Only red light can be absorbed deep below the surface, giving the water a rusty color when viewed from above.

The change in available light also affects some photosynthetic algae.

"If phytoplankton do not have pigments that can absorb red light, then they will not be able to photosynthesize," Tammi Richardson, an oceanographer at the University of South Carolina, told NASA's Earth Observatory at the time. This can have big knock-on effects on the food webs across the coastal ecosystems, she added.

However, some plankton, such as cryptophytes and diatoms, can still absorb red light, which lets them thrive in blackwater, according to NASA's Earth Observatory.

Nearly half of China's major cities are sinking due to groundwater extraction and the sheer weight of urban buildings and infrastructure, a new study finds.

The affected cities, which include Beijing and Tianjin, are concentrated in the eastern part of the country and along the coast. Combined with sea level rise, falling cities could expose around 10% of China's coastal population — between 55 and 128 million people — to flooding and irreparable damage by 2120.

For the study, published Thursday (April 18) in the journal Science, researchers measured land subsidence in every Chinese city with a population of more than 2 million people over the period from 2015 to 2022. Of the 82 cities they examined, 45% are sinking by more than 0.1 inches (3 millimeters) per year, with 16% falling by more than 0.4 inches (10 mm) per year.  

These major cities are home to three-quarters of China's urban population, which totaled 920 million people in 2020 — the largest of any country in the world, according to the study.

"The subsidence appears to be associated with a range of factors such as groundwater withdrawal and the weight of buildings," the researchers wrote in the study. "High-rise buildings are sprouting up, road systems are expanding, and groundwater is being used, all at a rapid pace."

Related: East Coast cities are sinking at a shocking rate, NASA images show

While it was already known that Chinese cities are subsiding, the study provides a first snapshot of the problem on a national scale. The researchers used data from the Sentinel-1 satellites, which measure vertical changes in Earth's surface with Interferometric Synthetic Aperture Radar (InSAR) instrumentation, and combined these land motion results with groundwater assessments from monitoring wells and building weight data.

"In addition to the national pattern of city subsidence, we identified several natural and human factors that were associated with city subsidence," the team wrote in the study. Natural factors included the geological setting of each city and the depth of the bedrock, which influenced the amount of weight the ground could hold up without sinking.

The researchers found a strong link between sinking cities and groundwater loss, which leaves empty pore space in the crust that becomes compacted as weight piles on above. "Most of the groundwater changes were anthropogenic," the researchers wrote, with natural rainfall patterns making up for just 12% of the variation. 

Groundwater extraction is causing cities to sink worldwide, including on the U.S. East Coast.

Other factors contributing to subsidence were urban transportation networks — with trains adding to the weight and producing vibrations — as well as hydrocarbon extraction and mining, which both create empty pockets in the ground that eventually collapse and compact.

But "the key to addressing China's city subsidence could lie in the long-term, sustained control of groundwater extraction," the researchers emphasized.

Subsidence threatens infrastructure and people by destabilizing and fissuring the ground, and by increasing the risk of floods, according to the study. Sinking cities on China's east coast could soon drop below sea level, with up to 26% of the country projected to deflate below that threshold in the next 100 years. Currently, around 6% of Chinese land sits below sea level. 

"Subsidence jeopardizes the structural integrity of buildings and critical infrastructure and exacerbates the impacts of climate change in terms of flooding, particularly in coastal cities where it reinforces sea-level rise," Robert Nicholls, a professor of climate adaptation at the University of East Anglia in the U.K., who was not involved in the research, said in a statement.

Nicholls agreed with the study authors that slowing groundwater extraction could stave off subsidence, as it has previously done in Tokyo. "Tokyo subsided around the port area, up to five meters [16.4 feet] in the 20th century," Nicholls said. In the 1970s, authorities "provided good piped water from other areas and they also had a law saying 'you will not use well water' and essentially it stopped the subsidence."

Scientists have created a "digital twin" of our planet that can be used to predict weather far faster than traditional services.

The technology could help prevent some of the catastrophic impacts of disasters such as typhoons and flooding. The intensive data-crunching system could also give us a more detailed view of the future effects of climate change and reveal clues about how to mitigate it.

The system is built by Nvidia, a multinational company that builds graphics processing units (GPUs), which are electronic circuits that can carry out high-speed mathematical equations that enable activities such as machine learning, a type of artificial intelligence (AI).

The platform, called Earth-2, contains a suite of machine learning technologies developed by Nvidia, all of it driven by supercomputers to provide the immense processing power needed to do the job.

Combined, these create "a virtual replica of a physical object or system, in this case, Earth's climate," Dion Harris, head of data center product marketing at Nvidia, told Live Science.

The system takes the form of an interactive interface that runs simulations of weather and climate across the planet, allowing users to set different parameters and simulate weather in different locations at a highly detailed 1.2-mile (2 kilometers) scale.

Related: Atlantic's hurricane alley is so hot from El Niño it could send 2024's storm season into overdrive

The AI technology has been trained on global datasets that provide hourly estimates of land, atmospheric and ocean climate variables. This system "synthesizes hundreds of observations and reconstructs Earth's weather and climate over the last 50 years or so," Harris said.

The intensive training means the AI can quickly sift through troves of weather and climate data, churning out thousands upon thousands of potential outcomes and ultimately calculating the probability of certain weather outcomes in a particular location.

When it comes to approaching weather systems that could put lives at risk and cause millions in damage, Nvidia's system can therefore provide real-time predictions in seconds, rather than minutes or days, Harris said.

That can make the difference between life and death in places like Taiwan, where typhoons are frequent and catastrophic.

"When a typhoon warning is launched, the priority is to minimize casualties by carrying out early evacuations," Harris said. For these reasons, Taiwan's Central Weather Administration is one of the first to trial Nvidia's Earth-2 system and will be using it to forecast, plan for and protect against extreme weather events this year.

The technology can also provide a detailed longer view of climate change. Predicting how climate change will unfold, and what its effects will be, requires the processing of vast and numerous data streams on greenhouse gas emissions, temperature, global water cycles, land-use change, ocean chemistry and more. It also requires knowing how changes will unfold on global, regional and local scales, necessitating high data resolution.

Earth-2's supercomputing power could rapidly parse through these vast data streams to build accurate, predictive simulations, its developers say. That might help cities explore the likelihood and intensity of future heat waves, for instance, and take steps now to start mitigation measures.

Park rangers in Death Valley are scratching their heads as to how the desert's phantom lake has persisted for more than half a year — likely its longest lifespan in living memory. A recent rain dump also means that the puzzling pool of water, which normally dries up within weeks of appearing, could remain intact for several more months.

The ephemeral, or temporary, lake is found in the heart of Badwater Basin — a large, flat drainage basin located within the eastern border of Death Valley National Park in California. The basin is around 282 feet (86 meters) below sea level — the lowest point in North America — and is normally a dry, dusty wasteland. Most of the time, it's covered in crystalized salt, as well as occasional puddles of toxic water that seep up from a submerged spring. But after heavy rainfall, water from the rest of the park flows into the basin and creates a shallow freshwater lake.   

Normally, the lake only lasts for a few weeks because Death Valley's scorching heat causes the water to evaporate faster than any fresh water can be added. Most years, the lake barely forms due to a lack of precipitation: On average, the park receives just 2 inches (5.1 centimeters) of rain annually.

On Aug. 20, 2023, the remnants of Hurricane Hilary unleashed around 2.2 inches (5.6 cm) of rain on Death Valley, creating a large lake in the basin that was up to 7 miles (11.3 kilometers) long, 4 miles (6.4 km) across and 2 feet (0.6 m) deep — its largest size for almost 20 years, according to NASA's Earth Observatory. 

Over winter, the lake shrank to more than half this size and was just a few inches deep — but it did not completely dissipate.

Related: Over half of the world's largest lakes and reservoirs are losing water

"Most of us thought the lake would be gone by October," Death Valley park ranger Abby Wines said in a National Parks Service (NPS) statement. "We were shocked to see it still here after almost six months."

Between Feb. 4 and Feb. 7, an atmospheric river — corridors of atmospheric water vapor that can stretch for thousands of miles — dumped another 1.5 inches (3.8 cm) of rain across Death Valley, which refilled the lake back to close its original size, prolonging its lifespan for the foreseeable future. In total, 4.9 inches (12.4 cm) of rain have fallen in Death Valley over the last six months. 

Records aren't normally kept for the size of the lake and how long it has previously lasted, Wines told Live Science in an email. The last time the phantom lake reached a similar maximum size, in 2005, it only lasted for a few weeks before drying up, according to the Earth Observatory. Therefore, the lake's current lifespan is a major anomaly.

Park rangers have "no idea" why the lake has persisted so long, Wines added. "This is weird!"

The lake is currently deep enough to allow park visitors to kayak on its surface, according to FOX Weather. The lake is not expected to stay this deep for long, but Wines believes it could still be there in late April.

The recent atmospheric river also brought a rare dusting of snow to the tallest peaks in Death Valley, which is another extremely rare phenomenon, according to NPS.

 A strong El Niño could cause more floods across cities along the western coasts of the Americas this year, swamping roads and inundating buildings, a NASA analysis warns.

This year's El Niño — a warming of surface temperatures from the Central to East Pacific Ocean — could unleash up to five "10-year flood events" this winter in cities such as Seattle and San Diego.

Ten-year floods (those that have a 1-in-10 chance of occurring in any given year) lead to moderate flooding, according to the National Oceanic and Atmospheric Administration, causing exposed roads and buildings to be partially inundated and prompting limited evacuations. There is a 55% chance of El Niño being at least “strong” and a 35% chance of it being "historically strong" this November-to-January season, the U.S. Climate Prediction Center (CPC) said.

Related: Florida waters now 'bona fide bathtub conditions' as heat dome engulfs state

And by the 2030s, climate change and rising sea levels could cause similar floods along the West Coast each year without El Niño, the researchers said.

"I'm a little surprised that the analysis found these 10-year events could become commonplace so quickly," Phil Thompson, an oceanographer at the University of Hawaii at Mānoa and a scientist on NASA's sea-level-change science team, said in a statement. 

The El Niño Southern Oscillation occurs every two to seven years and is a natural shift in sea surface temperatures that causes equatorial trade winds, which tend to blow water east to west, to weaken or reverse, causing warm water to flow eastward. This causes global temperatures to increase by about 0.36 degrees Fahrenheit (0.2 degrees Celsius), according to the World Meteorological Organization. 

The effects of an El Niño event, which typically last' nine months to two years, are global. The current El Niño, which began in June 2023 and is expected to last until at least April 2024, has already paired with climate change to make 2023 the hottest year on record, causing record droughts across East Africa, Indonesia, Australia and the Americas. 

And the biggest effects are likely still to come, given that the strongest effects tend to happen between January and March.

To investigate how the oscillation is affecting this year's sea levels, NASA used the Surface Water and Ocean Topography (SWOT) and Sentinel-6 Michael Freilich satellites to gauge the height of the ocean before and after this year's El Niño.

The coming flooding is a harbinger of the effects of rising sea levels.

"As climate change accelerates, some cities will see flooding five to 10 times more often," said Nadya Vinogradova Shiffer, a SWOT program scientist and the director of the ocean physics program at NASA.

By monitoring sea surface temperatures, programs like SWOT can help planners prepare ocean defenses and evacuation plans, the researchers said.

An oasis teeming with ponds and wildflowers has formed at Death Valley National Park, one of the hottest and driest places in the world, following a major hurricane this summer.

Hurricane Hilary, which hit the area in August, provided some much-needed rainfall for the national park, located in eastern California, according to CNN.

"It is definitely a rare and special event," Death Valley National Park spokesperson Abby Wines told CNN. She added that this kind of precipitation event occurs only about once a decade.

Related: Drought in the US Southwest is worst recorded in history

The hurricane arrived in Death Valley on Aug. 19 and continued dousing the desert for 24 hours. Records indicate that 2.2 inches (5.6 centimeters) of rain was measured at Furnace Creek, a site inside the 5,270-square-mile (13,650 square kilometers) national park, breaking the previous record of 1.7 inches (4.3 cm), set in 2022, according to the National Park Service (NPS).

A month after the storm, park officials took a boat onto the ephemeral lake that had formed at Badwater Basin, a salt flat that marks the park's lowest point, and measured its depth at roughly 1 foot (0.3 meters). In the time since, the water has receded to only a few inches.

"I wish we knew exactly how long it will last," Wines told CNN, but she estimated that the pool could hang around until November. If visitors want to see the oasis for themselves, "the sooner, the better," she suggested.

Due to flooding, officials shut down the park temporarily. The park has since reopened, but several roads remain closed, according to the NPS.

"Every road in the park was damaged," Wines told CNN. "We still have a lot of work ahead of us. It was a lot of rain [from Hilary], and it's going to take a while for all that water to evaporate — even in the desert."

The last time a lake sprang up in Death Valley was in 2019, when a 10-mile-long (16 kilometers) body of water formed. 

Hurricane Idalia has reached northern Florida and continues to batter the state with torrential rain and howling winds, despite dropping from a Category 4 to a Category 2 storm.

Idalia made landfall in Florida's Big Bend region around 7:45 a.m. local time on Wednesday (Aug. 30), according to the National Hurricane Center (NHC). The storm first hit the west of Cuba on Monday and Tuesday (Aug. 28 and 29), where it destroyed homes and flooded villages on the island. It then intensified over the Gulf of Mexico and traveled north with sustained winds of 130 mph (210 km/h) and gusts up to 160 mph (260 km/h), before weakening to a Category 3 storm as it reached the Florida coast. At least two people have died in crashes, the Washington Post reported.

Hurricane Idalia dropped to a Category 2 storm an hour after making landfall near Keaton Beach, about 75 miles (120 kilometers) southeast of Tallahassee. 

Off-the-charts sea temperatures likely fueled Hurricane Idalia — the most powerful storm to ever strike the Big Bend region, which extends from the top of the peninsula to the west of Florida.

The storm's "rapid intensification is definitely feeding off that warmth that we know is there," Kristen Corbosiero, an associate professor of atmospheric and environmental sciences at the University of Albany, told AP News.

Related: Which hurricane caused the most damage? 

Ocean temperatures this year have broken every record since satellite measurements began, especially in the Atlantic and the Gulf of Mexico. Hurricanes draw energy from warm waters, and experts warned that Florida's bathtub conditions would likely strengthen storms and hurricanes coming the state's way.

These sizzling sea temperatures are being driven by a combination of human-caused climate change and an El Niño event, which is forecasted to substantially exceed the last strong event in early 2016.

Idalia rode northward on pools of warm, deep water that carried the storm into the Gulf of Mexico, Corbosiero said. Deep water is usually colder than the top layers, and storms can stall themselves by churning these currents up to the surface. But these deep waters may not be as cold as they have been in other years, and Florida's west coast is not deep enough for them to cool down significantly, experts told AP News.

Another factor that may have powered flooding from Idalia is a rare blue supermoon rising Wednesday, which may raise tides above normal and boost seawater surging over the coastline. Supermoons intensify the gravitational pull on Earth, which may contribute to worse tidal flooding brought by the hurricane across Florida, Georgia and South Carolina.

"I would say the timing is pretty bad for this one," Brian Haines, a meteorologist in charge of the National Weather Service office in Charleston, South Carolina, told AP News.

Idalia's destructive advance is likely to be felt through Thursday (Aug. 31), with 4 to 8 inches (10 to 20 centimeters) of rain predicted in some isolated areas, according to the NHC.

Within the next 50 years, many of the freshwater basins in the United States could struggle to meet the population's water demands.

Climate change is causing severe droughts and greater aridity — extreme dryness that can affect humans and the natural systems they depend on, especially in western states. Greater aridity leads to more climate extremes, drier soil and greater stress on agricultural production and ecosystems. 

And water supplies could decline by a third by 2071, even as the population mushrooms to 404 million by 2050, compared with 334 million today. 

So will America run out of water? 

The simple answer is no — but freshwater will not always be available where and when humans need it. 

Water continuously circulates between Earth's surface and the atmosphere. Climate change intensifies this cycle: As air temperatures increase, more water evaporates into the air, causing more precipitation.

"The issue is not about running out of water, it's about having water in the right place," Lis Mullin Bernhardt, an ecosystem expert at the United Nations Environment Programme (UNEP), told Live Science.

Water shortages are most severe in the American Southwest, especially near the Colorado River Basin, which provides the only large sustainable water supply to more than 40 million people across seven U.S. states.

Related: Over half of the world's largest lakes and reservoirs are losing water 

"That part of the country is the food basket of not only the U.S. but many parts of the world," Bernhardt said. Climate change is already making the region more arid, but the situation has been exacerbated by chronic overuse of water resources for agricultural purposes, which puts "tremendous strain" on lakes, rivers and reservoirs.

The Colorado River, for example, is facing an existential crisis due to decades of unsustainable withdrawals. The flow of the river has declined by about 20% in the last century. And since 2020, this region has been gripped by  a "megadrought" that is believed to be the most severe the West has seen in 1,200 years. 

More than half of all water for irrigation comes from surface water, according to a U.S. Department of Agriculture survey, with the remaining water obtained from groundwater sources. Surface water-fed irrigation is most common in the West, where many water-intensive crops, such as alfalfa, are grown.

In California, severe water shortages are a consequence of rising temperatures, groundwater depletion and the diminishing Colorado River. These shortages impact food production, the environment and the economy — while exacerbating droughts and wildfires. 

A historic new deal was reached in April to protect the Colorado River Basin from dropping to critical levels over the next few years. Federal officials agreed to conserve at least 3 million acre-feet (370,000 hectare meters) of water from the river by paying people in California, Arizona and Nevada to use less water, officials wrote in a statement. An acre-foot fills 1 acre (0.4 hectare) of land with 1 foot (0.3 m) of water, or approximately 326,000 gallons (1.5 million liters).

In the eastern states, the challenge is managing too much water. Although population density is much higher there than in the West, there is less farmland and so less need for irrigation. And eastern states get more rain and snow than western states and they have high humidity.

On average, the eastern half of the country has experienced more rain over the last 30 years than it did during the whole of the 20th century, according to the New York Times. So the East is dealing with record-breaking rains that have caused devastating flash floods. In July, deadly flash floods hit several states in the Northeast, with New York governor Kathy Hochul calling downpours in the Hudson Valley "a 1,000-year event."

But of course, flash floods can affect many areas in the West too. 

"In California, we are at risk of having very significant flooding that could be catastrophic," Sandi Matsumoto, director of the Nature Conservancy California Water Program at the Public Policy Institute of California, told Live Science. "We have had floods that have filled the great Central Valley which is hundreds of miles long — a massive area — and then obviously we have droughts too."

California's Central Valley, a drought-hit basin that is typically filled with pistachio and almond groves, was hit by historic rains in April, which drowned thousands of acres of farmland and brought the previously drained Tulare Lake back from the dead. This was due to an atmospheric river — a narrow band of water vapor that carries moisture from the tropics to higher latitudes. 

"I think it's important to recognize that we have both problems," Matsumoto said. "Too much water at the wrong times and too little at other periods."

Bernhardt believes that by changing how water is managed, U.S. supplies can be saved. "This involves changing the way we farm, the kinds of foods we're farming and how much water we use," she said. "We need to get much better at managing the extremes. When water floods or we get a lot of rain at once, we have to be able to store that water to use it in times when we’ve got less."

A vast number of stone walls spread across more than 600 miles (1,000 kilometers) of the Nile River were constructed over a period of 3,000 years and "functioned as flood and flow control structures," new research reveals. 

The walls, called "groynes," stretch from the first cataract of the Nile River, in what is now Egypt, to the fourth cataract, in what is now Sudan. To study the groynes, researchers used a mix of satellite and aerial photography, as well as ground survey and archaeological excavation. They looked at aerial photographs of the region taken decades ago to document groynes that are now heavily damaged or destroyed, as well as interviewed local people. In total, the researchers documented more than 1,200 groynes, the team wrote in a paper published May 27 in the journal Geoarchaeology. 

The groynes appear to have been built over a span of thousands of years. Some examples found near the ancient site of Amara West, in modern-day Sudan, date back more than 3,000 years, but others are only decades old. Some may have been constructed when ancient Egypt controlled the area, while others were built at a time when the Kingdom of Kush, or various other states flourished in the region. 

"Around 10% of the groynes we surveyed have a distinctive construction technique also seen in medieval stone buildings in the area," Matthew Dalton, a research associate at the University of Western Australia and lead author of the paper, told Live Science in an email. "Some were built in living memory, as recently as the 1970s."

Related: Vanished arm of Nile helped ancient Egyptians transport pyramid materials

The sizes of the stone walls vary. Some are small and were likely built by an individual or small group in a matter of days, Dalton said, while some are immense. One example, found at an ancient site called Soleb in modern-day Sudan, is about 2,300 feet (700 meters) long (and 13 feet (4 m) wide, and is made of quartz boulders weighing 220 pounds (100 kilograms) or more, Dalton said. The wall's height in ancient times is unclear, but based on its remains, it would have taken at least 1,680 tons (1,520 metric tons) of quartz to build it, he added. 

Modern-day farmers in the region that researchers interviewed said that walls like these help capture silt from floods, which makes the soil more fertile. The walls also help prevent erosion by the Nile River, the farmers said. 

"The groynes that the team describe from the Nile Valley are very interesting and [consistent] with observations of other water-management systems across Egypt during the period [in ancient times]," Judith Bunbury, a geoarchaeologist at the University of Cambridge who wasn't involved in the research, told Live Science in an email. 

Some of the groynes appear to date to the Kerma period, which lasted from roughly 2500 B.C. to 1500 B.C., said Julia Budka, a professor of Egyptian archaeology and art at the Ludwig Maximilian University of Munich who has studied groynes at a number of sites in Sudan. 

Budka, who was not involved in the research, said she agrees with the authors that the construction of groynes is "a very long-lasting tradition, clearly based in indigenous knowledge in Sudan."

Sea levels are likely rising faster than previously thought, meaning low-lying coastal cities in the U.S. could flood far more regularly in the coming decades, a NASA study has revealed.

According to the study, which analyzed three decades of satellite observations, by 2050, sea levels along the coastlines of the contiguous U.S. could rise as much as 12 inches (30 centimeters) above current waterlines, the research team said in a statement. The Gulf Coast and Southeast are expected to be most severely impacted, and will likely experience increased storm and tidal flooding in the near future, according to the study, published Oct. 6 in the journal Communications Earth & Environment.

The findings support the "higher-range" scenarios laid out in February in the multi-agency Sea Level Rise Technical Report. The report suggested that "significant sea level rise" is liable to hit U.S. coasts within the next 30 years, predicting 10 to 14 inches (25 to 35 cm) of rise on average for the East Coast; 14 to 18 inches (35 to 45 cm) for the Gulf Coast; and 4 to 8 inches (10 to 20 cm) for the West Coast."

NASA's study built on methods used in the earlier multi-agency report, and was headed by a team of researchers and scientists based at the Jet Propulsion Laboratory in California, which is dedicated to both exploring the deepest recesses of space, and also using satellites to "advance understanding" of Earth.

NASA's research harnessed satellite altimeter measurements of sea surface height and then correlated them with National Oceanic and Atmospheric Administration (NOAA) tide gauge records dating back over 100 years. As a result, NASA can confidently state that its satellite readings are not anomalous, and are fully supported by findings on the ground.

Related: Climate summit agrees to 'historic' loss-and-damage fund — but misses warming goals

While the new study's findings are undoubtedly cause for concern, Jonathan Overpeck, an interdisciplinary climate scientist at the University of Michigan who was not involved with the research, suggested that the projections have by no means come out of the blue. 

"NASA's findings appear robust and they are not surprising. We know that sea level rise is accelerating and we know why," he told Live Science in an email. "More and more polar ice is melting, and this is on top of the oceans expanding as they warm. Clearly, the sea level rise will get worse as long as we let climate change continue."

This viewpoint is shared by David Holland, a physical climate scientist and professor of mathematics at New York University who was not involved with the study. "The quality of the satellite data is excellent, and so the findings are reliable," Holland told Live Science in an email. "The study shows that the global ocean is rising, and more than that, the rise is accelerating. The projected rise for the Gulf coast of about 1 foot by 2050 is enormous. This can make hurricane-related storm surges even worse than is presently the case."

Other factors may also contribute to rising sea levels along the U.S. coastline. The study indicated that the issues associated with rising sea levels could be "amplified by natural variabilities on Earth," such as the effects of El Niño and La Niña by the mid-2030s, with every U.S. coast set to encounter "more intense high-tide floods due to a wobble in the moon's orbit that occurs every 18.6 years," according to the statement.

The effects of El Niño — the warming of surface temperatures in the Pacific Ocean near South America which can lead to increased rainfall — and La Niña — the cooling of surface ocean waters in the Pacific — can make accurately forecasting sea level rise a challenge, and can potentially skew readings. Ben Hamlington, leader of the NASA Sea Level Change Team, noted that natural events and phenomena will always need to be taken into consideration, and said that all forecasts will inevitably be refined as satellites gather data over time.

Despite the study's bleak findings, some experts are hopeful that impactful, high-profile research such as this will compel decision-makers to focus on addressing the ongoing climate crisis and encourage the public to demand effective measures be introduced.

"It is impossible to ignore. I think this [increased flooding] is catalyzing action, as many coastal communities are discussing these issues and how they respond," said Robert Nicholls, director of the Tyndall Centre for Climate Change Research in the U.K., who was not involved with the study. "We have the means to deal with this challenge in terms of mitigation to stabilize global temperatures and slow — but not completely stop — sea level rise, which, unfortunately, will continue for centuries due to the warming we have already experienced."

Ultimately, humanity will need to adapt as climate change alters our planet's oceans and seas. 

"This could involve retreat in some places, raising land in other places, and defenses elsewhere," Nicholls told Live Science. "There is no one solution that will be applicable everywhere. If we follow this path the future is manageable. Equally, if governments and society ignore these issues, the future will be a real mess."

When Hurricane Ian slammed into Lee County, Florida, as a near-Category 5 storm last month, it left in its wake not just widespread destruction but also a surge of rare "flesh-eating" bacterial infections, state health data shows.

Flesh-eating bacteria can cause "necrotizing fasciitis" — an infection that triggers aggressive inflammation in the tissue surrounding muscles and other organs, causing that tissue to rapidly die, according to the Centers for Disease Control and Prevention (CDC). The bacteria enter the body through broken skin, and necrotizing fasciitis can set in quickly thereafter, leading to life-threatening complications like shock and organ failure. Up to 20% of people with necrotizing fasciitis die, some within days of the infection's start.

The type of flesh-eating bacteria behind Florida’s surge in infectionsis called Vibrio vulnificus. The salt-loving bacteria can be found in warm, brackish water, meaning a mix of fresh and salt water typically found in estuaries, salt marshes and the points where rivers meet the ocean, according to the CDC. Concentrations of the bacteria tend to be highest between May and October, when water temperatures rise, and the vast majority of V. vulnificus infections occur in that time window. Hurricanes, storm surges and coastal flooding can raise the risk of infection by increasing the likelihood that people come in contact with contaminated water.

"Flood waters and standing waters following a hurricane pose many risks, including infectious diseases such as Vibrio vulnificus," the Florida Department of Health in Lee County warned shortly after Hurricane Ian made landfall in Florida. "For that reason, the Florida Department of Health in Lee County is urging the public to take precautions against infection and illness caused by Vibrio vulnificus."

Related: 'Flesh-eating' bacteria may be spreading to beaches once thought off-limits. Here's why. 

Before the hurricane struck, 37 cases of V. vulnificus infection had been reported for 2022 in Florida, according to Florida Department of Health data. Shortly after the storm, the number shot up to 65. Most of the newly reported cases occurred in Lee County, where Ian made landfall, and one occurred in Collier County, its neighbor to the south. The department's website notes that these counties experienced an "abnormal increase [in cases] due to the impacts of Hurricane Ian." 

Out of the 65 people with reported infections, 11 have died, according to the health department.

In 2021, Florida reported 34 cases of V. vulnificus infection, 10 of which were fatal, and in 2020, the state reported 36 cases, seven of which were fatal. The number of cases seen this year is unusual — since the health department began reporting data in 2008, annual reported cases have generally ranged from 16 to 50 a year.   

Thankfully, since the hurricane-related surge in infection, the rate of new cases now seems to be waning, Florida Department of Health spokesperson Jae Williams said Oct. 18, according to CNN. 

The Lee County residents who were infected by V. vulnificus after the storm did so through "exposure to Hurricane Ian flood waters that occurred from the storm-surge entering their homes or during post-storm clean-up," department spokesperson Tammy Soliz told CNN in an email. But as the storm waters have abated, so too have the flesh-eating bacterial infections.  

With Cuba and Florida left reeling after Hurricane Ian, which made landfall in September 2022 and was one of the region's most powerful and destructive storms in decades, it is tempting to attribute the carnage of yet another deadly hurricane season to climate change. But is climate change the culprit? Recent studies have linked climate change to environmental conditions that fuel hurricane season, but the connection between global warming and individual hurricanes is far from settled science. 

While there is overwhelming evidence that human activities have directly caused sea levels to rise and the planet to get warmer — both of which are factors that make hurricanes deadlier — it remains unclear if climate change is fueling a significant increase in the number of hurricanes or intensifying tropical storms that make landfall.

"Hurricane activity is occurring on the backdrop of higher sea levels, which increases coastal flooding risk — that much is clear," said Thomas Knutson, who studies climate change and hurricanes at the National Oceanic and Atmospheric Administration's (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL). 

"The overall risk — how the frequency and intensity of storms is affected by global warming — is much more complicated," Knutson told Live Science.

Related: Hurricane season 2022: How long it lasts and what to expect

A warming planet will, as a rule, give us more intense hurricane seasons, researchers have discovered. Rising sea levels, driven by climate change, mean more coastal flooding from storm surges when hurricanes make landfall. And global warming also affects precipitation, with an estimated 7% increase in rainfall for every 1 degree Celsius (1.8 degrees Fahrenheit) of increased sea surface temperature, scientists reported April 12 in the journal Nature Communications. As human activities cause sea levels and surface temperatures to rise, hurricanes are packing more of a punch, in the form of flooding and heavy rainfall, Live Science previously reported.

Along these lines, some climate models have predicted that a 2-degree-Celsius (3.6 F) increase in global temperatures would result in a greater percentage of hurricanes reaching Category 5 (sustained wind speeds of 157 mph, or 252 km/h), would increase hurricane wind speeds by about 5% on average, and would lead to more storms making landfall in the U.S., researchers reported in 2013 in the Journal of Climate. In an earlier study, published in 2005 in the journal Nature, scientists found such a strong correlation between Atlantic hurricanes and sea surface temperatures that they warned we could see a 300% increase in hurricane activity by 2100. 

But in spite of these dire predictions, we have not yet seen a significant increase in global hurricane activity. One confounding factor is that, while warmer sea surfaces are ideal breeding grounds for hurricanes, storms that collide with a warm atmosphere tend to fizzle out before causing much damage, researchers reported in a Nature study published June 27. This may explain why, even as human activities have caused the planet to warm by 1 C since the late 1800s, we haven't seen an upward trend in the number or intensity of hurricanes over the past century — and why the Nature study found that climate change may be linked to a global decrease in the number of hurricanes. 

"Increased greenhouse gases may cause sea surface warming, which increases hurricane intensity," Knutson said. "But there's even more warming in the upper troposphere, and that puts the brakes on hurricane intensity." Knutson nonetheless expects to ultimately see an uptick. "We think global warming will still result in a net increase in hurricane intensity, but not nearly as much as if we had only sea surface warming," he said.

Although we haven't necessarily seen more hurricanes globally over the past century, there has been an increase in hurricane frequency and intensity in the Atlantic basin over the past 40 years. But even that increase may not necessarily be due to climate change. Other factors, such as the reduced manufacture and use of aerosol products, which harm Earth's ozone layer, had a surprising impact on global temperatures that may have temporarily affected hurricane formation, according to a 2022 study published in Science Advances. While greenhouse gases cause global warming, aerosols block sunlight and cool the planet. When the U.S. began cutting back on aerosols, this dramatic reduction may have caused a temporary temperature bump that increased the frequency and intensity of Atlantic hurricanes, the researchers reported.

However, it's possible that factors other than aerosols alone were responsible for this change.

"There has been a big uptick in hurricanes in the Atlantic basin since 1980, but we don't know whether that's a greenhouse gas-driven signal, because of changes in aerosol use or just natural variability," Knutson said.

Given the number of variables that can affect hurricane formation and strength, it is therefore  "premature to conclude with high confidence that human-caused increasing greenhouse gasses have had a detectable impact on past Atlantic basin hurricane activity," according to an Oct. 3 report authored by Knutson for NOAA's Geophysical Fluid Dynamics Laboratory. The report cites lingering concerns that increases in storm activity in the Atlantic Ocean since 1980 may be attributable to a combination of factors, including decreases in the manufacture and use of aerosol products, global volcanic activity, and even natural variability.

Nevertheless, Knutson added, climate change will almost certainly make future hurricane seasons more dangerous,  with more frequent coastal flooding, increased rainfall, and warming seas favoring the formation of more intense storms.

Indeed, the shift is already well underway. In 2020, researchers analyzed data from 4,000 tropical cyclones spanning 39 years, from 1979 to 2017, and concluded that hurricanes are getting stronger and major tropical cyclones are becoming more frequent — just as models predicted, Live Science reported.  

"On average, we expect hurricanes to get more intense and have higher rates of rainfall due to climate change," Knutson said. As for Hurricane Ian, which caused hundreds of deaths and was Florida's deadliest hurricane since 1935, according to the The Washington Post, "instead of saying that Ian is a result of climate change, we'd rather say that storms like Ian are likely more intense than they would have been had they occurred in preindustrial times," Knutson said.

Coastal Alaska is recovering on Monday (Sept. 19) after a weekend of dramatic flooding caused by the remnants of Typhoon Merbok. 

The storm brought flooding to coastal communities, impacting 1,000 miles (1,609 kilometers) of coastline, Alaska governor Mike Dunleavy said at a news conference on Sunday (Sept. 18), and hundreds of people huddled in temporary shelters on Saturday (Sept. 17), according to Alaska Public Media. Roads were washed out and homes were damaged by winds gusting near 70 mph (114 km/hour), CBS News reported. In Nome, at least one home was torn from its foundations and seen floating down a river. 

Water levels remained high in many areas on Monday, with storm surge expected to recede throughout Monday and Tuesday (Sept. 20) morning, the National Weather Service Fairbanks tweeted.

"Merbok was a rare and historic storm for the Bering Sea and Western Alaska," NWS meteorologist Virginia Rux told Alaska Public Media on Sunday. "Many of the coastal communities are still recovering, and we are not anticipating any storm like what we just experienced anytime soon."

The typhoon originated on Sept. 11 in the central Pacific, east of the Northern Mariana Islands,, according to Accuweather. It lost strength by the time it neared the Alaska coast, but still produced winds strong enough to whip up a combination of waves (caused by local winds) and swells (caused by the cumulative effects of the more distant storm winds) up to 50 feet (15.2 meters) tall. 

Read more: Hurricanes, typhoons, and cyclones

Winds from the storm have now peaked and are concentrated west of Point Hope, Alaska, where they will remain for the next few days, according to the NWS. Meteorologists are not expecting any more impacts from what's left of the storm. 

But coastal Alaska is now taking stock of the damage. A popular restaurant on Nome's Front Street burned down on Saturday evening in a conflagration fueled by extreme winds, according to the Anchorage Daily News. The Nome Nugget reported failing seawalls, dislodged fuel tanks, submerged roads, and homes knocked from their foundations, including one that lodged under the Snake River Bridge after floating downstream.

On Sept. 17, Melissa Frey, a meteorologist with KTUU/KYES Anchorage, shared photos on Twitter that showed severe flooding in Newtok, St. George and Hooper Bay, with homes partially submerged and wreckage littering the coastline.

The storm was reminiscent of the 2011 Bering Sea Superstorm, which struck in November and brought wind gusts of up to 93 mph (150 km/h) to the region, according to the NWS Fairbanks. Gov. Dunleavy declared a state of emergency on Saturday and said he was in contact with the federal government for relief. Time is of the essence, he said in a news conference on Saturday, , because some communities will experience their first freezing temperatures of the year in just a few weeks. 

"We just have to impress upon our federal friends that it’s not a Florida situation where we’ve got months to work on this," the governor said. "We’ve got several weeks to work on this."

Originally published on Live Science.

New satellite images show the extent of the catastrophic floods now inundating Pakistan, leaving approximately one-third of the country underwater. The worst of the floods occurred along a stretch of the Indus River that overflowed, forming a massive lake.

The flooding, driven by unusually heavy monsoon rains, has affected more than 33 million people in Pakistan and killed more than 1,100 since mid-June, including hundreds of children, NPR reported. Millions of acres of cropland, thousands of miles of roads and more than a million homes have been damaged by the floodwaters. In a video posted to Twitter, Sherry Rehman, a Pakistani senator and the country's top climate official, called the historic floods "serious climate catastrophe, one of the hardest in the decade."

Satellite images, shared by the NASA Earth Observatory on Aug. 28, revealed how the floodwaters transformed the country's landscape between early and late August. For example, on Aug. 4, about 30 miles (48 kilometers) of land stood between the Indus River and Hamal Lake, located west of the river in the Qambar Shahdadkot District of Pakistan. But by Aug. 28, the two bodies of water had merged with one another. 

The European Space Agency shared similar images of the flooding on Aug. 30, with submerged land marked in blue and black. These images, captured by the Copernicus Sentinel-1 satellite, highlighted the region between the cities of Dera Murad Jamali and Larkana, which respectively lie northeast and due east of Hamal Lake. Again, the snapshots show where the once-winding Indus River has now been replaced by a vast lake.

Related: Has the Earth ever been this hot before? 

NASA Earth Observatory also shared images of the cities of Qambar and Shikarpur in Sindh province that revealed how dramatically the floodwaters advanced between early and late August. Both cities have seen about 500% higher-than-average rainfall between July 1 and Aug. 31. 

Overall, the recent rainfall in Pakistan has been about three times heavier than the 30-year nationwide average, The New York Times reported. This increase in rainfall can likely be attributed to climate change, as Pakistan's chief climate official indicated.  

Experimental data and climate models suggest that, as average global temperatures rise, historically wet regions will face more extreme precipitation events, like monsoons, while historically dry regions will grow drier as the rising heat drives water to evaporate more efficiently, Live Science previously reported. So climate change essentially intensifies the water cycle, leading to more extreme and more frequent weather events.

In addition to devastating monsoons, Pakistan had been contending with glacial-outburst floods, or the sudden release of water from glacial lakes, according to NASA Earth Observatory. Pakistan, with its roughly 7,000 glaciers, contains the most glacial ice of any country beyond the polar regions. Particularly in northern regions of the country, the meltwater from these glaciers sometimes compounds the damage caused by rainwater.

Originally published on Live Science.

Sea levels are rising rapidly. The rate at which they are rising has more than doubled, from 0.06 inch (1.4 millimeters) annually throughout most of the 20th century to 0.14 inch (3.6 millimeters) per year from 2006 to 2015, according to the National Oceanic and Atmospheric Administration (NOAA).

NOAA predicts that sea levels will likely rise by at least 1 foot (0.3 m) above the levels seen in 2000 by the start of the next century, while the United Nations Intergovernmental Panel on Climate Change estimates that they will rise by 16 to 25 inches (40 and 63 centimeters) by 2100.

Should sea levels rise to this extent, it could wreak havoc around the globe. As many as 250 million people, spanning all continents, could be "directly affected" by 2100, according to a 2019 study in the journal Nature Communications.

So, will any of these countries, cities or states disappear entirely in our lifetime, and is there anything that can be done to avert disaster?

"Whether cities or countries disappear depends on whether we as humans are doing something to counteract the threat," Gerd Masselink, a professor in coastal geomorphology at the University of Plymouth in the United Kingdom, told Live Science in an email. "Most of the Netherlands is already below sea level but is not disappearing, because the Dutch are building and maintaining their coastal defenses."

Related: How will sea levels change with climate change?

Which countries will be most affected?

First, let's look at the countries with the lowest elevations.

According to the Union of Concerned Scientists (UCS), the Maldives, made up of 1,200 small coral islands and home to around 540,000 people, is the flattest country on Earth, with an average elevation of just 3 feet (1 m). Should the Maldives experience sea level rise on the order of just 1.5 feet (45 cm), it will lose around 77% of its land area by 2100, according to the UCS.

Another country with an extremely low average elevation — around 6 feet (1.8 m) above sea level — is Kiribati. This small island in the heart of the Pacific, with a population of close to 120,000, could lose two-thirds of its land if sea levels rise by 3 feet.

In fact, nearly everyone who lives on a Pacific island is likely to be severely affected by rising sea levels. Around 3 million Pacific islanders live within 6.2 miles (10 km) of the coast and, therefore, might need to relocate before the end of the century, according to the Science and Development Network, a nonprofit focused on facilitating scientific learning.

Sea level rise has already led to the disappearance of at least five "vegetated reef islands" that were previously part of the Solomon Islands, with "a further six islands experiencing severe shoreline recession," according to a 2016 study in the journal Environmental Research Letters.

These Pacific islands, though very much in jeopardy, tend to have relatively small populations. So what larger nations might be hit hardest?

The country where the most people will potentially be affected by sea level change is China, with 43 million people in precarious coastal locations. Other countries subject to face major issues related to rising sea levels include Bangladesh, where 32 million people will be at risk by 2100, and India, with 27 million, according to the European Union-funded Life Adaptate project.

So, while various countries around the world are set to see the consequences of rising sea levels firsthand by the end of the century and many millions will be affected, it seems unlikely that any countries, even those with very low elevations, will disappear entirely by 2100 — though it could be just a matter of time before some are consumed by the ocean.

Coastal cities

While no country is likely to be devoured by 2100, numerous major cities are at very serious risk of being inundated. One of the most clear-cut examples of rising sea levels causing significant, real-world difficulties is Jakarta, the capital of Indonesia.

Jakarta, home to around 10 million people, has been dubbed the "fastest-sinking city in the world" by the BBC; it is sinking by 2 to 4 inches (5 to 10 cm) each year due to "excessive groundwater drainage," according to Earth.org, a nonprofit environmental organization based in Hong Kong.

When coupled with rising sea levels, this is a recipe for disaster. According to the World Economic Forum, much of Jakarta could be underwater by 2050. In fact, Jakarta's situation is so dire that it is being replaced as Indonesia's capital by Nusantara, a soon-to-be built city on the east coast of Borneo, around 1,200 miles (2,000 km) from Jakarta.

But Jakarta is far from the only city with an uncertain future. According to the World Economic Forum, by 2100, Dhaka, Bangladesh (population 22.4 million); Lagos, Nigeria (population 15.3 million); and Bangkok, Thailand (population 9 million) could also be entirely drowned or have vast tracts of land underwater and unusable.

Rising sea levels are also likely to majorly impact the United States. Based on recent projections, many U.S. cities could face serious issues by 2050, with vast swathes of land potentially rendered unlivable. 

According to NOAA, "in many locations along the U.S. coastline, high-tide flooding is now 300% to more than 900% more frequent than it was 50 years ago," which suggests that sea levels are a valid cause for concern.

New York City is most at risk, according to research from Climate Central. The report states that, by 2050, nearly half a million (426,000) New Yorkers will be living on "threatened land." New York's vulnerability to flooding was seen clearly in 2012, when the city was heavily impacted by Hurricane Sandy. At least 43 people in the city died as a result of the superstorm, around a quarter of a million vehicles were destroyed, and there was at least $32 billion worth of "damage and loss," then-Gov. Andrew Cuomo said at the time, according to Politico.

However, in terms of susceptibility to flooding, Florida seems certain to be the state that is hit hardest. According to Climate Central's research, 36 of the 50 U.S. cities that are most vulnerable to coastal flooding are in the Sunshine State.

Are we doomed?

So, what can be done? Are these cities and countries doomed, or can they be saved?

Countries that invest in infrastructure, such as the Netherlands, may be able to avoid some effects of flooding. But some investments, such as those being proposed in Florida, cannot be applied everywhere. For example, the restoration of mangroves, as suggested by The Nature Conservancy, and the expansion of coral reefs, are viable only in certain climatic regions. Moreover, such measures are expensive.

Officials in Miami-Dade County, Florida, recently announced a mitigation strategy that will involve "elevating homes and roads," as well as creating open space that will allow flooding to take place without damaging infrastructure, according to The New York Times.

However, these plans have not been greeted with universal praise. Some experts, such as Rob Moore, a senior policy analyst with the Natural Resources Defense Council, told the New York Times that he's "not sure if it's really owning up to the problems that are in Miami's future," while others have implied that the proposals have "downplayed the magnitude of the threat."

Elsewhere in Florida, there have been conversations around whether it is economically viable, or indeed worthwhile, attempting to protect all infrastructure, with suggestions that it could be better to accept defeat in some regions, according to an article published by Yale Climate Connections, a nonpartisan media outlet focused on climate change.  

While countries such as the United States may be able to invest in coastal protection projects — and have the ability to learn via trial and error — most developing nations don't have the same luxury. When compared to countries like the Netherlands and United States in terms of having the financial clout to implement such projects, "Bangladesh is not in such a fortunate position," Masselink said.

So, a key factor in determining whether a city or country will disappear is not necessarily the rate of sea level rise, but more the capacity of a city or country to address the problem and develop long-term defenses.

"A low-lying but politically stable and prosperous country might be fine for decades to come, but a low-lying, unstable and poor country will not be able to keep the sea at bay," Masselink said. "This, therefore, particularly exposes low-lying cities and countries in developing nations."

With that in mind, what will our planet look like in 100 years?

"This is really difficult to foresee, as in addition to the uncertain rate of sea level rise — which depends strongly on our greenhouse gas emissions — the main factor is how nations and society intend to mitigate against rising sea level."

Originally published on Live Science.

Hurricane Sally is strengthening in the Gulf of Mexico and is expected make landfall somewhere on the central Gulf Coast later today (Sept. 14).

The slow-moving storm has been drifting northwest off the coast toward Louisiana, and was officially upgraded from tropical storm to hurricane this afternoon. The National Hurricane Center (NHC) said it's still too soon to tell where exactly its center will move onshore. It's packing an "extremely dangerous and life-threatening storm surge" that threatens people living on the Louisiana, Mississippi and Alabama coastlines, the NHC said. And with forecasts suggesting that it will remain partly over the Gulf's warm, storm-feeding water as it moves ashore, the NHC said Sally could remain a dangerous hurricane for a long time after landfall.

Dangerous flash floods are also likely, according to the NHC, as well as major flooding along rivers and in urban areas.

Related: A history of destruction: 8 great hurricanes

The Gulf Coast has already taken a beating this hurricane season, with the one-two punch of tropical storm Marco and the monster hurricane Laura hitting western Louisiana in the same week in August. According to the Post and Courier, 134,000 people were still without power in Louisiana this past weekend, two weeks after Laura. 

Twenty-three thousand are still living in Red Cross housing from that last pair of storms in Louisiana, the Post and Courier reported, though they've gotten less attention than the more than 100,000 people fleeing massive wildfires on the West Coast. Scientists believe that both the more intense hurricanes and hotter and larger wildfires occurring right now are consequences of climate change.

While this storm is the only Atlantic cyclone posing an immediate threat to land, it's not the only storm in the Atlantic. The NHC is simultaneously tracking four other significant storms right now, including hurricane Paulette, which passed directly over Bermuda today (several hundred miles east of North Carolina). None besides Sally and Paulette pose immediate threats to land.

Sally, like most hurricanes this year, is also a record setter: Atlantic cyclones are named in alphabetical order as they reach tropical storm strength, and no "S" storm has ever come this early before. Sally was named on Sept. 12. That's 21 days earlier than the previous "S" record-holder: Stan in 2005.

With Tropical Storms Teddy and Vicky forming in the Atlantic this morning, 21 and 22 days earlier than record-holders, Azores (which reached Tropical Storm strength on Oct. 4, 2005, but was named out of order), and Tammy (Oct. 5, 2005). Teddy is already forecast to become a major hurricane and is expected to move north through the Atlantic without impacting the Carribean or North American mainland.

Related: 10 signs that Earth's climate is off the rails

There's only one slot left on the NHC's list of Atlantic storm names: Wilfred. (The list skips the letters Q, X, Y and Z.)

Once the prepared names are exhausted, the NHC will move on to Greek letters for storms. In 2005, the previous busiest storm year, six Greek-letter storms formed, culminating in Zeta (the sixth of 24 possible Greek letters) on Dec. 30.

Most tropical storms form during August, September and October.

Originally published on Live Science.

Tropical storm Marco will hit Louisiana and Texas later today (Aug. 24), and will likely cause significant flooding. Just a day and a half later, another cyclone, Laura, will likely ram itself against the same stretch of coastline — and will pack an even greater punch.

Marco never developed into a hurricane, so last week's uncertain forecast of a record-setting two simultaneous hurricanes in the Gulf of Mexico didn't materialize. But the one-two punch of tropical storm Marco Monday afternoon and Laura Wednesday (Aug. 26) afternoon still poses a rare and serious threat. Marco will drop a deluge of water on Louisiana and Texas, according to the National Hurricane Center (NHC) — 3 to 6 inches (8 to 15 centimeters) in most areas, maxing out at 10 inches (25 cm) in the hardest hit spots. The land will have little time to dry between the storms. And when the ground is already wet, according to the National Weather Service, each additional drop of rain is more likely to sit on the surface rather than absorb into the dirt or drain away into rivers and streams.

"From Wednesday afternoon into Friday, Laura is expected to produce rainfall of 4 to 8 inches [10 to 20 cm], with isolated maximum amounts of 12 inches [30 cm] across portions of the west-central U.S. Gulf Coast," according to the NHC. "This rainfall could cause widespread flash and urban flooding, small streams to overflow their banks, and minor to isolated moderate river flooding."

Related: Hurricane season: How long it lasts and what to expect

Marco is already forecast to cause a significant storm surge as it comes ashore in Louisiana before its likely trek into Texas. Two to 4 feet (0.6 to 1.2 meters) of storm surge is likely across a stretch of coastline in Louisiana and Mississippi. Laura's track isn't yet predictable enough for storm surge watches, but the NHC could release the earliest forecasts this evening.

Louisiana has ordered evacuations along the coast, and Texas said evacuation orders for Laura are possible later in the week. That brings the total number of states ordering natural disaster evacuations across the country this month to five, with California, Oregon, Washington and Colorado all also evacuating residents in the face of major wildfires. Texas would be the sixth if it evacuates its coastline. Iowa, where a destructive derecho wind storm caused major damage statewide, also saw some small local evacuations, but they were not state-ordered.

As Live Science previously reported, evacuations during a global pandemic are even more complicated than usual. Evacuations will potentially contribute to the virus's spread, as people who would otherwise shelter in place are forced to gather with others, according to research from Columbia University.

Wildfires, major hurricanes and global pandemics are all becoming more severe threats due to climate change, several studies have shown.

The last time two tropical cyclones shared the Gulf of Mexico was 1959. And it was only ever recorded once before that, in 1933. Marco and Laura are also record setters as the earliest 12th and 13th tropical cyclones in a year, as meteorologist Matt Lanza noted.

Eight other storms this year have set similar records, making 2020 already one of the busiest tropical cyclone seasons ever.

Originally published on Live Science.

Record-breaking rainfall from the tropical storm Imelda is soaking southeastern Texas. Some areas have been swamped with 20 to 42 inches (51 to 107 centimeters) of rain over just three days, causing catastrophic flooding that is among the worst in U.S. history.  

Imelda, the first named storm to strike this part of Texas since 2017's devastating Hurricane Harvey, is currently the fifth-wettest tropical storm to drench the contiguous U.S., The Weather Channel tweeted today (Sept. 19). Storms that drop this much rain are estimated to appear once in a millennium, according to precipitation models created by the National Oceanic and Atmospheric Administration (NOAA). But the last 1,000-year-rainfall to inundate Texas was Hurricane Harvey — which slammed the state just two years ago. 

The unrelenting rain caused "significant and life-threatening flash flooding," the National Hurricane Center (NHC) reported this morning, leading Texas Gov. Greg Abbott to declare a state of disaster in 13 counties. 

Related: In Photos: Hurricane Harvey Takes Aim at Texas

To put this quantify of rain into perspective, 41 inches (104 cm) over a two-month period would be considered exceptional in this part of Texas, said meteorologist Eric Holthaus in a tweet. Such an event would happen about once in a century "in a stable climate," Holthaus said. But recent and accelerating climate change is thought to foster conditions that make seasonal tropical storms wetter, windier and potentially more destructive, Live Science previously reported.

Photos and videos shared on social media show grim scenes of the historic flooding: highways completely submerged under choppy waves and search-and-rescue operations to save people trapped by the floods. In a video tweeted by Katherine Marchand, a reporter with ABC-13 Houston, a man floats down U.S. Highway 59 South, clinging to a pool noodle.

Other images shared on Twitter by Rachel Keller, an anchor with 12News Now, showed  cars abandoned on a flooded road, a newsroom with inches of water covering the floor and an alligator swimming near someone's porch, purportedly snapped from the porch of a home.

In 2017, Harvey left southeastern Texas reeling under flood levels that exceeded predictions for 500,000 years, Live Science previously reported. By the time Harvey was done, it had dropped more than 51 inches (130 cm) of rain in some parts of the state, making Harvey the wettest tropical storm to ever make landfall in the contiguous U.S. But Imelda has submerged some areas that were left untouched by Harvey, according to The Weather Channel. For now, the extent of the damage the storm will do remains to be seen.

• Hurricane Season 2019: How Long It Lasts and What to Expect
• Hurricanes from Above: Images of Nature's Biggest Storms
• Photos: Hurricane Michael Toppled Over Trees and Uprooted 19th Century Artifacts

Originally published on Live Science.

Historic floods across the Midwest have left three dead, prompted mass evacuations, and drowned cities.

The floods aren’t isolated incidents, however: Two giant waves of water are rolling down from the country's far-northern middle expanse. One wave is following the path of the Missouri River toward the Mississippi River, carrying with it big chunks of ice. The second wave is taking a similar path down the Mississippi River from Minnesota. Both are the result of a long winter of heavy snowfall in Minnesota and the Dakotas followed by a short, sharp melt.

Both floods are more or less each one giant wave traveling at the speeds of their rivers, said Darone Jones, director of the Water Prediction Operations Division (WPOD) at the National Weather Service’s National Water Center (NWC) in Alabama.

The North Dakota wave traveled down the Missouri River to Nebraska and yesterday (March 18) reached northwestern Missouri. After passing Kansas City it will turn left, following the river, and make its way toward the joining of the Missouri and Mississippi rivers in St. Louis. [Top 10 Ways to Destroy Earth]

The Minnesota wave is taking the more straightforward route down the Mississippi River through Iowa, past St. Louis and into the ocean. Along the way, both waves should lose some water, so the downstream floods may not be as intense as those upstream.

It takes about 28 days for a drop of water originating in North Dakota to make its way down the Missouri River to the ocean, Jones told Live Science. This series of floods is the result of excess water swelling the northern stretches of the Missouri River following a sudden melting event last week.

Snowpack, melting

The WPOD has known that there was a lot of potential meltwater in the northern Midwest in the form of snowpack, Jones said. The whole region had a very rough winter.

(Figuring out how much potential meltwater there is isn't just a matter of seeing how high the snow is piled, but weighing it, Jones added. Light, fluffy snow doesn't produce as much water when it melts as heavier, more tightly packed snow.)

Indeed, the NWC has a spring flooding forecast due for release at the end of this week that will warn (perhaps too late) that this winter dumped a lot of heavy snow in the northern Plains and Midwest, creating significant flooding risks. But the extent of flooding is a factor of how fast the snow melts, not just how much snow is up there, Jones said.

Thanks to a strong storm system last week, the snow is melting very fast. That storm dumped heavy snow on Colorado and then turned into rain over North Dakota and Minnesota, Jones said. That rain was very cold, but still warm enough to trigger a sudden snowmelt. Ultimately, a couple inches of rainwater across a wide area combined with several inches of snowmelt to produce this intense flood wave.

And the chunks of ice in the flood make things worse, Jones said. Periodically, they clump up as the flood moves south, creating temporary ice dams. Those dams cause water to back up behind them, worsening the flooding before they break and release the wave again.

Forecasters aren't sure yet just how bad this flood season will be, Jones added. That depends a lot on whether there are many more sudden melting events like the one that caused this wave, he said, or whether the region has a chance to warm slowly.

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Originally published on Live Science.

A 10-mile-long (16 kilometers) lake just popped up in the middle of the hottest place on Earth.

Last week, a storm blew through Death Valley National Park in California, drenching the desert and the rest of Southern California. Now, amid the desert's echoing landscape, there sits a very misplaced lake.

The lake formed near Salt Creek, an area near the eastern edge of the park, according to SFGate. It's unclear exactly how big the lake is, but representatives from the park estimated it to be around 10 miles long. [Hell on Earth: Tour Death Valley]

Death Valley is not only the hottest place in the world, with temperatures that can reach 134 degrees Fahrenheit (57 degrees Celsius), but also the driest place in North America.

On average, Death Valley receives less than 2 inches (5 centimeters) of rain a year, according to the National Park Service. Typically, about 0.3 inches (0.76 cm) of that rainfall comes in March, but within a single day last week, 0.84 inches (2.13 cm) of rain fell in the park, according to SFGate.

This isn't much when compared with the rainfall in the rest of the country, or even the rain that this storm brought to other parts of Southern California. But unlike other areas, the desert has dry, compact soil that doesn't absorb water well, a National Weather Service meteorologist Todd Lericos told SFGate.

In the aftermath of the storm, California-based photographer Elliot McGucken captured just how bad California's famous desert is at absorbing water in his gorgeous images of the pop-up lake.

Editor's Note: This story was updated to correct the amount of rainfall that fell in Death Valley. It was 2.13 cm, not 213 cm.

• In Images: Mysterious Desert Varnish
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Originally published on Live Science.

The largest child sacrifice on record took place after a torrential rainfall, when about 140 children and 200 young llamas likely had their hearts ripped out by the ancient Chimú culture in A.D. 1450, in what is now Peru.

The reason for the sacrifice, however, remains a mystery, according to a new study. Even so, the scientists of the study have several ideas.

For instance, heavy rainfall and flooding from that year's El Niño weather pattern may have prompted Chimú leaders to order the sacrifice, but without more evidence, we'll likely never know the real reason, said study co-researcher John Verano, a professor in the Department of Anthropology at Tulane University in New Orleans. [25 Cultures That Practiced Human Sacrifice]

Study lead researcher Gabriel Prieto, an assistant professor in archaeology at the National University of Trujillo, Peru, learned about the sacrificial site in 2011, after a father approached him while he was doing fieldwork on another project. The father described a nearby dune with bones poking out of it. The father said, "Look, my kids are bringing bones back every day, and I'm tired of it," said Verano, who later joined the project in 2014.

Once at the dune, Prieto immediately realized that the site had archaeological significance, and he and his colleagues have been working on it since, excavating and studying the human and llama (Lama glama) remains at the site, know as known as Huanchaquito-Las Llamas.

"It's the largest child sacrifice event in the archaeological record anywhere in the world," Verano said. "And it's the largest sacrifice with llamas in South America. There's nothing like this anywhere else."

Who were the victims?

The site holds the remains of at least 137 boys and girls and 200 llamas. Many of the children and the llamas had cut marks on their sterna, or breastbones, as well as displaced ribs, suggesting that their chests had been cut open, perhaps to extract the heart, the researchers wrote in the study.

The children ranged in age from 5 to 14 and were generally in good health, according to an analysis of their bones and teeth. These youngsters were wrapped in cotton shrouds and buried either on their backs with extended legs, on their backs with flexed legs or and resting on one side with flexed legs. Many were buried in groups of three and placed from youngest to oldest.

Some had red cinnabar paint (a natural form of mercury) on their faces, and others, especially the older children, wore cotton headdresses. The llamas were either laid next to or on top of the children's bodies. In many cases, llamas of different colors (brown and beige) were buried together, but facing different directions.

Also buried at the site, near the children's remains, were the bodies of two women and a man. These adults do not have cut marks on their sterna, suggesting their hearts weren’t removed. Rather, one woman likely died from a blow to the back of the head and another suffered from blunt force trauma to her face. The man had rib fractures, but it wasn't clear whether these injuries happened before or after death, possibly due to the weight of the rocks that were placed over his body, the researchers said. [Photos: Hundreds of Mummies Found in Peru]

The children weren't buried with any discernible offerings, but the researchers did find a pair of ceramic jars and wooden paddles on the edge of the site, next to a single llama.

What happened?

The Chimú culture dominated a large part of the Peruvian coast from the 11th to 15th century. It thrived, in part, because of its intensive agriculture; the Chimú watered their crops and livestock with a sophisticated web of hydraulic canals, the researchers wrote in the study.

This area is typically dry, drizzling only a few times a year. But it's possible an extreme El Niño event, when warm water evaporates from the southern Pacific and falls as torrential rain on Peru's coast, caused havoc in the society, not only flooding the Chimú's lands but also driving away or killing marine life off the coast, Verano said.

Evidence shows that when the children and llamas were sacrificed, the area was sodden with water, even capturing human and animal footprints in the muck that still exist today. It's unclear why this particular site, located almost 1,150 feet (350 meters) from the coast about 2 miles (3.2 kilometers) north of the city of Chan Chan, was chosen for the sacrifice, but researchers have some idea for why the children were chosen.

Children are often seen as innocent beings who aren't yet full members of society, and thus might be viewed as appropriate gifts or messengers to the gods, Verano said.

Moreover, these children were not all locals. Some of the children had experienced head shaping, and an analysis of carbon and nitrogen isotopes (an isotope is a variation of an element) in their remains showed that these kids came from different regions and ethnic groups within the Chimú state, the researchers found.

It's unclear why their hearts were removed, but "worldwide, everyone is aware that the heart is a very dynamic organ," Verano said. "You can feel and hear it beating. It's very vital. If you take the heart out, a lot of blood comes out and the person dies."

Today, some people in the Peruvian highlands and Bolivia still remove the hearts from sacrificed llamas, Verano noted. Sometimes the removed heart is burned and the animal’s blood gets splashed on places like mines, a measure thought to protect the workers within. However, it's unknown how the Chimú viewed and treated hearts in antiquity, Verano said. [Photos: Ancient Circular Geoglyphs Etched into the Sand in Peru]

The children's remains are now safely stored by Peru's Ministry of Culture, and the researchers have submitted permits so they can continue to study them, Verano said.

The discovery shows "the importance of preserving cultural patrimony and archaeological material," Verano said. "If we had had not dug this, it would probably be destroyed now by housing and urban expansion. So we've saved a little chapter of prehistory."

The study is "an incredible insight into the ritual and sacrificial practices of the Chimú kingdom," said Ryan Williams, a curator, professor and head of anthropology at The Field Museum in Chicago, who has worked as a South American archaeologist for more than 25 years.

He added that while human sacrifice is reviled in our modern society, "we have to remember that the Chimú had a very different world view than Westerners today. They also had very different concepts about death and the role each person plays in the cosmos," Williams, who was not involved with the study, told Live Science in an email.

Given that the sacrifice may have been in response to devastating floods, "perhaps the victims went willingly as messengers to their gods, or perhaps Chimú society believed this was the only way to save more people from destruction," Williams said.

The study was published online today (March 6) in the journal PLOS ONE.

• 7 Bizarre Ancient Cultures That History Forgot
• Photos: The Amazing Mummies of Peru and Egypt
• Photos: Mummy Hair Reveals Ancient Last Meals

Originally published on Live Science.

Some of the biggest storms in recent years were fueled by climate change, which increased the amount of their drenching rainfall. Future storms could be even windier, wetter — and potentially more destructive — according to a new study.

Researchers evaluated 15 tropical cyclones (which are called hurricanes when they form in the Atlantic) from the past decade and then simulated how the storms would have performed during preindustrial times, prior to the advent of recent climate change. They also peered into possible future scenarios, modeling what the storms might look like if they took shape during the late 21st century, should Earth's climate continue to warm.

Some hurricanes dumped up to 10 percent more rainfall as a result of climate change, and similar storms in the coming decades could deliver 30 percent more rainfall, the simulations revealed. [In Photos: Hurricane Maria Seen from Space]

The scientists' findings, published online today (Nov. 14) in the journal Nature, paint a sobering picture of a future marked by supercharged hurricane seasons.

In simulations that required millions of hours of computing time, the researchers investigated the role that a warming climate could play in hurricane winds and rainfall, looking at factors such as greenhouse gas concentrations, humidity and temperature variations in the air and in ocean water. They found that hurricane rainfall increased under climate-change scenarios, with Hurricanes Katrina, Irma and Maria producing about 5 to 10 percent more rain than they might have generated under preindustrial conditions.

Wind speeds for storms in the recent past, on the other hand, would probably have been more or less the same at the time of preindustrial Earth, according to the study. However, future storms will likely become windier, with peak wind speeds rising by as much as 33 mph (53 km/h). Rainfall is also predicted to increase in hurricanes by about 25 to 30 percent, if present-day emissions continue unchecked, the scientists reported.

Warming oceans are already recognized as a fuel source for more intense hurricane seasons. And rapidly accumulating evidence shows how climate change is directly affecting individual storms. In September, climate change was identified as a contributor to Hurricane Florence, with scientists estimating that the storm produced 50 percent more rain than it would have in a preindustrial world.

"We're already starting to see anthropogenic factors influencing tropical cyclone rainfall," lead study author Christina Patricola, a research scientist with the Climate and Ecosystem Sciences Division at Lawrence Berkeley National Laboratory, said in a statement.

"And our simulations strongly indicate that as time goes on we can expect to see even greater increases in rainfall," Patricola added.

Urbanization raises the risk

More rainfall during seasonal hurricanes brings a greater risk of flooding to regions near coastlines. But the hazards of coastal living can also be intensified by another factor — human transformation of rural and suburban areas into more urban environments, according to another study, also published today in the journal Nature.

Researchers modeled simulations of Harvey's rainfall and flooding, measuring how Houston might have been affected if the city's urban development had stalled in the 1950s. They found that urbanization in Houston made the disastrous impacts of 2017's Hurricane Harvey even more damaging.

By comparing the simulations to Harvey's real impact in 2017, the scientists discovered that urbanization significantly increased how much rain fell during the storm and also increased the risk of flooding. New buildings in the city changed the airflow over Houston, leading to heavier precipitation; at the same time, more asphalt and concrete cover likely raised the risk of flooding.

Overall, the researchers found that urbanization in Houston increased the probability of extreme flooding from Harvey "by about 21 times." Climate modelers and urban planners alike therefore need to address and confront the threats faced by growing cities that are vulnerable to extreme precipitation, the study authors concluded.

Originally published on Live Science.

So, what's the worst that could happen?

Astronaut and geophysicist Alexander Gerst called Florence a "nightmare" after glimpsing its eye from the International Space Station this morning, saying in a tweet: "Get prepared on the East Coast, this is a no-kidding nightmare coming for you."

Despite the public's fascination with high winds, it turns out that most of the damage could come from the historic amounts of water the hurricane releases, climate and health experts told Live Science. [Hurricane Florence: Photos of a Monster Storm]

"This storm is about flooding," Perry Samson, a professor of climate and space science at the University of Michigan, told Live Science.

As of 2 p.m. EDT today (Sept. 12), Florence was a Category 3 hurricane with winds of 125 mph (205 km/h) at its location about 435 miles (700 kilometers) southeast of Wilmington, North Carolina, according to the National Hurricane Center in Miami.

Florence is expected to make landfall late Thursday or early Friday (Sept. 13 or 14), likely as a Category 3 hurricane, meaning it will have winds blowing at a minimum of 111 mph (178 km/h), Samson said.

As hurricane-force winds approach the coast, they'll push the ocean's waves ashore, causing storm surges of up to 13 feet (4 meters) in parts of North Carolina, the National Hurricane Center reported. Coastal North Carolina may receive up to 40 inches (100 centimeters) of rain, the National Hurricane Center said. (To put that number in perspective, the rainy city of Seattle gets just over 37 inches (94 cm) of rain each year.)

Then, as the high-pressure system steering Florence weakens, the hurricane is expected to hang out inland for days, showering the region with rain much like Hurricane Harvey did to Houston last year.

All that water is worrisome for a region that just had a rainy season, meaning the soil there is fairly saturated and the rivers there are already high. "So, there's not a lot of capacity to soak up the extra water," Samson said.

Moreover, high tides around noon and midnight these next few days will make the storm surges even worse, Samson said. "If you haven't already evacuated, shore up your house as best you can," Samson recommended. "I would go visit a relative somewhere away from the shoreline."

What happens next

As for people staying put, the authorities used to advise that people get three days' worth of supplies, but now it's best to get two weeks' worth of supplies, Sue Anne Bell, an assistant professor of nursing at the University of Michigan, told Live Science.

That’s because in addition to the extensive flooding, the hurricane is expected to knock out power along the coast, according to an analysis done by a team headed by Seth Guikema, an associate professor of civil and environmental engineering at the University of Michigan. These power outages could last days to weeks, Brock Long, a spokesperson with the Federal Emergency Management Agency (FEMA), told Reuters.

In anticipation of the winds and water, 1.7 million people living along the coasts of the Carolinas and Virginia were ordered to evacuate ahead of the storm. [The 20 Costliest, Most Destructive Hurricanes to Hit the US]

Meanwhile, some of North Carolina's 2,100 industrial-size hog farmers are scrambling to drain waste pools containing manure before the hurricane hits, according to NPR. These pools are full of poop-eating bacteria that help break down the manure, but farmers don't want to see animal waste get into drinking water supplies. So, they're pumping the liquid out of the lagoons and spraying them as fertilizer on fields, which gives the lagoons more capacity to hold rainwater, NPR reported.

Floodwaters could also spread mercury-containing coal ash that's held in pits operated by Duke Energy, the state's main electricity company, the AP reported. But the company reported that wastewater levels inside the pits were low, and that "we’re more prepared than ever," Duke Energy spokesman Bill Norton told the AP.

The blasting wind and surging water may also damage some of the 16 nuclear reactors located in North Carolina, South Carolina and Virginia. Some of these reactors — including Duke Energy's Brunswick and Harris nuclear plants in North Carolina and Dominion Energy's Surry plant in Virginia — may be directly in the hurricane's path, Reuters reported.

However, since the Fukushima disaster in 2011, U.S. power plants have installed more safety equipment, such as waterproofing, portable pumps and generators, Duke Energy spokeswoman Mary Kathryn Green told Reuters. Some reactors are undergoing prestorm checks now, and their reactors will be shut down 12 hours before the hurricane arrives, Green said.

Original article on Live Science.

Many people will likely decide to stay put despite evacuation orders ahead of Hurricane Florence. And if history is any guide, they may not be fully thinking through the problems they'll face in the aftermath.

I conducted a research survey in Harris County, Texas, which contains much of metro Houston, after the city was flooded by Hurricane Harvey in August 2017, and found a common thread. Few respondents who stayed in place during the storm planned in advance for coping with extended service interruptions, such as road closures, power and water outages and communications interruptions.

I am a civil engineer and study interactions between people and infrastructure in disasters. In this survey, I wanted to understand how different sub-populations prepare for and adjust to service disruptions during these events.

Hurricanes don't always prompt mandatory evacuations, and even when they do, many people choose not to go. My results show that planning for losing key services, potentially for days or weeks, should be part of preparing to weather storms in place. And cities should keep their most vulnerable residents in mind as they make decisions about storm-proofing critical infrastructure systems, such as power and water.

No electricity, no phone, no toilet

Harvey flooded sewers, closed roads, downed power lines and interrupted telecommunications services across southeast Texas. Unlike tornadoes, which can selectively level one neighborhood and leave another unscathed, hurricanes are perversely egalitarian. In Houston, tony and disadvantaged neighborhoods alike bore the brunt of Harvey.

Most residents in hurricane-prone areas know to store food, stock up on water, check their flashlights and radios and plan for evacuations. But I found that relatively few Houstonians were ready for infrastructure service disruptions.

My survey was conducted three month after Harvey and included 750 Harris County residents. They rated sewer, water, electricity and communications as the most important household services, and found sewage backing up into homes from overwhelmed public water systems to be the most onerous disruption. Even households with individual on-site septic systems experienced septic tank overflow due to flooding.

Loss of potable water, which affected hygiene, drinking and food preparation, was the next greatest hardship. Electricity and telecommunications outages tied for third place, followed by road closures due to fallen trees, debris and flooding.

My students and I found that 53 percent of the people we surveyed were not well prepared for service disruption. Even the 47 percent who had laid in provisions to weather the storm had not thought specifically about service outages. Most people who self-identified as prepared underestimated the extent and length of service disruptions, and many ran out of stored food and water. A whopping 80 percent of households who were without power after the storm had not even considered the possibility of extended outages. 

Most affected: Low-income and minority households, families with young children

Regardless of how well cities harden their infrastructure, service disruptions are inevitable during and after major hurricanes. Once residents accept that fact, they can adopt practical strategies for weathering storms in place.

Families that live outside of hurricane paths or flood plains can still experience extended disruptions – for example, if high winds damage power distribution networks, or local roads are blocked by downed trees. It is critical for households to understand the likelihood of service disruptions, assess their basic needs objectively and prepare for possible extended outages.

Our research showed that some population groups were especially vulnerable to losing specific services. Households with children 10 and younger self-reported that losing electricity was the most onerous hardship for them, since it made it impossible for them to refrigerate and prepare food. On the other hand, respondents age 65 and older reported that road closures were their greatest burden because they could not drive to work, grocery stores, health care facilities or pharmacies.

We also found that low-income residents and racial and ethnic minorities were less prepared overall and experienced greater hardship during post-Harvey service losses. Disaster researchers widely view these groups as vulnerable populations, since they have fewer resources to prepare or adapt to disruptions.

Interestingly, we found that seniors over 65 were better prepared to endure sewer, water and telecommunications losses after Harvey. For many of them prior experience with storms had instilled the value of preparation, and on the whole they were ready for the impending storm.

Some people choose to shelter in place during disasters because they cannot afford to leave their homes for unknown destinations.

Hardening infrastructure with people in mind

Houston is investing in a swath of flood control and flood risk reduction projects. Notably, on Aug. 25 the city adopted a $2.5 billion bond measure to overhaul the region's flood-protection system..

Protecting homes is important, but cities should also invest in hardening infrastructure systems, such as power and water lines, to support residents who shelter in place during storms. Local communities can handle some of these upgrades. For instance, some Houston neighborhoods lost internet connectivity for as long as six weeks due to submerged utility boxes housing network electronics. This problem could be solved by raising the boxes above potential flood levels.

Identifying and hardening infrastructure components, such as power sub-stations and wastewater treatment plants, that are highly vulnerable to future storms is a critical task for utilities and city planners. Also, recognizing and protecting vulnerable sub-populations who are most affected by service outages should be a priority.

As households prepare for an storm, consideration of possible power outages, sewer backup, and road closures should factor into their decisions about evacuating or sheltering in place. If they stay, they should not underestimate the likelihood of service disruptions. No one likes to lose power or internet, but imagining the possibility of extended service outages and the resulting hardship can help households prepare and cope with the disruptions.

Ph.D. student Amir Esmalian and technical writer Jan Gerston contributed to this article.

Ali Mostafavi, Assistant Professor of Civil Engineering, Texas A&M University

This article is republished from The Conversation under a Creative Commons license. Read the original article. Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google +. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.

Residents of a small town on Greenland's western coast were evacuated after a giant iceberg parked itself nearby, bringing a threat of a tsunami and flooding that could wash much of the village away.

The iceberg, which was first sighted on July 12, is now settled to the north of the town of Innaarsuit, The New York Times reported. It measures a staggering 656 feet (200 meters) wide and rises about 328 feet (100 m) above sea level, according to satellite data, and is thought to weigh more than 12 million tons (11 million metric tons), according to the Times.

In photos, the enormous berg dominates the horizon near Inaarsuit, which is home to 169 people. The iceberg is an impressive sight, but it also brings significant risk to the village; should the berg disintegrate, massive chunks of ice falling into the bay could send powerful waves washing over the town. On Friday (July 13), 33 people in Innaarsuit who lived closest to the water were evacuated and fishing boats were moved inland, local news outlet Sermitsiaq reported. Meanwhile, residents are waiting to see if the berg will break up or if rising tides and winds will push it to a safe distance in Baffin Bay. [Images: Greenland's Gorgeous Glaciers]

By the morning of July 14, the iceberg had drifted about 1,969 feet (600 m) farther north, and local officials were monitoring it to assess the danger to residents and to decide whether further evacuations would be necessary, Police Chief Aqqaluk Petersen told Sermitsiaq.

Video footage shared by Greenland's KNR News on YouTube highlights the scale of the towering iceberg; fuel tanks and a power station visible near the coast are especially vulnerable to flooding should the iceberg break apart, Sermitsiaq reported.

Meanwhile, a satellite view tweeted on July 14 by Antti Lipponen, a research scientist at the Finnish Meteorological Institute, demonstrates the size of the berg (along with another, smaller iceberg slightly to the north), as well as its proximity to the Greenland coastline.

Iceberg visits are not new to Innaarsuit, but this is the largest one the village has seen in some time, according to village council member Susanne K. Eliassen, Australia's Special Broadcasting Service reported.

"There are cracks and holes that make us fear it can calve anytime," Eliassen said.

Recently, a glacier in eastern Greenland cracked and calved an iceberg that measured 4 miles (6 kilometers) long — and scientists were there to capture the event on video, documenting the birth of a berg that was about half the length of Manhattan, Live Science previously reported.

The fate of the Innaarsuit iceberg — and the town — depends on local weather, as warm rainfall could cause the berg to break up and trigger destructive flooding, according to The Sydney Morning Herald.

Original article on Live Science.