Mangrove forests around the world provide a largely overlooked nitrogen-pollution cleanup service — one that, if humans had to pay for it, would cost $8.7 billion per year, a new study estimates.

Mangroves are salt-tolerant plants that grow between the high-tide and low-tide marks in tropical and subtropical coastal regions. Their tall, tangled roots trap sediments rich in microbes that break down nitrogen in the water into nitrogen gas (N₂) and nitrous oxide (N₂O), effectively removing this nutrient from the ecosystem.

Researchers were aware that mangrove forests are valuable carbon sinks and provide a host of other ecosystem services, including coastal defense against storm surges and a buffer against erosion. But these forests' ability to remove nitrogen is poorly understood, despite the havoc that nitrogen pollution is known to wreak in aquatic ecosystems, the authors of the new study told Live Science.

"We're still really in the infancy of trying to understand what is driving this nitrogen removal," Benoit Thibodeau, an assistant professor in the Department of Earth and Environmental Science at The Chinese University of Hong Kong, said in a joint interview with his co-author Ziyan Wang, a doctoral student in environmental science at the same university. "You're taking reactive nitrogen … and you're removing it to the atmosphere as N₂, which is nonreactive and has a residence time of thousands of years."

Nitrogen pollution is caused by excess nutrient runoff into water systems due to human activities such as agriculture. Between 2002 and 2010, this runoff amounted to 35.9 million tons (32.6 million metric tons) of nitrogen per year in freshwater ecosystems. This pollution promotes algal growth, leading to blooms that massively reduce oxygen availability for other species and release toxins into the water that can make animals and people sick.

Mangroves forests cover less than 0.1% of Earth's land surface, but they remove about 960,000 tons (870,000 metric tons) of nitrogen from water systems each year, the new study found. That's roughly equivalent to the mass of 650 giant sequoia (Sequoiadendron giganteum) trees — but optimal conditions for mangroves could boost their removal capacity to more than 5.5 million tons (5 million metric tons) per year, which is equivalent to the weight of over 4,000 giant sequoias. The findings were published April 29 in the journal Earth's Future.

Thibodeau and Wang analyzed the results of 51 previous studies, as well as measurements they took themselves, to estimate global nitrogen-removal rates in mangrove forests. They divided the data into actual removal rates, which are those observed in nature, and potential removal rates, which capture the amount of nitrogen that mangrove forests could soak up if temperature, salinity and nitrogen levels were optimal.

Then, the researchers calculated averages for the actual and potential rates — and these, together with a global mangrove area estimate of 52,459 square miles (135,869 square kilometers), yielded an actual removal rate of 960,000 tons per year and a potential removal rate of over 5.5 million tons per year.

Microbes in mangrove forests remove nitrogen via two main pathways: denitrification and anaerobic ammonium oxidation (anammox). Denitrification transforms nitrate in the water into nitrogen gas and nitrous oxide, which is a greenhouse gas. Anammox, on the other hand, converts nitrite and ammonium into nitrogen gas, which makes up 78% of the atmosphere and is not a greenhouse gas. These pathways work best with relatively high nitrogen concentrations, but there is a threshold past which removal slows, according to the study.

These pathways also occur in seagrass meadows and other coastal environments, but mangrove forests are especially good at removing nitrogen because their sediments are oxygen-poor, which promotes the right kind of microbial activity, Wang said.

Similar to carbon credits that people can purchase to offset their emissions from activities like flying, the researchers used a market-based credit approach to calculate the economic value of nitrogen removal in mangrove forests. Based on what municipalities in countries like Australia and the U.S. pay to get rid of nitrogen in their water systems, Thibodeau and Wang settled on a price of just over $10,000 for every metric ton of nitrogen removed anywhere in the world.

"Carbon has a very mature credit market now, but for nitrogen, it's not that mature," Wang said. "We did a very early investigation about how different markets, or different industries, deal with this kind of nitrogen pollution."

At the current rate of nitrogen removal, mangroves' cleanup service is worth $8.7 billion per year globally. If removal rose to 5.5 million tons per year, it would be worth around $57 billion annually, according to the study.

The researchers also calculated the economic value of carbon sequestration in mangrove forests and found it was 12 times smaller than that of nitrogen removal. Notably, carbon sequestration is also less stable than nitrogen removal is, because mangroves store carbon in sediments that can be disturbed. On the flip side, mangrove forests convert nitrogen in the water mostly into nitrogen gas, which stays in the atmosphere, Thibodeau said. Nevertheless, mangrove forests "have a very high rate of storage of carbon compared to other ecosystems," he added.

Mangroves are mostly threatened by sea-level rise and land clearance for infrastructure, Thibodeau said. The results highlight that "we're not only losing space or nature, but we're also losing a very important financial value."

Mangroves have a relatively high heat tolerance, but rising global temperatures could alter how the microbes they host consume nitrogen, Wang said. Specifically, these microbes may start to rely more on denitrification, which could release more of the greenhouse gas N₂O than at present.

Behind the phenomena of global warming and climate change lies the increase in greenhouse gases in our atmosphere. A greenhouse gas is any gaseous compound in the atmosphere that is capable of absorbing infrared radiation, thereby trapping and holding heat in the atmosphere. By increasing the heat in the atmosphere, greenhouse gases are responsible for the greenhouse effect, which ultimately leads to global warming. (The effects of global warming can been seen across the globe.)

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

Solar radiation and the "greenhouse effect"

Global warming isn't a recent scientific concept. The basics of the phenomenon were worked out well over a century ago by Swedish physicist and chemist Svante Arrhenius, in 1896. His paper, published in the Philosophical Magazine and Journal of Science, was the first to quantify the contribution of carbon dioxide to what scientists now call the "greenhouse effect."

The greenhouse effect occurs because the sun bombards Earth with enormous amounts of radiation that strike Earth's atmosphere in the form of visible light, plus ultraviolet (UV), infrared (IR) and other types of radiation that are invisible to the human eye. UV radiation has a shorter wavelength and a higher energy level than visible light, while IR radiation has a longer wavelength and a weaker energy level. About 30% of the radiation that strikes Earth is reflected back out to space by clouds, ice and other reflective surfaces. The remaining 70% is absorbed by the oceans, the land and the atmosphere, according to NASA's Earth Observatory.

As they heat up, the oceans, land and atmosphere release heat in the form of IR thermal radiation, which passes out of the atmosphere and into space. It's this equilibrium of incoming and outgoing radiation that makes the Earth habitable, with an average temperature of about 59 degrees Fahrenheit (15 degrees Celsius), according to NASA. Without this atmospheric equilibrium, Earth would be as cold and lifeless as its moon, or as blazing hot as Venus. The moon, which has almost no atmosphere, is about minus 243 F (minus 153 C) on its dark side. Venus, on the other hand, has a very dense atmosphere that traps solar radiation; the average temperature on Venus is about 864 F (462 C).

The exchange of incoming and outgoing radiation that warms the Earth is often referred to as the greenhouse effect because an agricultural greenhouse works in much the same way. Incoming shortwave UV radiation easily passes through the glass walls of a greenhouse and is absorbed by the plants and hard surfaces inside. Weaker, longwave IR radiation, however, has difficulty passing through the glass walls and is thereby trapped inside, warming the greenhouse.

How greenhouse gases cause global warming

The gases in the atmosphere that absorb radiation are known as "greenhouse gases" (abbreviated as GHG) because they are largely responsible for the greenhouse effect. The greenhouse effect, in turn, is one of the leading causes of global warming. The most significant greenhouse gases, according to the Environmental Protection Agency (EPA), are: water vapor (H2O), carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). 

"While oxygen (O2) is the second most abundant gas in our atmosphere, O2 does not absorb thermal infrared radiation," Michael Daley, an associate professor of environmental science at Lasell College in Massachusetts, told Live Science.

Global warming and the greenhouse gases that cause it occur naturally — without them, Earth's average surface temperature would be a gelid zero degrees F (minus 18 C). But the amount of greenhouse gases in the atmosphere has skyrocketed to detrimental levels in recent history. 

Related: Carbon dioxide soars to record breaking levels not seen in at least 800,000 years

During the 20,000-year period before the Industrial Revolution, atmospheric CO2 fluctuated between about 180 parts per million (ppm) during ice ages and 280 ppm during interglacial warm periods. However, since the beginning of the Industrial Revolution in the 1750s, the amount of CO2 has risen nearly 50%, according to NASA’s Global Climate Change portal. Today, CO2 levels stand at over 410 ppm.

Fluorinated gases — gases to which the element fluorine has been added — are created during industrial processes and are also considered greenhouse gases. These include hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride. Although they are present in the atmosphere in very small concentrations, they trap heat very effectively, making them high "global warming potential" (GWP) gases.

Chlorofluorocarbons (CFCs), once used as refrigerants and aerosol propellants until they were phased out by international agreement, are also greenhouse gases.

Related: Global warming vs. solar cooling: The showdown begins in 2020

There are three factors that affect the degree to which a greenhouse gas will influence global warming: Its abundance in the atmosphere, how long it stays in the atmosphere and its GWP. For example, water vapor is the most abundant greenhouse gas, but carbon dioxide has a more significant impact on global warming due to its abundance in the atmosphere plus its relatively long atmospheric lifetime of 300 to 1,000 years, according to NASA. Water vapor, on the other hand, has an atmospheric lifetime of no more than 10 days, according to a 2020 study published in the Journal of the Atmospheric Sciences.

Methane is about 21 times more efficient at absorbing radiation than CO2, giving it a higher GWP rating, even though it stays in the atmosphere for only about 12 years, according to the United Nations Framework Convention on Climate Change (UNFCCC). Although methane and other GHGs are capable of trapping more heat than CO2, scientists still consider carbon dioxide to be the dominant greenhouse gas because its warming effect outlives the others' effects by centuries.

Sources of greenhouse gases

Some greenhouse gases, such as methane, are produced through agricultural practices, in the form of livestock manure, for example. Others, like CO2, largely result from natural processes like respiration, and from the burning of fossil fuels like coal, oil and gas.

Another primary source of CO2 is deforestation. When trees are felled to produce goods or heat, they release the carbon that is normally stored for photosynthesis. This process releases up to 4.8 billion metric tons of carbon into the atmosphere every year, according to the World Resources Institute.

Forestry and other land-use practices can offset some of these greenhouse gas emissions. "Replanting helps to reduce the buildup of carbon dioxide in the atmosphere as growing trees sequester carbon dioxide through photosynthesis," Daley told Live Science. "However, forests cannot sequester all of the carbon dioxide we are emitting to the atmosphere through the burning of fossil fuels, and a reduction in fossil fuel emissions is still necessary to avoid buildup in the atmosphere."

Worldwide, the output of greenhouse gases is a source of grave concern. According to NOAA’s Climate.gov, over the past 60 years, atmospheric CO2 has increased at an annual rate that's 100 times faster than previous natural increases. The last time global atmospheric CO2 amounts were this high was 3 million years ago, when temperatures were up to 5.4 degrees F (3 degrees C) higher than during the pre-industrial era. As a result of modern-day CO2-induced global warming, 2016 was the warmest year on record, with 2019 and 2020 ranking as the next warmest, respectively. In fact, the six hottest years on record have all occurred since 2015, according to the World Meteorological Organization.

"The warming we observe affects atmospheric circulation, which impacts rainfall patterns globally," said Josef Werne, an associate professor in the Department of Geology and Planetary Science at the University of Pittsburgh. "This will lead to big environmental changes, and challenges, for people all across the globe."

Our planet's future

If current trends continue, scientists, government officials and a growing number of citizens fear that the worst effects of global warming — extreme weather, rising sea levels, plant and animal extinctions, ocean acidification, major shifts in climate and unprecedented social upheaval — will be inevitable.

In an effort to combat GHG-induced global warming, the U.S. government created a climate action plan in 2013. And in April 2016, representatives from 73 countries signed the Paris Agreement, an international pact to combat climate change by investing in a sustainable, low-carbon future, according to the UNFCCC. Although the U.S. withdrew from the Paris Agreement in 2017, it rejoined in late-January 2021. President Biden's administration has also set a target of reducing U.S. emissions by 50-52% of 2005 levels by the year 2030. (Emissions are routinely compared to those in 2005 — the year U.S. emissions of CO2 peaked at nearly 6 billion tons.)

In 2020, global carbon dioxide emissions fell 6.4% (13% in the U.S. alone) — the first time in decades the annual rate hasn’t climbed, Nature reported. This was in part due to the decrease in fossil fuel combustion resulting from the switch to natural gas from coal, but largely because of the forced standstill in economic, social and transportation activities in response to the COVID-19 pandemic. Scientists expected the annual emissions decline to actually be larger than it was, but emissions rebounded as restrictions were lifted in some nations and activities recovered toward the end of 2020. 

Related: Global carbon emissions dropped an unprecedented 17% during the coronavirus lockdown — and it changes nothing

In order to limit global warming to the 2.7 degree F (1.5 degree C) target set by the Paris Agreement, the world still needs to cut its CO2 emissions by 7.6% for the next decade, according to the UN Environment Programme. 

Researchers around the world continue to work toward finding ways to lower greenhouse gas emissions and mitigate their effects. One potential solution scientists are examining is to suck some of the carbon dioxide out of the atmosphere and bury it underground indefinitely. Advocates argue that carbon capture and storage is technologically feasible, but market forces have prevented widespread adoption. 

Whether or not removing already-emitted carbon from the atmosphere is feasible, preventing future warming requires stopping the emissions of greenhouse gases. The most ambitious effort to forestall warming thus far is the 2016 Paris Agreement. This nonbinding international treaty aims to keep warming "well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius," according to the United Nations. Each signatory to the treaty agreed to set their own voluntary greenhouse gas emission limits and to make them stricter over time. Climate scientists said that the emissions limits committed under the agreement wouldn't keep warming as low as 1.5 or even 2 degrees C, but that it would be an improvement over the "business-as-usual" scenario.

Additional resources

• Find out the latest research and policy updates regarding global warming via NOAA's Climate.gov portal.
• Learn more about the Global Carbon Project.
• Read more about the impact of COVID-19 on 2020 CO2 emissions, according to Carbon Brief.

Would you ever go on vacation to the North Pole? Unless you like subzero temperatures and Nordic-ski treks, probably not. But if you lived 56 million years ago, you might answer differently. Back then, you would have enjoyed balmy temperatures and a lush green landscape (although you would have had to watch out for crocodiles). That's because the world was in the middle of an extreme period of global warming called the Paleo-Eocene Thermal Maximum, when the Earth was so hot that even the poles reached nearly tropical temperatures.

But was the planet ever as hot as it is today, when every month the globe seems to be breaking one high-temperature record after another?

It turns out that the Earth has gone through periods of extreme warming more than once. The poles have frozen and thawed and frozen again. Now, the Earth is heating up again. Even so, today's climate change is a different beast, and it's clearly not just part of some larger natural cycle, Stuart Sutherland, a paleontologist at the University of British Columbia, told Live Science. [How Often Do Ice Ages Happen?] 

Earth's climate does naturally oscillate — over tens of thousands of years, its rotations around the sun slowly change, leading to variations in everything from seasons to sunlight. Partially as a result of these oscillations, Earth goes through glacial periods (better known as ice ages) and warmer interglacial periods.

But to create a massive warming event, like the Paleo-Eocene Thermal Maximum, it takes more than a change in the tilt of Earth's axis, or the shape of its path around the sun. Extreme warming events always involve the same invisible culprit, one we're all too familiar with today: a massive dose of carbon dioxide, or CO2.

This greenhouse gas was almost certainly responsible for the Paleo-Eocene Thermal Maximum. But how did CO2 concentrations get so high without humans around? Scientists aren't absolutely sure, said Sébastien Castelltort, a geologist at the University of Geneva. Their best guess is that volcanoes spewed carbon dioxide into the atmosphere, trapping heat, and perhaps melting frozen pockets of methane, a greenhouse gas more potent than CO2 that had been long sequestered under the ocean. Just because extreme warming events spurred by greenhouse gases have happened before, doesn't mean these events are harmless. Take, for instance, the Permian-Triassic extinction event, which struck a few million years before dinosaurs arose on the planet. If the word "extinction" isn't enough of a clue, here's a spoiler: it was an absolute disaster for Earth and everything on it.

This warming event, which occurred 252 million years ago, was so extreme that Sutherland calls it the "poster child for the runaway greenhouse effect." This warming event, which was also caused by volcanic activity (in this case, the eruption of a volcanic region called the Siberian Traps), triggered climate chaos and widespread death.

"Imagine extreme drought, plants dying, the Saharah spreading throughout the continent," Sutherland told Live Science.

Temperatures rose 18 degrees Fahrenheit (10 degrees Celsius). (This is compared with the 2.1 F (1.2 C) rise in temperature we've seen since humans began burning fossil fuels). Around 95% of marine life and 70% of terrestrial life went extinct.

"It was just too hot and unpleasant for creatures to live," Sutherland said.

It's uncertain how high greenhouse gas concentrations were during the Permian-Triassic extinction event, but they likely were far higher than they are today. Some models suggest they grew as high as 3,500 parts per million (ppm). (For perspective, today's carbon dioxide concentrations hover a little over 400 ppm — but that's still considered high).

But it's the rate of change in CO2 concentrations that makes today's situation so unprecedented. During the Permian Triassic extinction event, it took thousands of years for temperatures to rise as high as they did — according to some studies, as many as 150,000 years. During the Paleo-Eocene Thermal Maximum, considered an extremely rapid case of warming, temperatures took 10,000 to 20,000 years to reach their height.

Today's warming has taken only 150 years.

That is the biggest difference between today's climate change and past climatic highs. It's also what makes the consequences of current climate change so difficult to predict, Castelltort said. The concern isn't just "but the planet is warming." The concern is that we don't know how rapid is too rapid for life to adjust, he said. Based on past warming events, no experts could possibly say that the current rate of warming won't have dramatic consequences, he said. "We just don't know how dramatic," he added.

• What is a Carbon Sink?
• What If a Giant Asteroid Had Not Wiped Out the Dinosaurs?
• Why Weather Affects Climate Change Belief

Originally published on Live Science.

Scientists and security analysts have warned for more than a decade that global warming is a potential national security concern.

They project that the consequences of global warming — rising seas, powerful storms, famine and diminished access to fresh water — may make regions of the world politically unstable and prompt mass migration and refugee crises.

Some worry that wars may follow.

Yet with few exceptions, the U.S. military's significant contribution to climate change has received little attention. Although the Defense Department has significantly reduced its fossil fuel consumption since the early 2000s, it remains the world's single largest consumer of oil — and as a result, one of the world's top greenhouse gas emitters.

A broad carbon footprint

I have studied war and peace for four decades. But I only focused on the scale of U.S. military greenhouse gas emissions when I began co-teaching a course on climate change and focused on the Pentagon's response to global warming. Yet, the Department of Defense is the U.S. government's largest fossil fuel consumer, accounting for between 77% and 80% of all federal government energy consumption since 2001.

In a newly released study published by Brown University's Costs of War Project, I calculated U.S. military greenhouse gas emissions in tons of carbon dioxide equivalent from 1975 through 2017.

Today China is the world's largest greenhouse gas emitter, followed by the United States. In 2017 the Pentagon's greenhouse gas emissions totaled over 59 million metric tons of carbon dioxide equivalent. If it were a country, it would have been the world's 55th largest greenhouse gas emitter, with emissions larger than Portugal, Sweden or Denmark.

The largest sources of military greenhouse gas emissions are buildings and fuel. The Defense Department maintains over 560,000 buildings at approximately 500 domestic and overseas military installations, which account for about 40% of its greenhouse gas emissions.

The rest comes from operations. In fiscal year 2016, for instance, the Defense Department consumed about 86 million barrels of fuel for operational purposes.

Why do the armed forces use so much fuel?

Military weapons and equipment use so much fuel that the relevant measure for defense planners is frequently gallons per mile.

Aircraft are particularly thirsty. For example, the B-2 stealth bomber, which holds more than 25,600 gallons of jet fuel, burns 4.28 gallons per mile and emits more than 250 metric tons of greenhouse gas over a 6,000 nautical mile range. The KC-135R aerial refueling tanker consumes about 4.9 gallons per mile.

A single mission consumes enormous quantities of fuel. In January 2017, two B-2B bombers and 15 aerial refueling tankers traveled more than 12,000 miles from Whiteman Air Force Base to bomb ISIS targets in Libya, killing about 80 suspected ISIS militants. Not counting the tankers' emissions, the B-2s emitted about 1,000 metric tons of greenhouse gases.

Quantifying military emissions

Calculating the Defense Department's greenhouse gas emissions isn't easy. The Defense Logistics Agency tracks fuel purchases, but the Pentagon does not consistently report DOD fossil fuel consumption to Congress in its annual budget requests.

The Department of Energy publishes data on DOD energy production and fuel consumption, including for vehicles and equipment. Using fuel consumption data, I estimate that from 2001 through 2017, the DOD, including all service branches, emitted 1.2 billion metric tons of greenhouse gases. That is the rough equivalent of driving of 255 million passenger vehicles over a year.

Of that total, I estimated that war-related emissions between 2001 and 2017, including "overseas contingency operations" in Afghanistan, Pakistan, Iraq and Syria, generated over 400 million metric tons of CO2 equivalent — roughly equivalent to the greenhouse emissions of almost 85 million cars in one year.

Real and present dangers?

The Pentagon's core mission is to prepare for potential attacks by human adversaries. Analysts argue about the likelihood of war and the level of military preparation necessary to prevent it, but in my view, none of the United States' adversaries — Russia, Iran, China and North Korea — are certain to attack the United States.

Nor is a large standing military the only way to reduce the threats these adversaries pose. Arms control and diplomacy can often de-escalate tensions and reduce threats. Economic sanctions can diminish the capacity of states and nonstate actors to threaten the security interests of the U.S. and its allies.

In contrast, climate change is not a potential risk. It has begun, with real consequences to the United States. Failing to reduce greenhouse gas emissions will make the nightmare scenarios strategists warn against — perhaps even "climate wars" — more likely.

A case for decarbonizing the military

Over the past last decade the Defense Department has reduced its fossil fuel consumption through actions that include using renewable energy, weatherizing buildings and reducing aircraft idling time on runways.

The DOD's total annual emissions declined from a peak of 85 million metric tons of carbon dioxide equivalent in 2004 to 59 million metric tons in 2017. The goal, as then-General James Mattis put it, is to be "unleashed from the tether of fuel" by decreasing military dependence on oil and oil convoys that are vulnerable to attack in war zones.

Since 1979, the United States has placed a high priority on protecting access to the Persian Gulf. About one-fourth of military operational fuel use is for the U.S. Central Command, which covers the Persian Gulf region.

As national security scholars have argued, with dramatic growth in renewable energy and diminishing U.S. dependence on foreign oil, it is possible for Congress and the president to rethink our nation's military missions and reduce the amount of energy the armed forces use to protect access to Middle East oil.

I agree with the military and national security experts who contend that climate change should be front and center in U.S. national security debates. Cutting Pentagon greenhouse gas emissions will help save lives in the United States, and could diminish the risk of climate conflict.

Neta C. Crawford, Professor of Political Science and Department Chair, Boston University

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

There is more carbon dioxide in the atmosphere than there has been for 800,000 years — since before our species evolved.

On Saturday (May 11), the levels of the greenhouse gas reached 415 parts per million (ppm), as measured by the National Oceanic and Atmospheric Administration's Mauna Loa Observatory in Hawaii. Scientists at the observatory have been measuring atmospheric carbon dioxide levels since 1958. But because of other kinds of analysis, such as those done on ancient air bubbles trapped in ice cores, they have data on levels reaching back 800,000 years. [8 Ways Global Warming Is Already Changing the World]

During the ice ages, carbon dioxide levels in the atmosphere were around 200 ppm. And during the interglacial periods — the planet is currently in an interglacial period — levels were around 280 ppm, according to NASA.

But every story has its villains: Humans are burning fossil fuels, causing the release of carbon dioxide and other greenhouse gases, which are adding an extra blanket on an already feverish planet. So far, global temperatures have risen by about 1.8 degrees Fahrenheit (1 degree Celsius) since the 19th century or pre-industrial times, according to a special report released last year by the United Nation's Intergovernmental Panel on Climate Change.

Every year, the Earth sees about 3 ppm more carbon dioxide in the air, said Michael Mann, a distinguished professor of meteorology at Penn State University. "If you do the math, well, it's pretty sobering," he said. "We'll cross 450 ppm in just over a decade."

The subsequent warming is already causing changes to the planet — shrinking glaciers, bleaching coral reefs and intensifying heat waves and storms, among other impacts. And carbon dioxide levels higher than 450 ppm "are likely to lock in dangerous and irreversible changes in our climate," Mann told Live Science.

"CO2 levels will continue to increase for at least the next decade and likely much longer, because not enough is being done worldwide," said Donald Wuebbles, a professor of atmospheric sciences at the University of Illinois at Urbana-Champaign. "The long-term increase is due to human-related emissions, especially the emissions of our burning of fossil fuels."

However, he noted that the annual peak in carbon dioxide, which fluctuates throughout the year as plants change their breathing rhythms, occurs right now. The annual average value will be more like 410 to 412 ppm, he said. Which … is still very high.

"We keep breaking records, but what makes the current levels of CO2 in the atmosphere most troubling is that we are now well into the 'danger zone' where large tipping points in the Earth’s climate could be crossed," said Jonathan Overpeck, the dean of the School for Environment and Sustainability at the University of Michigan. "This is particularly true when you factor in the additional warming potential of the other greenhouse gases, including methane, that are now in the atmosphere."

The last time atmospheric carbon dioxide levels were this high, way before Homo sapiens walked the planet, the Antarctic Ice Sheet was much smaller and sea levels were up to 65 feet (20 meters) higher than they are today, Overpeck told Live Science.

"Thus, we could soon be at the point where comparable reductions in ice sheet size, and corresponding increases in sea level, are both inevitable and irreversible over the next few centuries," he said. Smaller ice sheets, in turn, might reduce the reflectivity of the planet and potentially accelerate the warming even more, he added.

"It's like we're playing with a loaded gun and don't know how it works."

• Images of Melt: Earth's Vanishing Ice
• The Reality of Climate Change: 10 Myths Busted
• 5 Ways Climate Change Will Affect Your Health

Originally published on Live Science.

The ocean is the hottest it's ever been, and no, this is not normal.

A new report released in the journal Advances in Atmospheric Sciences on Jan. 15 reveals that ocean temperatures in 2018 reached their highest point since accurate measurements first began in the 1950s.

The heat increase in the world's oceans from 2017 (the previous record holder) to 2018 is equivalent to about 388 times the total electricity generation of China in 2017, according to a statement about the research released by the Institute of Atmospheric Physics in China.

Ocean temperatures down to 2,000 meters (6,600 feet) were calculated using data from various measurement devices. Those includes Argo, a set of free-floating devices that measure temperature and salt concentration in the waters.

After 2018 and 2017, the third warmest year for ocean temperatures was 2015, followed by 2016 and finally 2014. And, not surprisingly, this is all our fault. [8 Ways Global Warming Is Already Changing the World]

The change in ocean temperatures is a good way to gauge the effect that human activity is having on our planet, because the vast majority of heat trapped by greenhouse gases in the atmosphere gets absorbed by the oceans, the paper said.

Warming oceans can have far-reaching effects. As water warms, temperature and moisture levels in the air also rise, which can lead to increased intensity and duration of storms and heavy rains, according to the paper.

Increased ocean temperatures can also accelerate the melting of sea ice, leading to sea level rise and increased coastal flooding. In the water, higher temperatures can reduce oxygen levels, leading to so-called dead zones, where plants and animals can't survive. And if the surface of the ocean warms by 2 degrees Celsius (3.6 degrees Fahrenheit) this century, 99 percent of the world's coral reefs will be bleached, leaving them more vulnerable to disease, the paper said.

The new data, together with a rich body of literature, serve as an additional warning to both the government and the general public that we are experiencing inevitable global warming," study lead author Lijing Cheng, an associate professor at the Institute of Atmospheric Physics of the Chinese Academy of Sciences, said in the statement. The warming is already causing damage and losses to economy and society, he added.

Just last week, another study, this one published in the Proceedings of the National Academy of Sciences by a different group, modeled ocean temperatures further back in time. That study found that ocean temperatures have warmed by 426 x 10^21 since 1871. According to The Guardian, this is about 1,000 times the annual energy use of the entire globe.

• The Reality of Climate Change: 10 Myths Busted
• Predicting the Future of Our Climate
• 6 Unexpected Effects of Climate Change

Originally published on Live Science.

It's now beyond official: Greenhouse gases, such as carbon dioxide, pose a danger to public health and welfare, according to an exhaustive review that looked at 275 scientific studies published over the past nine years.

Researchers did the report to investigate whether the Environmental Protection Agency's (EPA) 2009 Endangerment Finding, which found that greenhouse gases pose a risk to human health, still held up. The new study showed that there is now even more evidence that greenhouse gases are harming human health and welfare. The investigation also found an additional four areas, not listed in the original report, in which greenhouse gases threaten people.

"There's absolutely no scientific basis for questioning the Endangerment Finding," review lead researcher Philip Duffy, president and executive director of the Woods Hole Research Center in Falmouth, Massachusetts, told Live Science. "The case for endangerment is stronger than ever." [6 Unexpected Effects of Climate Change]

What is the Endangerment Finding?

The original Endangerment Finding was a long time in the making. It began when Massachusetts and other states sued the EPA during President George W. Bush's administration, asking the agency to regulate greenhouse gases. In 2007, the Supreme Court ruled that not only does the EPA have the authority to regulate greenhouse gases under the Clean Air Act, but it also can't refuse to do so if these pollutants are found to endanger people.

"The Supreme Court said 'if you determine that greenhouse gases are dangerous, then you have to regulate them,'" Duffy said. "But, of course, the Supreme Court wasn't itself going to say whether greenhouse gases are dangerous. That's a scientific process not a legal one. So, the EPA undertook the scientific assessment of the dangerousness or not-dangerousness of greenhouse gases."

In December 2009, the EPA released that report, which found that greenhouse gases do endanger human health and welfare by causing climate change. The administration of President Barack Obama used this finding to implement new regulations, such as the Clean Power Plan and stronger vehicle mileage standards for cars and light trucks, Duffy said.

But now, people in and out of President Donald Trump's administration have discussed overturning or revisiting the endangerment finding, Duffy said. In response to these statements, Duffy and his colleagues decided to look at scientific studies published since the endangerment finding came out, to see whether the science strengthened or weakened the case for endangerment.

What the science shows

The new review grouped the findings into different categories: public health, air quality, agriculture, forests, water resources, sea level rise, infrastructure and wildlife. The four new categories include ocean acidification, national security, economic well-being and violence. Here are more in-depth looks at several of them.

Overview of public health

People in more than 200 U.S. cities have an increased risk of premature death because of future warming, the researchers found. Extreme heat is linked with sleep loss, kidney stones, low birth weight, violence and suicide. Exposure to ozone and other air pollutants, including smoke from forest fires, can be bad for human health. Extreme weather events intensified by climate change can lead to physical trauma, disease outbreaks, interruption of health care delivery and mental health problems. Rising temperatures and carbon dioxide levels are also increasing the length of pollen season, which affects people with allergies. Certain crops are expected to produce fewer nutrients. Population displacement and armed conflict can also amplify risks to human health. [Photos Show Horrifying Scenes from California Wildfires]

Water resources

With less snowpack in the mountains, the West and Southwest may experience more droughts. Reduced snowpack can lead to reduced river flow, which can threaten rare and endangered species, such as salmon and wolverines. Climate change is also expected to erode water quality in the United States because of nutrient loading (such as from fertilizer or animal waste), especially in the Midwest and Northeast.

Sea level rise

High sea levels will increase the risk to coastal communities, economies and infrastructure, largely because of flooding, erosion and extreme events. These effects can lead to displacement through "climate gentrification," in which people living at higher elevations have higher-priced properties. The movement of goods among major port cities will likely be affected, too, causing economic disruptions. Sea level rise may also disrupt the U.S. military, as well as disaster and humanitarian relief efforts.

National security

The United States' existing security will likely need to change as the planet warms. For example, in the Arctic, reduced sea ice will clear the way for more Chinese trade routes and Russian oil and gas extraction, possibly causing tensions between these countries and the U.S., the researchers wrote.

Economic well-being

An increase of 1.8 degrees Fahrenheit (1 degree Celsius) over 75 years is expected to permanently reduce U.S. gross domestic product (GDP) by about 3 percent. The U.S. GDP is expected to be about 4 percent greater if warming is limited to 2.7 degrees F (1.5 degrees C) than if it's 3.6 degrees F (2 degrees C) above pre-industrial levels. Economies in poorer countries are expected to have an economic burden from climate change that is about five times larger than that of wealthier counties, the researchers found.

Violence and instability

Rising temperatures and increased rainfall can amplify violence and instability. In the U.S., higher temperatures are associated with higher rates of domestic violence, rape, assault and murder. Warmer periods may also elevate the risk of self-harm, including suicide, emerging evidence suggests.

Takeaway message

These findings "highlight this contrast between the science and the policies," Duffy said. "The scientific evidence is going in one direction, and the policies are going in exactly the opposite direction."

But this report shouldn't come as a surprise to anyone, said Jason Smerdon, a climate scientist at the Lamont-Doherty Earth Observatory of Columbia University in New York, who wasn't involved with the review.

"If you've been paying attention, the Endangerment Finding in 2009 was very well-reasoned, and it's only gotten stronger since that time," Smerdon told Live Science. "It's basically a tsunami of evidence in support of the fact. People have very clearly connected the changing climate, which we're causing, to the downstream impacts."

The review also drives home that climate change will affect everybody, not just people in distant lands.

"Reports like this all point out that every one of us will be impacted by climate change in different ways, and it's going to be in all of our backyards," Smerdon said. "It's not something that's going to be far away."

The review was published online yesterday (Dec. 13) in the journal Science.

• The Reality of Climate Change: 10 Myths Busted
• Top 10 Ways to Destroy Earth
• Photos of Melt: Glaciers Before and After

Originally published on Live Science.

After a few promising years of minimal carbon-emission growth, the world is on pace to burn a bunch more fossil fuels. According to a new estimate, global carbon emissions will hit a record-breaking 37.1 billion metric tons in 2018.

That's a 2.7 percent increase over 2017's global emissions output of 36.2 billion metric tons, researchers with the Global Carbon Project reported Dec. 5. And 2017's numbers represented a 1.6 percent increase over the year before.

"For three years, we saw flat greenhouse gas emissions at the same time [that] the world economy grew. That was good news," said Robert Jackson, a professor of Earth system science at Stanford University. "We hoped that represented peak emissions. It didn't." [The Reality of Climate Change: 10 Myths Busted]

To turn off the emissions spigot, countries will have to focus on renewable energy, and quickly, Jackson said.

Rising emissions

Climate change is already underway. A 2010 NASA study found that Earth's average surface temperature rose 1.44 degrees Fahrenheit (0.8 degrees Celsius) over the 20th century. The Arctic, in particular, is responding rapidly to this change, exhibiting record levels of melt. Surface meltwater from Greenland alone now contributes nearly a millimeter of global sea-level rise to the oceans each year.

In October, the United Nations Intergovernmental Panel on Climate Change warned that the world will have to slash carbon emissions to 45 percent below 2010 levels by the year 2030 and then halt all emissions by 2050 in order to keep global average temperatures from rising more than 2.7 degrees F (1.5 degrees C).

Currently, emissions are headed in the wrong direction, Jackson and his team found. Between 2017 and 2018, China is estimated to have increased its carbon output by 4.7 percent. The U.S. output has risen about 2.5 percent in the same period. India saw the sharpest increase in carbon output between 2017 and 2018, at an estimated 6.3 percent. The European Union has increased its outputs as well, by 0.7 percent.

The drivers of these trends are both meteorological and economic, the researchers reported. An especially cold winter in the eastern United States and a hot summer across the country increased fossil fuel emissions from the heating and cooling of homes and other structures. A decline in the price of oil led to the purchase of larger cars and trucks in the United States. Meanwhile, a sluggish economy in China has leaders there incentivizing heavy industry and instituting coal-power projects that had been on hold, Jackson said. Economic development in India has that nation scrambling to build any energy project it can.

"They're building coal, nuclear and renewables at breakneck pace," Jackson said. "Every coal plant they build is likely to be polluting 40 years from now."

Turning it around

Despite the sobering trends, there are glimmers of hope. The United States and Canada have seen a decrease in coal consumption of about 40 percent since 2005, Jackson said. And despite the vocally pro-coal administration of president Donald Trump, some 15 gigawatts of coal plants are slated to close this year in the U.S., a potential record, Jackson added.

"The pricing for wind and solar is now competitive with [that of] fossil fuels in many cases," Jackson added.

The transportation sector is a bigger challenge, Jackson said, as low oil prices lead consumers to drive more frequently and buy larger vehicles. Incentivizing electric vehicles — which can be charged with power generated by clean energy — would make a big impact in emissions, Jackson said.

Globally, the picture is complex. India, for example, is striving to bring any electric power at all to millions of people who have none.

"They need financial incentives to reduce reliance on new coal plants" and to build renewable-energy infrastructure instead, Jackson said.

Though it's discouraging to see emissions rising so quickly, Jackson said, he's an optimist at heart. "I believe green energy will eventually win," he said. The only question is how much warming will have to occur first and how hard it will be to rein in today's excesses.

"The higher we go in emission today," Jackson said, "the faster or the deeper the cuts need to be in a decade or two decades or beyond."

Jackson and his colleagues on the Global Carbon Project published their estimates on Dec. 5 in the journals Environmental Research Letters and Earth System Science Data.

• 8 Ways Global Warming Is Already Changing the World
• Photographic Proof of Climate Change: Time-Lapse Images of Retreating Glaciers
• Images of Melt: Earth's Vanishing Ice

Originally published on Live Science.

Climate change reaches all the way to the bottom of the sea.

The same greenhouse gas emissions that are causing the planet's climate to change are also causing the seafloor to dissolve. And new research has found the ocean bottom is melting away faster in some places than others.

The ocean is what's known as a carbon sink: It absorbs carbon from the atmosphere. And that carbon acidifies the water. In the deep ocean, where the pressure is high, this acidified seawater reacts with calcium carbonate that comes from dead shelled creatures. The reaction neutralizes the carbon, creating bicarbonate.

Over the millennia, this reaction has been a handy way to store carbon without throwing the ocean's chemistry wildly out of whack. But as humans have burned fossil fuels, more and more carbon has ended up in the ocean. In fact, according to NASA, about 48 percent of the excess carbon humans have pumped into the atmosphere has been locked away in the oceans. [7 Ways the Earth Changes in the Blink of an Eye]

All that carbon means more acidic oceans, which means faster dissolution of calcium carbonate on the seafloor. To find out how quickly humanity is burning through the ocean floor's calcium carbonate supply, researchers led by Princeton University atmospheric and ocean scientist Robert Key estimated the likely dissolution rate around the world, using water current data, measurements of calcium carbonate in seafloor sediments and other key metrics like ocean salinity and temperature. They compared the rate with that before the industrial revolution.

Their results, published Oct. 29 in the journal Proceedings of the National Academy of Sciences, were a mix of good and bad news. The good news was that most areas of the oceans didn't yet show a dramatic difference in the rate of calcium carbonate dissolution prior to and after the industrial revolution. However, there are multiple hotspots where human-made carbon emissions are making a big difference — and those regions may be the canaries in the coalmine.

The biggest hotspot was the western North Atlantic, where anthropogenic carbon is responsible for between 40 and 100 percent of dissolving calcium carbonate. There were other small hotspots, in the Indian Ocean and in the Southern Atlantic, where generous carbon deposits and fast bottom currents speed the rate of dissolution, the researchers wrote.

The western North Atlantic is where the ocean layer without calcium carbonate has risen 980 feet (300 meters). This depth, called the calcite compensation depth, occurs where the rain of calcium carbonate from dead animals is essentially canceled out by ocean acidity. Below this line, there is no accumulation of calcium carbonate.

The rise in depth indicates that now that there is more carbon in the ocean, dissolution reactions are happening more rapidly and at shallower depths. This line has moved up and down throughout millennia with natural variations in the Earth's atmospheric makeup. Scientists don't yet know what this alteration in the deep sea will mean for the creatures that live there, according to Earther, but future geologists will be able to see man-made climate change in the rocks eventually formed by today's seafloor. Some current researchers have already dubbed this era the Anthropocene, defining it as the point at which human activities began to dominate the environment.  

"Chemical burndown of previously deposited carbonate-rich sediments has already begun and will intensify and spread over vast areas of the seafloor during the next decades and centuries, thus altering the geological record of the deep sea," Key and his colleagues wrote. "The deep-sea benthic [bottom] environment, which covers ~60 percent of our planet, has indeed entered the Anthropocene."  

Originally published on Live Science.

Arctic lakes could release a vast reservoir of ancient carbon buried deep under the permanently frozen ground, or permafrost, thereby accelerating climate change.

These lakes, which form when surface ice melts and the ground beneath it collapses, could thaw underground permafrost much faster than scientists thought was possible, a new study reveals. [Images of Melt: Earth's Vanishing Ice]

Previously, scientists thought the bulk of this deep thawing of Arctic permafrost would likely not happen until after 2100.

Rapid changes in the Arctic

Climate change is taking hold in the Arctic faster than it is on the rest of the planet, and one of the biggest risks associated with warming temperatures in the region is permafrost melt.

The deep layers of permanently frozen soil that underlie much of the Arctic hide massive reservoirs of organic carbon, in the form of thousands of years' worth of trapped plant matter and even animal carcasses. As the soil gradually melts, these buried organisms will decay and release the greenhouse gases carbon dioxide and methane into the atmosphere, which can, in turn, lead to even more warming.

But most scientists believed it would take decades of warming to melt permafrost buried beneath the active layer of soil that freezes and thaws with the seasons.

"The conclusions that permafrost-carbon modelers were reaching was that, until you thaw really deep, we're not going to get this large, old carbon signal and that the really deep thaw of carbon on land is not going to happen until beyond 2100," study leader Katey Walter Anthony, an ecologist and biogeochemist at the University of Alaska Fairbanks, told Live Science. "What our study shows is that in a lake, you thaw that deep really fast on a scale of decades. Lakes tap into that old carbon much sooner, and they will release that permafrost carbon much sooner than that thaw on land."

Walter Anthony and her colleagues have been studying so-called thermokarst lakes, which are created when the ice-rich ground thaws, thus causing the earth underneath to collapse and form a pit, where the melted water pools. Thermokarst lakes often look like cookies that have been bitten around their edges, Walter Anthony explained, because the liquid water does indeed take bites out of the surrounding frozen margins, causing the lake to expand.

The lakes can also be up to 100 feet (30 meters) deep, and if the water doesn't freeze all the way to the bottom in the winter, the heat in the liquid water causes the permafrost beneath that lake to thaw, Walter Anthony said.

"As that permafrost thaws, we get what we call a thaw bulb, and that thaw bulb can deepen and expand laterally," Walter Anthony said. When that happens, "what was previously frozen soil with organic carbon in it becomes thawed, and that thawed soil releases this organic matter to microbes that decompose it and make carbon dioxide and methane."

The researchers wanted to quantify just how much methane —the major component of the gas bubbling up from the lakes —thermokarst lakes are emitting today and what their projected emissions are for the future. The team used a combination of computer models and measurements taken from fieldwork in Alaska, Canada and Siberia to map the growth and emissions of thermokarst lakes.

According to their results, published Aug. 15 in the journal Nature Communications, the lakes would double previous estimates of permafrost-caused greenhouse warming.

"It's still a lot smaller than fossil fuel emissions, but it's about equivalent to land-use change," which is the second-biggest source of human-caused climate change, Walter Anthony told Live Science.

Original article on Live Science

A note published in a New Zealand paper 106 years ago today (Aug. 14) predicted the Earth's temperature would rise because of 7 billion tons of carbon dioxide produced by coal consumption.

"The effect may be considerable in a few centuries," the article stated.

The clip was one of several one-paragraph stories in the "Science Notes and News" section of The Rodney and Otamatea Times, published Wednesday, Aug. 14, 1912.  

The paragraph seems to have been originally printed in the March 1912 issue of Popular Mechanics as the caption for an image of a large coal factory. The image goes with a story titled "Remarkable Weather of 1911: The Effect of the Combustion of Coal on the Climate — What Scientists Predict for the Future," by Francis Molena. [Photographic Proof of Climate Change: Time-Lapse Images of Retreating Glaciers]

In the article, Molena described how carbon dioxide in the air is associated with warmer temperatures, and "since burning coal produces carbon dioxide, it may be inquired whether the enormous use of that fuel in modern times may be an important factor in filling the atmosphere with this substance, and consequently indirectly raising the temperature of the Earth."

When Molena's story was published, scientists had already been predicting the effects of coal combustion on climate for the past few decades. Researchers were studying the topic at least as early as 1882, as evidenced by H.A. Phillips' paper titled "Pollution of the Atmosphere," published that year in the journal Nature.

Jeff Nichols, a historian at the University of Illinois at Chicago, told Quartz that he's found many examples of newspaper articles published between 1883 and 1912 that make predictions about how rising carbon dioxide levels alter the climate. The New York Times, The Philadelphia Inquirer, and The Kansas City Star all published articles about rising carbon dioxide levels affecting the climate more than a hundred years ago, Quartz reported.

Carbon dioxide continues to make up 65 percent of global greenhouse gas emissions, having increased by 90 percent between 1900 and 2010, according to estimates from the Environmental Protection Agency (EPA). As of 2014, the top carbon dioxide-producing regions were China, the United States, the European Union, India, the Russian Federation and Japan, according to the EPA.

Original article on Live Science.

There may be a hidden source of greenhouse gas that we aren't accounting for.

Plastic may release the heat-trapping, climate-warming gases as soon as it's exposed to light, new research from the University of Hawaii at Manoa has found. Light not only breaks down plastic, but also releases methane and ethylene — two of the most problematic greenhouse gases. Though the gases from degrading plastic probably account for a small percentage of global emissions, it's likely their contributions will grow. [In Images: The Great Pacific Garbage Patch]

To learn what gases plastics were releasing, the research team collected samples of the seven most common types of consumer plastic — both newly produced pieces and fragments fished from the ocean — and monitored the objects' gas production while floating in seawater or exposed to air. All of the samples emitted methane and ethylene, but low density polyethylene (LDPE) exposed to air produced more gases than all other material-environment combinations. A thin material found in plastic wrap and grocery bags, LDPE is one of the main plastics in production and one of the most frequently discarded, said Sarah-Jeanne Royer, a marine biologist at the University of Hawaii at Manoa and the lead researcher on the paper.

The longer the LDPE sat in the sun, the more methane and ethylene it released, the researchers reported in the new study, which was published Aug. 1 in the journal PLOS One.

Royer and her team said the gases result from ultraviolet (UV) rays slowly breaking down the material. As plastic ages, it breaks apart, which is how fingernail-size fragments of plastic end up floating in the ocean. Royer reasoned that smaller pieces mean more surface area for light to damage, so her team evaluated gas emissions from LDPE pieces of different sizes. LDPE powder, they found, emitted 500 times more methane than LDPE pellets.

If the amount of gas from plastic is small now, the constantly increasing surface area of degrading plastics explains why the problem will probably only worsen, Royer said. "It's very worrying, because all the plastic we've produced since 1950 is still here on Earth, and it's degrading as we speak, so it will produce more and more [methane]," Royer told Live Science.

Chris Ellison, a chemical engineering and material science professor at the University of Minnesota, who was not involved in the current research, agreed that the paper shows that light is triggering greenhouse gas release from our plastics.

"Light is well-known to accelerate all kinds of reactions, some desired and some not desired," Ellison told Live Science in an email. He said he was also curious what percent of global methane levels stem from this newfound source, but that's a notoriously difficult type of question to answer. One bit of good news: Most plastic ends up buried in landfills, with little to no light exposure as it falls apart, Ellison noted.

It's also hard to tell if plastic in the real world behaves like it did in Royer's lab. The team analyzed pure samples of each plastic, but the contents of ocean and landfill plastic aren't usually pure. Plastic producers add strengthening additives to pure plastics, and the recipes are proprietary. Royer contacted producers for exact contents, she said, but all refused to supply that information.

Even if this research doesn't replicate real-life conditions perfectly, it's a jumping off point, Royer said. Learning just how much of the world's methane comes from plastic, as well as which plastics are the worst offenders, is next on the list, she said.

Originally published on Live Science.

Scientists say they've developed a new technological solution to the climate crisis: an affordable method for sucking carbon dioxide out of the atmosphere to turn it into gasoline. But how does this process even work? And is it really a magic-bullet solution to climate change?

According to the researchers, the new technique would cost between $94 and $232 per metric ton. As Robinson Meyer, who first reported the story over at The Atlantic, reported, that figure is between 16 and 39 percent of what researchers expected this technology would cost back in 2011. It's cheap enough, he wrote, that it would cost just $1 to $2.50 to remove from the atmosphere the carbon dioxide released by burning a gallon of gasoline in a car. [The Craziest Climate Change Fixes]

Carbon dioxide is a major greenhouse gas and a key driver of climate change (though not the only one). So the prospect of sucking CO2 right out has potential to help abate climate change. Even if that CO2 gets released again when the gasoline is burned, no new greenhouse gas gets pumped into the sky; the researchers pitch it as a kind of recycling for greenhouse gas emissions.

The researchers were a team from Harvard University and a new company set up for this project called Carbon Engineering. They wrote in their paper, published Thursday (June 8) in the journal Cell, that their innovation isn't the development of any brand-new system for carbon capture, or pulling CO2 out of the atmosphere. Rather, they said they're figuring out how to build and power an industrial-scale plant affordably. Meyer gave his article on the paper, which went viral, an eye-catching headline: "Climate Change Can Be Stopped by Turning Air Into Gasoline."

The process

As the researchers described in the paper, turning atmospheric CO2 into fuel is basically a four-step process:

1. Suck in a lot of air.
2. Pull carbon dioxide out of the air and stick it into a liquid.
3. Separate the carbon dioxide from the liquid again.
4. Mix in some hydrogen to turn the whole mess into combustible fuels, like gasoline.

The actual process is pretty complicated, but it all comes down to those four steps. And a lot of that is basic chemistry. Mixing CO2 into a liquid, for example, is just a matter of exposing lots of air to a strong base, or something with a pH much greater than 7. In this case, the base is a solution made up of water, ionic hydroxide, carbon trioxide and potassium. CO2 is acidic, so it will separate from the air in order to mix itself into the basic liquid, the researchers wrote.

The most difficult part of the whole process, the researchers wrote, is sourcing the materials for the factory so that this chemical reaction can happen at a large scale. For the process to be cost-effective, they wrote, the researchers have to be able to pull it off without the massive costs of designing and constructing all-new factory parts. For it to be actually good for the environment, the emissions involved in building or powering the factory can't be so significant that they wipe out the factory's carbon benefits.

The researchers said they pulled all of that off by designing a factory based entirely on parts that suppliers could already make cheaply, by powering their prototype factory using natural gas, and by keeping careful track of their emissions and costs and each stage of the design and production process. (Natural gas is a fossil fuel, but it releases far less in the way of greenhouse gases when it burns than, for example, gasoline or coal.

Is this a good idea?

The researchers noted that if their factory were run only for the purpose of pulling CO2 out of the atmosphere and not making fuel that would release it again, it could permanently sequester 90 percent of every ton of CO2 it sucked in. But it's worth taking a serious look at the costs involved.

In 2017, the world emitted about 32.5 gigatons of carbon dioxide. If this technology were built at a scale to suck all that back out of the atmosphere at $93 to $232 per ton, simple arithmetic indicates that the total cost would be between about $3.02 trillion and $7.54 trillion.

Experts have already raised significant objections to the idea that this represents anything more than the illusion of a solution to climate change.

Glen Peters, a researcher at the Center for International Climate and Environmental Research in Oslo, Norway, wrote on Twitter that these technologies obscure the real challenges presented by climate change. Policymakers and journalists assume that some sort of "negative emissions" tech will play a significant role in keeping climate change in check, he wrote. ("Negative emissions" refers to any technology that reduces greenhouse gases in the atmosphere, rather than increasing them.)

He pointed to a paper published in the journal Environmental Research Letters in May that found that (assuming costs between $100 and $300 per ton for direct-air-capture plants like the one from Carbon Engineering) no single technology is likely to actually suck enough CO2 out of the atmosphere to meet emissions targets. At those prices, the researchers wrote, it will be impossible to build enough negative emissions plants to suck enough CO2 from the atmosphere to meet global climate goals.

Peters also pointed to a commentary he co-authored, which was published in the journal Science in 2016, where he argued against relying on negative emissions, arguing that we still don't know if those technologies will work. (The Paris Agreement, signed that year, assumed that negative emissions technology would be a significant part of reaching global emissions targets.)

"There is a real risk [that people who are working on negative emissions technology] will be unable to deliver on the scale of their promise," he and his co-author wrote. "This is not to say that [negative emissions technologies] should be abandoned. They could very reasonably be the subject of research, development, and potentially deployment, but the mitigation agenda should proceed on the premise that they will not work at scale. The implications of failing to do otherwise are a moral hazard par excellence."

In other words, if these things turn out not to work, and we bet the Earth's future on them, we might all regret it.

Originally published on Live Science.

With the world facing increased warming, melting ice caps, rising sea levels, intense weather events and other global disasters, scientists are exploring ways to re-engineer the planet to counter the effects of global warming.

Earth's surface has warmed, on average over land and sea, 1.53 degreesFahrenheit (0.85 degrees Celsius) since 1880, according to the Intergovernmental Panel on Climate Change, an international organization created by the United Nations to evaluate the state of climate change science. [Changing Earth: 7 Ideas to Geoengineer Our Planet]

In the most recent issue of the journal Science, published online Thursday (July 20), two researchers provided perspective on two geoengineering methods that could reduce the so-called greenhouse effect, under which gases and clouds in Earth's atmosphere trap the sun's heat. Both schemes could contribute to a cooler climate, but they are not without risks. And as both researchers made clear, neither idea addresses the rising levels of carbon dioxide (CO2) in the atmosphere that is primarily to blamefor global warming and higher levels of oceanic acid. This acidity is killing the coral reefs that shelter marine life and support the fish that humans eat. 

Ulrike Lohmann and Blaž Gasparini, both researchers at the Institute of Atmospheric and Climate Scienceat ETH Zurich inSwitzerland, proposed a counterintuitive plan: Seed the upper atmosphere with tiny particles of desert dust to reduce cirrus clouds. These are the wispy, nearly invisible clouds that form at high altitudes. Unlike fat, billowy clouds that reflect sunlight, these clouds trap heat energy radiating up from Earth out into space.

"If cirrus clouds behave like a blanket around the Earth, you're trying to get rid of that blanket," Lohmann, a professor of experimental atmospheric physics at ETH Zurich, told Live Science.

Thinning the clouds

Seeding the atmosphere with dust would paradoxically thin out cirrus clouds, Lohman said. Under normal circumstances, the atmosphere at altitudes of about 16,000 to 40,000 feet (4,800 to 12,200 meters) is full of tiny particles. Some are solid particles like mineral dust, and some are liquid aerosols, such assulfuric acid. The liquid aerosols freeze instantly and create ice crystals that form long-lasting cirrus clouds. 

Cirrus thinning changes this dynamic, Lohman said. The idea, Lohmann said, is to inject solid particles, like desert dust, into the atmosphere at spots slightly lower than where cirrus clouds would naturally form. The quantity of dust introduced would be far less than the number of particles that exist higher up. This part is key, because fewer particles will attract more water vapor, creating larger crystals. As the ice crystals grow to larger and heavier, they would and fall as precipitation, and depending on the conditions would evaporate before reaching the ground.

"You remove the water vapor, you remove the humidity and you prevent the normal cirrus cloud formation," Lohmann said. [8 Ways Global Warming is Already Changing the World]

Ideally, the method would be applied to locations most susceptible to cirrus cloud formation, Lohmann said — geographical latitudes above 60 degrees, including the Arctic, where temperature increases from CO2 are the greatest. 

The researchers' computer models have shown that if done correctly, cirrus thinning could reduce global temperatures by 0.9 degrees F (0.5 degrees C), Lohmann said. But if done incorrectly, the activity could produce cirrus clouds where none existed before, contributing to the very problem it's meant to solve, she added. 

Risky business

The risk of doing more harm than good is a concern, said Ulrike Niemeier, a climate scientist at the Max Planck Institute for Meteorology in Hamburg, Germany, and her colleague Simone Tilmes, a project scientist at the National Center for Atmospheric Research in Boulder, Colorado. Niemeier and Tilmes published a separate commentary in this week's issue of the journal Science that discusses a geoengineering method called stratospheric aerosol modification (SAM).

SAM involves injecting sulfur aerosols into the stratosphere to increase the reflectivity of Earth's atmosphere. Computer models have shown that SAM could reduce the amount of sunlight that reaches the planet's surface. The effect would resemble that of ash clouds that linger after volcanic eruptions, which have been shown to lower global temperatures, the researchers wrote.

But the science behind SAM is in its very early stages, and the technologies to deploy it are not developed, the researchers added.

"It was our intention to say that [geoengineering] is not something that we should have in the back of our minds as the main solution," Niemeier told Live Science.

Niemeier and Tilmes wrote that different computer models consistently identify side effects to SAM. For example, reducing incoming solar radiation also reduces evaporation, which in turn reduces precipitation, and that can slow the hydrological cycle, particularly in the tropics, the authors wrote. Less rainfall could increase droughts that are already devastating parts of the world.

Although computer models tend to agree that it’s best to inject the aerosols into the stratosphere above the tropics or subtropics, and that the aerosols would disperse globally, the models differ on the extent of injection required for a given level of cooling, the authors wrote.

"Most current Earth-system models do not adequately capture important interactions, such as the coupling between stratospheric aerosols, chemistry, radiation and climate. They cannot, therefore, simulate the full impact of the interventions," Niemeier and Tilmes wrote.

Complicated solutions

Even if scientists could figure out a precise method, the economics are mind-boggling. Using SAM to bring down global temperatures just 2 degrees F (1 degree C), to preindustrial levels, would require injection amounts equivalent to one volcanic eruption per year the size of the 1991 Mount Pinatubo blast in the Philippines — the largest volcanic eruption in the last 100 years, according to the U.S. Geological Survey. The cost of dispersing that much content artificially would cost $20 billionper year and require 6,700 aircraft flights per day over 160 years, the researchers wrote.

No single method can solve the climate change problem as a whole, either, they said.

"Any geoengineering method we know of can only offset part of the global warming that we have," Lohmann said.

And no method designed to cool the planet deals with the gases in the atmosphere that are the sources of the problem and are contributing to increasing levels of acid in the oceans, the researchers said.

"It doesn't get at the heart of the problem," Lohmann said. "The ocean acidification is ongoing."

If society decides to undertake any geoengineering method, she said, this action should be accompanied by large efforts to reduce greenhouse gas emissions.

Niemeier said emission reductions should be the primary focus. "We are quite critical about [geoengineering], and we want people to be aware it would be a difficult."

Original article on Live Science.

When President Donald Trump announced on June 1 that the United States would exit the Paris climate accord, U.S. cities mounted a massive response: Hundreds of mayors pledged to remain committed to reducing U.S. greenhouse gas emissions.

Combining climate-friendly politics with high energy usage, U.S. cities are in a position to make major reductions in greenhouse gas emissions. Residents and local governments in these urban areas not only tend to support such goals, but are also often located in coastal areas that face severe climate dangers. One such example is Philadelphia, which recently sent out a request for information to increase its renewable power purchases.

"We're interested in reducing carbon emissions and preparing for climate change because it matters to Philadelphians," Sarah Wu, deputy director of sustainability in that city, told Live Science. "We're already experiencing extreme weather. … It's a global problem with local consequences."

But how much can cities do on their own, without the federal government supporting the Paris accord, to curb climate change? We talked with climate experts to find out. [The Reality of Climate Change: 10 Myths Busted]

Cities respond

Under the Paris Agreement, adopted in 2015 by the U.S. and 193 other countries and the European Union, nations committed to establishing their own plans to lower greenhouse gas emissions. The accord states that countries will limit temperature increases this century to "well below" 3.6 degrees Fahrenheit (2 degrees Celsius) above preindustrial levels and will work toward limiting increases to 2.7 degrees F (1.5 degrees C) — measures that experts say would help to prevent the worst effects of climate change.

The day after Trump pulled the U.S. out of what he called a "draconian" accord that imposed unfair burdens on the country, more than 80 mayors signed a pledge, posted by the Climate Mayors group, promising to uphold the accord. That pledge has since swelled to include 340 mayors, representing 65 million Americans who live in those cities.

The commitments of these cities are significant, said Janos Pasztor, executive director of the Carnegie Climate Geoengineering Governance Initiative nonprofit. "Across the world, the largest concentration of activities happens to be in the big cities," he said. "The emissions are also linked very much to big cities."

Indeed, nine of the 10 biggest U.S. cities are located in the 10 states with the greatest greenhouse gas emissions in 2014, according to the EPA. Globally, cities account for 70 percent of greenhouse gas emissions.

U.S. cities' climate capacity

These cities can, therefore, make significant emissions reductions, said Seth Schultz, director of science and innovation for C40, a network of global "megacities" committed to climate action. That group's Deadline 2020 study looked at the world's "carbon budget," or the level of greenhouse gases the planet can emit and still stay below a 1.5-degree C increase.

The study showed that "if left unchecked, C40 cities … by 2060, would consume the entire planet's carbon budget," he said. "It makes a very compelling case for how important cities are."

The C40 report showed that C40 cities (including the 12 in the United States, such as Chicago, New Orleans and Portland) could, via their own actions, achieve over half of their share of the emissions reductions needed to stay on a 1.5-degree trajectory. (The remaining 49 percent of the cities' necessary reductions depend on things beyond a city's control, such as freight, rail and power grids connected to coal-burning power plants, which a city might not control or may only partially influence, Schutlz told Live Science.)

But with Climate Mayors' swelling ranks, the nation's urban centers can do even more. If all U.S. cities with populations over 50,000 were to follow the C40 cities' plans, they could achieve 36 percent of the emissions reductions needed to meet the country's Paris pledge. (The U.S. pledged to reduce greenhouse gas emissions 19-21 percent below 2015 levels by 2025.) This estimate comes from the Deadline 2020 report, which investigated emissions levels and the impact of emissions-reductions actions in cities. [8 Ways Global Warming Is Already Changing the World]

In an effort led by former New York City Mayor Michael Bloomberg, cities could work with a coalitionof states, schools and businesses to help achieve an even loftier goal: meeting all of the United States' emissions-reductions targets under Paris. "We're going to do everything America would have done if it had stayed committed," Bloomberg told The New York Times.

City steps

There's no single large action that cities can take to reduce their contribution to climate change, said David G. Victor, a climate expert at the University of California, San Diego. Rather, C40 counts 430 smaller, discrete actions cities can take. Cities had been taking such actions in the lead-up to the Paris accord, intensified those actions after the agreement and seem to be further committing themselves after Trump's announcement, "so this is very encouraging," Pasztor said. [Trump Pulls Out of Paris Climate Deal: 5 Likely Effects]

"We are continuing to take action," Dan Zarrilli, senior director of New York City's climate policy and programs,told Live Science. "We just realize now we have to redouble our efforts. We directed our own agencies about how we can accelerate our efforts to fight climate change."

Other Climate Mayors city officials agreed. "Here, in light of Trump canceling the Paris agreement, committing to the Paris accord goals is a continuation of the work we're already doing, but it's also a signal to the rest of the world that there is a significant portion of Americans who are committed to this goal," Wu of Philadelphia said.

The most impactful efforts cities can take include shifting publicly owned utilities to renewables and reducing energy use, C40 told CityLab. For example, renewables make up 23 percent of Austin Energy's power generation mix.

In Knoxville, Tennessee, the electricity utility has moved away from coal, while the city has worked to increase public transit ridership by offering amenities such as Wi-Fi, Erin Gill, director of Knoxville's Office of Sustainability, told Live Science. The planned conversion of city lights to LEDs will, combined with the city's other efforts, push Knoxville past its goal of a 20 percent reduction in municipal emissions, Gill said.

Both Philadelphia and New York have worked to increase energy efficiency in buildings, as this electricity usage accounts for most of those cities' carbon emissions. Under Philadelphia's benchmarking program, begun in 2012, buildings receive report cards with tailored pointers on efficiency improvements. New York's building energy-efficiency programs, announced in 2016, will produce emissions cuts equivalent to taking more than half a million cars off the road.

Houston is in a deregulated energy state, which means the power utility is not publicly owned, but the city has arranged renewable-energy purchase agreements with its private utility. The city also helped pioneer a program in which all city departments share one fleet of hybrid vehicles, and "efficiency skyrocketed," Lara Cottingham, deputy assistant director of sustainability and strategic customer initiatives for the city of Houston, told Live Science.

Collective efforts

Cities can do even more via collaborations. One of the greatest benefits of networks such as Climate Mayors, Zarrilli said, is that cities learn from one another. For example, Philadelphia and other cities based their building benchmarking programs on a New York initiative, Wu said. Many climate actions would take years to enact if started from scratch, but a program can spread rapidly after pioneering cities figure it out, Schultz told CityLab.

"We've made it a priority to engage with other cities … to make sure the things we learn here in New York City can be exported out," Zarrilli said.

And those groups recently moved to the even more powerful tactic of collective action, he said. For instance, New York and other Climate Mayors cities made a joint request to manufacturers for over 115,000 electric vehicles to use in city government fleets. Such actions particularly help smaller cities, Zarilli said, because the large joint purchases made with a city like New York can convince manufacturers to lower prices.

City coalitions also raise the volume of mayors' voices politically, as they can speak for hundreds of millions of Americans who care about climate change, Wu said.

Federal action is still needed

As the C40 study shows, U.S. cities can do a lot, but not everything. Nonurban U.S. areas must also make significant reductions, Schultz said. Several crucial efforts will require federal and state action, including funding for alternative transportation and enforcement of the Clean Power Plan, according to a World Wildlife Fund and Local Governments for Sustainability report. The Trump administration has signaled that it will dismantle Obama's Clean Power Plan, which required states to reduce emissions from power plants by 32 percent within 25 years.

The goal of cities and states, however, isn't to replace federal action indefinitely, John Coequyt, Sierra Club policy director, told CityLab, but to do as much as possible over the next four years.

Follow Michael Dhar @michaeldhar. Follow us @livescience, Facebook& Google+. Original article on Live Science.

It's been a week since President Trump announced he was pulling the U.S. out of the Paris Agreement. In that time, a remarkable transformation has taken place.

As the federal government abdicates its responsibility to address climate change, a groundswell of support has sprung up at the state, city and corporate levels. Those sub-national actors are making the case on the international stage that the U.S. will meet its Paris Agreement commitment.

That includes a first-of-its-kind effort called America's Pledge, spearheaded by Bloomberg Philanthropies, that's been dubbed a "societally nationally determined contribution." States, cities and other groups can sign on to meet the U.S. pledge to the Paris Agreement of reducing carbon pollution 26-28 percent below 2005 levels by 2025.

David Hart, a political scientist at George Mason University, said that the new initiative bears some similarity to the 1980s anti-nuclear movement when cities and states declared themselves "nuclear-free" zones, but it's the only time he can recall sub-national action in the U.S. being linked to an international treaty.

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"It's astonishing, I've never seen anything like it," Carl Pope, a senior advisor to Michael Bloomberg and former head of the Sierra Club, said. "Donald Trump has created a new American climate movement. What we were trying to send is a message that it's not up to the federal government. It's up to all of us."

The pledge can't take the place of the federal government's commitment, but it's part of a huge shift in the climate landscape. The speed with which the shift has happened has put the movement in uncharted territory on the international stage and legally. The United Nations Framework Convention on Climate Change (UNFCCC) is responsible for tracking countries' pledges and is working to figure out how to incorporate the sudden surge of local action in the U.S.

"We welcome this initiative because it illuminates just how much support there is for the Paris Climate Change Agreement across so many sectors of society in the U.S. and across the globe," Nicholas Nuttall, a spokesman for UNFCCC, said.

The current actions by states, cities and corporations have a high upside internationally. The U.S. is the world's biggest historical climate polluter, and getting it on board was crucial for the Paris Agreement to come to fruition. Having it leave the pact could jeopardize the agreement even though big players like Europe and China have reaffirmed their commitments.

America's Pledge sends a strong signal to any wavering countries that the U.S. may formally be leaving the agreement, but it's not going away.

"It's really important to the international community that the perception of the U.S. stepping out of agreement needs to be dispelled," Hart said. "India is a country you might want to look at. They have huge challenges and huge coal reserves so it's not easy to commit to the type of things they did. If they perceive society is in for this, and we're going to have an Congressional election next year, maybe they can wait and see if the U.S. is completely reneging."

While Bloomberg Philanthropies is hosting America's Pledge, Pope said it's not alone in recognizing the need for non-federal leaders to step into the power vacuum left behind by the Trump administration.

A coalition of more than 1,200 local governments, corporations and universities wrote an open letter to the world about their commitment to the pact; the mayors of Paris and Pittsburgh penned an op-ed in solidarity; and Hawaii is now the first state to sign a law to commit to meet the U.S. Paris pledge.

"People understand that if there wasn't some response to what Trump did, American leadership would be badly compromised," Pope said.

States and cities have a lot of avenues to reduce emissions. There are already a number of ways local governments can address their carbon pollution, some that could yield unexpectedly large benefits and that are vastly different than what the federal government can do to reduce emissions.

"Our building blocks will be different," Pope said of America's Pledge. "We'll commit to do what our stakeholders can do (to reduce emissions)."

California, for example, has a waiver to set car pollution standards that are stricter than federal ones. A number of other states have adopted those standards, and automakers have had to respond by producing cars to meet them.

Residential and commercial buildings account for nearly 40 percent of all U.S. energy consumption and represent another huge opportunity to cut emissions at the city level.

"Building codes are a completely unsexy area, but they're starting to shift," Lara Fowler, an energy lawyer at Penn State, said.

Fowler cited the Bullitt Center, the first net-zero building in Seattle, as an example that "paved the regulatory way" for future low or no emissions buildings. Green infrastructure and other building codes to reduce energy consumption can be used to further lower building emissions.

The actions could face federal resistance. The UNFCCC accounts for non-national climate commitments through something called the Non-State Actor Zone for Climate Action, but it's more of a showcase for those commitments than a formal mechanism.

Nuttall said the United Nations is looking at ways to assess local climate action pledges more formally, including ways to measure how successful cities and states are at meeting their commitments.

How states and cities proceed is crucial to determining the legality of their actions. Constitutionally, only the federal government can enter into treaties.

"The day Trump announced his decision, (California Gov.) Jerry Brown says he's going to China and then strikes an agreement," Fowler said. "Well what kind of agreement is that? Is it a treaty? Is it an alliance? That’s an international gray area."

States can set more stringent carbon pollution standards than the federal government, but those also come with risks. California, for example, has a waiver to set more strict auto pollution standards, which could be key in forcing automakers to sell more fuel efficient cars. The Trump administration has hinted that they could pull that waiver, taking away a key tool to reduce transportation emissions, which account for 27 percent of all U.S. carbon pollution.

The Trump administration could also put up roadblocks to state and city action by threatening to withhold funding for infrastructure, environmental cleanup or other projects. That's something the administration has already threatened to do with sanctuary cities that don't cooperate with immigration authorities, though Fowler said if that happens, states would likely sue the federal government in response.

In the background of all this is the reality that clean energy is becoming cheaper. That's reflected in commitments by corporations to going renewable and a number of states led by Republicans pushing hard for wind and solar power. Hart said getting those states on board with America's Pledge or committed in other ways would only reinforce to the world that the U.S. is still all-in on climate action even in today's currently polarized political climate.

"If we can help Republican governors to talk about clean energy and build around that, it could be powerful," he said.

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Originally published on ClimateCentral.

President Donald Trump's decision to pull the United States out of the Paris climate agreement could deal a staggering blow to the nascent international cooperation on climate change.

"The United States will withdraw from the Paris Climate Accord, but begin negotiations to reenter either the Paris Accord or an entirely new transaction on terms that are fair to the United States, its businesses, its workers, its people, its taxpayers," Trump announced in the Rose Garden at the White House today (June 1). "So we're getting out."

Without the United States, other signatories on the deal will likely soldier on, experts say. But the likelihood of international cooperation on carbon-cutting goals past 2025 is on far shakier ground, and the United States will be forfeiting a seat at the table to shape the climate future.

"It's really hard to move forward on climate without the cooperation of the United States," said Michael Wara, a professor of law at Stanford University and a fellow at Stanford's Woods Institute for the Environment. "We're too big of a trading partner, we're obviously a major fossil fuel producer … It's really hard for other countries to make meaningful, deep reductions without the United States playing ball." [The Reality of Climate Change: 10 Myths Busted]

The consequences of the decision aren't fully mapped. But here are five ways that the choice today (June 1) will likely affect both the climate and the United States' global standing.

1. No promises on warming

The Paris climate agreement sets a goal for its signatories to keep warming below 3.6 degrees Fahrenheit (2 degrees Celsius), compared with preindustrial times, by 2100, with an eye toward the ambitious goal of keeping global warming to a mere 2.7 degrees Fahrenheit (1.5 degrees Celsisus). Each country sets its own voluntary goals for emissions cuts, pledging to become stricter as time goes by, and there are no binding rules about how the countries should meet those goals. In reality, as Climate Interactive's analysis found, the commitments by signatory countries are already short of the 3.6 degree F goal and would likely lead to about 6 degrees F (3.3 degrees C) of warming by 2100. That's less, however, than the "business- as-usual" scenario that would cause 7.6 degrees F (4.2 degrees C) of warming relative to preindustrial temperatures. 

Under the Obama administration, the United States agreed to reduce its greenhouse gas emissions to between 26 percent and 28 percent of 2005 levels by 2025. The agreement does not officially go into effect until 2020, but meeting those goals would require the country to take steps — like setting standards for vehicle emissions, appliances and power plants — before 2020.

"We had a lot of work to do," Wara said.

The Kyoto Protocol of the 1990s, which the United States never ratified, included countries responsible for just 14 percent of global emissions, said Robert Stavins, director of the Harvard Environmental Economics Program. The Paris Agreement, in contrast, includes 126 countries, which are responsible for 97 percent of the world's greenhouse gas emissions. The agreement was a breakthrough, Stavins said.

"Withdrawal from Paris Climate Agreement puts [the] USA with Nicaragua and Syria," Stavins wrote in an email to Live Science, naming the two countries in the world that are not part of the pact. [8 Ways Global Warming Is Already Changing the World]

The United States could have stayed in the Paris Agreement and simply renegotiated to a less-strict timeline for emissions cuts, Stavins said, but now there is no timeline at all. The United States' pledged emissions cuts had represented 21 percent of the total cuts pledged by all signing countries. According to Climate Interactive, not following through with the agreement essentially means putting an extra 1.4 gigatons of carbon dioxide into the atmosphere each year up until 2025, compared with following through. 

2. No chance to negotiate

The United States' emissions alone aren't the only outcome that matters. America's lack of commitment will likely ripple outward. As part of the Paris Agreement, the United States had the opportunity to shape negotiations going forward, Wara told Live Science.

"The Paris Agreement is not a single deal. It's not about one target," he said. "It creates an ongoing process for renewing the commitment every five years."

Trump's decision to withdraw damages that process, Wara said, and kicks the feet out from under an international effort that was just taking its first steps.

Though the withdrawal process takes four years during which the United States will technically be a party to negotiations, it's unlikely that other countries will put much stock in a power that is about to exit the agreement, Wara said. If Trump had stayed in, his administration could have helped articulate the next U.S. commitment past 2025, and the United States could have been a part of negotiating how countries will report their emissions and how the program will be implemented in reality.  

3. Uncertainty about developing economies

The fact that the Paris Agreement included developing economies was a huge step, Stavins and Wara said. India, for example, was nervous about joining the agreement, Wara said, but has been committing itself strongly to renewable and clean energy sources. India committed to lowering its emissions by 33 percent to 35 percent below 2005 levels under the Paris accord, according to Climate Action Tracker, and is likely to reach its goal of getting 40 percent of its power from non-fossil fuel sources by 2022, not 2030, as was its original goal.

It's likely that everyone else in the Paris Agreement will meet their 2025 goals, Wara said, but not so clear whether they'll commit to similar levels of ambition for the next five-year phase.

"It remains to be seen what happens if the U.S. walks away from that," Wara said.

4. No reason to innovate

In the United States, electricity emissions are falling, with or without the Paris agreement. This change has been driven in large part by simple economics — natural gas is inexpensive and is replacing carbon-heavier coal as a feedstock, and more renewable sources are coming online, too, Wara said. But there's a limit to how much simple economics can drive the climate equation. Because innovation in oil and gas exploration has driven down the price of oil, gasoline is cheap and vehicle emissions are headed in the wrong direction, Wara said. Paris might have pushed the United States to make changes in sectors that have not been as sensitive to the economic pressures facing coal, such as making cleaner-energy cars.

"I think we'll achieve the Clean Power Plan without the Clean Power Plan," Wara said, referring to an Environmental Protection Agency (EPA) program to reduce greenhouse gas emissions that Trump is expected to eliminate. "But that's not nearly enough."

5. No reason for trust

Perhaps most alarming, Wara said, is how Trump's decision on climate policy will affect national security.

"The withdrawal of the U.S. from Paris does enormous damage to our international credibility, in general, Wara said. Other issues requiring international cooperation, like corralling North Korea or coping with the Syrian crisis, are going to be harder to negotiate without trust from other nations, Wara said.

"The U.S. desperately needs that kind of trust in order to get the kind of outcomes we need internationally," he said.

The withdrawal from international negotiations is becoming a pattern, both Wara and Stavins noted. The United States withdrew from the Trans-Pacific Partnership trade deal under Trump's first executive order. Trump is also hostile to the North Atlantic Treaty Organization (NATO), in which members pledge military cooperation with one another. With the United States stepping back from cooperation, Stavins said, nations like China and Russia are freer to pursue their interests — and that is true for climate, as well.

"Withdrawal from Paris Climate Agreement hands leadership in this realm and others to China," Stavins said.

Original article on Live Science. 

Craters as wide as 12 city blocks on the Arctic seafloor were put there by giant eruptions of underground methane gas.

Some of these craters had been discovered in the early 1990s, but only now have scientists mapped the features in detail. Researchers have discovered that there are many more craters than first believed — more than 100 giant ones and perhaps thousands of smaller pockmarks — and that these features probably formed about 11,600 years ago. This happened as the retreat of ice sheets destabilized frozen gas under the seafloor. Some mounds of frozen gas exploded, creating the craters still seen today.    

"It's an analog for events that could take place in the future around contemporary ice sheets," said study researcher Karin Andreassen, a marine geologist and geophysicist at the Arctic University of Norway in Tromsø. Methane is a potent greenhouse gas, Andreassen said, so studying these undersea eruptions is important for understanding how they might affect the climate. [8 Ways Global Warming Is Already Changing the World]

Frozen methane

Andreassen and her colleagues were funded through the Research Council of Norway with grant money earmarked for understanding methane release from the seafloor. It's well-known that methane bubbles up from the sediments under the ocean in the Arctic, Andreassen told Live Science, but these small seeps don't reach much higher than 650 feet (200 meters) into the water column above the ocean bottom. The gas dissolves back into the ocean water before it can reach the atmosphere.

Explosive methane eruptions might be much different. Andreassen and her team took the research vessel Helmer Hanssen to the Barents Sea off the northern coast of Norway. The researchers used a variety of techniques, such as collecting seafloor sediment samples. They also beamed acoustic and seismic signals to the ocean floor and subsurface and used the echoes to map the contours below.

The researchers discovered more than 100 giant craters, each up to 0.6 miles (1 kilometer) wide and nearly 100 feet (30 meters) deep, in an area of 170 square miles (440 square km). The scientists also discovered many previously undiscovered mounds, known as pingos. These pingos are lumps of methane hydrate, or methane gas frozen within a lattice of water molecules.

Exploding pingos

It's these pingos that can explode when the conditions are right. Andreassen and her colleagues used mathematical modeling to figure out what kind of pressures, temperatures, water depths and other factors are required to keep the methane hydrate locked in the subsurface, and under what conditions the gas explodes.

Their findings told the story of how the craters came to be. During the icy Pleistocene, which began 2.5 million years ago, an enormous ice sheet more than a mile (2 kilometers) thick covered the Barents Sea. As this sheet ebbed and flowed and scraped along the seafloor, it altered the pressures on deep reservoirs of gas far below the sea surface. The gas, mainly methane, moved upward into shallower sediments, Andreassen said. There, it was stable within the upper 1,444 feet (440 m) of the subsurface, frozen as methane hydrate and capped under the pressure of the ice sheet.

But then the ice started to retreat about 17,000 years ago. The release of pressure allowed deeper hydrates to bubble up and travel to shallower sediments. Eventually, Andreassen said, this cycle led to the creation of pingos made of a thin, concentrated layer of methane hydrate under great pressure from the gas below. When the methane-hydrate crust finally gave way, the underground gases erupted out like shaken champagne.

"We think that the forces must have been enormous," Andreassen said.  

The eruptions left behind the craters seen today. The researchers obtained further confirmation of the date of these eruptions by looking at ice scours on the seafloor. These scours indicated that the eruptions happened as the ice sheet was retreating, but while there was still ice in the area, the researchers said. Individual gashes from icebergs dragging their bottoms can be seen in some craters. [Gallery: An Expedition into Iceberg Alley]

Atmospheric effects

Such giant eruptions could very well have sent methane spewing into the atmosphere, Andreassen said, but there is not yet proof that the exploding pingos did, in fact, do so. Nor does anyone know whether the methane released affected the climate, she said. (Methane is 84 times more effective at trapping heat than carbon dioxide in the first decades after its release, so smaller amounts can cause greater warming relative to carbon dioxide.)

Exploding pingos can't happen just anywhere that ice is retreating, Andreassen said — big underground gas reservoirs must be present, too. There are areas today where that combination exists, though. The east coast of Greenland is one example, Andreassen said, along with the many Arctic basins north of Siberia and some portions of Arctic Alaska and the northwest Canadian interior.

If a pingo collapsed tomorrow, though, there's no guarantee humanity would notice. These areas are remote and largely unmonitored, Andreassen said.

"These are vast areas," she said. It takes weeks by boat to reach Greenland even from Norway, she added.

Nevertheless, the researchers said they plan to hunt for more craters and mounds around Greenland and to the north, east and west of the Barents Sea.

"We definitely know that [the eruptions] were important for the changes in the chemistry of the ocean, but we don't know yet how important it was with regard to the atmosphere and the climate," Andreassen said. "That is something we need to explore."

Original article on Live Science.

The Earth is home to a range of climates, from the scorching dunes of the Sahara to the freezing ridges of Antarctica. Given this diversity, why are climate scientists so alarmed about a worldwide temperature increase of just 2.7 degrees Fahrenheit (1.5 degrees Celsius)?

Changing the average temperature of an entire planet, even if it's just by a few degrees, is a big deal, said Peter deMenocal, a paleoclimate scientist at Lamont-Doherty Earth Observatory at Columbia University in New York.

"A person living in any one location can experience huge changes in weather and even in climate, but those are often compensated by changes on opposite sides of the world," deMenocal told Live Science. [Is Global Warming Melting Antarctica's Ice?]

Right now, the world is about 2.1 degrees F (1.2 degrees C) warmer than it was during preindustrial times, deMenocal said. The 144 countries participating in the 2016 Paris Agreement announced that the world should limit the global increase in this century to 2.7 degrees F (1.5 degrees C), a stricter limit than the former goal of a 3.6 degrees F (2 degrees C) increase.

To put 2.7 degrees F into perspective, just about 9 degrees F (5 degrees C) separates the modern world from the last ice age, which ended about 15,000 years ago, deMenocal said. During that time, sea levels were about 350 feet (106 meters) lower than they are today, because an extensive amount of water was stored as ice at the poles, he said. During that ice age, about 32 percent of Earth was covered in ice, compared to just about 10 percent today, according to the National Snow and Ice Data Center.

Earth's climate changes over time — the last ice age is evidence of that — but it's the rapid rate of change and the amount of the greenhouse gas carbon dioxide filling up the atmosphere that have scientists concerned, deMenocal said. Moreover, global warming doesn't just increase temperatures; it also threatens the food, water, shelter, energy grid and health of humans, he said.

Food

Climate change affects the ecosystems that provide food, "and therefore our security of food is linked to the security of those ecosystems," deMenocal said.

The oceans, for instance, provide people with about 20 percent of their dietary protein, deMenocal said. However, ocean acidification caused by climate change makes it difficult, if not impossible, for thousands of species, including oysters, crabs and corals, to form their protective shells, which in turn disrupts the food web, Live Science previously reported.

On land, an increase of 3.6 degrees F (2 degrees C) would almost double the water deficit and would lead to a drop in wheat and maize harvests, according to NASA.

Northern latitudes may see a temporary boost in soy and wheat farming, partly because of the warmer temperatures farther north and partly because increased carbon dioxide helps plants grow, NASA said. But at an increase of 3.6 degrees F (2 degrees C), this advantage almost disappears for soy, and entirely vanishes for wheat, NASA reported.

If temperatures get too hot when these plants are flowering, their growth can become stunted, leading to decreased or no edible food crop, such as corn or grain, NASA said. [How Often Do Ice Ages Happen?]

Shelter

As temperatures warm and glaciers melt, the corresponding sea-level rise can destroy homes and cities. About 40 percent of the world's population lives within 62 miles (100 kilometers) of the coast, deMenocal said. In 2010, more than 123 million people, or 39 percent of the United States' population, lived in counties touching the shoreline, according to the National Ocean Service.

"Collectively, that is the single biggest investment at risk due to climate change as sea level rises," deMenocal said.

From 1901 to 1990, the average global sea levels rose about 0.04 inches (1.2 millimeters) per year, but from 1993 to 2010, the levels rose about 0.11 inches (3 mm) a year, meaning the rate of rise more than doubled, according to a 2015 report in the journal Nature.

Energy

About 7 percent of the United States' electricity generation in 2013 came from hydropower, which accounted for 52 percent of the nation's generated renewable energy that year, according to the Department of Energy.

However, reduced snowpack and shifting rainfall patterns may reduce hydropower in the long run, deMenocal said.

"This is now threatening the American West and some European areas as well," he said.

Health

Increases in temperature and changing rain patterns are associated with the spread of vector-borne diseases (which another organism transmits between humans or from animals to humans), such as Lyme disease and malaria, deMenocal said.

"Even if it [a vector-borne disease] is eradicated locally in a particular region, the weather changes associated with climate change can lead to migrations of these vector-borne diseases to new regions," he said.

Furthermore, because of health concerns, some regions of the globe, such as parts of the Middle East and the American West, may become inhabitable to humans because of extreme temperatures, deMenocal said.

That's because humidity often increases with the heat index. When both are high, the human body is unable to evaporate sweat to cool itself. "If you're unable to evaporate [sweat], you can actually die from exposure," deMenocal said.

Extreme temperatures can also lower productivity among workers. According to a 2014 Bloomberg report on the economic risks of climate change, extreme heat, especially in the American Southeast, may lead to a 3 percent drop in outdoor worker productivity, including among people who work in construction, utility maintenance, landscaping and agriculture. This drop is twice that of the "productivity slowdown" that happened in the 1970s, which likely occured because of high inflation and economic instability, the report said.

All of these threats are just around the corner, deMenocal said. The Earth is anticipated to exceed the 2.7 degrees F (1.5 degrees C) milestone in about 15 years — between 2032 and 2039, deMenocal said. The planet is expected to surpass the 3.6 degrees F (2 degrees C) benchmark between 2050 and 2100, he said.

"If we're on our current emissions scenario, it's even sooner than that," he said. "Even over the last 8,000 years, we haven't seen a temperature extreme this rapid and this fast and large."

Original article on Live Science.

This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

Carbon is a building block of life on our planet. It is stored in reservoirs on Earth – in rocks, plants and soil – in the oceans, and in the atmosphere. And it cycles constantly between these reservoirs.

Understanding the carbon cycle is crucially important for many reasons. It provides us with energy, stored as fossil fuel. Carbon gases in the atmosphere help regulate Earth's temperature and are essential to the growth of plants. Carbon passing from the atmosphere to the ocean supports photosynthesis of marine phytoplankton and the development of reefs. These processes and myriad others are all interwoven with Earth's climate, but the manner in which the processes respond to variability and change in climate is not well-quantified.

Our research group at the University of Oklahoma is leading NASA's latest Earth Venture Mission, the Geostationary Carbon Observatory, or GeoCarb. This mission will place an advanced payload on a satellite to study the Earth from more than 22,000 miles above the Earth's equator. Observing changes in concentrations of three key carbon gases – carbon dioxide (CO2), methane (CH4) and carbon monoxide (CO) – from day to day and year to year will help us to make a major leap forward in understanding natural and human changes in the carbon cycle.

GeoCarb is also an innovative collaboration between NASA, a public university, a commercial technology development firm (Lockheed Martin Advanced Technology Center) and a commercial communications launch and hosting firm (SES). Our "hosted payload" approach will place a scientific observatory on a commercial communications satellite, paving the way for future low-cost, commercially enabled Earth observations.

Observing the carbon cycle

The famous "Keeling curve," which tracks CO2 concentrations in Earth's atmosphere, is based on daily measurements at Mauna Loa Observatory on Hawaii. It shows that global CO2 levels are rising over time, but also change seasonally due to biological processes. CO2 decreases during the Northern Hemisphere's spring and summer months, as plants grow and take CO2 out of the air. It rises again in fall and winter when plants go relatively dormant and ecosystems "exhale" CO2.

A closer look shows that every year's cycle is slightly different. In some years the biosphere takes more CO2 out of the atmosphere; in others it releases more to the atmosphere. We want to know more about what causes the year-to-year differences because that contains clues on how the carbon cycle works.

For example, during the El Niño of 1997-1998, a sharp rise in CO2 was largely driven by fires in Indonesia. The most recent El Niño in 2015-2016 also led to a rise in CO2, but the cause was probably a complex mixture of effects across the tropics – including reduced photosynthesis in Amazonia, temperature-driven soil release of CO2 in Africa and fires in tropical Asia.

These two examples of year-to-year variability in the carbon cycle, both globally and regionally, reflect what we now believe – namely, that variability is largely driven by terrestrial ecosystems. The ability to probe the climate-carbon interaction will require a much more quantitative understanding of the causes of this variability at the process level of various ecosystems.

Why study terrestrial emissions from space?

GeoCarb will be launched into geostationary orbit at roughly 85 degrees west longitude, where it will rotate in tandem with the Earth. From this vantage point, the major urban and industrial regions in the Americas from Saskatoon to Punta Arenas will be in view, as will the large agricultural areas and the expansive South American tropical forests and wetlands. Measurements of carbon dioxide, methane and carbon monoxide once or twice daily over much of the terrestrial Americas will help resolve flux variability for CO2 and CH4.

GeoCarb also will measure solar induced fluorescence (SIF) – plants emitting light that they cannot use back out into space. This "flashing" by the biosphere is strongly tied to the rate of photosynthesis, and so provides a measure of how much CO2 plants take in.

NASA pioneered the technology that GeoCarb will carry on an earlier mission, the Orbiting Carbon Observatory 2 (OCO-2). OCO-2 launched into a low Earth orbit in 2014 and has been measuring CO2 from space ever since, passing from pole to pole several times per day as the Earth turns beneath it.

Though the instruments are similar, the difference in orbit is crucial. OCO-2 samples a narrow 10-km track over much of the globe on a 16-day repeat cycle, while GeoCarb will look at the terrestrial Western Hemisphere continuously from a fixed position, scanning most of this land mass at least once per day.

Where OCO-2 may miss observing the Amazon for a season due to regular cloud cover, GeoCarb will target the cloud-free regions every day with flexible scanning patterns. Daily revisits will show the biosphere changing in near-real time alongside weather satellites such as GOES 16, which is located at 105 degrees west, helping to connect the dots between the components of Earth's system.

Nuances of the carbon cycle

Many processes affect levels of CO2 in the atmosphere, including plant growth and decay, fossil fuel combustion and land use changes, such as clearing forests for farming or development. Attributing atmospheric CO2 changes to different processes is difficult using CO2 measurements alone, because the atmosphere mixes CO2 from all of the different sources together.

As mentioned earlier, in addition to CO2 and CH4, GeoCarb will measure CO. Burning fossil fuel releases both CO and CO2. This means that when we see high concentrations of both gases together, we have evidence that they are being released by human activities.

Making this distinction is key so we do not assume that human-induced CO2 emissions come from a decrease in plant activity or a natural release of CO2 from soil. If we can distinguish between man-made and natural emissions, we can draw more robust conclusions about the carbon cycle. Knowing what fraction of these changes is caused by human activities is important for understanding our impact on the planet, and observing and measuring it is essential to any conversation about strategies for reducing CO2 emissions.

GeoCarb's measurement of methane will be a crucial element in understanding the global carbon-climate system. Methane is produced by natural systems, such as wetlands, and by human activities such as natural gas production. We do not understand the methane portion of the carbon cycle as well as CO2. But just as with CO2, methane observations tell us a lot about the functioning of natural systems. Marshes release methane as part of the natural decay in the system. The rate of release is tied to how wet/dry and warm/cool the system is.

It is uncertain how much natural gas production contributes to methane emissions. One reason to quantify these emissions more accurately is that they represent lost revenue for energy producers. The Environmental Protection Agency estimates a U.S. leakage rate of around 2 percent, which could add up to billions of dollars annually.

We expect based on simulations that GeoCarb will produce maps that highlight the largest leaks with only a few days of observations. Finding leaks will reduce costs for energy producers and reduce the carbon footprint of natural gas. Currently, energy companies find leaks by sending personnel with detection equipment to suspected leak sites. Newer airborne sensors could make the process cheaper, but they are still deployed on a limited basis and in an ad hoc manner. GeoCarb's regular observations will provide leakage information to producers in a timely manner to help them limit their losses.

Watching the planet breathe

With daily scans of landmasses in the Western Hemisphere, GeoCarb will provide an unprecedented number of high-quality measurements of CO2, CH4 and CO in the atmosphere. These observations, along with direct measurements of photosynthetic activity from SIF observations, will raise our understanding of the carbon cycle to a new level.

For the first time we will be able to watch as the Western Hemisphere breathes in and out every day, and to see the seasons change through the eyes of the biosphere. Equipped with these observations, we will begin to disentangle natural and human contributions to the carbon balance. These insights will help scientists make robust predictions about Earth's future.

Berrien Moore III, Vice President, Weather & Climate Programs; Dean, College of Atmospheric & Geographic Sciences; Director, National Weather Center, University of Oklahoma and Sean Crowell, Research Scientist, University of Oklahoma

This article was originally published on The Conversation. Read the original article.

The head of the Environmental Protection Agency (EPA) said he does not believe that carbon dioxide is a main driver of climate change.

"I think that measuring with precision human activity on the climate is something very challenging to do, and there's tremendous disagreement about the degree of impact. So no, I would not agree that it's a primary contributor to the global warming that we see," EPA chief Scott Pruitt told CNBC's morning news show "Squawk Box" yesterday (March 9).

Pruitt's comments are in opposition to the scientific research on climate change. But when even the head of the EPA doubts the consensus, it can be hard to cut through the noise to understand what research scientists are really using when they express climate-change concern. [The Reality of Climate Change: 10 Myths Busted]

"I think plenty of people have pretty serious concerns in their life and they just don't have the time to do all of the homework and the background to figure this out," said Katherine Moore Powell, a climate ecologist at the Field Museum in Chicago.

So here's a primer explaining exactly why scientists know the climate is changing and that human activities are causing it.

Earth is warming

At this point, even the staunchest climate deniers would be hard-pressed to argue that the climate is not warming. Simply put, it's getting hotter out there. Combining land and ocean measurements from 1850 to 2012, researchers have found that the average surface-air temperature globally has risen by 1.4 degrees Fahrenheit (0.8 degrees Celsius) since the beginning of the industrial age. That's according to the fifth report of the Intergovernmental Panel on Climate Change (IPCC), released in 2014. The top graph in the figure from the IPCC report summary for policy makers shows the temperature anomaly in Celsius.

The next graph in this sequence shows sea-level rise, which has gone up globally by about 7.4 inches (0.19 meters) on average since 1901. According to the IPCC, the rate of sea-level rise since the middle of the 1800s has been higher than the rate during the previous two millennia. Scientists use tide gauges and satellite measurements to track sea-level changes, according to the National Oceanic and Atmospheric Administration (NOAA). Geologists and other Earth scientists can study rocks, fossils and sediment cores to get a longer-term look at sea-level changes, according to NASA.

The bottom two graphs show rising greenhouse-gas concentrations and estimated emissions of carbon dioxide by humans since 1850. The rising trend is evident on each figure. Scientists monitor carbon dioxide in the atmosphere by pumping air into an artificial chamberand shining an infrared light through the sample. Carbon dioxide absorbs infrared light very efficiently — more on that in a minute — so the amount of infrared absorbed can be used to calculate the amount of CO2 in the sample. [Top 10 Ways to Destroy Earth]

The premier (and longest-standing) site for these measurements is the Mauna Loa Observatory in Hawaii, which recently reported that the planet's atmospheric carbon dioxide concentration has surpassed 400 parts per million. In 1958, when observations at Mauna Loa began, the annual carbon dioxide concentration in the atmosphere was 315 parts per million.

The physics of greenhouse gases

Carbon dioxide is no dark-horse candidate for the warming of the atmosphere. In 1896, Swedish scientist Svante Arrhenius (who would later win the first-ever Nobel Prize for Chemistry) published a paper in the Philosophical Magazine and Journal of Science that laid out the basics of what's now known as "the greenhouse effect."

The effect is a result of how energy interacts with the atmosphere. Sunlight enters the atmosphere as ultraviolet and visible light; some of this solar energy is then radiated back toward space as infrared energy, or heat. The atmosphere is 78 percent nitrogen and 21 percent oxygen, which are both gases made up of molecules containing two atoms. These tightly bound pairs don't absorb much heat.

But the greenhouse gases, including carbon dioxide, water vapor and methane, each have at least three atoms in their molecules. These loosely bound structures are efficient absorbers of the long-wave radiation (also known as heat) bouncing back from the planet's surface. When the molecules in carbon dioxide and other greenhouse gases re-emit this long-wave radiation back toward Earth's surface, the result is warming.

Is it really carbon dioxide?

So, temperatures are rising, as are levels of atmospheric carbon dioxide. But are the two connected?

Yes. The evidence is strong. In 2006, scientists presented a poster at the 18th Conference on Climate Variability and Change that even measured the effect directly. Using spectrometers (tools that measure spectra to identify particular wavelengths), the researchers analyzed the wavelengths of infrared radiation reaching the ground. Based on the varying wavelengths, the scientists determined that more radiation was occurring due to the contribution of specific greenhouse gases.

Overall, they found that greenhouse gas radiation had increased by 3.5 watts per square meter compared with preindustrial times, a rise of just over 2 percent. Other researchers have noted "missing" infrared wavelengths in radiation into space, a phenomenon that happens because these missing wavelengths get stuck in the atmosphere.

Scientists also know that the extra carbon in the atmosphere is the very same carbon that comes from burning fossil fuels. By analyzing molecular variations called isotopes, researchers can trace the origin of atmospheric carbon, Moore Powell said.

"We know what the burning of fossil fuels looks like, in a scientific sense," she said.

That's not to say that the climate is as simple as an actual greenhouse. Many factors influence global temperatures, including volcanic eruptions and variations in the solar cycle and Earth's orbit that alter the amount of sunlight reaching the planet.

But scientists know that volcanoes and the sun aren't to blame for recent climate change. According to the IPCC, volcanic carbon dioxide emissions have been, at most, a hundredth of human CO2 emissions since 1750. In addition, volcanic eruptions cause changes for short timescales of about two years, not the longer-term changes being observed currently.

The sun is more complex, but researchers have found that the recent solar-cycle minimum (between 1986 and 2008) was actually lower than the previous two solar-cycle minimums (the sun moves between quiet minimums and active maximums about once every five years). If anything, the IPPC concluded, recent solar activity should have resulted in cooling, not warming. Likewise, a 2012 study found that between 2005 and 2010, a period when solar activity was low, the Earth still absorbed 0.58 watts of excess energy per square meter, continuing to warm despite the lower level of solar energy going into the system.

Where's the real uncertainty?

Given the weight of the evidence, scientists have come to a consensus that climate change is happening, and that human greenhouse gas emissions are the primary cause.

So where are the real scientific debates?

There are still a lot of questions left about how fast climate change will happen and what the precise effects will be.

"What I would say is most uncertain is simply how quickly things are chaning," Moore Powell said. "I'm very interested in the pace."

One of the major unknowns is the ultimate influence of clouds on climate: Clouds are white, so they reflect sunlight back toward space, which could have a cooling effect. But clouds are also water vapor, which traps heat. And different types of clouds might have warming or cooling effects, so the precise role of clouds in the feedback loop of global warming remains difficult to untangle, scientists have said.

Another burning question is how high, and how quickly, the sea level will rise as warming sea waters expand and Antarctic and Arctic ice melts. The IPCC forecasted a rise of 20 to 38 inches (52 to 98 cm), assuming no efforts are made to curb greenhouse gas emissions.

That range is broad, largely because the dynamics of Antarctic ice sheets are not completely understood. If Antarctica's land-based glaciers slough off to the sea rapidly with a little bit of warming, that will be bad news for coastal communities, researchers have said. That's why scientists are watching closely right now as a rift is splitting the Larsen C ice shelf on the Weddell Sea. If the giant iceberg-calving event about to occur destabilizes the ice shelf, it could result in the rapid flow of the land-based glaciers behind it into the ocean. This type of rapid glacial flow already occurred nearby, when the Larsen B ice shelf crumbled in 2002.

For an ecologist like Moore Powell, there are also myriad questions to answer about how ecosystems will respond to a changing climate. If the pace is slow enough, plants and animals can adapt. But in many places, the change is happening very quickly, Moore Powell said.

"There's not enough time at this pace for natural adaptation to take over," she said.

Original article on Live Science. 

Engineers have taken a tip from Medusa, it seems. They have stared down the pesky greenhouse gas carbon dioxide and turned it to stone.

The process they used was not as easy as simply eyeballing the gas, though. Essentially, they relied on a sped-up version of natural processes to take the carbon dioxide (CO2) spewed from a power plant in Iceland and transform the gas into a solid.

This ability to capture carbon dioxide and store it indefinitely may help curb the levels of heat-trapping gases in the atmosphere and stem global warming, the researchers noted. [Changing Earth: 7 Ideas to Geoengineer Our Planet]

"We need to deal with rising carbon emissions," lead study author Juerg Matter, now an associate professor of geoengineering at the University of Southampton in the United Kingdom, said in a statement. "This is the ultimate permanent storage — turn them back to stone."

Natural carbon storage

Human-caused global warming occurs mostly because of greenhouse gases, such as carbon dioxide and methane, that get poured into the air by humans burning fossil fuels for energy and other processes. These gases trap heat before it can escape out into space. Carbon dioxide is the biggest factor in this warming, scientists have said, because billions of tons of the gas are released every year and it stays in the atmosphere for long periods of time.

Ordinarily, this gas is drawn out of the atmosphere by plants, which use it for photosynthesis, and a chemical process called weathering of rocks. This process happens when carbon dioxide and other gases that dissolve in water form weak acids that then chemically react with minerals in rocks to form other solids, like clays. However, both of those uptake processes are relatively slow, and they can't keep up with human output, the study researchers noted. [The Reality of Climate Change: 10 Myths Busted]

As such, engineers and other scientists have been working on several efforts to somehow inject the carbon dioxide into the ground. For instance, carbon dioxide is pumped into the tiny holes, or pores, in sedimentary rock — the kind laid down by layers of sand, for example, on the ocean floor.

The problem is that the carbon dioxide is a gas, and tends to rise. To keep it underground requires a placing a layer of less porous rock on top of the porous rock where the gas is stored. The carbon dioxide will eventually react with the porous rock and turn into a solid, carbonate compound, but that process can take centuries, if not millennia, according to study co-authorSigurdur Gislason, research professor at the University of Iceland in Reykjavik.

A new way to hide CO2

The team, led by Juerg Matter, now an associate professor of geoengineering at the University of Southampton, tried something different. The researchers took the carbon dioxide emitted by a power plant in Iceland, pressurized it to 25 atmospheres. They then pumped the CO2 into a borehole that was filled with water, dissolving the gas and making something like seltzer water. The mixture was then pumped into a layer of porous, volcanic rock located some 1,640 feet (500 meters) below the surface of the ground. The rock reacted with the mixture and formed carbonate compounds.  

Essentially, the researchers sped up the weathering of rocks, Gislason told Live Science. Here's how it works: The carbon dioxide in the water forms carbonic acid, which dissolves the basalts and makes them more porous. Meanwhile, the carbon and oxygen from the CO2 make new compounds, largely magnesium, iron and calcium carbonates, which are solids that can't go anywhere. "Calcium, iron, magnesium can all form carbonates," Gislason said.

The process is very like what happens naturally, except that when stone — either as mountains or stone buildings – weathers, it happens as it rains, and rainwater only converts a small amount of carbon at a time. In addition, because the CO2 added to the water is under a lot more pressure than it is in the atmosphere, the concentration of carbonic acid is many times higher than in rainwater, or even in the carbonated water that people drink.

The study was conducted over a two-year period, noted study co-author Martin Stute, a research scientist at Columbia University's Lamont-Doherty Earth Observatory in New York. In that time, the team monitored the water as it percolated through the rock using monitoring stations placed some distance from the injection site. They detected no CO2.

Even though the process requires a lot of water initially, that water can be recycled, because the other elements in it — the carbon dioxide and the compounds in the rock — are all removed in the reactions that form the carbonates, said Stute. He added that another advantage is that the water needn't be fresh; seawater should work just as well, though that hasn't been tried yet.

The next steps will be conducting more experiments and scaling up, the researchers said.

Both Gislason and Stute noted that the carbon dioxide would need to be transported to pumping sites if projects like this were built commercially, so the technique probably lends itself best to power plants that are close to areas with porous basaltic rock. Gislason said that describes many areas with power plants. "There are opportunities for this in Indonesia, or Japan," he said.

Still, the method offers a possible way to get rid of carbon dioxide quickly and cleanly, he said. "In a sense, you just mimic nature," Gislason said. "Just speeding up the process."

The study is detailed in the June 10 issue of the journal Science. 

Original article on Live Science.

Bubbles in ancient Australian lava reveal that the early Earth's atmosphere might have been half as thick as it is today, scientists say.

The findings contradict the decades-long belief that Earth's early atmosphere was thick and, if confirmed, would expand the list of the types of planets capable of supporting life, the researchers said in a new study. [In Photos: Watery Ocean Hidden Beneath Earth's Surface]

Even so, other Earth scientists say the claim is sure to be controversial.

"Here you have a young Earth with an atmosphere completely different than today, and yet was very much alive," lead study author Sanjoy Som, director of the Blue Marble Space Institute of Science, told Live Science in an email. At the time, some 2.7 billion years ago, the Earth was spinning faster, and its newly formed moon raised much higher tides than Earth experiences today, Som said. It also may have been exposed to more ultraviolet light, as there was not yet an ozone layer. "[That] makes the early Earth the closest thing we have to an inhabited exoplanet [a planet outside our solar system]," Som added.

Keeping Earth warm

The study is one of many attempts to solve the "faint young sun" paradox, first raised by astronomers Carl Sagan and George Mullen in the 1970s. Under this paradox, astrophysical models of the sun's evolution say that our host star should have been fainter billions of years ago — so faint, in fact, that the Earth should have been covered in glaciers. Something was keeping the Earth warmer, and recent studies pointed to a thick nitrogen atmosphere with higher levels of water vapor, carbon dioxide, methane and other greenhouse gases as possible culprits. [In Photos: The World's Oldest Living Things]

Som and David Catling, a professor of earth and space sciences at the University of Washington, are proposing a radically different idea: that 2.7 billion years ago, Earth had a thin atmosphere that was still mostly nitrogen and whose pressure was, at most, just half of Earth's current pressure — equivalent to the pressure at about 17,000 feet (5,180 meters) above sea level.

A thinner atmosphere would ordinarily mean an overall colder Earth, the researchers said, because gases trap heat, and more gas traps more heat. But Som noted that the lower pressure actually might have meant a higher concentration of greenhouse gases because, due to the thin atmosphere, the water on this early Earth would have boiled more easily.

"This would increase the amount of water vapor in the air, which is the strongest of the greenhouse gases," Som said. All of that water vapor, along with more carbon dioxide and methane, would have kept the Earth relatively balmy, the researchers suggested.

Ancient lava bubbles

The evidence for such a thin blanket of air on the early Earth came from ancient rocks in Australia. Som and his team examined the bubbles trapped in the rock. Bubbles in lava (or any other liquid) are different sizes depending on the pressure of the surrounding air. Therefore, measuring the volume of the bubbles can tell scientists what the air pressure was when the liquid (in this case, lava) solidified. The bubble size that Som and his colleagues found indicated that the atmosphere 2.7 billion years ago was thinner.

The lava also had "lava toes" — small, lobe-shaped forms — with glassy bits on the bottom. These usually indicate that the molten rock flowed into wet beach gravel — strong evidence that they formed at sea level, the researchers said.

The next question to answer was how the air got so thin. Just after Earth formed, its atmosphere still would have been thicker than it is today, scientists say. That's because nitrogen was coming from several sources, including from the atmosphere itself and from the crust and mantle, which had just been heated up by the impact that formed the moon and would release a lot of gases. (The combined amount of nitrogen from all three stays roughly the same over time — the difference is what form it is in.)

For this thinner atmosphere to be created, something had to take the nitrogen out of the air and put it somewhere else, locking it into chemical compounds. "We think biology did it," Som said.

The bacterial life-forms that emerged on Earth would have pulled the nitrogen out of the air and combined it with other elements to make new compounds, such as ammonium, the researchers said. Life-forms do this now as well — except with oxygen from the air, bacteria can return nitrogen to the atmosphere, creating part of the modern nitrogen cycle.

Those compounds, such as ammonium (NH4 ions), would get deposited into clays in the nascent seas and be carried back into the Earth as tectonic plates slid beneath each other, taking their nitrogen with them, Som said.

How did the atmosphere thicken again?

After the Great Oxygenation Event, which happened about 2.5 billion years ago, single-celled living things started emitting oxygen as waste.

Som posits two possible mechanisms responsible for putting the nitrogen back into the air as a gas at that time. First, oxygen-breathing creatures would release nitrogen in reactions with oxygen. (This happens today, and the process is called denitrification.) Another possibility is that the nitrogen that went into the Earth's mantle as ammonium got broken down into nitrogen (N2) again, allowing volcanoes to release more of it back into the atmosphere over a period of about 330 million years.   

Therefore, when life was emerging on Earth, it could clearly do so with a wider range of air pressures than anyone thought possible, Som said. The research also points to the idea that the air pressure on the Earth might have fluctuated a lot more over time than scientists had thought. It also means that if life could make it here with half an atmosphere or less, it could do so elsewhere.

Life on other planets

Sami Mikhail, an assistant professor of geology at the University of St Andrews in Scotland who wasn't involved in the study, said the work will be controversial. "It's exciting because the result seems robust," Mikhail told Live Science. He has also done studies on the Earth's early atmosphere, and the results of those studies also pointed to a thin atmosphere on early Earth. "If they are right, we will have to rethink what we know about the Earth's evolution," he said. [7 Theories on the Origin of Life on Earth]

Mikhail said the work expands the kinds of worlds on which scientists think life might be possible.

"When we take a look at [an exoplanet] system with an Earth-like planet, we might find some with thin atmospheres like this," he said. "This means they could evolve into Earths" billions of years in the future, he added.

The research was detailed online May 9 in the journal Nature Geoscience.

Follow Live Science on Twitter @livescience. We're also on Facebook & Google+. Original article on Live Science.

The annual growth rate of carbon dioxide in the atmosphere rose more in 2015 than scientists have ever seen in a single year, the National Oceanic and Atmospheric Administration announced Thursday.

It was the fourth year in a row that carbon dioxide concentrations grew by more than 2 parts per million, with an annual growth rate of 3.05 parts per million in 2015. ­The spike comes in the same year that Earth reached an ominous global warming milestone -- scientists last year measured the highest atmospheric concentrations of carbon dioxide ever recorded.

Carbon dioxide emissions from people burning fossil fuels are the driving force behind climate change and have risen to greater than 400 ppm — more than 120 ppm above pre-industrial levels. Earth has warmed more than 1.6°F over that period.

As of February, the average atmospheric carbon dioxide concentration in the earth's atmosphere was about 402.6 ppm, according to NOAA data. The findings are based on measurements made at the Mauna Loa Observatory in Hawaii.

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"Carbon dioxide levels are increasing faster than they have in hundreds of thousands of years," Pieter Tans, lead scientist of NOAA's Global Greenhouse Gas Reference Network, said in a statement.

The rate of increase in carbon dioxide concentrations is 200 times faster than the previous extreme jump between 11,000 and 17,000 years ago, when levels rose 80 ppm over about 6,000 years.

NOAA scientists are blaming last year's spike in carbon dioxide concentrations on what will likely be the most extreme El Niño ever recorded, as ecosystems respond to the changes in temperature and precipitation it has caused.

Michael Mann, an atmospheric science professor and director of the Earth System Science Center at Penn State University, who is unaffiliated with NOAA, said the carbon dioxide milestone shouldn't be over-interpreted.

"This spike is almost certainly due in substantial part to the ongoing El Niño event, which is a fleeting effect that increases carbon dioxide concentrations temporarily," Mann said. "Carbon dioxide concentrations are a lagging indicator, and they don't accurately reflect recent trends in the more important variable — our actual carbon emissions."

Emissions, he said, have stabilized somewhat in recent years and dropped slightly in 2015, reflecting human progress in transitioning away from a fossil fuel economy, he said.

"Those are the numbers to keep a close eye on," he said. "If they continue to decline, we will see carbon dioxide concentrations beginning to stabilize."

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Originally published on Climate Central.

The gas leak that forced the evacuation of 1,800 homes in the mountains above Los Angeles late last year was the largest methane leak in U.S. history and shows the climate risks of aging natural gas infrastructure, according to a study published Thursday in the journal Science.

The Aliso Canyon leak near the Porter Ranch neighborhood was so big that it emitted 97,100 tons of methane — the equivalent of the annual greenhouse gas pollution from 572,000 cars, according to the study, which used aircraft to measure methane concentrations in the atmosphere near Aliso Canyon during the leak.

Though the global climate impacts of the leak were minimal, it showed that aging and degraded natural gas wells and pipelines in the U.S. could be at risk of emitting millions of tons of methane into the atmosphere, with significant implications, the study's authors say.

"If you look at it in the spectrum of all the individual (methane) sources, it's a monster," said study lead author Stephen Conley, a University of California-Davis atmospheric scientist who owns Scientific Aviation, a company that uses private aircraft to measure pollutants in the air.

Study Ties U.S. to Spike in Global Methane Emissions Huge Methane Emissions ‘Hot Spot’ Found in U.S. Determining Methane Leaks Is Key to Climate Goals

Methane is 86 times more potent as a greenhouse gas as carbon dioxide over the span of 20 years, or about 35 times as potent over a span of a century, a characteristic known as global warming potential.

The U.S. has played a major role in an increase in global methane emissions in recent years. Research published this month shows that the U.S. may be responsible for between 30 and 60 percent of the growth in emissions since 2002.

The Aliso Canyon leak was discovered Oct. 23 at the Aliso Canyon Storage Facility, one of about 400 underground natural gas storage reservoirs nationwide. The facility stores natural gas in depleted underground crude oil formations, serving millions of homes in the Los Angeles area. The leak was fully stopped on Feb. 18.

The blowout, which leaked about 5 billion cubic feet of natural gas into the atmosphere, was the largest methane release in U.S. history — with an asterisk. A 2004 collapse of an underground gas storage facility near Moss Bluff, Texas, released 6 billion cubic feet of natural gas, but the gas exploded, preventing the methane from reaching the atmosphere.

The Aliso Canyon leak could have been much worse, the study says: Though it continued for five months, it emitted into the atmosphere only 3 percent of the storage facility's natural gas stockpile.

SoCalGas CEO Dennis Arriola said in a Feb. 18 letter to Aliso Canyon-area residents that the company will cooperate with California regulators in an ongoing investigation into the cause of the leak and find a way to offset its greenhouse gas emissions.

Numerous studies have shown that landfills and power plants are urban sources of methane, and natural gas fields and pipelines serving major metro areas have been found to leak large amounts of methane into the atmosphere partly because of aging and degrading infrastructure.

A 2014 study found 5,900 urban methane and other gas leaks in aging pipes in Washington, D.C., and an unrelated study published this week shows that the Los Angeles basin has 213 methane leak "hotspots" from landfills, cattle growing and oil and gas facilities.

The Aliso Canyon leak was particularly notable because a rupture in a well that taps the underground storage facility leaked about 9 percent of California's annual methane emissions — roughly the same annual methane emissions of some small European countries.

"Compared to the worldwide methane budget, it's small," said study co-author Thomas Ryerson, leader of the National Oceanic and Atmospheric Administration's tropospheric chemistry program in Boulder, Colo.

But, he said, the Paris climate agreement signed last year requires countries to do their part in reducing greenhouse gas emissions the best they possibly can, and the Aliso Canyon gas leak shows that one single leak can eclipse the annual greenhouse gas emissions of a country such as Austria.

"In the post-COP21 world, rapid evaluation of episodic releases of GHGs like the Aliso Canyon blowout will be an essential contribution to meeting these requirements," the study says, referring to the Paris climate negotiations.

Scientists unaffiliated with the study emphasized that the Aliso Canyon leak was serious, but not necessarily for its climate implications.

Rob Jackson, an earth system science professor at Stanford University whose research has focused in part on methane leaks from natural gas infrastructure, said the Aliso Canyon leak was unprecedented in size, but small in a global context.

"Its biggest legacy will be in displacing thousands of people," Jackson said. "Aliso Canyon highlights the vulnerability of our natural gas infrastructure and the opportunity we have to reduce all leaks."

Gabrielle Petron, an atmospheric scientist at NOAA and the University of Denver who studies pollution near oil and gas operations, said the Aliso Canyon leak and others like it shouldn't distract the U.S. from focusing on reducing carbon dioxide emissions.

She said there is a risk that making large investments in the improvement and expansion of natural gas infrastructure may be setting the U.S. on a trajectory of increased fossil fuel consumption. But, she said, she is unsure if the U.S. can meet its greenhouse gas emissions reductions goals with the natural gas infrastructure currently in place.

"There is no silver bullet to reducing greenhouse gas emissions," Petron said. "Methane is a significant player in the short term, but carbon dioxide is the dominant driver of climate change."

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Originally published on Climate Central.

It’s official: 2015 was the hottest year on record, beating out 2014 by the widest margin in 136 years of record keeping, U.S. government agencies announced Wednesday. But this new record may not stand for long, as one of the strongest El Niños ever measured combines with the continued warming of the planet to potentially push 2016 to yet another record.

“2015 was remarkable even in the context of the larger, long-term warming trend,” Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, said in a statement.

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The year’s incredible heat serves as a stark reminder of how much the Earth’s temperature has risen due to the steady buildup of heat-trapping greenhouse gases in the atmosphere from human activities like power generation, transportation and forest clearing. That temperature reached the point in 2015 where it was 1°C (1.8°F) above that of the late 19th century at the same time as carbon dioxide levels likely permanently rose above 400 parts per million.

The end of the year also saw international negotiators agree to a plan to limit greenhouse gas emissions to keep that temperature from rising beyond 2°C (3.6°F) above pre-industrial levels to limit the adverse impacts of warming, such as melting glaciers, rising sea levels and potentially more extreme weather.

Both NASA and the National Oceanic and Atmospheric Administration (NOAA) reported that 2015 easily took over the top spot from 2014. By NASA’s measure, 2015 was 0.23°F (0.13°C) warmer than 2014 — the second largest-ever jump from a previous record. By NOAA’s measure it was 1.62°F (0.9°C) above the 20th century average and the largest jump from a previous record, at 0.29°F (0.16°C) above 2014.

Global Warming Key Driver of 2015’s Record Heat December Heat Boosts 2015 to 2nd Warmest Year for U.S.

“That’s the rather remarkable part of the story, we think, this year,” Thomas Karl, director of NOAA's National Centers for Environmental Information, said during a press teleconference.

The two agencies use slightly different methods of assembling the global temperature data, leading to the slightly varying numbers, though both datasets show the clear warming of the planet.

The oceans were one of the clear warm areas of the globe during the year, particularly the Indian Ocean and the tropical Pacific Ocean, which was under the influence of an incredibly strong El Niño. Record warmth was found in parts of Europe, Africa, Asia, Australia, South Africa and North America. It was the second warmest year on record for the U.S., helped by an incredibly toasty December in the eastern half of the country.

While El Niño contributed to the record, a Climate Central analysis has shown that 2015’s high temperature was overwhelmingly the result of manmade warming.

“We would not have seen the record warming without the long-term trend,” Schmidt said.

Pacific Ocean temperatures in the key El Niño region likely peaked in November, but it takes about three to five months for that heat to spread beyond the tropical Pacific and warm the broader atmosphere. The peak global heat from El Niño likely hasn’t happened yet, Anthony Barnston, chief forecaster for Columbia University’s International Research Institute for Climate and Society, said.

That peak is likely to come in the next few months, “so, while 2015 may be the warmest year on record so far, 2016 may well be even warmer,” Barnston said in an email.

This could be the case even if the tropical Pacific transitions into a La Niña later this year, Barnston said. La Niña is the cold counterpart to El Niño, featuring below-normal temperatures in the tropical Pacific Ocean and cooler global temperatures.

The overall background warming of the globe means that even La Niña years now are warmer than El Niño years of previous decades. And the temperature effects of a La Niña later this year wouldn’t be felt until the year was nearly over, Barnston said.

The U.K.’s Met Office predicts that 2016 will be 1.5°F (0.84°C) above the 1961-1990 average, while 2015 was 1.3°F (0.72°C) above this average. (That prediction assumes there are no major volcanic eruptions, which have a cooling influence.)

"This forecast suggests that by the end of 2016 we will have seen three record, or near-record years in a row for global temperatures,” Adam Scaife, head of long-range prediction at the Met Office, said in a statement.

Scientists don’t expect every year to be warmer than the last, as natural fluctuations like La Niña can have a cooling influence, but overall manmade warming tips the odds in favor of record hot over record cold. The last globally record cold year was 1911, while 15 of the 16 hottest years on record have occurred since 2001, according to NASA.

Originally published on Climate Central.

The U.S. solar power industry continued its hiring spree in 2015, growing nearly 12 times faster than overall U.S. employment.

The solar industry has seen 123 percent growth in employment since 2010, adding 115,000 jobs in that time. Last year, industry employment totaled 208,859, with 35,000 new jobs added in 2015, up from about 31,000 in 2014, according to the annual solar jobs census released by The Solar Foundation on Tuesday.

"Solar is surging," former U.S. Labor Secretary Hilda Solis said in a statement. "Renewable energy employment is on track to transform our world, helping to lessen our reliance on coal and other polluting fossil fuels."

The foundation had expected jobs in the industry to grow by 36,000, but it missed that projection. Overall, year-over-year employment growth in the U.S. solar power industry was somewhat flat, growing by 20.2 percent in 2015, down from 21.8 percent in 2014. Growth in 2013 was 19.9 percent, adding 23,682 jobs that year.

Solar Foundation Executive Director Andrea Luecke said she did not know why the industry's job growth was flat last year, but that the pace of earlier hiring may have been tied to the industry's rush to expand before a 30 percent federal solar investment tax credit expired.

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Congress extended the tax credit at the end of last year, however, which will likely result in lower solar industry employment growth in 2016, according to the census. Growth this year is expected to total about 30,000 new jobs.

Solar power in the U.S. has seen tremendous growth since 2010 as solar panel costs have continued to fall and state and federal climate policies, such as the Obama administration's Clean Power Plan, have given solar and other low-carbon electricity sources a boost.

Solar is seen as one of the primary low-carbon alternatives to coal-fired power plants, the globe's largest source of greenhouse gas emissions driving climate change. About 25 percent of all the nation's solar power capacity has been installed in just the last year, according to the census. However, solar remains a small player in the U.S., representing about 1 percent of U.S. electric power generation.

Most of the employment growth in the solar industry is in solar panel installation, which covers about 80 percent of all the jobs in the industry.

Solar jobs are well-paying. Installers earn an average of $21 per hour, while designers make $27 per hour and sales and marketing workers earn $29 per hour.

"It takes people to install (solar panels), and you have 80 percent of the jobs on the demand side," Luecke said. "The more demand you have, the more need you have for those jobs — a signal the industry is healthy and growing."

Eventually, the solar industry will begin growing much faster than its employment as technology advances, she said.

"At some point, we may see solar workers leveling out as the industry becomes more efficient and automated," Luecke said.

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Originally published on Climate Central.

We’re coming to the end of arguably the most influential year ever when it comes to climate change. The agreements struck at the Paris climate talks gave the world hope that nations could finally get their acts together to cut carbon emissions and with them, the risks climate change poses.

And talk about a good timing. On top of being the hottest year on record, 2015 also saw a significant carbon dioxide milestone passed, sea level rise projections raised and one of the strongest El Niño’s on record.

Next year will be a new chapter in the evolving story of our relationship with climate change. But here are the main storylines that developed in 2015.

The globe has been crazy hot all year. Signs that this would be the hottest year on record began popping up as early as April. If it were a horse race for the hottest year, 2015 would own the lead from start to finish.

On land and sea, from pole to pole, 2015 has been ridiculously hot for the world and almost all of it can be attributed to global warming. This year also marks the first time the globe will end a year with average temperatures reaching 1°C(1.8°F) above pre-industrial levels.

Our days of a world below 400 parts per million are behind us. Climate change can be traced back to one simple gas: carbon dioxide. It’s risen by 40 percent since the start of the Industrial Revolution, sparking the aforementioned rise in temperatures.

This year has continued the ever-rising march of carbon dioxide in the atmosphere to new heights. In the process, levels passed the symbolic threshold of 400 parts per million and they likely won’t dip below it again in our lifetimes.

Climate action on the international level looks more realistic than ever. It’s not all bad news on the climate front this year. The Paris climate talks yielded an agreement that’s high on ambition and has the backing of all the world’s major carbon polluters. While the climate pledges aren’t enough to meet the current goal of keeping the world from warming 2°C — let alone the more difficult task of 1.5°C — they’re a sign that nations around the world are finally planning to address climate change. Now comes the hard part of doing it.

El Niño has set records and piqued public interest. The world has been watching this El Niño since 2014, but it really became a global phenom (and source of head-scratching tweets and headlines) in 2015. Marked by warm waters in the tropical Pacific, this El Niño is among the strongest on record. It’s helped kick up huge fires in Indonesia, gave Californians a twinge of hope that their four-year drought could end and increased the risk of sunny day floods.

Ocean Drive Miami

Sea level rise projections are, well, on the rise. There’s only one direction sea level rise projections have pointed: up. Evidence is mounting that part of Antarctica and Greenland are melting faster than anticipated and that we could be locking in up to 20 feet of sea level rise. That rise could take centuries, but it would require current generations to start rethinking how and where we build our major coastal cities, and adapt to rising seas and increasing threats of flooding.

Religious leaders, including the Pope, lend some climate hope. In June, Pope Francis released his encyclical for the environment and gave climate change. The document made the grade for scientific accuracy, but it also framedclimate change as a moral issue about taking care of the world’s poorest.

Muslim leaders also released a declaration in September similarly espousing the need to address climate change to protect “the gifts bestowed on us by God, whom we know as Allah.”

Attributing extreme events to climate change, especially heat, is easier than ever. Just a few years ago attributing single events to climate change was impossible. But advances in science and computing power have nowmade attribution possible, including in near real time. Researchers, including a Climate Central-led project, are examining heat waves, winter storms and hurricanes in an effort to suss out the role of climate change. Of all the extreme weather events out there, the connection between climate change and heat has never been clearer.

NASA’s amazing visuals and science are making climate change clearer and clearer. NASA might be the dopest federal agency ever. They send people and stuff to space, which in itself is an amazing feat. But all that work isn’t just for the sake of making a more accurate Matt Damon movie about life on Mars. It’s so we can better understand the planet on which we currently live. The science is obviously important, but there’s no denying the agency knows how to make a splash visually and this year was no exception, from tracking carbon around the planet to sending a climate message from the International Space Station, NASA continues to inspire wonder about our home.

Originally published on Climate Central.

Since the 1970s, it has been suggested that kangaroos don't fart — or rather, the (ahem!) gas they emit contains very little, if any, methane. But now, new research suggests this isn’t true.

Methane is naturally created by bacteria in an animal's gut. Kangaroos, cows and many other plant eaters use these bacteria to help them digest grass and leaves. In the 1970s and 1980s, research suggested that kangaroos don't produce much methane, which made scientists think they might have special low-methane-emitting bacteria living in their guts.

"The idea that kangaroos have unique gut microbes has been floating around for some time and a great deal of research has gone into discovering these apparently unique microbes," said study co-author Adam Munn, a professor in the School of Biological Sciences at the University of Wollongong in Australia. [See how animal farts impact global warming (infographic)]

The new findings, however, suggest that kangaroos actually produce about the same amount of methane as other animals of their size. Kangaroos do emit lower levels of methane than some animals, such as cows, but the marsupials are roughly on the same level as horses, the researchers said. This means kangaroos likely don't have special bacteria, after all.

One of the reasons this research is important is because understanding methane could help mitigate the effects of climate change, according to Alex Hristov, a professor of animal nutrition and diet at Pennsylvania State University.

Methane is a greenhouse gas that comes from natural sources, such as decomposing organic matter and human activities, ranging from farm animals (and the manure they produce) to oil and gas operations. Methane is less abundant in the atmosphere than carbon dioxide, but it is more effective at trapping heat (infrared radiation).

"It has a global-warming potential [about] 25 times — depends on how you look at it — that of carbon dioxide. So it's an important greenhouse gas," Hristov told Live Science. And while carbon dioxide is still the most abundant greenhouse gas produced by humans, methane emissions should not be ignored, he added.

Cows can produce up to 200 liters of methane every day and there are an estimated 1.4 billion of them in the world, so figuring out a way to reduce those emissions could potentially help address some climate-change concerns.

In the past, scientists have tried to introduce bacteria from kangaroos into cows, in hopes of reducing methane emissions from cows. In 2004 in the United States, manure and expelled body gas from livestock (predominantly cows and pigs) contributed more than 13 millions tons of methane, according to a 2014 study published in the Journal of Geophysical Research: Atmospheres. To put that figure into context, oil and gas operations contributed 7 million tons of methane.

This kind of research could also be important to farmers, Munn said. When the bacteria break down food into methane, they’re essentially robbing the cow of some of the food's nutrients. If farmers could somehow reduce methane emissions from livestock, more nutrients would go to the cow itself, which could help them grow better.

For the new study, the scientists put 10 kangaroos inside individual sealed rooms at the University of New South Wales' Fowlers Gap Research Station and fed them food. The rooms were set up so that the scientists could measure what gases were emitted in the air. The researchers also collected the animals’ poop to measure how many nutrients were left behind, and experimented with giving the animals different amounts of food.

It may still be the case that kangaroo guts actually do hold special secrets, the researchers said. How the marsupials maintain their bacterial garden, for instance, may work differently than other plant eaters.

"What we've done here is to really show that kangaroos probably don’t have a unique microbiome," Munn said, "it''s simply that that biome interacts with the food in a different way." The next steps would be to compare these results to those of other animals, he added.

This research was published online yesterday (Nov. 4) in the Journal of Experimental Biology.

Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

The United States is sending more than twice as much solid waste into its landfills as previously thought, a new study finds.

Researchers found that people threw away 289 million tons of municipal solid waste in 2012, a figure that is more than double the 135 million tons that the Environmental Protection Agency (EPA) calculated for that same year. The new estimate also exceeds by 4 percent the World Bank's predictions for the amount of waste the United States will generate in 2025, the researchers said.

The finding is problematic for climate change models, the researchers added. If there is more solid waste in landfills, the amount of greenhouse gases released by landfills is likely also higher than has been previously estimated, the researchers said. In particular, the scientists are concerned about the release of methane — a greenhouse gas emitted by landfills that traps heat in the atmosphere 25 times more effectively than does carbon dioxide, according to the EPA.

Reducing greenhouse gas emissions from landfills is crucial, and may be achieved by implementing more and better methods to capture methane before it reaches the atmosphere, the researchers said. [In Photos: World's Most Polluted Places]

Why the difference?

The new estimate and the EPA's estimate are dramatically different because they rely on different datasets. The EPA traditionally bases its waste estimates on information from industry associations, businesses, the U.S. Census and the Department of Commerce — which all provide numbers on how much waste ends up in landfills.

In contrast, the new figure is based on actual weight measurements, said study lead author Jon Powell, a doctoral student of chemical and environmental engineering at Yale University.

In 2010, due to the U.S. Greenhouse Gas Reporting Rule that was passed the year before, large landfills began providing the weight of trash entering their premises. To do this, landfill operators usually weigh trucks before and after they dump waste into the landfill, taking the difference to determine the weight of the trash.

As with any new law, it took a while for industry to meet the requirements. The first complete dataset is from 2012, the year the researchers analyzed, Powell said. It includes data from more than 1,200 municipal solid waste landfills, of which about 900 are open, or actively accepting waste.  

"Essentially, the data we reported is a summation of those landfills which are open," Powell told Live Science. "We did not do any estimates or extrapolations."

Greenhouse gasses and waste

An analysis shows that closed landfills are 17 percent more effective at capturing greenhouse gases than open landfills are. This is no surprise, as open landfills often have huge mounds of exposed, decomposing waste. (Operators usually cover this waste with soil at the day's end, which can oxidize methane and reduce odor. But still, open landfills were responsible for 91 percent of landfill emissions in 2012.) Closed landfills are usually fully covered to prevent the gas from escaping. [Top 10 Surprising Results of Global Warming]

There are several ways to collect greenhouse gases before they are released into the atmosphere, the researchers said. One method is to place a geomembrane, a thin plastic cover, over the waste. This helps landfill operators capture and then destroy methane by combusting it into less potent carbon dioxide and water. Other landfills collect methane and use it as an energy source, much like other natural gases, Powell said.

"Improving the collection of landfill gas at open landfills must be a target for policy makers, researchers and practitioners to achieve near-term greenhouse gas emission reductions in the waste sector," the researchers wrote in the study.

The scientists also found that the average landfill has about 33 years left in capacity, but that overall waste is increasing by 0.3 percent a year, according to data collected from 2010 to 2013.

"I think the disposal rate and capacity numbers are interesting on their own, but I think in the bigger picture, it provides us a distinct, data-driven roadmap for where we can target emissions reductions in the waste sector," Powell said in a statement.

The country won't run out of landfill space anytime soon, but sometimes the landfills that have more space are far away from cities that need their services, said Morton Barlaz, a professor and head of the Department of Civil, Construction and Environmental Engineering at North Carolina State University, who was not involved with the study.

He added that "the method used to estimate waste quantity in the Yale study is more reliable than the method used by [the] EPA." However, the new study also has some approximations in its measurements, including the amount of ash from burned solid waste put into landfills, Barlaz said.

In an email to Live Science, the EPA said it was looking forward to reviewing this study. The EPA is currently calculating the country's greenhouse gas emissions for the Inventory to the United Nations Framework Convention on Climate Change. "As a part of this process, the EPA assesses studies such as these for new, high-quality data that could inform inventory updates," the agency said.

The new study was published online Monday (Sept. 21) in the journal Nature Climate Change.

Follow Laura Geggel on Twitter @LauraGeggel. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Pope Francis’ much-anticipated encyclical on climate change and the environment was officially released Thursday, with high expectations that it could be a watershed moment in bolstering support for taking international action to solve what he calls in his message, “one of the principal challenges facing humanity in our day.”

The text of document, released in several languages, does not appear to differ substantially from the non-final Italian version leaked on Monday. In it, Francis lays out the myriad environmental problems, including global warming, faced by the world today, as well as the moral and religious arguments for combating them.

Francis' aim is to use his, and the Catholic Church’s, authority to try and spread an acceptance of these issues and spur efforts to solve them.

While “the Church does not presume to settle scientific questions or to replace politics,” he wrote, “ . . . I am concerned to encourage an honest and open debate so that particular interests or ideologies will not prejudice the common good.”

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Here are the four main points that the Pope makes in the 180-page message, including quotes from the text, as well as what the next steps in international efforts might be.

1. We all have a moral (and, for Catholics, a religious) obligation to take care of the Earth and the poorest.

“The climate is a common good, belonging to all and meant for all. At the global level, it is a complex system linked to many of the essential conditions for human life.

“I urgently appeal, then, for a new dialogue about how we are shaping the future of our planet. We need a conversation which includes everyone, since the environmental challenge we are undergoing, and its human roots, concern and affect us all.”

2. Humans are driving the bulk of observed global warming, as well as numerous other environmental problems that pollute the air and water. We must own up to that fact and work to fix the problems we have caused.

“A very solid scientific consensus indicates that we are presently witnessing a disturbing warming of the climatic system. In recent decades this warming has been accompanied by a constant rise in the sea level and, it would appear, by an increase of extreme weather events, even if a scientifically determinable cause cannot be assigned to each particular phenomenon. Humanity is called to recognize the need for changes of lifestyle, production and consumption, in order to combat this warming or at least the human causes which produce or aggravate it.”

3. The way primarily Western, developed society currently lives is wasteful and unsustainable. Its consequences are disproportionately felt by the poor, developing nations who don’t get the benefits of that way of life.

“We all know that it is not possible to sustain the present level of consumption in developed countries and wealthier sectors of society, where the habit of wasting and discarding has reached unprecedented levels. The exploitation of the planet has already exceeded acceptable limits and we still have not solved the problem of poverty.

“Many of the poor live in areas particularly affected by phenomena related to warming, and their means of subsistence are largely dependent on natural reserves and ecosystemic services such as agriculture, fishing and forestry. They have no other financial activities or resources which can enable them to adapt to climate change or to face natural disasters, and their access to social services and protection is very limited.”

4. If we don’t act now to solve climate change and other environmental ills, we leave a compounding crisis to future generations. The action that we take must come soon and must be real, substantial and a true global effort.

“There is an urgent need to develop policies so that, in the next few years, the emission of carbon dioxide and other highly polluting gases can be drastically reduced, for example, substituting for fossil fuels and developing sources of renewable energy.”

“A global consensus is essential for confronting the deeper problems, which cannot be resolved by unilateral actions on the part of individual countries.

“But the international community has still not reached adequate agreements about the responsibility for paying the costs of this energy transition.

“The global economic crises have made painfully obvious the detrimental effects of disregarding our common destiny, which cannot exclude those who come after us.”

The Pope’s comments are already being widely discussed and dissected, and are likely to receive further attention during several future events that will be carefully watched. These include upcoming speeches to be made by the Pope to the U.S. Congress and the United Nations, as well as the crucial international climate talks to be held in Paris in December. The primary goal of those talks is to reach a binding international agreement to limit warming below the 2°C (3.6°F) of warming that some scientists say is necessary to prevent the worst outcomes of climate change. (Since the beginning of the 20th century, the world has already warmed by 1.6°F.)

Many climate scientists, commentators and those involved in such negotiations are hopeful that the moral weight of the Pope’s message will provide a push to those efforts.

“I think it is difficult to underestimate the moral authority that the Pope brings to acting on climate with this encyclical,” Michael Mann, a Penn State climate scientist, said in an email. “I suspect we will look back at this moment as a turning point, and we will view Pope Francis as one of the great heroes in modern history.”

Encyclical Letter Laudato Si’ Of The Holy Father Francis: On Care For Our Common Home

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Originally published on Climate Central.

More efficient cars, trucks and airplanes. Less-polluting electric power plants. So many solar and wind farms that no transcontinental road trip in an electric car could take place beyond the sight of one.

Those may be the most obvious changes everyone sees if and when America’s proposed climate policies fully bloom in the next decade or so. The biggest of those policies, the Clean Power Plan, was announced a year ago and is slated to take effect in 2016. It could help low-carbon energy such as wind and solar spread quickly across the country and significantly change where Americans get their electricity and the effect it has on the climate.

In a nutshell, the Clean Power Plan aims to cut the United States’ biggest source of climate change-driving greenhouse gas emissions — carbon dioxide from existing power plants that run on fossil fuels, especially coal. The goal, as the EPA proposed it, is to slash those emissions 30 percent below 2005 pollution levels through 2030 by allowing states to find their own ways cut pollution. They’ll do that mainly by boosting overall energy efficiency, switching a lot of electric power generation from coal to natural gas and using more wind, solar and other renewables.

Here are four things to know about what the Clean Power Plan means for electricity in the U.S., based on a recent analysis by the U.S. Energy Information Administration (EIA):

Energy Diversity Will Rule the Future

To a degree, the U.S. already gets its electricity from a variety of sources. Hawaii, for example, uses crude oil to generate most of its power. Washington state gets nearly 30 percent of its power from hydroelectric dams. Texas gets about a 10th of its electricity from wind. And natural gas, which is the source of about 32 percent of electricity in the U.S.,  is gaining on coal, which generates 35 percent, as the top source of electricity nationwide.

In other words, the U.S. relies on many different energy sources, but coal and natural gas are the heavy lifters today. As states begin to comply with federal climate policy, wind, solar and other renewables will do the heavy lifting alongside natural gas as coal begins to diminish.

So, if the Clean Power Plan works as proposed, the EIA projects that by 2040, renewables, natural gas and coal will generate about the same amount of the nation’s electricity — between 26 and 29 percent each.

Coal Goes Down, But Not Out

That means coal, the biggest source of greenhouse gas emissions from electricity production,  isn’t going away anytime soon. More than half of U.S. electricity was generated by coal in 2000. By 2040, it could drop to 26 percent under the Clean Power Plan.

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The mines that provide all of that coal will take a hit from climate policy. And that’s one of the main reasons major coal-producing states such as Kentucky are vehemently opposed to the Clean Power Plan and are suing the Obama administration to stop it before it takes effect. The plan is expected to reduce coal production in the U.S. by about 25 percent after 2020, when most of its provisions take effect.

Solar and Wind Power Are About to Grow . . . A Lot

It’s a no-brainer that slashing emissions from fossil fuels means boosting wind, solar and other renewables. And grow they will. Nationwide, solar and wind power and other renewables could be set to grow by 5 percent each year, so that they could make up about 25 percent of all U.S. electricity generation by 2030 — the year the Clean Power Plan’s goals must be met. That’s up from about 14 percent today, about 6 percent of which is wind and solar. The rest is hydropower.

Renewables growth will be unique to each region, EIA analyst Chris Namovicz said. The fastest growth under the Clean Power Plan is expected to be in places that have weak renewable energy mandates today or none at all. So Southern states, most of which have no renewables mandates, will see annual renewables growth rates of 10 percent or higher over the next 15 years.

Other states, where renewables are already big business, could see a slower rate of growth because they have a head start on building up their wind, solar and other clean energy sources. California, for example, may see its renewables grow about 2 percent each year after 2020.

Nuclear Power? Not So Much

One thing that isn’t likely to change much under the Clean Power Plan is nuclear power. Yes, several new nuclear reactors are expected to start operating in Georgia, South Carolina and Tennessee by 2017 — the first new nuclear reactors in the U.S. in nearly 30 years — but the amount of power that nuclear reactors will generate in the coming decades is expected to fall slightly.

Today, about 20 percent of U.S. power comes from nuclear. That is expected to shrink to 16 percent by 2040 under the Clean Power Plan, which the EIA says favors renewables and natural gas over nuclear power.

In other words, the Obama administration is betting on no new nuclear power plants other than those that are being built today.

The caveat to all of this is that Clean Power Plan as it was proposed could change dramatically by the time it takes effect. Fourteen states, many of them major coal producers, are suing to stop it before it becomes official. And, when the final version of the plan is released, the details could change significantly.

So, stay tuned.

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Originally published on Climate Central.

A whiff of air frozen in ice for 1 million years provides a new snapshot of Earth's ancestral climate.

Scientists uncovered the ancient climate record from Antarctic blue ice. The ice core was drilled from a region called the Allan Hills, about an hour by plane from the McMurdo research station. Bubbles inside the ice are tiny windows into Earth's former atmosphere. Gases such as carbon dioxide and methane were trapped and preserved inside the bubbles when snow fell in the past.

Though the ice core doesn't capture a continuous climate record, the "time machine" does offer the oldest picture yet of Earth's bygone climate from Antarctic ice, researchers said.

The timeworn ice suggests a strong link between carbon dioxide levels and glacial cycles for the past million years. In the oldest ice, levels of the greenhouse gas were about 30 parts per million (ppm) higher, at most, than more recent measurements from between 800,000 to 450,000 years ago, according to the findings, reported today (May 11) in the Proceedings of the National Academy of Sciences. Parts per million denotes the volume of a gas in the air; in this case, for every 1 million air molecules, 300 are carbon dioxide. [Album: Stunning Photos of Antarctic Ice]

The new findings could help scientists tackle a big question in climate science. About 1 million years ago, Earth's ice ages would wax and wane on a roughly 40,000-year cycle, different than today. After around 800,000 years ago, the planet entered a cooler climate phase and the ice ages shifted to a 100,000-year cycle. Many researchers think lower carbon dioxide levels were a key player in the changeover. Directly measuring levels of the gas could reveal whether a drop in carbon dioxide triggered the flip.

"Gas bubbles are the gold standard for reconstructing climate," said lead study author John Higgins, a geochemist at Princeton University.

The ice analysis reveals there weren't any major swings in greenhouse gas levels while the planet was in its warmer phase, an interglacial period, before 800,000 years ago, the study reported. Also, for the past 1 million years, carbon dioxide levels never rose above about 300 ppm. (Carbon dioxide levels are currently at about 400 ppm and rising due to human activity, such as fossil fuel emissions.)

"In general, the variability is like what we've seen for the last 800,000 years, and this is not unexpected," Higgins told Live Science. "We're seeing a very strong correlation between carbon dioxide and glacial cycles that extends back a million years."

Higgins also said that levels of atmospheric methane were surprisingly low in the oldest ice, for reasons that are as yet unknown.

The study is only a first step in filling in the climate record during this critical shift in Earth's temperature. Because the ice is so old, the layers are no longer stacked like pancakes. Some layers are missing, so there is a gap of missing time reported in the study, between the oldest ice and the ice at the surface. 

The ice was drilled from the "blue ice" region of the Allan Hills. Blue ice forms where landmasses such as mountain ranges force glacial ice to flow upward, bringing old ice to the surface. Strong winds in the region also scour and remove snow and ice from the surface, further exposing the old ice.

The research team plans to return to Allan Hills this winter to collect more ice for further testing, Higgins said. Antarctic scientists hope to eventually find ice that may date back as far as 2.5 million years.

Higgins' co-authors included Michael Bender, also of Princeton, Paul Mayewski of the University of Maine and Ed Brook of Oregon State University.

Follow Becky Oskin @beckyoskin. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

Another month, another carbon dioxide record. This time the record extends beyond the rocky slopes of Mauna Loa, Hawaii, home to the most storied carbon dioxide record, and includes 39 other sites around the globe to paint a troubling picture of a greenhouse gas rise with no signs of slowing down.

For the first time since record keeping began, carbon dioxide levels have surpassed 400 parts per million (ppm) globally, according to newly published data for March. CO2 emissions are the main driver of climate change and have risen more than 120 ppm since pre-industrial times. The planet has warmed 1.6 degrees Fahrenheit over that period as well.

NASA Shows Stark Year in the Life of CO2 The Meteoric Rise of Carbon Dioxide in 1 Video 2015 Begins With CO2 Above 400 PPM Mark

This isn't the first time 400 ppm has made news. In May 2013, CO2 measurements taken at Mauna Loa surpassed 400 ppm for the first time. Measurements have been taken continuously at the site since 1958 and present the longest running record of atmospheric CO2 on the planet.

In April of last year, 12 observatories in the northern hemisphere, including Mauna Loa, averaged 400 ppm for the first time on record. And Mauna Loa rang in 2015 by registering a 400 ppm measurement, the earliest occurrence on record for the site.

But what makes the new record more profound is that 400 ppm is officially part of the global record. Concentrations will likely remain above that mark until May when blooming plants in the northern hemisphere start to suck CO2 out of the air.

The reason it has taken a bit longer for the global measurement to catch up with the northern hemisphere record is due to a handful of factors. The main reason is because southern hemisphere CO2 measurements lag behind their northern counterparts because there are more sources of human CO2 emissions in the northern half of the globe. Though CO2 moves around in the atmosphere, it takes time to spread.

Regardless of location, all CO2 measuring stations have shown an upward trend with little signs of slowing down.

The 400 ppm milestone is largely a symbolic one. But the new global data, which comes courtesy of the National Oceanic and Atmospheric Administration, serves as an important reminder that while CO2 emissions stabilized in 2014, that's not the same as dropping to zero. As a result, CO2 continues to pile up in the atmosphere.

The only ticket to reducing the amount of CO2 in the atmosphere is to cut emissions completely. And that's a long ways off.

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Originally published on Climate Central.

A methane "hot spot" over the Four Corners region of the U.S. Southwest is undergoing serious scrutiny as scientists work to figure out why levels of the gas in the area are so high.

The mysterious methane was first detected from space, via a European Space Agency satellite that can measure this potent greenhouse gas. Researchers reported the discovery in October in the journal Geophysical Research Letters, but couldn't explain where the extra methane was coming from. The "hot spot" persisted from 2003 until at least 2009. And the amount of methane was significant, the researchers reported — equal to nearly 10 percent of all U.S. methane emissions from natural gas.

Now, a team of researchers is tackling the mystery of the extra methane. The scientists will fly two Twin Otter aircraft over the Four Corners area, where the borders of Colorado, New Mexico, Utah and Arizona meet. These planes will carry two instruments: the Next-Generation Airborne Visible/Infrared Imaging Spectrometer (AVIRISng), which can detect and map methane in great detail, according to NASA's Jet Propulsion Laboratory; and the Hyperspectral Thermal Emission Spectrometer (HyTES).

This second instrument is sensitive to methane emissions and will be used to survey and measure suspected methane emissions sites. By combining the data from these two instruments, the researchers hope to make maps that will show methane variations over every few feet of the region. They also plan to track the emissions over several months to determine how weather conditions influence methane levels. [Gallery: See Images of Amazing Atlantic Methane Seeps]

"With all the ground-based and airborne resources that the different groups are bringing to the region, we have the unique chance to unequivocally solve the Four Corners mystery," Christian Frankenberg, a scientist at NASA's Jet Propulsion Laboratory, said in a statement. (The new effort is a collaboration among JPL; the Cooperative Institute for Research in Environmental Sciences, or CIRES, in Boulder, Colorado; the National Oceanic and Atmospheric Administration, or NOAA; and the University of Michigan, Ann Arbor.)

The trail is not entirely cold. The timing and persistence of the hot spot suggests the methane may be coming from gas extraction, coal mining, and coal-bed methane mining and processing in the region, the researchers reported in their paper on the discovery in the Geophysical Research Letters journal. Naturally occurring gas seeps are another possibility, NASA said.

If the methane hot spot is man-made, the measurements researchers make in the coming months over Four Corners could help reduce the emissions.

"If we can verify the methane detected by the satellite and identify its sources, decision-makers will have critical information for any actions they are considering," CIRES scientist Gabrielle Pétron said in the statement.

Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

The 2011 tsunami that struck Japan released thousands of tons of ozone-destroying chemicals and greenhouse gases into the air, a new study shows.

Thanks to the country's strict building codes, the enormous magnitude-9 Tohoku earthquake left Japan's homes and businesses relatively untouched. But the earthquake triggered a deadly tsunami that roared through coastal cities and villages, destroying almost 300,000 buildings, according to the National Police Agency of Japan.

The damaged insulation, refrigerators, air conditioners and electrical equipment unleashed 7,275 tons (6,600 metric tons) of halocarbons, the study reported. Halocarbon emissions rose by 91 percent over typical levels in the year following the earthquake, said Takuya Saito, lead study author and senior researcher at the National Institute for Environmental Studies in Tsukuba, Japan. [In Pictures: Japan Earthquake & Tsunami]

"It was not a single, short-term pulse," Saito said.

The six halocarbons measured in the study are a group of chemicals that attack the Earth's protective ozone layer and can also contribute to global warming. The halocarbons include banned gases such as chlorofluorocarbons (CFCs), as well as hydrochlorofluorocarbons (HCFCs), which are being phased out of use. The researchers also found significant increases in hydrofluorocarbons (HFCs) and sulfur hexafluoride, both greenhouse gases.

Emissions of the banned chemical CFC-11 were 72 percent higher than before the March 11, 2011, earthquake. "This was surprising to us, because it had been banned in Japan 15 years before the disaster," Saito told Live Science in an email interview. "We had almost forgotten the fact that this ozone-depleting gas still exists around us."

About 50 percent of the halocarbon emissions after the earthquake were of HCFC-22. Its concentration rose by 38 percent between February 2011 and March 2012, the study reported.  Emissions of HFC-134a and HFC-32 rose by 49 percent and 63 percent compared to the years before the quake.

Saito and his colleagues launched the study after noticing unusually high emissions of the halocarbon HFC-32 at Cape Ochiishi in Hokkaido, Japan, following the earthquake. The researchers have studied atmospheric halocarbons at this site since 2006, Saito said. The researchers then took air-monitoring data from several stations in Japan and used atmospheric modeling to determine how much of the emissions were due to the 2011 earthquake and tsunami.

The findings were published March 12 in the journal Geophysical Research Letters.

Although the global effect of this one event is small, no countries account for natural disasters, such as earthquakes and tsunamis, in their annual estimates of greenhouse-gas releases to the atmosphere. "It is apparent that there are unreported emissions," Saito said.

The new study shows it may be necessary to include the amount of halocarbons released by catastrophic events in emissions estimates, Steve Montzka, a research chemist at the National Oceanic and Atmospheric Administration in Boulder, Colorado, who was not involved in the research, said in a statement.

Based on global halocarbon emission estimates, the extra emissions from the 2011 Tohoku earthquake would account for 4 percent or less of total global halocarbons, Saito said. And the halocarbons were weak contributors to global warming compared to carbon dioxide and methane. The gases released by the tsunami accounted for less than 1 percent of greenhouse gas emissions in the year following the earthquake.

Follow Becky Oskin @beckyoskin. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

Global emissions of carbon dioxide — one of the leading causes of global warming — stalled in 2014, marking the first time in 40 years that there was no climb in CO2 emissions during a time of economic growth. The results suggest that efforts to reduce emissions may be on the upswing, but experts say the situation is not so simple.

In fact, some scientists say that the findings, announced last week by the International Energy Agency (IEA), represents only one data point and that the overall trend in carbon dioxide emissions is continuing upward.

Global CO2 emissions have stalled three times in the 40 years in which the IEA has been collecting data: in the early 1980s, in 1992 and in 2009. But each of those periods correlated with a downturn in the economy, whereas last year, the global economy expanded by 3 percent. This kind of separation between economic growth and CO2 emissions could be a hopeful sign, according to groups dedicated to combatting climate change. [8 Ways Global Warming Is Already Changing the World]

In the United States, energy-related CO2 emissions fell during seven of the past 23 years. Emissions in 2013 (and 2014) were higher than in 2012 but still 10 percent lower than they were in 2005, according to the U.S. Energy Information Administration. As such, global increases during this time period are typically attributed to the rapid industrialization of countries such as China and India.

China's CO2 emissions fell by 2 percent in 2014, as the country shifted more toward renewable energy sources, and the IEA is crediting last year's flat line to that crucial fall.

But scientists can't be so sure.

"There's so much going on in the climate system that you can't only look at one year, or even one decade," said Thomas Peterson, principal scientist at the National Oceanic and Atmospheric Administration's (NOAA) National Climatic Data Center. There are factors other than CO2 governing surface temperature and therefore global warming.

These include cloud cover, the amount of heat absorbed by the ocean, El Niño events and more, Peterson said. So despite the IEA's promising announcement, members of the climate community aren't resting easy.

And even though energy-related emissions remained constant last year, 2014 was still the hottest year on record, according to an annual report by NASA and NOAA scientists.

The reason for this is that CO2 lingers in the atmosphere for hundreds to thousands of years.

"If emissions remain constant, the concentrations [of greenhouse gases] will still increase in the atmosphere for a long time," said Don Wuebbles, a professor of atmospheric science at the University of Illinois at Urbana-Champaign. "The climate response that we're seeing in the atmosphere now is largely due to emissions that happened 20 years ago."

It would take about 100 years for the amount of carbon dioxide in the atmosphere to reduce to 37 percent of current levels, according to the Intergovernmental Panel on Climate Change (IPCC). This means that even if emissions are cut today, the atmospheric concentration of greenhouse gases would still increase for decades. It's like adding water to a bathtub: If you add more water than the drain is able to empty, the tub will eventually overflow. [Earth in the Balance: 7 Crucial Tipping Points]

"We need to take CO2 down below where emissions are today by quite a bit in order just to stabilize at a particular concentration,” Peterson told Live Science.

The latest report by the IPCC, the international organization tasked with assessing the science of climate change and its impacts, predicts that in order to keep the increase in average global surface temperature under 3.6 degrees Fahrenheit (2 degrees Celsius), total future CO2 emissions cannot exceed 1 trillion tons. After that, countries would have to curb all greenhouse gas emissions to avoid drastic consequences, such as severe weather and rising sea levels.

It's unclear how many billion tons of carbon have already been burned, but the IPCC argues that the planet cannot emit another 500 billion tons in order to stay below the recommended threshold. (Greenpeace has issued a more alarming forecast, saying that the figure is likely closer to 350 billion tons.)  

Wuebbles, however, says the cap should be less than the number of tons of carbon emitted to date, whether that’s 500 billion tons or 650 billion tons.

"We're already seeing severe weather as a result of changes in climate and significant increases in precipitation coming as larger events, more droughts in some places, more floods in others, etc.," he said.

Yet he remains hopeful that the effects of climate change can be mitigated.

"I don't think it's too late,” Wuebbles said. "I think we should be acting now."

Follow Shannon Hall on Twitter @ShannonWHall. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

The climate-changing greenhouse effect exists and has been directly measured in the United States, a new study reports.

The results confirm what scientists had already proved through models and laboratory experiments: Pumping carbon dioxide gas into the atmosphere is warming the Earth's surface.

"We're actually measuring the fact that rising carbon dioxide concentrations are leading to the greenhouse effect," said lead study author Dan Feldman, a scientist at the Lawrence Berkeley National Laboratory in California. "This is clear observational evidence that when we add carbon dioxide to the atmosphere, it will push the system to a warmer place."

Since the late 1950s, scientists have documented rising levels of carbon dioxide and other "greenhouse gases" in Earth's atmosphere. Laboratory tests and physics experiments indicated that these gases absorb some of the infrared radiation that Earth emits into space, thereby raising the planet's temperature. This is called the greenhouse effect because it is similar to how a glass greenhouse traps heat, warming the air inside. Put simply, more energy is flowing into the greenhouse than is getting out, a concept that scientists call radiative forcing. [Infographic: Earth's Atmosphere Top to Bottom]

The research team measured radiative forcing on the Earth's surface due to carbon dioxide at two long-running atmospheric research sites owned by the Department of Energy. One is in Oklahoma and the other is near Barrow, Alaska, above the Arctic Circle.

Powerful spectrometers calibrated by the United States Office of Weights and Measures tracked the infrared radiation coming down to the surface, Feldman said. Greenhouse gases in the atmosphere absorb the Earth's infrared energy and then scatter it in all directions, some back downward toward the surface. The instruments can detect the "fingerprint" of carbon dioxide's infrared signal because the molecule emits and absorbs infrared energy at distinctive wavelengths.

Between 2000 and 2010, atmospheric concentrations of carbon dioxide rose at both research sites by 22 parts per million. (The parts per million number refers to the volume of carbon dioxide molecules in every million air molecules.) At the same time, the amount of downward-directed infrared energy from carbon dioxide increased. This meant the surface radiative forcing, or energy imbalance, also increased at both sites, the researchers report today (Feb. 25) in the journal Nature.

In translation: More gas in the atmosphere meant more infrared energy was reflected back at the Earth instead of escaping into space.

"This is another direct piece of evidence that supports that the increase in carbon dioxide is indeed contributing to global warming," said Dave Turner, an atmospheric physicist at the National Severe Storms Laboratory in Oklahoma, who was not involved in the study. "It's a roadmap as to how we can do exactly the same thing for other trace gases."

The scientists ruled out or removed possible warming effects from clouds, weather, water vapor or problems with instrument calibration.

The added radiative forcing was 0.2 watts per square meter per decade, which is about 10 percent of the total increase due to all human activities, according to the Intergovernmental Panel on Climate Change .

"I would hope that even people who raise their eyebrows at this whole field can see there is a really robust observation underlying this," Feldman told Live Science.

The research team is now investigating the contributions to global warming from other greenhouse gases, such as methane.  

Follow Becky Oskin @beckyoskin. Follow LiveScience @livescience, Facebook & Google+. Originally published on Live Science.

A massive outpouring of carbon dioxide from the deep ocean may have helped end the last ice age, scientists report today.

There is strong evidence that changes in Earth's orbit set the pace of the planet's ice ages, by altering how much sunlight reaches the Northern Hemisphere. Yet, carbon dioxide levels in the atmosphere also wobble with the advance and retreat of massive ice sheets, according to observations of ice cores and old ocean sediments. Carbon dioxide levels are lower during an ice age and higher when an ice age ends.

Now, scientists have documented a source for the massive exhalations of potent climate-altering gas seen at the end of the last ice age, about 16,000 years ago. [Photos: The 8 Coldest Places on Earth]

"The oceans were leaking carbon dioxide to the atmosphere," said study co-author Gavin Foster from the University of Southampton in the United Kingdom.

The researchers, led by Miguel Angel Martínez-Botíz of Britain’s National Oceanography Center in Southampton, looked at ice-age seafloor sediments in two regions where ocean currents force deep- ocean water to the surface. They examined the shells of single-celled microbes called foraminifera, which preserve the ratio of chemicals in seawater as they grow. A certain chemical ratio involving boron is a proxy for the carbon dioxide concentration in seawater thousands of years ago, when the microbes lived and died.

The samples tested in the study come from two seafloor drilling sites. One is located in the southern Atlantic Ocean, midway between South America and Africa, and the other is offshore Ecuador on the underwater Carnegie Ridge.

Very high concentrations of dissolved carbon dioxide suddenly appeared in surface waters of the southern Atlantic Ocean and the eastern equatorial Pacific Ocean at the end of the last ice age, the researchers said today (Feb. 11) in the journal Nature. Surface waters in both regions show a dramatic rise in dissolved carbon dioxide levels at the same time as the recorded rise in atmospheric carbon dioxide in ice cores, the researchers report.

During the early Holocene Epoch, about 10,000 years ago, the carbon dioxide exhalations continued, yet gas levels stabilized in the atmosphere, according to the new study. This suggests that something starting sucking up the gas, perhaps re-growing forests or expanding peat bogs on land, the researchers said.

The findings suggest these regions were pumping carbon dioxide to the atmosphere. The gas concentrations in the two regions spiked at different times, hinting that different processes underlie the rise in ocean carbon, the researchers said. However, in both cases the scientists think carbon dioxide levels in these two regions jumped because water rich in carbon and nutrients welled up from the deep ocean.

This is not the first study to suggest that sharp increases in carbon dioxide coincided with the warming that began as Earth emerged from its most recent ice age. Earlier studies from the western equatorial Pacific Ocean also suggest the tropics were a significant source of carbon dioxide during deglaciation. Antarctic ice cores also record a jump in carbon dioxide levels in the atmosphere, followed by warmer temperatures.

Yet scientists still puzzle over what triggered these giant burps in greenhouse gas. Leading theories include changes in ocean currents or wind patterns. Some researchers recently suggested that sea-level drops triggered underwater volcanoes to erupt more vigorously, belching carbon dioxide in the process.

"We don't know the ultimate case," Foster said. "[But] we're one step toward the answer."

The researchers plan to test additional sites and examine how carbon dioxide levels changed through the glacial cycle, he said.

Follow Becky Oskin @beckyoskin. Follow LiveScience @livescience, Facebook & Google+. Originally published on Live Science .

The world is "3 minutes" from doomsday.

That's the grim outlook from board members of The Bulletin of the Atomic Scientists. Frustrated with a lack of international action to address climate change and shrink nuclear arsenals, they decided today (Jan. 22) to push the minute hand of their iconic "Doomsday Clock" to 11:57 p.m.

It's the first time the clock hands have moved in three years; since 2012, the clock had been fixed at 5 minutes to symbolic doom, midnight. [End of the World? Top Doomsday Fears]

The Bulletin of the Atomic Scientists doesn't use the clock to make any real doomsday predictions. Rather, the clock is a visual metaphor to warn the public about how close the world is to a potentially civilization-ending catastrophe. Each year, the magazine's board analyzes threats to humanity's survival to decide where the Doomsday Clock's hands should be set.

Experts on the board said they felt a sense of urgency this year because of the world's ongoing addiction to fossil fuels, procrastination with enacting laws to cut greenhouse gas emissions and slow efforts to get rid of nuclear weapons.

"We are not saying it is too late to take action but the window for action is closing rapidly," Kennette Benedict, executive director of The Bulletin of the Atomic Scientists, said in a news conference this morning in Washington, D.C. "We move the clock hand today to inspire action."

For instance, if nothing is done to reduce the amount of heat-trapping gasses, such as carbon dioxide, in the atmosphere, Earth could be 5 to 15 degrees Fahrenheit (3 to 8 degrees Celsius) warmer by the end of century, said Sivan Kartha, a senior scientist at the Stockholm Environment Institute.

Some people might not feel alarmed when they see those numbers; they might normally experience that kind of temperature swing in the course of a single day, Kartha said. But, he said a temperature increase of that magnitude was enough to bring the world out of the last ice age, and it will be enough to "radically transform" the Earth's surface in the future.

Sharon Squassoni, another board member and director of the Proliferation Prevention Program at the Center for Strategic and International Studies, said nuclear disarmament efforts have "ground to a halt" and many nations are expanding, not scaling back, their nuclear capabilities. Russia is upgrading its nuclear program, India plans to expand its nuclear submarine fleet, and Pakistan has reportedly started operating a third plutonium reactor, Squassoni said.

She said the United States has good rhetoric on nuclear nonproliferation, but at the same time is in the midst of a $335 billion overhaul of its nuclear program. (That figure seems to come from a Congressional Budget Office report from December 2013.)

"The risk from nuclear weapons is not that someone is going to press the button, but the existence of these weapons costs a lot of time, effort and money to keep them secure," Squassoni said, adding that there have been troubling safety discrepancies reported in recent years at power plants.

The Bulletin of the Atomic Scientists was founded in 1945 by scientists who created the atomic bomb as part of the Manhattan Project and wanted to raise awareness about the dangers of nuclear technology. The Doomsday Clock first appeared on a cover of the magazine in 1947, with its hands set at 11:53 p.m.

The clock's hands shifted quite a bit over the following seven decades. They were closest to midnight in 1953, set at 11:58 p.m., after both the United States and the Soviet Union conducted their first tests of the hydrogen bomb. The clock's hands were pushed all the way back to 11:43 p.m., 17 minutes to midnight, in December 1991, after the world's superpowers signed the Strategic Arms Reduction Treaty, which at the time, seemed like a promising move toward nuclear disarmament.

Follow Megan Gannon on Twitter. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Melting glaciers dump massive amounts of carbon into the world's oceans, a new study finds.

The organic carbon could be a temporary boon for tiny creatures at the bottom of the aquatic food chain that gobble the compound as food, but if this manna disappears because the glaciers have vanished, the overfed ocean ecosystems may collapse, the study authors warned.

"It could change the whole food web. We do not know how different ecological systems will react to a new influx of carbon," study co-author Robert Spencer, an assistant professor of oceanography at Florida State University, said in a statement.

Organic carbon is derived from plants or animals. The compound typically ends up in glaciers from microbes living in the ice, or from soot and other oil and gas byproducts. [Image Gallery: Greenland's Melting Glaciers]

Eran Hood, lead study author, and his colleagues estimated how much organic carbon is trapped in the world's glaciers and ice sheets, and how much will be released into the sea if melting continues its rapid pace. The supply of organic carbon in the world's waterways will increase by 50 percent in the next 35 years, according to the study, which was published Monday (Jan. 19) in the journal Nature Geoscience. That's about half the amount of organic carbon spilled into the sea each year by the Mississippi River, the researchers said.

"This research makes it clear that glaciers represent a substantial reservoir of organic carbon," said Hood, a scientist at the University of Alaska Southeast. "As a result, the loss of glacier mass worldwide, along with the corresponding release of carbon, will affect high-latitude marine ecosystems, particularly those surrounding the major ice sheets," he said. These high-latitude ecosystems are now receiving fairly limited inputs of organic carbon from land, Hood said in the statement.

Glaciers are shrinking nearly everywhere on Earth because of global warming, research studies have found. In West Antarctica, melt rates have tripled in the last decade, according to a study published in December 2014 in the journal Geophysical Research Letters. Ice loss in Greenland is five times faster now than in the early 1990s, scientists reported in November 2012 in the journal Science.

The researchers said they are planning follow-up studies to determine whether the predicted glacial carbon will be a menace or a mere nuisance to ocean ecosystems.

"We know we're losing glaciers, but what does that mean for marine life, fisheries, things downstream that we care about? There's a whole host of issues besides the water issue," Spencer said.

Follow Becky Oskin @beckyoskin. Follow LiveScience @livescience, Facebook & Google+. Originally published on Live Science.

The new year has only just begun, but we’ve already recorded our first days with average carbon dioxide levels above 400 parts per million, potentially leading to many months in a row above this threshold, experts say.

The Scripps Institution of Oceanography records of atmospheric carbon dioxide levels show that Jan. 1 was the first day of the new year above that concentration, followed by Jan. 3 and Jan. 7. Daily averages have continued at this level or higher through Jan. 9, though they could continue to dance up and down around that mark due to day-to-day variations caused by weather systems. But even with those fluctuations, 2015 will likely see many months above 400 ppm, possibly starting with the very first month of the year.

“My guess at this point is that January 2015 will be very slightly above 400 ppm, but it's too early to tell for sure,” Ralph Keeling, the scientist in charge of the CO2 monitoring project atop Hawaii’s Mauna Loa, said in an email. Keeling’s father, Charles, began the project in 1958. The graph that shows the decades-long rise in CO2 is eponymously called the Keeling Curve.

The 400 ppm mark was first passed on May 9, 2013. In 2014, it happened two months earlier, in March. The average CO2 concentrations for March, April and June 2014 were all above 400 ppm, the first time that has been recorded. The peak CO2 measurement of 2014 was just shy of 402 ppm in May.

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While the 400 ppm mark is somewhat symbolic (as the increase in warming between 399 ppm and 400 ppm is small), it is a large increase from pre-industrial CO2 concentrations, which were around 280 ppm. The progressively earlier occurrence of these high CO2 levels — not seen in somewhere between 800,000 and 15 million years — points to the inexorable buildup of heat-trapping gas in the atmosphere as human emissions continue unabated. That increase in CO2 and other greenhouse gases has raised Earth’s average temperature by 1.6°F since the beginning of the 20th century. Some scientists say that to avoid the worst consequences of climate change, that warming needs to stay under 2°C, or 3.6°F.

CO2 concentrations wax and wane with the seasonal plant cycle. Carbon dioxide levels begin to rise in late fall as the death of Northern Hemisphere vegetation releases it into the atmosphere, reaching a peak in May, after which the spring and summer plant growth causes it to decline once again. NASA’s new OCO-2 satellite mission has recently taken the most detailed snapshot of atmospheric CO2 to date, in the hopes of learning exactly where CO2 sources and sinks are, said mission scientist Christopher O'Dell, of Colorado State University.

The world’s plants can only pull so much CO2 out of the atmosphere in a given season, while human emissions keep rising. This is leaving an excess of about 2 ppm of CO2 in the atmosphere every year, meaning the 400 ppm mark will keep occurring earlier and earlier. In just a year or two, carbon dioxide levels will likely be about 400 ppm year-round.

“I am not surprised that we are seeing daily means greater than 400 already popping up regularly. Next year that should start happening in November,” Pieter Tans, a climate scientist with the National Oceanic and Atmospheric Administration, said in an email.

NOAA’s own CO2 record-keeping varies slightly from the Scripps numbers, coming it at nearly 400 ppm. The differences are due to different methods of dealing with the data, though those differences are quite small, Keeling said.

Tans initially expected February to be the first month of the year above 400 ppm, but predicting that threshold is tricky because CO2 concentrations depend both on emissions and natural ecosystem processes, which can be influenced by climate phenomena like the El Nino Southern Oscillation cycle, he said.

The 400 ppm mark, regardless of when it occurs, is a symptom of the larger story of humans altering Earth's climate.

"Because of the likely major negative ramifications of CO2-induced warming on the climate, it serves as an important reminder: if we want to bequeath a liveable climate to future generations, we need to act now and not delay," O'Dell said in an email.

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Originally published on Climate Central.

It’s official: 2014 has taken the title of hottest year on record. That ranking comes courtesy of data released Monday by the Japan Meteorological Agency (JMA), the first of four major global temperature recordkeepers to release their data for last year.

The upward march of the world’s average temperature since 1891 is a trademark of human-influenced global warmingwith 2014 being the latest stop on the climb. All 10 of the hottest years have come since 1998.

The average temperature was 1.1°F above the 20th century average according to JMA’s data. That edges 1998, the previous warmest year, by about 0.1°F.

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One big difference between 2014 and 1998 is that the latter was on the tail end of a super El Niño, which has the tendency to spike temperatures. In comparison, 2014 was the year of the almost El Niño.

Instead, record warmth in other parts of the Pacific as well as the hottest year on record in Europe were some of the main drivers in fueling the heat. Joe Romm of Climate Progress also notes that heat in Australia early in the year and California’s hottest year further contributed to the heat.

Seasonal temperatures also paint a picture of a planet that didn’t get a break. Spring, summer and fall were all record-setting hot. Last winter was the only season not to set a record, and even that was still the sixth-warmest winter.

JMA is one of the four major groups that use both ground measurements and satellites to compute the planet’s average temperature. The other three include NASA and the National Oceanic and Atmospheric Administration in the U.S. and the Hadley Center in the U.K. There are subtle differences in how they analyze temperature data, but there’s generally broad agreement, particularly the upward trend in temperatures over the past century.

The other groups are expected to release their data in the coming weeks and confirm that 2014 was indeed the hottest year on record. And some scientists think it could get even hotter sooner. Strong trade winds in the Pacific have likely had a dampening effect on the global average temperature by essentially allowing the ocean to store more heat, but those winds are expected to weaken in the near future as part of a natural fluctuation.

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Originally published on Climate Central.

Editor’s Note: This is one in a series of stories in which we look back at key issues and events of 2014 and why they will continue to make headlines in 2015.

Probing a blue abyss can be an abysmal recipe for the blues.

For every 10 joules of energy that our greenhouse gas pollution traps here on Earth, about 9 of them end up in an ocean. There, the effects of global warming bite into fisheries, ecosystems and ice. But those effects are largely imperceptible to humans — as invisible to a landlubber as an albatross chomping on a baited hook at the end of a long line.

What scientists discovered in 2014 is that since the turn of the century, oceans have been absorbing more of global warming’s heat and energy than would normally be expected, helping to slow rates of warming on land. What they will be talking about in 2015, and beyond, is when that trend might come to an end — likely following a routine shift in Pacific Ocean trade winds. Much of that extra sunken heat will eventually be belched back into the atmosphere by the overheating seas. The effects of ocean warming might be imperceptible to most of us, but they are far-reaching. They are driving fishing fleets further out to sea, ushering tropical fish into polar waters, and worsening flood hazards for coastal communities.

It can be difficult to probe the ocean, but it doesn’t help to look away. So scientists have been finding innovative new ways of peering beneath the swells, conscripting everything from seals to climate models to improve their grasp of marine temperature trends. Titanic international projects that are just kicking off, including the National Science Foundation-funded Ocean Observatories Initiative and Southern Ocean Carbon and Climate Observations and Modeling project, promise to pile on reams of new data and knowledge in the coming years — not all of it expected to be postcard pretty. Many of the discoveries from similar research during the past year were decidedly feverish.

During 2014, as rising ocean heat fueled planetary temperature records, and as it continued to eat away at Antarctic ice, scientists discovered that the oceans have been warming far more quickly than anybody had realized — and doing so for decades. Stark findings were published online in Nature Climate Change in October, relying on data from the global flotilla of thousands of Argo floats. These drone-like seafarers have been plumbing inhospitable depths since 2000, beaming back data on ocean temperatures and other variables.

Using float data, scientists recalibrated sparse historical measurements and estimates of ocean warming, concluding that the upper 2,700 feet of the world’s oceans had warmed by between a quarter and a half more than had previously been realized. The largest discrepancies with existing data were discovered in the Southern Hemisphere, where historical records are as sparse as the shipping traffic that traditionally provided so much of the planet’s ocean weather information. There, it appears that ocean warming has been occurring at twice the previously-understood rate.

“We continue to be stunned at how rapidly the ocean is warming,” Sarah Gille, a Scripps Institution of Oceanography professor, said when we spoke with her earlier this year. “Extra heat means extra sea level rise, since warmer water is less dense, so a warmer ocean expands.”

As seas continue to swell, flooding cities and infrastructure, they’re also going to continue to become more acidic.

The impacts of ocean acidification, which is caused when carbon dioxide dissolves into seas and reacts with water, is a topic that scientists and governments are only just starting to grasp in meaningful ways. With taskforces and research projects being launched across the globe, 2015 promises more answers not only on ocean warming, but on the shellfish-ravaging and fish-baffling effects of falling pH levels.

Best of Ocean Warming Coverage From 2014: Clues in Coral Hint at Looming Temperature Spike Climate Change Could Double Likelihood of Super El Ninos Driven by Ocean Heat, World Sets Mark for Hottest June Warm Water Invasion Is Fueling Striking Antarctic Ice Melt Oceans Getting Hotter Than Anybody Realized Pacific Northwest Warming May Have Natural Roots Short on Ocean Data, Scientists Turn to Seals for Help What Will Survive in Hot, Acidic Oceans?

Originally published on Climate Central.

A striking new video from NASA reveals how the greenhouse gas carbon dioxide spreads across Earth in a single year.

The mesmerizing video was produced by a supercomputer model that took more than two months to run. Called GEOS-5, the model recreates the atmosphere's chaotic interplay among wind, weather and geography.

To show how carbon dioxide gas travels around the world, NASA scientists fed decades of weather and carbon dioxide data into the detailed computer model in a simulation called "Nature Run." The simulation includes carbon dioxide from both natural sources, such as volcanoes, and human-related emissions, such as those created during the burning of fossil fuels.

The results focus on a period between May 2005 and June 2007. At the time, carbon dioxide concentrations in the atmosphere ranged from 375 to 395 parts per million. Earlier this year, CO2 levels hit more than 400 parts per million for three months in a row. (That number means there were 400 molecules of carbon dioxide in the air for every 1 million air molecules.) [Watch: Time-Lapse Video of CO2 in Earth's Atmosphere]

In the simulation, the planet's three biggest polluters — the United States, China and Europe — are clearly pumping out plumes of carbon dioxide pollution. But the model also highlights the influence of seasonal cycles and local patterns on the amount of carbon dioxide in the atmosphere.

Earth's carbon dioxide levels peak in the spring, and then drop in summer, when Northern Hemisphere plant growth absorbs gas from the atmosphere. Concentrations rise again during fall and winter, continuing the cycle. Plant growth in the Northern Hemisphere has a greater effect on CO2 levels than it does in the Southern Hemisphere because there is more land in the Northern Hemisphere.

In North America, the major emissions sources are in the Midwest and along the East Coast. Westerly winds in the Gulf Stream carry the greenhouse gas eastward over the Atlantic Ocean, the model shows.

In Asia, the Himalayas block and divert winds that swirl around the high mountains. East of the Himalayas, these winds pick up carbon dioxide emissions from the industrialized Asian countries and carry the gas toward the Pacific Ocean.

In the Southern Hemisphere, plumes of carbon dioxide and carbon monoxide rise from forest fires in South America and southern Africa.

"It's fascinating to see how local emission sources and weather systems produce gradients of [carbon dioxide] concentration on a very regional scale," Bill Putman, lead scientist on the project at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. "Simulations like this, combined with data from observations, will help improve our understanding of both human emissions of carbon dioxide and natural fluxes across the globe."

Follow Becky Oskin @beckyoskin. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

Towering rocks at the bottom of the ocean hold a surprising secret: Life.

These rocks, near natural methane seeps on the seafloor, are home to methane-munching microbes, new research finds. What's more, it appears these tiny rock-dwellers may chow down on enough methane to effect global levels of the gas, which can contribute to climate change.

"We've recognized for awhile that the deep ocean is a sink for methane, but primarily it has been thought that it was only in the sediment," said study researcher Jeffrey Marlow, a graduate student at Caltech. "The fact that it appears to be active in the rocks itself sort of redistributes where that methane is going." [Gallery: Amazing Images of Atlantic Methane Seeps]

Methane and microbes

About 15 years ago, Caltech geobiologist Victoria Orphan and her colleagues discovered that the mud on the seafloor near methane seeps is anything but dead dirt. Instead, it's full of microbes — bacteria and nucleus-free organisms called archaea — that eat the natural methane bubbling up from subsurface reservoirs. Between 6 and 22 percent of the world's methane (a greenhouse gas) is released through these seeps, or cracks in the ocean floor, said Marlow, who is one of Orphan's students. Microbes eat about 80 to 90 percent of that.

Dominating the landscape at these sites, however, are enormous rocks, hundreds of feet tall and hundreds of feet long. The rocks are carbonates, meaning they are made of minerals from the surrounding seawater. No one had ever studied these rocks to see if they, like the seafloor mud, hosted life, Marlow said. [See Photos of Weird Deep-Sea Life]   

The researchers launched two expeditions to the deep at a place called Hydrate Ridge 62 miles (100 kilometers) off the coast of Oregon. This undersea formation is dotted with methane vents. There, in the near-freezing waters 2,625 feet (800 meters) down, the scientists took samples of rock near active methane seeps as well as from spots without methane activity. One expedition used Alvin, a manned research submersible operated by the Woods Hole Oceanographic Institution (WHOI). The other used the remotely operated submersible Jason, also run by the WHOI. 

Rock-dwelling life

Jason and Alvin returned 24 rock samples, which the researchers studied alongside samples from other methane seep areas in the Eel River Basin off northwestern California and the Costa Rica margin off Costa Rica. Using microscopes, they saw that rocks adjacent to the methane seeps were full of clusters of microbes. DNA analysis revealed both bacteria and archaea in similar ratios as seen in the seafloor mud.

But what were these microbes doing? To find out, the researchers attached certain molecules to methane that they then exposed to the rock-dwelling microbes. These molecules acted as tracking devices, allowing the researchers to see where the methane and its components ended up.

The tracking studies revealed that the methane ended up in the bellies of the microbial beasties discovered inside the rocks — and then in the rocks themselves. It appears that the microbes process the methane and excrete byproducts that mineralize around them, forming the towering rocks in a process of "gradual self-entombment," the researchers report today (Oct. 14) in the journal Nature Communications.

"We think that the microbes are processing the methane into bicarbonate, and then that bicarbonate links up with calcium in the seawater to make calcium carbonate," Marlow explained.

Granted, entombing oneself in rock doesn't seem like the best bet for survival, Marlow said. But it's likely that the microbes still get their methane supply through pores or fissures in the rock. Researchers only sampled from the first few inches of rock, so they aren't sure how deep the microbial communities penetrate below the surface.

Like carbon dioxide, methane is a greenhouse gas, capable of trapping heat from the sun in the Earth's atmosphere. Though carbon dioxide is more abundant and thus contributes a greater proportion of global warming, methane is actually about 30 times as potent as CO2 at trapping heat. Marlow, Orphan and their colleagues aren't yet sure how much of the microbial methane-munching activity happens in rocks versus in seafloor mud, but the rock-dwellers "might be a very strong contributor," Marlow said.

What's more, the methane-eating microbes are likely the basis of an alien ecosystem on the seafloor, playing the same role that plants play on land.

"There are worms crawling in and around in the rocks, in the sediments, that are very likely eating these clumps of cells," Marlow said. "So they really are the primary producers in this entire system."

Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

A remote, coal-rich patch of the Southwest produces the highest methane concentrations in the United States, a new study reports.

The methane hotspot is centered over New Mexico's San Juan Basin, where some 40,000 wells suck out natural gas trapped in coal seams. (Natural gas is almost entirely methane.) The tiny patch covers 2,500 square miles (6,500 square kilometers) near the Four Corners intersection of Arizona, Colorado, New Mexico and Utah.

Between 2003 and 2009, the hotspot spewed 0.59 million metric tons (0.65 million tons) of methane each year, scientists report today (Oct. 9) in the journal Geophysical Research Letters. That's about 10 percent of all U.S. methane emissions each year.

The leaks likely come from natural gas drilling and production, the researchers said. The study predates the use of hydraulic fracturing, also known as fracking, in San Juan Basin, lead study author Eric Kort, of the University of Michigan, Ann Arbor, said in a statement. "There's been so much attention on high-volume hydraulic fracturing, but we need to consider the industry as a whole," Kort said.

Methane is one of the four greenhouse gases primarily responsible for global warming. The gas is more effective than carbon dioxide at trapping infrared radiation (the greenhouse effect). However, methane breaks down more quickly, disappearing after about a decade, compared with carbon dioxide's life span of hundreds to thousands of years. [8 Ways Global Warming Is Already Changing the World]

The Environmental Protection Agency (EPA) has come under fire this year from independent scientists and its own inspector general for failing to control methane leaks from natural gas production and distribution.

Recent studies have found that total methane emissions in the United States are nearly twice the amount estimated by the EPA and by the International Emissions Database for Global Atmospheric Research (EDGAR).

The Four Corners methane levels reported in the new study are 1.8 times higher than EPA's "bottom-up" estimates from surveying methane sources on the ground. The mismatch is even higher (3.5 times as much) for the widely used EDGAR database.

Kort and his co-authors measured methane levels in the atmosphere with the European Space Agency's Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) instrument. The measurements were checked against a ground instrument in the Four Corners region that is part of a worldwide greenhouse gas monitoring network.

"Satellite data cannot be as accurate as ground-based estimates, but from space, there are no hiding places," said study co-author Christian Frankenberg, of NASA's Jet Propulsion Laboratory in Pasadena, California.

The natural gas industry is one of the biggest methane emitters in the United States, according to a Feb. 13, 2014, study published in the journal Science. Leaks come from drilling, refining plants and transport and distribution, such as pipelines. While there are about 500,000 wells and some 2 million miles (3.2 million km) of pipeline in the United States, the authors of the earlier Science study said just a small number of "super-emitters" are responsible for most of the leaking methane.

Email Becky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Concentrations of carbon dioxide will surge to a new high in the atmosphere in 2014, scientists announced today in advance of the U.N. Climate Summit in New York City.

Global carbon dioxide emissions are projected to soar to 44 billion tons (40 billion metric tons) this year, a 2.5 percent increase from 2013 levels, according to joint studies published today (Sept. 21) in the journals Nature Climate Change and Nature Geoscience. The new estimates come from the Global Carbon Project, an international effort to track the global carbon cycle, from sky to sea.

This week, leaders of 125 countries will meet in New York for the U.N. Climate Summit, which is intended to jump-start a global pact to cut greenhouse gases and slow down climate change. [6 Unexpected Effects of Climate Change]

The study authors warn that the world has 30 years to reverse the ominous trend before global warming surpasses the 3.6 degrees Fahrenheit (2 degrees Celsius) target set at a 2009 climate summit in Copenhagen.

"Globally, emissions would need sustained and unprecedented reductions  of around 7 percent [each] year for a likely chance to stay within the quota," study co-author Glen Peters, of the Center for International Climate and Environmental Research in Oslo, Norway, said in a statement. "If carbon capture and storage technologies are not realized, it may not be possible to keep the temperature increase below 2 degrees Celsius."

About 75 percent of carbon dioxide emissions come from burning fossil fuels such as oil and gas, and from making cement, the study reports. In the atmosphere, carbon dioxide absorbs heat and raises temperatures on Earth. Because the gas lingers in the atmosphere for decades, even immediate and drastic cuts won't lower its levels for decades.

The biggest carbon dioxide offenders are China, India, the United States and the European Union. Data shows China's per capita emissions now outstrip Europe's for the first time. However, the United States still has the highest per capita consumption. Each person in the United States has a carbon footprint of 18 tons (16.4 metric tons) per year, more than twice that of a person in China and eight times that of someone in India.

"If this were a bank statement, it would say our credit is running out," Dave Reay, a climate scientist at the University of Edinburgh in Scotland who was not involved in the study, said in a statement. "[A]voiding dangerous climate change now requires some very difficult choices. Not least of these is how a shrinking global carbon allowance can be shared equitably between more than 7 billion people and where the differences between rich and poor are so immense."

Here are the emission counts for 2013:

India's emissions jumped by 5.1 percent, the biggest expansion of any country, thanks to that nation's rapid economic growth. But India's total emissions make up just 6.5 percent of the global total.

China's emissions increased by 4.2 percent, a somewhat smaller increase compared to previous years. China now accounts for 28 percent of global emissions, more than the United States and Europe combined.

The United States' emissions rose by 2.9 percent, due to a rebound in coal consumption. U.S. emissions had declined by 3.7 percent in 2012. The country's contribution last year made up 14 percent of global emissions.

The European Union's emissions fell by 1.8 percent, due to a weak economy in some member countries. Europe emitted 10 percent of global carbon dioxide.

Email Becky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Following a harrowing depletion in recent decades, Earth's protective ozone layer, high in the planet's atmosphere, is on the track to recovery, according to a new report released today (Sept. 10) at the United Nations headquarters in New York.

The evaluation, conducted by 282 scientists from 36 countries, credits much of this recovery to international action that phased out the production and use of ozone-depleting chemicals.

Since the last comprehensive ozone assessment in 2010, the use of most of these harmful substances has continued to drop, and the ozone may be on the path to recovery, according to the new report. [Earth in the Balance: 7 Crucial Tipping Points]

"There are telltale signs of ozone recovery in the upper part of the stratosphere," A.R. Ravishankara, a National Oceanic and Atmospheric Association (NOAA) emeritus scientist, professor at Colorado State University and co-chairman of the panel that prepared the report, said in a statement.

The ozone layer, located in Earth's stratosphere miles above the ground, shields the planet from much of the sun's damaging ultraviolet radiation. In the 1970s, researchers realized that gases such as chlorofluorocarbons (CFCs) and halons — which were commonly used in appliances such as refrigerators, spray cans, insulation foam and fire suppressants — led to the depletion of the ozone layer, NOAA researchers said. In 1985, the scientific community found a seasonal "ozone hole" over Antarctica, and spurred action to prevent its growth.

Starting in 1987, almost 200 countries joined together to ratify the Montreal Protocol, which is designed to phase out ozone-depleting substances, NOAA researchers said.

"There are positive indications that the ozone layer is on track to recovery towards the middle of the century," UN Under-Secretary-General and United Nations Environment Programme (UNEP) Executive Director Achim Steiner said in a statement. "The Montreal Protocol — one of the world's most successful environmental treaties — has protected the stratospheric ozone layer and avoided enhanced UV radiation reaching the Earth's surface."

If the Montreal Protocol had not passed, the use of ozone-depleting substances could have increased tenfold by 2050, UNEP officials said. Instead, by 2030, the protocol will have prevented an estimated 2 million cases of skin cancer annually, and will continue to protect wildlife and agriculture, according to the UNEP.

The new report also highlights the intricate links between the ozone layer's recovery and climate change, Ravishankara said. For instance, some chemicals that have replaced ozone-depleting substances are still potent greenhouse gases, which contribute to global warming.

To fight back, scientists from NOAA's Earth System Research Laboratory are testing potential substances that are safe for the ozone layer, climate and environment, experts said. 

If countries continue to abide by the Montreal Protocol, ozone levels across the globe are expected to recover to 1980 concentrations before the year 2050, but the hole over the South Pole likely won't heal until 2070, Ravishankara said.

Researchers affiliated with the UNEP and the World Meteorological Organization (WMO) plan to keep a close eye on ozone levels in the years to come, WMO Secretary-General Michel Jarraud said in a statement.

"Human activities will continue to change the composition of the atmosphere," Jarraud said. "WMO's Global Atmosphere Watch program will, therefore, continue its crucial monitoring, research and assessment activities to provide scientific data needed to understand and ultimately predict environmental changes, as it has done for the past 25 years."

Researchers will present the report, dubbed the Scientific Assessment of Ozone Depletion 2014, in November, at the annual meeting of the Parties to the Montreal Protocol in Paris. The full report, which is expected to inform policymakers, will be published in early 2015. 

Follow Laura Geggel on Twitter @LauraGeggel and Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Ants may be some of Earth's most powerful biological climate brokers, a provocative new study claims.

The average ant lives and dies in less than a year, but a long-term experiment tracking the insects' effects on soil suggests they cooled Earth's climate as their numbers grew.

"Ants are changing the environment," said lead study author Ronald Dorn, a geologist at Arizona State University in Tempe.

Dorn has discovered that certain ant species "weather" minerals in order to secrete calcium carbonate — better known as limestone. When ants make limestone, the process traps and removes a tiny bit of carbon dioxide gas from the atmosphere. [See Close-Up Photos of Amazing Ants of the World]

This ant limestone factory is a small-scale version of the massive planetary-cooling process that takes place in the oceans, known as carbon sequestration. Limestones deposited in the ocean hold more carbon than is present in the atmosphere today.

Dorn discovered that ants were powerful weathering agents by tracking the breakdown of basalt sand. At the start of his career, 25 years ago, Dorn buried sand at six sites in the Catalina Mountains in Arizona and Palo Duro Canyon in Texas. Every five years, Dorn has dug up a bit of sand from the sites and measured how much the minerals olivine and plagioclase have degraded from exposure to water, insect activity and chemicals from tree roots.

Dorn's experiment revealed that ants appear to break down the minerals 50 to 300 times faster than sand left undisturbed on bare ground. At the same time, the ants were gradually building up limestone within their nests. Dorn thinks the ants may be scavenging calcium and magnesium from the minerals and using these elements to make limestone. In the process, the insects may trap carbon dioxide, a greenhouse gas, in the rock. The transformation could take place when ants lick sand grains and stick them on the walls of their nests, but Dorn said the process is truly a scientific mystery.

"We don't know if they are licking it or pooping it, or if it's bacteria in the ant's gut or the fungi growing in the colonies," Dorn told Live Science.

The findings don't reveal how much atmospheric carbon might be missing thanks to ants, either. "We're very, very early in the game," Dorn said.

While he's only speculating at this point, Dorn said he thinks the sheer biological mass of ants working in concert could have removed significant quantities of carbon dioxide from the atmosphere since the insects expanded their numbers starting 65 million years ago. Eight ant species are known to secrete calcium carbonate in some form. Ant expert E.O. Wilson, a professor at Harvard University, once estimated the total biomass of ants on Earth is equal to that of humans.

David Schwartzman, a geochemist at Howard University in Washington, D.C., who was not involved with the study, said he finds the idea plausible. "Clearly, more studies on the role of ants and other animals populating soils are needed to broaden our understanding of their significance in global biotic enhancement of weathering," Schwartzman told Live Science.

The aim of study, published July 14 in the journal Geology, was to watch the minerals in basalt dissolve over time.

In general, weathering of minerals plays an important role in trapping and removing carbon from Earth's atmosphere, and Dorn was interested in directly measuring this effect.

"Ants were not the original focus," Dorn told Live Science. "I'm a weathering nerd. What better way to figure out weathering than to observe it in situ?"

Email Becky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook & Google+. Original article on Live Science.