Climate

Patricia Hidalgo-Gonzalez saw the future of energy on a broiling-hot day last September.

An email alert hit her inbox from the San Diego Gas & Electric Company. “Extreme heat straining the grid,” read the message, which was also pinged as a text to 27 million people. “Save energy to help avoid power interruptions.”

It worked. People cut their energy use. Demand plunged, blackouts were avoided and California successfully weathered a crisis exacerbated by climate change. “It was very exciting to see,” says Hidalgo-Gonzalez, an electrical engineer at the University of California, San Diego who studies renewable energy and the power grid.

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This kind of collective societal response, in which we reshape how we interact with the systems that provide us energy, will be crucial as we figure out how to live on a changing planet.

Earth has warmed at least 1.1 degrees Celsius since the 19th century, when the burning of coal, oil and other fossil fuels began belching heat-trapping gases such as carbon dioxide into the atmosphere. Scientists agree that only drastic action to cut emissions can keep the planet from blasting past 1.5 degrees of warming — a threshold beyond which the consequences become even more catastrophic than the rising sea levels, extreme weather and other impacts the world is already experiencing.

The goal is to achieve what’s known as net-zero emissions, where any greenhouse gases still entering the atmosphere are balanced by those being removed — and to do it as soon as we can.

Scientists say it is possible to swiftly transform the ways we produce and consume energy. To show the way forward, researchers have set out paths toward a world where human activities generate little to no carbon dioxide and other greenhouse gases — a decarbonized economy.

The key to a decarbonized future lies in producing vast amounts of new electricity from sources that emit little to none of the gases, such as wind, solar and hydropower, and then transforming as much of our lives and our industries as possible to run off those sources. Clean electricity needs to power not only the planet’s current energy use but also the increased demands of a growing global population.

Once humankind has switched nearly entirely to clean electricity, we will also have to counter­balance the carbon dioxide we still emit — yes, we will still emit some — by pulling an equivalent amount of carbon dioxide out of the atmosphere and storing it somewhere permanently.

Achieving net-zero emissions won’t be easy. Getting to effective and meaningful action on climate change requires overcoming decades of inertia and denial about the scope and magnitude of the problem. Nations are falling well short of existing pledges to reduce emissions, and global warming remains on track to charge past 1.5 degrees perhaps even by the end of this decade.

Yet there is hope. The rate of growth in CO2 emissions is slowing globally — down from 3 percent annual growth in the 2000s to half a percent annual growth in the last decade, according to the Global Carbon Project, which quantifies greenhouse gas emissions.

There are signs annual emissions could start shrinking. And over the last two years, the United States, by far the biggest cumulative contributor to global warming, has passed several pieces of federal legislation that include financial incentives to accelerate the transition to clean energy. “We’ve never seen anything at this scale,” says Erin Mayfield, an energy researcher at Dartmouth College.

Though the energy transition will require many new technologies, such as innovative ways to permanently remove carbon from the atmosphere, many of the solutions, such as wind and solar power, are in hand — “stuff we already have,” Mayfield says.

The current state of carbon dioxide emissions

Of all the emissions that need to be slashed, the most important is carbon dioxide, which comes from many sources such as cars and trucks and coal-burning power plants. The gas accounted for 79 percent of U.S. greenhouse gas emissions in 2020. The next most significant greenhouse gas, at 11 percent of emissions in the United States, is methane, which comes from oil and gas operations as well as livestock, landfills and other land uses.

The amount of methane may seem small, but it is mighty — over the short term, methane is more than 80 times as efficient at trapping heat as carbon dioxide is, and methane’s atmospheric levels have nearly tripled in the last two centuries. Other greenhouse gases include nitrous oxides, which come from sources such as applying fertilizer to crops or burning fuels and account for 7 percent of U.S. emissions, and human-made fluorinated gases such as hydrofluorocarbons that account for 3 percent.

Globally, emissions are dominated by large nations that produce lots of energy. The United States alone emits around 5 billion metric tons of carbon dioxide each year. It is responsible for most of the greenhouse gas emissions throughout history and ceded the spot for top annual emitter to China only in the mid-2000s. India ranks third.

Because of the United States’ role in producing most of the carbon pollution to date, many researchers and advocates argue that it has the moral responsibility to take the global lead on cutting emissions. And the United States has the most ambitious goals of the major emitters, at least on paper. President Joe Biden has said the country is aiming to reach net-zero emissions by 2050. Leaders in China and India have set net-zero goals of 2060 and 2070, respectively.

Under the auspices of a 2015 international climate change treaty known as the Paris agreement, 193 nations plus the European Union have pledged to reduce their emissions. The agreement aims to keep global warming well below 2 degrees, and ideally to 1.5 degrees, above preindustrial levels. But it is insufficient. Even if all countries cut their emissions as much as they have promised under the Paris agreement, the world would likely blow past 2 degrees of warming before the end of this century. 

Every nation continues to find its own path forward. “At the end of the day, all the solutions are going to be country-specific,” says Sha Yu, an earth scientist at the Pacific Northwest National Laboratory and University of Maryland’s Joint Global Change Research Institute in College Park, Md. “There’s not a universal fix.”

But there are some common themes for how to accomplish this energy transition — ways to focus our efforts on the things that will matter most. These are efforts that go beyond individual consumer choices such as whether to fly less or eat less meat. They instead penetrate every aspect of how society produces and consumes energy.

Such massive changes will need to overcome a lot of resistance, including from companies that make money off old forms of energy as well as politicians and lobbyists. But if society can make these changes, it will rank as one of humanity’s greatest accomplishments. We will have tackled a problem of our own making and conquered it.

Here’s a look at what we’ll need to do.

Make as much clean electricity as possible

To meet the need for energy without putting carbon dioxide into the atmosphere, countries would need to dramatically scale up the amount of clean energy they produce. Fortunately, most of that energy would be generated by technologies we already have — renewable sources of energy including wind and solar power.

“Renewables, far and wide, are the key pillar in any net-zero scenario,” says Mayfield, who worked on an influential 2021 report from Princeton University’s Net-Zero America project, which focused on the U.S. economy.

The Princeton report envisions wind and solar power production roughly quadrupling by 2030 to get the United States to net-zero emissions by 2050. That would mean building many new solar and wind farms, so many that in the most ambitious scenario, wind turbines would cover an area the size of Arkansas, Iowa, Kansas, Missouri, Nebraska and Oklahoma combined.

Such a scale-up is only possible because prices to produce renewable energy have plunged. The cost of wind power has dropped nearly 70 percent, and solar power nearly 90 percent, over the last decade in the United States. “That was a game changer that I don’t know if some people were expecting,” Hidalgo-Gonzalez says.

Globally the price drop in renewables has allowed growth to surge; China, for instance, installed a record 55 gigawatts of solar power capacity in 2021, for a total of 306 gigawatts or nearly 13 percent of the nation’s installed capacity to generate electricity. China is almost certain to have had another record year for solar power installations in 2022.

Challenges include figuring out ways to store and transmit all that extra electricity, and finding locations to build wind and solar power installations that are acceptable to local communities. Other types of low-carbon power, such as hydropower and nuclear power, which comes with its own public resistance, will also likely play a role going forward.

Get efficient and go electric

The drive toward net-zero emissions also requires boosting energy efficiency across industries and electrifying as many aspects of modern life as possible, such as transportation and home heating.

Some industries are already shifting to more efficient methods of production, such as steelmaking in China that incorporates hydrogen-based furnaces that are much cleaner than coal-fired ones, Yu says. In India, simply closing down the most inefficient coal-burning power plants provides the most bang for the buck, says Shayak Sengupta, an energy and policy expert at the Observer Research Foundation America think tank in Washington, D.C. “The list has been made up,” he says, of the plants that should close first, “and that’s been happening.”

To achieve net-zero, the United States would need to increase its share of electric heat pumps, which heat houses much more cleanly than gas- or oil-fired appliances, from around 10 percent in 2020 to as much as 80 percent by 2050, according to the Princeton report. Federal subsidies for these sorts of appliances are rolling out in 2023 as part of the new Inflation Reduction Act, legislation that contains a number of climate-related provisions.

Shifting cars and other vehicles away from burning gasoline to running off of electricity would also lead to significant emissions cuts. In a major 2021 report, the National Academies of Sciences, Engineering and Medicine said that one of the most important moves in decarbonizing the U.S. economy would be having electric vehicles account for half of all new vehicle sales by 2030. That’s not impossible; electric car sales accounted for nearly 6 percent of new sales in the United States in 2022, which is still a low number but nearly double the previous year.

Make clean fuels

Some industries such as manufacturing and transportation can’t be fully electrified using current technologies — battery powered airplanes, for instance, will probably never be feasible for long-duration flights. Technologies that still require liquid fuels will need to switch from gas, oil and other fossil fuels to low-carbon or zero-carbon fuels.

One major player will be fuels extracted from plants and other biomass, which take up carbon dioxide as they grow and emit it when they die, making them essentially carbon neutral over their lifetime. To create biofuels, farmers grow crops, and others process the harvest in conversion facilities into fuels such as hydrogen. Hydrogen, in turn, can be substituted for more carbon-intensive substances in various industrial processes such as making plastics and fertilizers — and maybe even as fuel for airplanes someday.

In one of the Princeton team’s scenarios, the U.S. Midwest and Southeast would become peppered with biomass conversion plants by 2050, so that fuels can be processed close to where crops are grown. Many of the biomass feedstocks could potentially grow alongside food crops or replace other, nonfood crops.

Cut methane and other non-CO2 emissions

Greenhouse gas emissions other than carbon dioxide will also need to be slashed. In the United States, the majority of methane emissions come from livestock, landfills and other agricultural sources, as well as scattered sources such as forest fires and wetlands. But about one-third of U.S. methane emissions come from oil, gas and coal operations. These may be some of the first places that regulators can target for cleanup, especially “super emitters” that can be pinpointed using satellites and other types of remote sensing.

In 2021, the United States and the European Union unveiled what became a global methane pledge endorsed by 150 countries to reduce emissions. There is, however, no enforcement of it yet. And China, the world’s largest methane emitter, has not signed on.

Nitrous oxides could be reduced by improving soil management techniques, and fluorinated gases by finding alternatives and improving production and recycling efforts.

Sop up as much CO2 as possible

Once emissions have been cut as much as possible, reaching net-zero will mean removing and storing an equivalent amount of carbon to what society still emits.

One solution already in use is to capture carbon dioxide produced at power plants and other industrial facilities and store it permanently somewhere, such as deep underground. Globally there are around 35 such operations, which collectively draw down around 45 million tons of carbon dioxide annually. About 200 new plants are on the drawing board to be operating by the end of this decade, according to the International Energy Agency.

The Princeton report envisions carbon capture being added to almost every kind of U.S. industrial plant, from cement production to biomass conversion. Much of the carbon dioxide would be liquefied and piped along more than 100,000 kilometers of new pipelines to deep geologic storage, primarily along the Texas Gulf Coast, where underground reservoirs can be used to trap it permanently. This would be a massive infrastructure effort. Building this pipeline network could cost up to $230 billion, including $13 billion for early buy-in from local communities and permitting alone.

Another way to sop up carbon is to get forests and soils to take up more. That could be accomplished by converting crops that are relatively carbon-intensive, such as corn to be used in ethanol, to energy-rich grasses that can be used for more efficient biofuels, or by turning some cropland or pastures back into forest. It’s even possible to sprinkle crushed rock onto croplands, which accelerates natural weathering processes that suck carbon dioxide out of the atmosphere.

Another way to increase the amount of carbon stored in the land is to reduce the amount of the Amazon rainforest that is cut down each year. “For a few countries like Brazil, preventing deforestation will be the first thing you can do,” Yu says.

When it comes to climate change, there’s no time to waste

The Princeton team estimates that the United States would need to invest at least an additional $2.5 trillion over the next 10 years for the country to have a shot at achieving net-zero emissions by 2050. Congress has begun ramping up funding with two large pieces of federal legislation it passed in 2021 and 2022. Those steer more than $1 trillion toward modernizing major parts of the nation’s economy over a decade — including investing in the energy transition to help fight climate change.

Between now and 2030, solar and wind power, plus increasing energy efficiency, can deliver about half of the emissions reductions needed for this decade, the International Energy Agency estimates. After that, the primary drivers would need to be increasing electrification, carbon capture and storage, and clean fuels such as hydrogen.

A lot of the technology needed for a future with fewer carbon dioxide emissions is already available. The Ivanpah Solar Electric Generating System in the Mojave Desert focuses sunlight to generate steam. That steam spins turbines to make electricity.ADAMKAZ/E+/GETTY IMAGES

The trick is to do all of this without making people’s lives worse. Developing nations need to be able to supply energy for their economies to develop. Communities whose jobs relied on fossil fuels need to have new economic opportunities.

Julia Haggerty, a geographer at Montana State University in Bozeman who studies communities that are dependent on natural resources, says that those who have money and other resources to support the transition will weather the change better than those who are under-resourced now. “At the landscape of states and regions, it just remains incredibly uneven,” she says.

The ongoing energy transition also faces unanticipated shocks such as Russia’s invasion of Ukraine, which sent energy prices soaring in Europe, and the COVID-19 pandemic, which initially slashed global emissions but later saw them rebound.

But the technologies exist for us to wean our lives off fossil fuels. And we have the inventiveness to develop more as needed. Transforming how we produce and use energy, as rapidly as possible, is a tremendous challenge — but one that we can meet head-on. For Mayfield, getting to net-zero by 2050 is a realistic goal for the United States. “I think it’s possible,” she says. “But it doesn’t mean there’s not a lot more work to be done.” More

CHICAGO – In January 2022, a cyclone blitzed a large expanse of ice-covered ocean between Greenland and Russia. Frenzied gusts galvanized 8-meter-tall waves that pounded the region’s hapless flotillas of sea ice, while a bombardment of warm rain and a surge of southerly heat laid siege from the air.

Six days after the assault began, about a quarter, or roughly 400,000 square kilometers, of the vast area’s sea ice had disappeared, leading to a record weekly loss for the region.

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The storm is the strongest Arctic cyclone ever documented. But it may not hold that title for long. Cyclones in the Arctic have become more frequent and intense in recent decades, posing risks to both sea ice and people, researchers reported December 13 at the American Geophysical Union’s fall meeting. “This trend is expected to persist as the region continues to warm rapidly in the future,” says climate scientist Stephen Vavrus of the University of Wisconsin–Madison.

Rapid Arctic warming and more destructive storms

The Arctic Circle is warming about four times as fast as the rest of Earth (SN: 8/11/22). A major driver is the loss of sea ice due to human-caused climate change. The floating ice reflects far more solar radiation back into space than naked seas do, influencing the global climate (SN: 10/14/21). During August, the heart of the sea ice melting season, cyclones have been observed to amplify sea ice losses on average, exacerbating warming.

There’s more: Like hurricanes can ravage regions farther south, boreal vortices can threaten people living and traveling in the Arctic (SN: 12/11/19). As the storms intensify, “stronger winds pose a risk for marine navigation by generating higher waves,” Vavrus says, “and for coastal erosion, which has already become a serious problem throughout much of the Arctic and forced some communities to consider relocating inland.”

Climate change is intensifying storms farther south (SN: 11/11/20). But it’s unclear how Arctic cyclones might be changing as the world warms. Some previous research suggested that pressures, on average, in Arctic cyclones’ cores have dropped in recent decades. That would be problematic, as lower pressures generally mean more intense storms, with “stronger winds, larger temperature variations and heavier rainfall [and] snowfall,” says atmospheric scientist Xiangdong Zhang of the University of Alaska Fairbanks.

But inconsistencies between analyses had prevented a clear trend from emerging, Zhang said at the meeting. So he and his colleagues aggregated a comprehensive record, spanning 1950 to 2021, of Arctic cyclone timing, intensity and duration.

Arctic cyclone activity has intensified in strength and frequency over recent decades, Zhang reported. Pressures in the hearts of today’s boreal vortices are on average about 9 millibars lower than in the 1950s. For context, such a pressure shift would be roughly equivalent to bumping a strong category 1 hurricane well into category 2 territory. And vortices became more frequent during winters in the North Atlantic Arctic and during summers in the Arctic north of Eurasia.

What’s more, August cyclones appear to be damaging sea ice more than in the past, said meteorologist Peter Finocchio of the U.S. Naval Research Laboratory in Monterey, Calif. He and his colleagues compared the response of northern sea ice to summer cyclones during the 1990s and the 2010s.

August vortices in the latter decade were followed by a 10 percent loss of sea ice area on average, up from the earlier decade’s 3 percent loss on average. This may be due, in part, to warmer water upwelling from below, which can melt the ice pack’s underbelly, and from winds pushing the thinner, easier-to-move ice around, Finocchio said.

Stronger spring storms spell trouble too

With climate change, cyclones may continue intensifying in the spring too, climate scientist Chelsea Parker said at the meeting. That’s a problem because spring vortices can prime sea ice for later summer melting.

Parker, of NASA’s Goddard Space Flight Center in Greenbelt, Md., and her colleagues ran computer simulations of spring cyclone behavior in the Arctic under past, present and projected climate conditions. By the end of the century, the maximum near-surface wind speeds of spring cyclones — around 11 kilometers per hour today — could reach 60 km/h, the researchers found. And future spring cyclones may keep swirling at peak intensity for up to a quarter of their life spans, up from around 1 percent today. The storms will probably travel farther too, the team says.

“The diminishing sea ice cover will enable the warmer Arctic seas to fuel these storms and probably allow them to penetrate farther into the Arctic,” says Vavrus, who was not involved in the research.

Parker and her team plan to investigate the future evolution of Arctic cyclones in other seasons, to capture a broader picture of how climate change is affecting the storms.

For now, it seems certain that Arctic cyclones aren’t going anywhere. What’s less clear is how humankind will contend with the storms’ growing fury. More

It was another shattering year.

Climate change amped up weather extremes around the globe, smashing temperature records, sinking river levels to historic lows and raising rainfall to devastating highs. Droughts set the stage for wildfires and worsened food insecurity. Researchers found themselves pondering the limits of humans’ ability to tolerate extreme heat (SN: 7/27/22).

The extreme events from 2022 pinpointed on the map below are just a sample of this year’s climate disasters. Each was exacerbated by human-caused climate change or is in line with projections of regional impacts.

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In its Sixth Assessment Report, released in 2021 and 2022, the United Nations’ Intergovernmental Panel on Climate Change, or IPCC, warned that humans are dramatically overhauling Earth’s climate (SN: 8/9/21). Earth’s average surface temperature has already risen by at least 1.1 degree Celsius since preindustrial times, thanks to human inputs of heat-trapping gases to the atmosphere, particularly carbon dioxide and methane (SN: 3/10/22). That warming has shifted the flow of energy around the planet, altering weather patterns, raising sea levels and turning past extremes into new normals (SN: 2/1/22).

And the world will have to weather more such climate extremes as carbon keeps accumulating in the atmosphere and global temperatures continue to rise. But IPCC scientists and others hope that, by highlighting the regional and local effects of climate change, the world will ramp up its efforts to reduce climate-warming emissions — averting a more disastrous future. More

The world needed bold climate action this year, and we got it.

California and other states announced plans to phase out gas-powered cars after 2035. The United States ratified an international treaty to slash production of the climate-warming hydrofluorocarbons used in cooling and refrigeration. The European Union is finalizing its plan to cut greenhouse gas emissions by 55 percent relative to 1990s levels by 2030. The list of legislative victories goes on.

But the biggest win came August 16, when President Joe Biden signed into law the Inflation Reduction Act.

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The historic legislation marks the first major move by the United States, which has emitted more carbon dioxide than any other country, toward neutralizing greenhouse gas emissions. It gets the ball rolling by investing $369 billion into accelerating the adoption of wind, solar and other renewable energy sources and decarbonizing the economy. By the end of the decade, the act will help cut U.S. greenhouse gas emissions by around 40 percent of the levels in 2005, when U.S. emissions nearly peaked, scientists project, bringing the nation within reach of fulfilling its pledge to halve emissions by 2030.

The legislation is no panacea for the climate emergency, but researchers and activists are optimistic that it will be the helping hand that clean energy needs to flourish. “There would be no way to really mitigate the climate crisis without the investments in this bill,” says Raul Garcia, a legislative director at Earthjustice, a nonprofit environmental law organization.

Here’s a look at some of the law’s major provisions and a few of its limitations.

Cheaper clean energy

The law aims to ease and incentivize the transition away from fossil fuels by creating tax credits that reduce the cost for companies to adopt clean energy. For instance, small businesses can qualify for credits that support up to 30 percent of the cost of transitioning to solar power.

The act also aims to help consumers, with $9 billion for rebates that help people ditch gas and buy appliances powered by electricity, such as electric induction cooktops and heat pump water heaters. Households can also get up to $7,500 in tax credits for electric vehicle purchases.

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“It’s huge,” Denise Mauzerall, an atmospheric scientist at Princeton University, says of the law’s potential to advance clean energy. But if the United States is to take full advantage of the increased clean energy capacity, it will be crucial to also construct sufficient infrastructure to deliver that energy, she notes. The bill offers only some support to build overhead power lines and other ways to transmit energy. “Without transmission,” she says, “we will really slow ourselves down.”

Clean energy jobs and goods

A major goal is to build up a clean energy economy by promoting high-quality jobs in industries such as solar and wind. To maximize tax credits, companies must pay workers a “prevailing wage” and employ apprentices to work a minimum number of hours on clean energy projects.

The legislation also invests in the domestic manufacturing of clean energy goods. Tax credits of up to 30 percent are available to companies that build or recycle wind turbine blades, solar panels, energy storage equipment and other clean energy products, and funds grants to retool factories to make electric vehicles.

Through tax credits, the Inflation Reduction Act promotes high-quality jobs in the wind and energy industries, like workers at solar power stations.Sinology/Moment/Getty Images

Reducing pollution

Methane — a greenhouse gas that can trap more than 25 times as much heat as CO2 — is another target. The legislation devotes $850 million to the monitoring and mitigation of methane emissions from fossil fuel operations. It also establishes a fine for operations that annually release amounts of methane that exceed 25,000 metric tons of CO2 equivalent.

And CO2 is legally defined as an “air pollutant,” cementing the Environmental Protection Agency’s authority to regulate its production under the Clean Air Act.

But there’s more to the climate problem than decarbonizing today’s pollutive energy industry, Mauzerall says. “Going forward, we need to pay more attention to reducing emissions from the agricultural sector,” she says. About 11 percent of U.S. greenhouse gas emissions and about a third of global emissions come from agriculture (SN: 5/7/22 & 5/21/22, p. 22).

Climate justice

Billions of dollars are slated to go toward climate justice, a movement that confronts the disproportionate impacts of climate change on marginalized communities. Funding includes $2.8 billion in grants for community-based projects, such as those that increase energy efficiency in affordable housing developments or monitor air quality in marginalized communities.

“But there are some troubling provisions,” Garcia says. The law authorizes new offshore oil and gas leases and provides fossil fuel companies with carbon capture and sequestration tax credits. These could prolong the life of pollutive oil and gas operations, which are often located near marginalized communities.

It will be crucial to follow these investments with laws that enforce both climate justice and the clean energy transition, Garcia says. “We need rules and regulations that hold industries’ feet to the fire, to make sure that those investments are going where they need to.” More

Sea level rise may proceed faster than expected in the coming decades, as a gargantuan flow of ice slithering out of Greenland’s remote interior both picks up speed and shrinks.

By the end of the century, the ice stream’s deterioration could contribute to nearly 16 millimeters of global sea level rise — more than six times the amount scientists had previously estimated, researchers report November 9 in Nature.

The finding suggests that inland portions of large ice flows elsewhere could also be withering and accelerating due to human-caused climate change, and that past research has probably underestimated the rates at which the ice will contribute to sea level rise (SN: 3/10/22).

“It’s not something that we expected,” says Shfaqat Abbas Khan, a glaciologist at the Technical University of Denmark in Kongens Lyngby. “Greenland and Antarctica’s contributions to sea level rise in the next 80 years will be significantly larger than we have predicted until now.”

In the new study, Khan and colleagues focused on the Northeast Greenland Ice Stream, a titanic conveyor belt of solid ice that crawls about 600 kilometers out of the landmass’s hinterland and into the sea. It drains about 12 percent of the country’s entire ice sheet and contains enough water to raise global sea level more than a meter. Near the coast, the ice stream splits into two glaciers, Nioghalvfjerdsfjord and Zachariae Isstrøm.

While frozen, these glaciers keep the ice behind them from rushing into the sea, much like dams hold back water in a river (SN: 6/17/21). When the ice shelf of Zachariae Isstrøm collapsed about a decade ago, scientists found that the flow of ice behind the glacier started accelerating. But whether those changes penetrated deep into Greenland’s interior remained largely unresolved.

“We’ve mostly concerned ourselves with the margins,” says atmosphere-cryosphere scientist Jenny Turton of the nonprofit Arctic Frontiers in Tromsø, Norway, who was not involved in the new study. That’s where the most dramatic changes with the greatest impacts on sea level rise have been observed, she says (SN: 4/30/22, SN: 5/16/13).

Keen to measure small rates of movement in the ice stream far inland, Khan and his colleagues used GPS, which in the past has exposed the tortuous creeping of tectonic plates (SN: 1/13/21). The team analyzed GPS data from three stations along the ice stream’s main trunk, all located between 90 and 190 kilometers inland.

The data showed that the ice stream had accelerated at all three points from 2016 to 2019. In that time frame, the ice speed at the station farthest inland increased from about 344 meters per year to surpassing 351 meters per year.

The researchers then compared the GPS measurements with data collected by polar-orbiting satellites and aircraft surveys. The aerial data agreed with the GPS analysis, revealing that the ice stream was accelerating as far as 200 kilometers upstream. What’s more, shrinking — or thinning — of the ice stream that started in 2011 at Zachariae Isstrøm had propagated more than 250 kilometers upstream by 2021. 

“This is showing that glaciers are responding along their length faster than we had thought previously,” says Leigh Stearns, a glaciologist from the University of Kansas in Lawrence, who was not involved in the study.

Khan and his colleagues then used the data to tune computer simulations that forecast the ice stream’s impact on sea level rise. The researchers predict that by 2100, the ice stream will have singlehandedly contributed between about 14 to 16 millimeters of global sea level rise — as much as Greenland’s entire ice sheet has in the last 50 years.

The findings suggest that past research has probably underestimated rates of sea level rise due to the ice stream, Stearns and Turton say. Similarly, upstream thinning and acceleration in other large ice flows, such as those associated with Antarctica’s shrinking Pine Island and Thwaites glaciers, might also cause sea levels to rise faster than expected, Turton says (SN: 6/9/22, SN: 12/13/21).

Khan and his colleagues plan to investigate inland sections of other large ice flows in Greenland and Antarctica, with the hopes of improving forecasts of sea level rise (SN: 1/7/20).

Such forecasts are crucial for adapting to climate change, Stearns says. “They’re helping us better understand the processes so that we can inform the people who need to know that information.” More

Wind turbines could offer a double whammy in the fight against climate change.

Besides harnessing wind to generate clean energy, turbines may help to funnel carbon dioxide to systems that pull the greenhouse gas out of the air (SN: 8/10/21). Researchers say their simulations show that wind turbines can drag dirty air from above a city or a smokestack into the turbines’ wakes. That boosts the amount of CO2 that makes it to machines that can remove it from the atmosphere. The researchers plan to describe their simulations and a wind tunnel test of a scaled-down system at a meeting of the American Physical Society’s Division of Fluid Dynamics in Indianapolis on November 21.

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Addressing climate change will require dramatic reductions in the amount of carbon dioxide that humans put into the air — but that alone won’t be enough (SN: 3/10/22). One part of the solution could be direct air capture systems that remove some CO2 from the atmosphere (SN: 9/9/22).

But the large amounts of CO2 produced by factories, power plants and cities are often concentrated at heights that put it out of reach of machinery on the ground that can remove it. “We’re looking into the fluid dynamics benefits of utilizing the wake of the wind turbine to redirect higher concentrations” down to carbon capture systems, says mechanical engineer Clarice Nelson of Purdue University in West Lafayette, Ind.

As large, power-generating wind turbines rotate, they cause turbulence that pulls air down into the wakes behind them, says mechanical engineer Luciano Castillo, also of Purdue. It’s an effect that can concentrate carbon dioxide enough to make capture feasible, particularly near large cities like Chicago.

“The beauty is that [around Chicago], you have one of the best wind resources in the region, so you can use the wind turbine to take some of the dirty air in the city and capture it,” Castillo says. Wind turbines don’t require the cooling that nuclear and fossil fuel plants need. “So not only are you producing clean energy,” he says, “you are not using water.”

Running the capture systems from energy produced by the wind turbines can also address the financial burden that often goes along with removing CO2 from the air. “Even with tax credits and potentially selling the CO2, there’s a huge gap between the value that you can get from capturing it and the actual cost” that comes with powering capture with energy that comes from other sources, Nelson says. “Our method would be a no-cost added benefit” to wind turbine farms.

There are probably lots of factors that will impact CO2 transport by real-world turbines, including the interactions the turbine wakes have with water, plants and the ground, says Nicholas Hamilton, a mechanical engineer at the National Renewable Energy Laboratory in Golden, Colo., who was not involved with the new studies. “I’m interested to see how this group scaled their experiment for wind tunnel investigation.” More

Some picturesque blue lakes may not be so blue in the future, thanks to climate change.

In the first global tally of lake color, researchers estimate that roughly one-third of Earth’s lakes are blue. But, should average summer air temperatures rise by a few degrees, some of those crystal waters could turn a murky green or brown, the team reports in the Sept. 28 Geophysical Research Letters.

The changing hues could alter how people use those waters and offer clues about the stability of lake ecosystems. Lake color depends in part on what’s in the water, but factors such as water depth and surrounding land use also matter. Compared with blue lakes, green or brown lakes have more algae, sediment and organic matter, says Xiao Yang, a hydrologist at Southern Methodist University in Dallas.

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Yang and colleagues used satellite photos from 2013 to 2020 to analyze the color of more than 85,000 lakes around the world. Because storms and seasons can temporarily affect a lake’s color, the researchers focused on the most frequent color observed for each lake over the seven-year period. The researchers also created an interactive online map that can be used to explore the colors of these lakes.

The approach is “super cool,” says Dina Leech, an aquatic ecologist at Longwood University in Farmville, Va., who was not involved with the study. These satellite data are “just so powerful.”

The scientists then looked at local climates during that time to see how they may be linked to lake color around the world. For many small or remote water bodies, records of temperature and precipitation don’t exist. Instead, the researchers also relied on climate “hindcasts” calculated for every spot on the globe, which are pieced together from relatively sparse records. 

Lakes in places with average summer air temperatures that were below 19° Celsius were more likely to be blue than lakes with warmer summers, the researchers found. But up to 14 percent of the blue lakes they studied are near that threshold. If average summer temperatures increase another 3 degrees Celsius — an amount that scientists think is plausible by the end of the century — those 3,800 lakes could turn green or brown (SN: 8/9/21). That’s because warmer water helps algae bloom more, which changes the properties of the water, giving it a green-brown tint, Yang says.

Extrapolating beyond this sample of lakes is a bit tricky. “We don’t even know how many lakes there are in the world,” says study coauthor Catherine O’Reilly, an aquatic ecologist at Illinois State University in Normal. Many lakes are too small to reliably detect via satellite, but by some estimates, tens of thousands of larger lakes could lose their blue hue.

If some lakes do become less blue, people will probably lose some of the resources they have come to value, O’Reilly says. Lakes are often used for drinking water, food or recreation. If the water is more clogged with algae, it could be unappealing for play or more costly to clean for drinking.

But the color changes wouldn’t necessarily mean that the lakes are any less healthy. “[Humans] don’t value lots of algae in a lake, but if you’re a certain type of fish species, you might be like ‘this is great,’” O’Reilly says.

Lake color can hint at the stability of a lake’s ecosystem, with shifting shades indicating changing conditions for the critters living in the water. One benefit of the new study is that it gives scientists a baseline for assessing how climate change is affecting Earth’s freshwater resources. Continued monitoring of lakes could help scientists detect future changes.

“[The study] sets a marker that we can compare future results to,” says Mike Pace, an aquatic ecologist at the University of Virginia in Charlottesville, who was not involved with the study. “That’s, to me, the great power of this study.” More