Tag: global-warming

Laser satellites expose a secret Antarctic carbon burst

Source:Chinese Academy of Sciences Headquarters

Summary:A new study shows that the Southern Ocean releases far more carbon dioxide in winter than once thought. By combining laser satellite data with AI analysis, scientists managed to “see” through the polar darkness for the first time. The results reveal a 40% undercount in winter emissions, changing how researchers view the ocean’s carbon balance and its impact on climate models.Share:

    

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Satellites Expose Secret Antarctic Carbon Burst
Researchers have found that the Southern Ocean emits about 40% more carbon dioxide during the Antarctic winter than previous estimates suggested. Using laser-based satellite technology, they uncovered a hidden seasonal flux that redefines the ocean’s role in the global carbon cycle. Credit: Shutterstock

A team of scientists has found that the Southern Ocean emits far more carbon dioxide (CO2) during the lightless Antarctic winter than researchers once believed. According to their new study, this wintertime release of CO2 has been underestimated by as much as 40%.

The research was led by scientists from the Second Institute of Oceanography, Ministry of Natural Resources (SIO-MNR), and the Nanjing Institute of Geography and Limnology (NIGLAS) of the Chinese Academy of Sciences. Their results were published in Science Advances on Nov. 5.

The Ocean’s Role in Earth’s Carbon Balance

The Southern Ocean is a major regulator of the global carbon cycle, absorbing a large share of the carbon released by human activity. Yet despite its importance, it remains the “largest source of uncertainty” in global CO2 flux calculations.

That uncertainty comes from a lack of winter observations. For months each year, the Southern Ocean lies in complete darkness and is lashed by extreme weather, making direct measurement nearly impossible. During this time, the region becomes an “observational black box.” Traditional satellites, which depend on reflected sunlight (passive sensors) to detect ocean properties, cannot collect data under these conditions, leaving scientists reliant on incomplete or estimated models.

Using Lasers to See in the Dark

To overcome this limitation, the researchers used an advanced approach that combined 14 years of data from a laser-based satellite instrument called LIDAR (on the CALIPSO mission) with machine learning analysis.

LIDAR, unlike passive sensors, sends out its own light signals, working similarly to radar but with lasers instead of radio waves. This technology allowed the team to observe the ocean even during the polar night and create the first continuous, observation-based record of winter CO2 exchange in the Southern Ocean.

The results revealed that earlier estimates had missed nearly 40% of the Southern Ocean’s wintertime CO2output. “Our findings suggest that the Southern Ocean’s role in the global carbon cycle is more complex and dynamic than previously known,” said Prof. Kun Shi of NIGLAS.

Rethinking the Ocean’s Carbon Dynamics

Beyond updating the numbers, the study redefines how scientists understand carbon movement in the Southern Ocean. The team introduced a new “three-loop framework” to explain how CO2 exchange varies across different regions.

In the Antarctic Loop (south of 60°S), physical factors such as sea ice and salinity are the main drivers of CO2exchange. In the Polar Front Loop (45°S-60°S), the interaction between atmospheric CO2 and biological activity (chlorophyll) becomes more influential. Meanwhile, in the Subpolar Loop (north of 45°S), sea surface temperature plays the dominant role.

Global Climate Implications

Filling this long-standing data gap could lead to more accurate global carbon budgets, which form the foundation of climate projections used by organizations such as the Intergovernmental Panel on Climate Change (IPCC).

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https://www.sciencedaily.com/releases/2025/11/251108014024.htm

Antarctica’s collapse may already be unstoppable, scientists warn

Source:Australian National University

Summary:Researchers warn Antarctica is undergoing abrupt changes that could trigger global consequences. Melting ice, collapsing ice shelves, and disrupted ocean circulation threaten sea levels, ecosystems, and climate stability. Wildlife such as penguins and krill face growing extinction risks. Scientists stress that only rapid emission reductions can avert irreversible damage.Share:

    

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Antarctica’s Collapse May Already Be Unstoppable
Antarctica’s ice and ecosystems are destabilizing faster than expected, threatening coastal cities and wildlife alike. Experts say urgent emission cuts are the only way to stop a cascade of irreversible changes. Credit: Shutterstock

Antarctica faces the possibility of sudden and potentially irreversible changes to its ice, oceans, and ecosystems. Scientists warn that without a sharp global reduction in carbon emissions, these transformations could have serious effects not only for the continent but also for Australia and the rest of the planet.

The warning comes from new research published in Nature by scientists from The Australian National University (ANU) and the University of New South Wales (UNSW), together with researchers from all of Australia’s major Antarctic science institutions.

The team found that multiple large-scale changes are now unfolding at once across Antarctica and that these processes are tightly “interlinked,” intensifying global pressure on the climate system, sea levels, and ecosystems.

The West Antarctic Ice Sheet: A Collapse in Motion

Researchers identified the West Antarctic Ice Sheet (WAIS) as being at extreme risk of collapsing as atmospheric carbon dioxide levels continue to climb. A full collapse of the WAIS could raise global sea levels by more than three meters, endangering coastal populations and major cities worldwide.

Dr. Nerilie Abram, Chief Scientist at the Australian Antarctic Division (AAD) and lead author of the study, warned that such an event would have “catastrophic consequences for generations to come.”

She noted that “rapid change has already been detected across Antarctica’s ice, oceans and ecosystems, and this is set to worsen with every fraction of a degree of global warming.”

Sea Ice Decline and Worsening Feedback Loops

According to Dr. Abram, the sharp decline in Antarctic sea ice is another alarming signal. “The loss of Antarctic sea ice is another abrupt change that has a whole range of knock-on effects, including making the floating ice shelves around Antarctica more susceptible to wave-driven collapse,” she said.

The reduction in sea ice, together with the weakening of deep ocean circulation in the Southern Ocean, indicates that these systems are more vulnerable to rising temperatures than previously believed.

As sea ice disappears, more solar heat is absorbed by the ocean’s surface, amplifying regional warming. Dr. Abram added that other critical systems may soon reach a point of no return, including the ice shelves that hold back parts of the Antarctic ice sheet.

Consequences Reaching Australia and Beyond

Professor Matthew England from UNSW and the ARC Australian Centre for Excellence in Antarctic Science (ACEAS), who co-authored the study, explained that these rapid Antarctic shifts could have severe effects for Australia.

“Consequences for Australia include rising sea levels that will impact our coastal communities, a warmer and deoxygenated Southern Ocean being less able to remove carbon dioxide from the atmosphere, leading to more intense warming in Australia and beyond, and increased regional warming from Antarctic sea ice loss,” he said.

Wildlife and Ecosystems in Jeopardy

The loss of sea ice is already threatening Antarctic wildlife. Professor England warned that emperor penguin populations are facing greater extinction risks because their chicks depend on stable sea ice to mature. “The loss of entire colonies of chicks has been seen right around the Antarctic coast because of early sea ice breakout events, and some colonies have experienced multiple breeding failure events over the last decade,” he said.

Other species are also under threat. The researchers reported that krill, as well as several penguin and seal species, could experience major declines, while key phytoplankton that form the base of the food web are being affected by ocean warming and acidification.

Professor England added that a potential collapse in Antarctic overturning circulation would be disastrous for marine ecosystems, preventing vital nutrients from reaching surface waters where marine life depends on them.

Urgent Global Action Needed

Dr. Abram emphasized that while efforts through the Antarctic Treaty System remain vital, they will not be sufficient on their own. “While critically important, these measures will not help to avoid climate-related impacts that are already beginning to unfold,” she said.

She urged that “the only way to avoid further abrupt changes and their far-reaching impacts is to reduce greenhouse gas emissions fast enough to limit global warming to as close to 1.5 degrees Celsius as possible.”

Governments, industries, and communities, she added, must now include these accelerating Antarctic changes in their planning for climate adaptation, especially in regions like Australia that will be directly affected.

A Global Effort to Understand Antarctica’s Rapid Change

The research represents a collaboration among leading Antarctic experts from Australia, South Africa, Switzerland, France, Germany, and the United Kingdom. It was led by the Australian Centre for Excellence in Antarctic Science (ACEAS), working with Securing Antarctica’s Environmental Future (SAEF), the Australian Antarctic Program Partnership (AAPP), and the Australian Antarctic Division (AAD).

This study supports the objectives of the Australian Antarctic Science Decadal Strategy 2025-2035, a long-term initiative to understand and address the sweeping changes underway in Earth’s southernmost region.

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https://www.sciencedaily.com/releases/2025/11/251106003941.htm#google_vignette

Earth has hit its first climate tipping point, scientists warn

Source:Goethe University FrankfurtSummary:Global scientists warn that humanity is on the verge of crossing irreversible climate thresholds, with coral reefs already at their tipping point and polar ice sheets possibly beyond recovery. The Global Tipping Points Report 2025 reveals how rising temperatures could trigger a cascade of system collapses, from the Amazon rainforest turning to savanna to the potential shutdown of the Atlantic Ocean circulation.Share:

    

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Earth Has Hit Its First Climate Tipping Point
Rising temperatures have pushed coral reefs to the brink and may have already destabilized parts of the polar ice sheets. Scientists warn of cascading climate failures but see hope in emerging positive social and technological shifts. Credit: Shutterstock

In a recently released report, a team of international climate scientists warns that saving many tropical coral reefs from destruction caused by rising ocean temperatures will now require extraordinary effort. The researchers also conclude that some regions of the polar ice sheets may have already crossed their tipping points. If this melting continues, it could cause irreversible sea level rise measured in several meters.

Scientists Warn of Cascading Climate System Failures

Among the lead authors of the Global Tipping Points Report 2025 (GTPR 2025) is Nico Wunderling, Professor of Computational Earth System Sciences at Goethe University’s Center for Critical Computational Studies | C3S and researcher at the Senckenberg Research Institute Frankfurt. Together with several co-authors, he led the chapter on “Earth System Tipping Points and Risks.”

Wunderling explains: “The devastating consequences that arise when climate tipping points are crossed pose a massive threat to our societies. There is even a risk of the tipping of one climate system potentially triggering or accelerating the tipping of others. This risk increases significantly once the 1.5°C threshold is exceeded.”

The World Nears a Cascade of Climate Tipping Points

According to the report, scientists have identified roughly two dozen parts of the global climate system that could reach tipping points. The first of these, involving tropical coral reefs, appears to have already been surpassed. The report projects that the global average temperature will rise 1.5°C above pre-industrial levels within the next few years. This would mark the start of a period in which multiple tipping points could be crossed, with profound outcomes such as rapid sea level rise from melting ice sheets or global temperature disruptions caused by a breakdown of the Atlantic Ocean circulation. The authors also recommend actions to prevent further temperature increases.

The coordinating lead author of the GTPR 2025 is Tim Lenton, Professor at the University of Exeter’s (UK) Global Systems Institute. More than 100 scientists from over 20 countries contributed to the report, which was released ahead of the 30th World Climate Conference beginning November 10, 2025, in Belém, Brazil. First published in 2023, the Global Tipping Points Report has already gained recognition as a leading reference for assessing both the risks and potential benefits of negative and positive tipping points within the Earth system and human societies.

Understanding Climate Tipping Points

Climate tipping points have become a major focus in climate research only within the past two decades. The GTPR authors describe a climate-induced tipping point as a level of warming at which key natural systems — such as coral reefs, the Amazon rainforest, or major ocean currents — undergo self-reinforcing and often irreversible change.

For example, once tropical coral reefs surpass their temperature threshold, they begin to die even if humanity later stabilizes or reduces global warming. The scientists warn that more tipping points may soon follow, as some lie near or at 1.5°C of warming. Systems already at risk include the Amazon rainforest (which could shift toward savanna), the ice sheets of Greenland and West Antarctica (which could raise sea levels by several meters), and the Atlantic Ocean circulation (whose collapse could sharply cool Europe).

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https://www.sciencedaily.com/releases/2025/10/251029002920.htm

Scientists predict a wetter, greener future for the Sahara Desert

Source:University of Illinois ChicagoSummary:UIC researchers predict that the Sahara Desert could see up to 75% more rain by the end of this century due to rising global temperatures. Using 40 climate models, the team found widespread precipitation increases across Africa, though some regions may dry out. The results suggest a major rebalancing of the continent’s climate. Scientists stress that adaptation planning is essential to prepare for both wetter and drier futures.Share:

    

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A Wetter, Greener Future for the Sahara Desert
Climate models suggest that global warming could dramatically increase rainfall in the Sahara and other parts of Africa. Credit: Shutterstock

The Sahara Desert is known as one of the driest places on Earth, receiving only about 3 inches of precipitation each year — roughly one-tenth of what falls in Chicago.

However, new research from the University of Illinois Chicago (UIC) suggests that this could change dramatically within the next few decades. By the latter half of the 21st century, rising global temperatures may bring much more rain to the region. The study, published in npj Climate and Atmospheric Science, predicts that the Sahara could receive up to 75% more precipitation than its historical average. Similar increases are also projected for parts of southeastern and south-central Africa under extreme climate scenarios.

Rising Rainfall Could Reshape Africa 

“Changing rainfall patterns will affect billions of people, both in and outside Africa,” explained lead author Thierry Ndetatsin Taguela, a postdoctoral climate researcher in UIC’s College of Liberal Arts and Sciences. “We have to start planning to face these changes, from flood management to drought-resistant crops.”

Taguela emphasized that understanding how temperature increases influence rainfall is vital for developing adaptation strategies. His research used an ensemble of 40 climate models to simulate African summer rainfall during the latter half of the 21st century (2050-2099) and compared the results with data from the historical period (1965-2014). Two climate scenarios were examined: one assuming moderate greenhouse gas emissions and another assuming very high emissions.

In both scenarios, rainfall across most of Africa was projected to rise by the end of the century, although the changes vary by region. The Sahara Desert showed the largest increase at 75%, while southeastern Africa could see about 25% more rainfall and south-central Africa about 17% more. In contrast, the southwestern part of the continent is expected to become drier, with precipitation decreasing by around 5%.

Surprising Outlook for a Dry Region 

“The Sahara is projected to almost double its historical precipitation levels, which is surprising for such a climatologically dry region,” said Taguela. “But while most models agree on the overall trend of wetter conditions, there’s still considerable uncertainty in how much rainfall they project. Improving these models is critical for building confidence in regional projections.”

The increase in precipitation is largely linked to the warming atmosphere. Higher temperatures allow the air to hold more moisture, which contributes to heavier rainfall in some areas. Shifts in atmospheric circulation patterns also affect how and where rain falls, sometimes leading to both wetter and drier regions across the continent.

“Understanding the physical mechanisms driving precipitation is essential for developing adaptation strategies that can withstand both wetter and drier futures,” Taguela said.

Taguela conducts his work as part of UIC’s Climate Research Lab, led by Akintomide Afolayan Akinsanola. Their team continues to investigate how changing atmospheric conditions could reshape Africa’s environment, agriculture, and long-term sustainability.

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https://www.sciencedaily.com/releases/2025/11/251102205025.htm

Scientists just found hidden life thriving beneath the Arctic ice

Source:University of Copenhagen

Summary:Melting Arctic ice is revealing a hidden world of nitrogen-fixing bacteria beneath the surface. These microbes, not the usual cyanobacteria, enrich the ocean with nitrogen, fueling algae growth that supports the entire marine food chain. As ice cover declines, both algae production and CO2 absorption may increase, altering the region’s ecological balance. The discovery could force scientists to revise predictions about Arctic climate feedbacks.Share:

    

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Hidden Life Thriving Beneath the Arctic Ice
Measurements of nitrogen fixation in the Arctic Ocean aboard RV Polarstern. Credit: Rebecca Duncan

The rapid loss of sea ice in the Arctic Ocean is often seen as an environmental catastrophe. Yet researchers have found that the same melting process could help sustain life in unexpected ways. As the ice retreats, it creates conditions that encourage the growth of algae, the foundation of the Arctic’s marine food web.

Algae form the base of most ocean ecosystems, but they depend on nitrogen to grow — and nitrogen is scarce in Arctic waters. Now, an international team led by the University of Copenhagen has discovered that more nitrogen may become available than scientists once believed. This shift could reshape the future of marine life in the region and influence how much carbon the ocean can absorb.

A Hidden Source of Nitrogen Beneath the Ice

The study is the first to confirm that nitrogen fixation — a process in which certain bacteria transform nitrogen gas (N2) dissolved in seawater into ammonium — occurs beneath Arctic sea ice, even in its most remote and central areas. Ammonium not only helps these bacteria thrive but also nourishes algae and, by extension, the creatures that depend on them.

“Until now, it was believed that nitrogen fixation could not take place under the sea ice because it was assumed that the living conditions for the organisms that perform nitrogen fixation were too poor. We were wrong,” says Lisa W. von Friesen, lead author of the study and former PhD student at the Department of Biology.

Less Ice, More Life

Unlike most other oceans where cyanobacteria dominate nitrogen fixation, the Arctic Ocean relies on an entirely different group of bacteria known as non-cyanobacteria. The researchers found the highest nitrogen fixation rates along the ice edge — where melting is most intense. While these bacteria can operate beneath the ice, they flourish along the melting boundary. As climate change accelerates ice retreat, this expanding melt zone could allow more nitrogen to enter the ecosystem.

“In other words, the amount of available nitrogen in the Arctic Ocean has likely been underestimated, both today and for future projections. This could mean that the potential for algae production has also been underestimated as climate change continues to reduce the sea ice cover,” says von Friesen.

“Because algae are the primary food source for small animals such as planktonic crustaceans, which in turn are eaten by small fish, more algae can end up affecting the entire food chain,” she adds.

Could This Help the Planet Absorb More CO2?

This new nitrogen source could also influence how much carbon dioxide the Arctic Ocean takes in. More algae mean more photosynthesis, which enables the ocean to capture greater amounts of CO2.

“For the climate and the environment, this is likely good news. If algae production increases, the Arctic Ocean will absorb more CO2 because more CO2 will be bound in algae biomass. But biological systems are very complex, so it is hard to make firm predictions, because other mechanisms may pull in the opposite direction,” explains Lasse Riemann, professor at the Department of Biology and senior author of the study.

The researchers emphasize that nitrogen fixation should now be considered in models predicting the Arctic’s future. “We do not yet know whether the net effect will be beneficial for the climate. But it is clear that we should include an important process such as nitrogen fixation in the equation when we try to predict what will happen to the Arctic Ocean in the coming decades as sea ice declines,” adds Riemann.

How Nitrogen Fixation Works

In the Arctic, non-cyanobacteria perform nitrogen fixation. These microorganisms consume dissolved organic matter — often released by algae — and in turn, produce fixed nitrogen that promotes further algal growth. This exchange creates a small but vital nutrient loop beneath the ice.

Algae play a double role in the ecosystem: they are both the starting point of the marine food chain and natural absorbers of CO2. As they grow, they pull carbon dioxide from the air, which can later sink to the ocean floor as part of their biomass.

Behind the Discovery

The study, published in Communications Earth & Environment, involved scientists from the University of Copenhagen (Denmark), Linnaeus University (Sweden), Alfred Wegener Institute (Germany), Aix Marseille University (France), National Oceanography Centre (United Kingdom), Max Planck Institute for Chemistry (Germany), Stockholm University (Sweden), and the Swedish University of Agricultural Sciences (Sweden).

Their findings are based on two major research expeditions aboard the icebreakers IB Oden and RV Polarstern. Samples and measurements were collected at 13 sites across the central Arctic Ocean, including regions off northeast Greenland and north of Svalbard.

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https://www.sciencedaily.com/releases/2025/10/251020092826.htm

China’s coastal cities are sinking as seas rise at record speed

Sea levels are rising faster than at any time in 4,000 years, and China’s sinking coastal cities are on the front lines.

Source:Rutgers University

Summary:Sea levels are rising faster than at any time in 4,000 years, scientists report, with China’s major coastal cities at particular risk. The rapid increase is driven by warming oceans and melting ice, while human activities like groundwater pumping make it worse. In some areas, the land itself is sinking faster than the ocean is rising. Still, researchers see progress as cities like Shanghai adopt new technologies to stabilize the ground and prepare for the future.Share:

    

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Sea Levels Are Rising Faster Than in 4,000 Years
Scientists have found that modern sea level rise is accelerating faster than at any time in the past 4,000 years, and China’s coastal megacities are among the most at risk. Credit: Shutterstock

A team of scientists led by Rutgers University researchers has found that sea levels today are climbing more quickly than at any time in the past 4,000 years, with China’s coastal cities facing some of the most severe risks.

To uncover this trend, the researchers analyzed thousands of geological records from natural indicators such as ancient coral reefs and mangrove formations. These environments preserve long-term evidence of past sea levels. Using this data, the team reconstructed ocean changes stretching back almost 12,000 years to the start of the Holocene epoch, which began after the last major ice age.

Fastest Rate of Rise Since 1900

Published in Nature, the study reports that global sea levels have risen by an average of 1.5 millimeters (about one-sixteenth of an inch) per year since 1900. This pace is faster than any century-long period recorded in the last four millennia.

“The global mean sea level rise rate since 1900 is the fastest rate over at least the last four millennia,” said Yucheng Lin, who conducted the research as a postdoctoral associate at Rutgers and is a scientist at Australia’s national research agency, the Commonwealth Scientific and Industrial Research Organization in Hobart.

Lin worked under the guidance of Robert Kopp, a Distinguished Professor in the Department of Earth and Planetary Sciences at Rutgers. “Dr. Lin’s work illustrates how geological data can help us better understand the hazards that coastal cities face today,” said Kopp, who also authored the study.

What’s Driving the Acceleration

According to Lin, two main processes are responsible for today’s rapid sea level rise: thermal expansion and melting ice. As climate change warms the planet, oceans absorb heat, causing the water to expand. At the same time, melting glaciers and ice sheets in Greenland and Antarctica add vast amounts of water to the seas.

“Getting warmer makes your ocean take up more volume,” Lin said. “And the glaciers respond faster because they are smaller than the ice sheets, which are often the size of continents. We are seeing more and more acceleration in Greenland now.”

China’s Coastal Cities Face a Double Threat

While sea level rise is a global concern, China faces a particularly dangerous combination of natural and human factors. Many of its largest cities — including Shanghai, Shenzhen and Hong Kong — sit in delta regions made of soft, water-saturated sediment that naturally sinks over time.

Human activities have accelerated this sinking.

“We’ve been able to quantify the natural rate of sea level rise for this area,” Lin said. “But human intervention, mostly groundwater extraction, makes it happen much faster.”

Subsidence, the gradual sinking or settling of the Earth’s surface, can occur through natural geological changes or from human-driven causes such as overuse of groundwater.

Delta Regions Under Pressure

To assess the risk to China’s deltas, the researchers combined geological records, measurements of land subsidence, and data on human impacts. They focused on the Yangtze River Delta and Pearl River Delta, two areas that are home to several megacities and key industrial zones.

In Shanghai, parts of the city sank more than one meter (around three feet) during the 20th century because of extensive groundwater pumping, Lin said. That rate is vastly higher than the current global average for sea level rise.

Delta regions are naturally flat and fertile, making them ideal for farming, transport, and urban development. But those same features make them exceptionally vulnerable to flooding.

“Centimeters of sea level rise will greatly increase the risk of flooding in deltas,” Lin said. “These areas are not only important domestically, they’re also international manufacturing hubs. If coastal risks happen there, the global supply chain will be vulnerable.”

Efforts to Slow the Sinking

Despite the alarming data, Lin noted that there are reasons for optimism. Some Chinese cities have begun taking effective steps to manage the problem. Shanghai, for example, has slowed its rate of subsidence by controlling groundwater extraction and reinjecting freshwater into underground aquifers.

“Shanghai now is not sinking that fast anymore,” Lin said. “They recognized the problem and started regulating their groundwater usage.”

The research team also created vulnerability maps to help local governments and city planners identify high-risk zones and prepare for future sea level rise.

A Global Lesson

Although the study focuses on China, its implications reach far beyond. Many major coastal cities, including New York, Jakarta and Manila, are built on low-lying plains and face similar threats.

“Deltas are great places, good for farming, fishing, urban development and naturally draw civilizations to them,” Lin said. “But they are really flat yet prone to human-caused subsidence, so sustained sea level rise could submerge them really fast.”

Modeling the Past to Protect the Future

The paper is an application of PaleoSTeHM, an open-source software framework for statistically modeling paleo-environmental data that Lin developed as a postdoctoral associate.

Praveen Kumar, a postdoctoral associate in the Department of Earth and Planetary Sciences, also contributed to the study.

The National Science Foundation and NASA supported the research.

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https://www.sciencedaily.com/releases/2025/10/251023031627.htm

Heat Waves Are Becoming More Frequent and Intense in Rivers

Heat waves are becoming more frequent and intense across the U.S., so perhaps this summer you took a dip in a river to cool off. However, according to new research it might not have been as refreshing as it once was. 

Credit: Dillon Groves/Unsplash

A new study from Penn State found that heat waves are happening in rivers too, and they’re accelerating faster than and lasting nearly twice as long as the heat waves in the air. It’s a surprising finding, given that many rivers are fed by snowmelt and underground streams, but the team found that periods of abnormally high temperatures in rivers are becoming more common, more intense, and longer-lasting than they were 40 years ago. Lead author Li Li (李黎) wrote in The Conversation that the increased heat puts stress on aquatic ecosystems and can also raise the cost of treating drinking water. 

The team collected river data at nearly 1,500 sites in the contiguous United States between 1980 and 2022. They found that temperatures rose above 59 °F (15 °C)—a threshold that can stress many species—at 82 percent of study areas for an average of 11.6 days per year. The places where the waters warmed the fastest were in the Northeast, the Rocky Mountains, and Appalachia.

The authors say climate change is driving river heat waves, as rising air temperatures affect water conditions. Changing precipitation patterns with global warming are shrinking winter snowpacks, leaving less meltwater to support river health. Low, slow-moving water warms more easily and holds less oxygen, creating dangerous conditions for aquatic life and increasing the chances of large-scale die-offs. The study adds that human activities, such as dams and agriculture, play a secondary role in shaping how and where rivers are most vulnerable to these impacts.

The study was published in the journal Proceedings of the National Academy of Sciences (PNAS).

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https://h2oradio.org/this-week-in-water/your-dogs-carbon-paw-print

Ocean heatwaves are breaking Earth’s hidden climate engine

Marine heatwaves are clogging the ocean’s carbon pump, threatening its power to fight climate change.

Source:Monterey Bay Aquarium Research Institute

Summary:Marine heatwaves can jam the ocean’s natural carbon conveyor belt, preventing carbon from reaching the deep sea. Researchers studying two major heatwaves in the Gulf of Alaska found that plankton shifts caused carbon to build up near the surface instead of sinking. This disrupted the ocean’s ability to store carbon for millennia and intensified climate feedbacks. The study highlights the urgent need for continuous, collaborative ocean observation.Share:

    

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Ocean Heatwaves Break Earth’s Climate Engine
Robotic floats can continuously collect detailed data about ocean conditions. A new study led by MBARI researchers from the Global Ocean Biogeochemistry Array project—with an interdisciplinary team of collaborators—has analyzed data from floats deployed in the Gulf of Alaska and records from ship-based plankton surveys and revealed that marine heatwaves reshape ocean food webs and affect the ocean’s ability to store carbon. Credit: © 2022 MBARI

New research shows that marine heatwaves can reshape ocean food webs, which in turn can slow the transport of carbon to the deep sea and hamper the ocean’s ability to buffer against climate change. The study, published in the scientific journal Nature Communications on October 6, was conducted by an interdisciplinary team of researchers from MBARI, the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, the Hakai Institute, Xiamen University, the University of British Columbia, the University of Southern Denmark, and Fisheries and Oceans Canada.

To explore the impacts of marine heatwaves on ocean food webs and carbon flows, the research team combined multiple datasets that tracked biological conditions in the water column in the Gulf of Alaska for more than a decade. This region experienced two successive marine heatwaves during this time, one from 2013 to 2015 known as “The Blob,” and another from 2019 to 2020.

“The ocean has a biological carbon pump, which normally acts like a conveyor belt carrying carbon from the surface to the deep ocean. This process is powered by the microscopic organisms that form the base of the ocean food web, including bacteria and plankton,” said the lead author, Mariana Bif, previously a research specialist at MBARI and now an assistant professor in the Department of Ocean Sciences at the Rosenstiel School. “For this study, we wanted to track how marine heatwaves affected those microscopic organisms to see if those impacts were connected to the amount of carbon being produced and exported to the deep ocean.”

The research team used information collected by the Global Ocean Biogeochemical (GO-BGC) Array, a collaborative initiative funded by the US National Science Foundation and led by MBARI that uses robotic floats to monitor ocean health. The GO-BGC project has deployed hundreds of autonomous biogeochemical Argo (BGC-Argo) floats, which measure ocean conditions such as temperature, salinity, nitrate, oxygen, chlorophyll, and particulate organic carbon (POC) up and down the water column every five to 10 days. The team also looked at seasonal data from ship-based surveys that tracked plankton community composition, including pigment chemistry and sequencing of the environmental DNA (eDNA) from seawater samples collected during the Line P program carried out by Fisheries and Oceans Canada.

The study found that marine heatwaves did impact the base of the ocean food web, and those impacts were connected to changes in the ways that carbon was cycled in the water column. However, the changes that occurred in the food web were not consistent across the two heatwaves.

Under typical conditions, plant-like phytoplankton convert carbon dioxide to organic material. These microorganisms are the foundation of the ocean food web. When they are eaten by larger animals and excreted as waste, they transform into organic carbon particles that sink from the surface through the ocean’s mesopelagic, or twilight, zone (200 to 1,000 meters, approximately 660 to 3,300 feet) and down to the deep sea. This process locks atmospheric carbon away in the ocean for thousands of years.

During the 2013-2015 heatwave, surface carbon production by photosynthetic plankton was high in the second year, but rather than sinking rapidly to the deep sea, small carbon particles piled up approximately 200 meters (roughly 660 feet) underwater.

During the 2019-2020 heatwave, there was record-high accumulation of carbon particles at the surface in the first year that could not be attributed to carbon production by phytoplankton alone. Instead, this accumulation was likely due to the recycling of carbon by marine life and the buildup of detritus waste. This pulse of carbon then sank to the twilight zone, but lingered at depths of 200 to 400 meters (roughly 660 to 1,320 feet) instead of sinking to the deep sea.

The team attributed these differences in carbon transport between the two heatwaves to changes in phytoplankton populations. These changes cascaded through the food web, leading to a rise in small grazers who do not produce fast-sinking waste particles, so carbon was retained and recycled at the surface and in the upper twilight zone rather than sinking to deeper depths.

“Our research found that these two major marine heatwaves altered plankton communities and disrupted the ocean’s biological carbon pump. The conveyor belt carrying carbon from the surface to the deep sea jammed, increasing the risk that carbon can return to the atmosphere instead of being locked away deep in the ocean,” said Bif.

This research demonstrated that not all marine heatwaves are the same. Different plankton lineages rise and fall during these warming events, underscoring the need for long-term, coordinated monitoring of the ocean’s biological and chemical conditions to accurately model the diverse, and expansive, ecological impacts of marine heatwaves.

“This research marks an exciting new chapter in ocean monitoring. To really understand how a heatwave impacts marine ecosystems and ocean processes, we need observation data from before, during, and after the event. This research included robotic floats, pigment chemistry, and genetic sequencing, all working together to tell the entire story. It’s a great example of how collaboration can help us answer key questions about the health of the ocean,” said MBARI Senior Scientist Ken Johnson, the lead principal investigator for the GO-BGC project and a coauthor of the study.

Ocean observations and models suggest that marine heatwaves have been expanding in size and intensifying over the past few decades. The ocean absorbs a quarter of the carbon dioxide emitted each year, thanks to the steady stream of carbon particles sinking from the surface to the deep sea. A warmer ocean can mean less carbon locked away, which in turn can accelerate climate change. Beyond the changes to carbon transport, the shifts in plankton at the foundation of the ocean food web have cascading impacts on marine life and human industry too.

“Climate change is contributing to more frequent and intense marine heatwaves, which underscores the need for sustained, long-term ocean monitoring to understand and predict how future marine heatwaves will impact ecosystems, fisheries, and climate,” said Bif.

This work was funded by the US National Science Foundation’s GO-BGC project (NSF Award 1946578 with operational support from NSF Award 2110258), with additional support from the David and Lucile Packard Foundation, China National Science Foundation (grant number: 42406099), Fundamental Research Funds for the Central Universities (grant number: 20720240105), Danish Center for Hadal Research (Grant No. DNRF145), and Fisheries and Oceans Line P program.

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https://www.sciencedaily.com/releases/2025/10/251007081819.htm

Climate changes lead to water imbalance, conflict in Tibetan Plateau

Melting glaciers are putting a hold on countries’ development

Source:Ohio State University

Summary:Climate change is putting an enormous strain on global water resources, and according to researchers, the Tibetan Plateau is suffering from a water imbalance so extreme that it could lead to an increase in international conflicts.Share:

    

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Climate change is putting an enormous strain on global water resources, and according to researchers, the Tibetan Plateau is suffering from a water imbalance so extreme that it could lead to an increase in international conflicts.

Nicknamed “The Third Pole,” the Tibetan Plateau and neighboring Himalayas is home to the largest global store of frozen water outside of the North and South Polar Regions. This region, also known as the Asian water tower (AWT), functions as a complex water distribution system which delivers life-giving liquid to multiple countries, including parts of China, India, Nepal, Pakistan, Afghanistan, Tajikistan and Kyrgyzstan.

Yet due to the rapid melting of snow and upstream glaciers, the area can’t sustainably support the continued growth of the developing nations that rely on it.

“Populations are growing so rapidly, and so is the water demand,” said Lonnie Thompson, distinguished university professor of earth sciences at The Ohio State University and senior research scientist at the Byrd Polar Research Center. “These problems can lead to increased risks of international and even intranational disputes, and in the past, they have.”

Thompson, who has studied climate change for nearly five decades, is intimately familiar with the precarious nature of the region’s hydrological situation. In 1984, Thompson became a member of the first Western team sent to investigate the glaciers in China and Tibet. Since then, he and a team of international colleagues have spent years investigating ice core-derived climate records and the area’s rapidly receding ice along with the impact it’s had on the local settlements that depend on the AWT for their freshwater needs.

The team’s latest paper, of which Thompson is a co-author, was published in the journal Nature Reviews Earth and Environment. Using temperature change data from 1980 to 2018 to track regional warming, their findings revealed that the AWT’s overall temperature has increased at about 0.42 degrees Celsius per decade, about twice the global average rate.

“This has huge implications for the glaciers, particularly those in the Himalayas,” Thompson said. “Overall, we’re losing water off the plateau, about 50% more water than we’re gaining.” This scarcity is causing an alarming water imbalance: Northern parts of Tibet often experience an overabundance of water resources as more precipitation occurs due to the strengthening westerlies, while southern river basins and water supplies shrink as drought and rising temperatures contribute to water loss downstream.

According to the study, because many vulnerable societies border these downstream basins, this worsening disparity could heighten conflicts or exacerbate already tense situations between countries that share these river basins, like the long-term irrigation and water struggles between India and Pakistan.

“The way that regional climate varies, there are winners and losers,” Thompson said. “But we have to learn to work together in order to ensure adequate and equitable water supplies throughout this region.” As local temperatures continue to rise and water resources become depleted, more people will end up facing ever diminishing water supplies, he said.

Still, overall increases in precipitation alone won’t meet the increased water demands of downstream regions and countries.

To combat this, the study recommends using more comprehensive water monitoring systems in data-scarce areas, noting that better atmospheric and hydrologic models are needed to help predict what’s happening to the region’s water supply. Lawmakers should then use those observations to help develop actionable policies for sustainable water management, Thompson said. If policymakers do decide to listen to the scientists’ counsel, these new policies could be used to develop adaptation measures for the AWT through collaboration between upstream and downstream countries.

After all, when things go awry in one area of the world, like the butterfly effect, they tend to have long-lasting effects on the rest of Earth’s population. “Climate change is a global process,” Thompson said. “It doesn’t matter what country or what part of the world you come from. Sooner or later, you’ll have a similar problem.”

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https://www.sciencedaily.com/releases/2022/06/220623140114.htm

Antarctica’s frozen heart is warming fast, and models missed it

First long-term study on the East Antarctic interior ice sheet region reveals the Indian Ocean mechanism driving this change

Source: Nagoya University

Summary: New research has revealed that East Antarctica’s vast and icy interior is heating up faster than its coasts, fueled by warm air carried from the Southern Indian Ocean. Using 30 years of weather station data, scientists uncovered a hidden climate driver that current models fail to capture, suggesting the world’s largest ice reservoir may be more vulnerable than previously thought. Share:

    

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Antarctica’s Frozen Heart Is Warming Fast
Scientists discovered that East Antarctica’s interior is warming faster than its coasts due to warm air flows from the Southern Indian Ocean. Current climate models don’t capture this effect, suggesting ice loss could be underestimated. Credit: Shutterstock

Scientists have confirmed that East Antarctica’s interior is warming faster than its coastal areas and identified the cause. A 30-year study, published in Nature Communications and led by Nagoya University’s Naoyuki Kurita, has traced this warming to increased warm air flow triggered by temperature changes in the Southern Indian Ocean. Previously considered an observation “blind spot,” East Antarctica contains most of the world’s glacial ice. This newly identified warming mechanism indicates that current predictions may underestimate the rate of future Antarctic ice loss.

Collecting data in Earth’s most extreme environment

Antarctica, the world’s coldest, driest, and windiest continent, contains about 70% of Earth’s freshwater frozen in its massive ice sheets. Climate change in the region has been studied using data from manned stations located mostly in coastal areas. However, the Antarctic interior has only four manned stations, with long-term climate data available for just two: Amundsen-Scott Station (South Pole) and Vostok Station (East Antarctic Interior). Therefore, the actual state of climate change in the vast interior remained largely undocumented.

The research group collected observation data from three unmanned weather stations in East Antarctica where observations have continued since the 1990s: Dome Fuji Station, Relay Station, and Mizuho Station. They created a monthly average temperature dataset spanning 30 years, from 1993 to 2022.

Annual average temperature changes showed that all three locations experienced temperature increases at a rate of 0.45-0.72°C per decade, faster than the global average. The researchers analyzed meteorological and oceanic data and traced this temperature rise to changes in the Southern Indian Ocean that alter atmospheric circulation patterns and transport warm air toward Antarctica’s interior.

Current climate models do not capture this warming process, so future projections of temperature for Antarctica may be underestimated. “While interior regions show rapid warming, coastal stations have not yet experienced statistically significant warming trends,” Professor Naoyuki Kurita from the Institute for Space-Earth Environmental Research at Nagoya University said. “However, the intensified warm air flow over 30 years suggests that detectable warming and surface melting could reach coastal areas like Syowa Station soon.”

The Southern Indian Ocean-East Antarctica climate connection

Ocean fronts — areas where warm and cold ocean waters meet — create sharp temperature boundaries in the Southern Indian Ocean. Because global warming heats ocean waters unevenly, it intensifies these temperature differences: stronger oceanic fronts lead to more storm activity and atmospheric changes that create a “dipole” pattern, with low pressure systems in mid-latitudes and high pressure over Antarctica. The high-pressure system over Antarctica pulls warm air southward and carries it deep into the continent.

Now, for the first time, scientists have comprehensive weather station data demonstrating that East Antarctica’s interior is warming faster than its coasts and have identified the major cause of this change. The study provides important insights into how quickly the world’s largest ice reservoir will respond to continued global warming.

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https://www.sciencedaily.com/releases/2025/09/250909031503.htm