Climate & Environment

House fires release harmful compounds into the air

Megan M Rogers — Fri, 27 Feb 2026 20:55:23 +0000

House fires release harmful compounds into the air Megan M Rogers Fri, 02/27/2026 - 13:55

CIRES

New CIRES-led research shows that common synthetic materials used in homes, like plastics and insulation, can release harmful compounds into the air when they burn.

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Political polarization can spur CO2 emissions, stymie climate action

Lisa Marshall — Wed, 25 Feb 2026 22:39:15 +0000

Political polarization can spur CO2 emissions, stymie climate action Lisa Marshall Wed, 02/25/2026 - 15:39

Lisa Marshall

In recent years, studies and media reports have blamed growing partisan hostility in the U.S. for shattered marriages, broken families, ruined holiday dinners and increased stress.

New �� Boulder research suggests it may have an even broader impact, hindering democracies’ capacity to address climate change around the world.

“There has been a lot of research on the effects of political polarization at the interpersonal level, but ours is the first study to look at how it impacts the ability of democracies to mitigate climate change,” said senior author Don Grant, professor of sociology and fellow with the Renewable and Sustainable Energy Institute (RASEI). “We find that in democracies marked by deep interparty animosity, power plants—some of the world’s largest carbon polluters—emit CO₂ at significantly higher rates. And these outcomes are not unique to the U.S.”

More polarization equals more CO₂

In a study published in the American Sociological Review, Grant and his colleagues looked at the annual CO₂ emission rates (CO₂ emissions per unit of electricity produced) from 20,115 fossil-fueled power plants across 92 democratic countries. They also looked at each country's level of what is known as "affective polarization," scored on a 0 to 4 scale. They found that in countries with greater affective polarization, or intense partisan hostility, democratic institutions are less able to effectively enforce climate regulation.

Don Grant

The study distinguishes ideological polarization—policy disagreements that can stimulate innovation—and affective polarization, a more personal and corrosive form of division in which citizens distrust and demonize those aligned with an opposing party. While robust debate about policy can strengthen democracy, affective polarization mobilizes citizens into rival stakeholder coalitions determined to obstruct policies advanced by their adversaries, said Grant.

“As these coalitions harden, governance becomes more difficult, existing policies lose effectiveness, and legislative processes designed to foster compromise are increasingly undermined,” he said.

Research shows affective polarization is on the rise globally, and climate change is a key wedge issue.

After controlling for other factors that could influence emissions, Grant’s study found that in countries with more affective polarization, plant-level CO₂ emission rates are significantly higher.

For example, in Uruguay, which had the lowest affective polarization score, emission rates were 11% below average. In Poland, which had the highest affective polarization score, emission rates were nearly 8% above average. The U.S. ranked near the top for affective polarization and above average for emission rates.

Changing times

In the early 1970s, political parties were, in many ways, less divided over issues like environmental protection. The U.S. Senate unanimously approved the Clean Air Act in 1970, authorizing the Environmental Protection Agency to establish national air quality standards. And utilities routinely included green-energy stakeholders as key collaborators in decision making.

Times have changed.

Grant argues that as people have grown more reluctant to associate with those with opposing views, utilities have disenfranchised many environmental groups, and power plants have become insulated from citizen and regulatory pressure. As a result, even in democracies with formal climate measures in place, the institutions meant to hold polluters accountable have failed to function as intended.

The study found that in countries with heightened interparty hostility, climate policies are less effective at curbing plants’ emissions. Also, government-owned power plants are particularly prone to emit more carbon.

“When polarization is higher, it may be harder to fully implement policies and for public utilities to reconcile the concerns of both pro-fossil fuel and pro-environment groups,” Grant said.

He speculates that if affective polarization continues, it may result in the repeal of long-standing climate mitigation policies.

“We already see evidence of this happening in the United States,” said Grant, referring to the EPA’s move on Tuesday to repeal the 2009 “endangerment finding,” which classified greenhouse gas emissions as a threat to public health. “Affective polarization is becoming a runaway phenomenon that threatens to erode democracies’ capacity to protect the planet.”

A ray of hope

While full of somber findings and predictions, the paper ends on a positive note.

It points to Great Britain, which despite its long history of rancorous politics, has been able to rein in its worst-polluting power facilities in recent years.

In September 2024, Britain closed its last operating coal plant, ending more than 140 years of reliance on coal.

Britain accomplished this, said Grant, by framing the shift toward renewable energy as a national endeavor rather than a political victory for one side over the other.

“At the same time that the U.S. is retreating from its climate promises, places like the U.K. show how it is possible to overcome the effect of polarization and follow through on climate commitments,” said Grant. “They provide a ray of hope.”

An analysis of more than 20,000 power plants across 92 democratic countries found that in nations with more political incivility, power plants emit more carbon.

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A power plant on the Ohio River in Pennsylvania. Source: Wikamedia Commons

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A power plant on the Ohio River in Pennsylvania. Source: Wikamedia Commons

Bushbabies reclassified as 'near threatened.' Scientists share how to protect these adorable primates

Daniel William Strain — Mon, 16 Feb 2026 22:25:30 +0000

Bushbabies reclassified as 'near threatened.' Scientists share how to protect these adorable primates Daniel William… Mon, 02/16/2026 - 15:25

Daniel Strain

Thick-tailed bushbaby (Credit: CC image via Wikimedia Commons)

Frank Cuozzo and Michelle Sauther first traveled to South Africa in 2012 to search for some of the most unusual primates on Earth—bushbabies.

These animals are nocturnal and small, often around the size of a housecat. Bushbabies have big ears, round eyes and get their names from the eerie, wailing noises they make at night.

Two species of bushbabies are native to South Africa: The thick-tailed bushbaby (Otolemur crassicaudatus) and the Moholbushbaby (Galago moholi). At the time, they had a reputation for being everywhere. They would sneak into towns to steal pet food from bowls and beg for handouts from tourists on safari.

But the more Cuozzo and Sauther looked, the more they realized that something didn’t seem right: They kept finding bushbabies killed on roads or mauled by dogs.

The dangers facing the animals, in fact, seemed to be mounting.

Thick-tailed bushbaby (Credit: Michelle Sauther)

Trail camera captures a bushbaby mysteriously grooming a bushbuck at night in South Africa. (Credit: Michelle Sauther)

Greater bushbaby seen crossing a canopy bridge at night. (Credit: Birthe Linden)

Now, after more than a decade of research by the primatologists and their colleagues, a major environmental organization in southern Africa has changed the conservation status of these cute animals. In January, the Endangered Wildlife Trust (EWT) redesignated thick-tailed bushbabies from a species of “least concern” to “near threatened.” This category isn’t as severe as “endangered” but indicates that bushbaby numbers are likely dropping at a concerning rate.

“Human threats are everywhere, for all species,” said Cuozzo, a scientist at the Lajuma Research Centre in South Africa and research fellow at the University of Pretoria’s Mammal Research Institute. “But we’ve been able to document that the human threats facing bushbabies, including deforestation and habitat loss, are increasing.”

Sauther, a professor of anthropology at �� Boulder, sees the new conservation listing as a culmination of years of work—and, perhaps, a new beginning for bushbabies.

“We don't want this species to ever become endangered,” Sauther said. “Now that we know they're near threatened, we can do something about it.”

The researchers also hope their findings will call attention to the many other plants and animals that live in the same forests as bushbabies.

“There are so many plant species there that botanists can’t even identify, the same with some of the reptiles and amphibian,” said Birthe Linden, a primatologist at Aberystwyth University in Wales. “It is a biodiverse area, and there are so many gaps in what we know.”

Rising deforestation

Thick-tailed bushbabies spend most of their lives in trees where they mostly eat acacia gum. They range widely across Southern Africa, thriving in the lush, green forests that grow around rivers.

Sauther said the animals never cease to amaze her.

Once, she and her colleagues caught a bushbaby on a trail camera grooming an antelope known as a bushbuck—the bushbuck stood still while the primate plucked insects from its fur and ate them.

“They’re our cousins, and they even have these connections to other species,” Sauther said. “They’re a lovely animal to understand.”

In 2023, she, Cuozzo and Linden began working with the EWT to reassess the status of this species.

The researchers aren’t sure exactly how fast bushbaby numbers are falling in southern Africa. But they gathered a wide range of data showing that the threats are growing.

Using satellite images, the researchers calculated that the habitats where bushbabies live are shrinking by about 3.6% per decade—faster than the average loss for natural areas in the region. Humans cut down bushbaby forests to make room for agriculture and suburban housing.

In one alarming example, bushbabies once abounded in the Mokopane Biodiversity Centre roughly 200 kilometers (124 miles) north of Pretoria, South Africa. When a dam was installed upriver about 20 years ago, the primates’ favorite forests dried up and died.

“In 2015, we tried to look for bushbabies there, and there was nothing,” said Cuozzo, who earned his doctorate in biological anthropology from �� Boulder in 2000. “We didn’t hear anything. We didn’t find a single individual.”

In previous studies, the team also showed that the pet trade, road kill and dog attacks might be taking a much bigger toll on primates in South Africa than scientists realized.

Keeping bushbabies safe

Cuozzo, Linden and Sauther hope their findings will inspire more researchers to take a closer look not just at bushbabies, but other understudied plants and animals around the world.

The researchers said South Africans care about their wildlife, and there’s a lot they can do to protect bushbabies today.

They encourage people not to feed primates or leave pet food out at night. These morsels encourage bushbabies to venture into human settlements where they can get attacked by dogs.

To stop roadkill, the researchers advocate for “canopy bridges.” They allow animals to cross roads without risking being hit by cars and can be as simple as two ropes stretched over a highway.

“We can’t protect anything if we don’t know about it,” Linden said. “There’s so little money available for conservation. The more we learn about a creature, the more we can spend that money in a way that’s really effective.

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After more than a decade of research by primatologists at �� Boulder and their colleagues, a major environmental organization has changed the conservation status of an unusual, and petite, species of primate that lives in southern Africa.

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Climate change media coverage fell 14% in 2025

Yvaine Ye — Mon, 16 Feb 2026 17:03:09 +0000

Climate change media coverage fell 14% in 2025 Yvaine Ye Mon, 02/16/2026 - 10:03

Brigitta Rongstad

In 2025—Earth's third warmest year on record—massive fires destroyed entire neighborhoods in Los Angeles, a deadly heatwave killed more than 24,000 in Europe and powerful storms triggered catastrophic flooding in Southeast Asia.

Scientists were quick to highlight the potential links between many of these disasters and a rapidly changing climate. But media coverage of climate change decreased by 14% in 2025 compared to 2024, according to a recent report from �� Boulder’s Media and Climate Change Observatory (MeCCO).

Max Boykoff

“Over the past three and a half decades, climate change has become a high-stakes, high-profile, and highly-politicized venture involving science, policy, culture, psychology, environment and society,” said Max Boykoff, professor of Environmental Studies and a fellow at the Cooperative Institute for Research in Environmental Sciences (CIRES).

Boykoff, who is also the faculty executive director of the SPIKE Center for Sustainability Education, leads MeCCO’s efforts to track media coverage of climate change and understand messaging trends here in the U.S. and across the world. �� Boulder Today sat down with him to chat about the shift and the implications.

What is the Media and Climate Change Observatory?

MeCCO is a collaborative project that monitors and assesses climate change and global warming coverage in 131 newspapers, radio and television outlets spanning 59 countries and 14 languages. There is no other open-access resource like it available to researchers and practitioners, interested media outlets and decision-makers across anywhere else in the world.

How do �� Boulder students support MeCCO?

In a new partnership between CIRES and the SPIKE Center for Sustainability Education, MeCCO is expanding student involvement and support at �� Boulder. As part of broader MeCCO activities, �� Boulder students also serve as SPIKE Student Emissaries, working with collaborators at universities, institutes and organizations worldwide. Together, the 30-member team monitors climate-related news and produces monthly and annual summaries and explainers. The partnership expands MeCCO’s reach while building competence and confidence among participating researchers and students.

How does your team track changes in media coverage about climate change?

In partnership with the University Libraries, MeCCO team members produce open access datasets each month at the global level for newspaper and radio coverage. The team also evaluates newspaper coverage in seven regions—Africa, Asia, Europe, Latin America, Middle East, North America and Oceania—as well as at the country level in Australia, Canada, Denmark, Finland, Germany, India, Japan, Korea, New Zealand, Norway, Russia, Spain, Sweden, the United Kingdom and the United States.

We use existing news archives to assemble data, making sure we have broad geographic coverage, high circulation and reliable access to material.

Media coverage of climate change or global warming in seven different regions around the world, from January 2004 through December 2025. (Credit: MeCCO/�� Boulder)

What contributed to the decline in coverage in 2025?

Ongoing political economic headwinds, and newsroom consolidation and reductions have contributed to this diminished coverage. Moreover, there is finite news space for competing stories, with the Trump administration flooding the public sphere with news stories across several domains.

News editors and reporters may also sense that their readers are getting tired of reading and hearing about climate change when making decisions about what stories to cover. Furthermore, journalists may be hesitant to connect the dots between ecological and meteorological events like wildfires, and a changing climate due to the ongoing politicization of climate science, despite the fact that those links are clear within relevant expert scientific communities.

How does this decline impact people’s awareness and understanding of climate change science?

People typically do not start their day with a cup of coffee and the latest peer-reviewed journal article. Instead, they turn to media—television, newspapers, radio, social media—to understand how science and policies could impact their everyday lives. This reality drives MeCCO’s work to monitor media coverage of climate change around the world and investigate how climate change coverage affects media consumers. When the media fail to cover these pressing climate issues abundantly and accurately, people may not recognize how climate change shapes their daily lives, livelihoods and challenges.

What are other ways scientists can reach people who might only hear about climate change issues from the news?

There are many ways scientists can creatively communicate and connect with different sectors of society. They can improve education and literacy, mobilize more effective advocacy efforts, raise individual-to collective-scale awareness, prompt behavior change and promote cultural change. Through video, theater, dance and writing, scientists can connect new and wider audiences to climate change—tapping into experiential, emotional, visceral and aesthetic ways of learning that go beyond traditional communication.

'Doom and gloom' messaging is prevalent in the media. How do you inspire hope?

There are many alternative pathways to effectively communicate about climate-related issues. In collaboration with �� Boulder students, my colleague, Beth Osnes-Stoedefalke in the Department of Theater, and I have explored avenues like studying fast fashion communication strategies and environmental impacts (an industry that contributes significantly to global warming) and sustainable fashion alternatives.

We also explore how comedy may unexpectedly offer new routes to learning about climate change, overcoming often sober or gloomy scientific assessments through experiential, narrative, emotive and relatable storytelling. Humor can help increase accessibility to the complex and often-distant dimensions of climate change by bringing a long-term set of issues into the immediate social context. While comedy can provide relief amid anxiety-producing scientific results, it also serves to bridge difficult topics and overcome polarized discussions through entertaining and non-threatening ways to recapture a missing middle ground.

These activities then provide space for young people—college-aged students most centrally—to hope and to work toward desirable, sustainable futures.

�� Boulder Today regularly publishes Q&As on news topics through the lens of scholarly expertise and research/creative work. The responses here reflect the knowledge and interpretations of the expert and should not be considered the university position on the issue. All publication content is subject to edits for clarity, brevity and university style guidelines.

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Despite rising impacts, climate change received less attention in media around the world in 2025. �� Boulder sociologist Max Boykoff shares the reasons and implications.

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Examples of newspaper front pages with climate change stories relating to the Los Angeles, California area fires in January 2025. (Courtesy of the MeCCO team)

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Examples of newspaper front pages with climate change stories relating to the Los Angeles, California area fires in January 2025. (Courtesy of the MeCCO team)

Snow news day: The challenge of climate reporting as newsrooms cut back

Megan M Rogers — Fri, 13 Feb 2026 18:59:49 +0000

Snow news day: The challenge of climate reporting as newsrooms cut back Megan M Rogers Fri, 02/13/2026 - 11:59

College of Communication, Media, Design and Information

The College of Communication, Media, Design and Information's Water Desk has expanded the services it offers to resource-starved reporters who need help covering complex stories around the Colorado River and climate change.

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One safety step sparks another

Megan M Rogers — Fri, 13 Feb 2026 14:57:41 +0000

One safety step sparks another Megan M Rogers Fri, 02/13/2026 - 07:57

Colorado Arts and Sciences Magazine

Research from �� Boulder environmental economist Grant Webster finds that wildfire risk mitigation and proactive evacuation preparation are complementary.

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Global collaboration to limit air pollution flowing across borders could save millions of lives

Daniel William Strain — Thu, 12 Feb 2026 18:25:10 +0000

Global collaboration to limit air pollution flowing across borders could save millions of lives Daniel William… Thu, 02/12/2026 - 11:25

This story is adapted from a version published by Cardiff University. Read the original version here.

Ambitious climate action to improve global air quality could save up to 1.32 million lives per year by 2040, according to a new study.

Researchers from �� Boulder and Cardiff University in the United Kingdom have found that developing countries, especially, rely on international action to improve air quality, because much of their pollution comes from outside their borders.

The new study, published in Nature Communications, analyzed cross-border pollution “exchanges” for 168 countries and revealed that if countries do not collaborate effectively on climate policy, it could lead to greater health inequality for poorer nations that have less control over their own air quality.

The team’s work focuses on the impact of exposure to fine particulate matter, what scientists call “PM2.5,” which is the leading environmental risk factor for premature deaths globally.

“Some climate policies could inadvertently make air pollution inequalities worse, specifically for developing nations that might rely heavily on their neighbors for clean air,” said Daven Henze, senior author of the new study and professor at the Paul M. Rady Department of Mechanical Engineering at �� Boulder.

“Holistic climate policy should therefore evaluate how dependent a nation is on others’ emissions reductions, how mitigation scenarios reshape air-pollution flows across borders, and whether global efforts are helping or harming equity.”

Lead author Omar Nawaz at the Cardiff University School of Earth and Environmental Sciences said: “While we know climate action can benefit public health, most research has ignored how this affects the air pollution that travels across international borders and creates inequalities between countries.

“Our analysis shows how climate mitigation decisions made in wealthy nations directly affect the health of people in the Global South, particularly in Africa and Asia.”

The research team used advanced atmospheric modeling and NASA satellite data to simulate different future emissions scenarios for the year 2040. The researchers used this data and a health burden estimation to understand how countries could make an impact through climate policy.

“We were surprised to find that although Asia sees the most total benefits from climate action to its large share of the population, African countries are often the most reliant on external action, with the amount of health benefits they get from climate mitigation abroad increasing in fragmented future scenarios,” said Nawaz.

According to the researchers’ projections, the balance of pollution flowing across borders could shift, even if total global air pollution declines.

These insights could inform policymaking and global aid work that seeks to address climate change.

In a sustainable socioeconomic development scenario, for example, pollution flowing across the U.S.-Mexico border would substantially decrease. Mexico would contribute much more to the health benefits that come from this shift than the United States.

The team plans to do further research exploring how climate change itself alters the weather patterns that transport this pollution, as well as looking at other pollutant types like ozone and organic aerosols.

“Ozone is transported even further in the atmosphere than PM2.5, contributes to significant health burdens, and shares common emission sources with PM2.5. We thus have follow-up studies in the works to investigate the interplay between climate policies and long-range health co-benefits associated with both species simultaneously,” said Henze.

First-of-its-kind study assesses how health benefits of aggressive climate policy travel across international borders.

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'Hiding in plain sight': Scientists reflect on years studying life in Antarctic desert

Daniel William Strain — Thu, 12 Feb 2026 05:02:41 +0000

'Hiding in plain sight': Scientists reflect on years studying life in Antarctic desert Daniel William… Wed, 02/11/2026 - 22:02

Amber Carlson

Antarctica—the coldest, driest and most remote continent on Earth—is proof that life can thrive even in the most unlikely of places.

For humans, it’s hard to imagine a much harsher environment: Inland temperatures in Antarctica can drop below negative 76 degrees Fahrenheit in the winter, and a sheet of ice and snow more than a mile thick covers most (though not all) of the land.

Few plants and animals can survive in Antarctica’s McMurdo Dry Valleys, a frigid desert that is free of ice. But researchers from �� Boulder have made trips to the area for more than 30 years to study the unique streams and organisms that inhabit the area in the summer months.

The water level in the region’s streams varies greatly year over year, so scientists are fascinated by how life has continued to thrive there at all. The organisms there must adapt to extreme conditions to survive—and they do.

Diane McKnight collects measurements from a stream during the Antarctic summer. (Credit: Diane McKnight)

Researchers pose for a photo near Lake Fryxell in Antarctica. (Credit: Mike Gooseff)

A helicopter perches on Canada Glacier while shepherding researchers to the McMurdo Dry Valleys. (Credit: Mike Gooseff)

“I've been struck by how robust these stream ecosystems are,” said Diane McKnight, a distinguished professor at �� Boulder’s Institute of Arctic and Alpine Research (INSTAAR) and a founding principal investigator of the McMurdo Dry Valleys Long-Term Ecological Research (LTER) Program.

“The idea of these stream ecosystems just waiting for water—that sounds like they're just at the edge of existence. But we've learned that isn't really true.”

McKnight, who has spent 27 seasons in Antarctica, reflected her years of Antarctic research at a campus event on Thursday, Feb. 5. She explained how environmental changes can easily upset the delicate ecological balance in the dry valleys. Still, the region has a lot to teach us, not only about the environment in Colorado and other parts of the world, but also about personal resilience in the face of adversity.

The talk was part of a series of events commemorating INSTAAR’s 75th anniversary.

Life in the McMurdo Dry Valleys

Despite the challenges of living in Antarctica, cold-water fish, seals, whales and penguins thrive in the freezing waters off the coast. Plankton, krill and algae provide vital food sources.

Inland, the landscape becomes more desolate. But even in the McMurdo Dry Valleys, streams still flow during the short Antarctic summer and are home to a diverse ecosystem of algae and microorganisms.

“You see it in stream beds. You see these carpets of algae. We see it under the lake ice or at the bottoms of the lakes,” said Mike Gooseff, a professor in the Department of Civil, Environmental and Architectural Engineering at �� Boulder and a fellow at INSTAAR.

Gooseff is also the current principal investigator of the Dry Valleys LTER, a decades-long research project that studies life in the region.

“A lot of that life is hiding in plain sight. If you walk through this environment, or you fly over it, you don't see it. It doesn't jump out at you as life. But there is this whole really interesting—and in some cases, sensitive—ecosystem,” he said.

McKnight said that some of the most interesting inhabitants of the region are diatoms—single-celled algae that are surrounded by glassy cell walls. Like plants, they can perform photosynthesis, converting sunlight to energy and carbon dioxide into oxygen. Diatoms collectively produce 20% to 50% of Earth’s atmospheric oxygen.

Research by McKnight, Gooseff and others has uncovered key features of the streams that allow life to thrive in the dry valleys. Algae growing on rocks underwater, for example, take up nutrients like nitrogen and phosphorus. Eventually, they release those nutrients, which settle into the sediment at the bottom of the streams. In a full-circle moment, the nutrients later filter back into the water from the sediment.

“This is not just happening in the dry valleys,” McKnight said. “It’s probably happening in lots of places where there are slimy rocks and algae growing on the rocks. We think this kind of cycle is happening in other desert streams, and these sediments underneath the streams are like repositories or reservoirs for nutrients when there is water and the algae can grow.”

But conditions in the environment can affect how well this cycle works. Gooseff remembers that in 2002, a particular bad flood season caused water levels in one lake to rise by about 40 inches. The extra water stirred up so much sediment in the lake that the phytoplankton couldn’t get enough light for photosynthesis.

These kinds of disturbances can have big impacts on the environment, not just in the Dry Valleys but in other aquatic environments around the world, too.

What’s ahead?

Both McKnight and Gooseff hope the LTER will continue long into the future. The Dry Valleys are a unique ecosystem where scientists can study specific processes, like those cycles of nutrients, without animals and plants affecting their results.

A long-term study like the LTER gives the researchers better perspective on what is and isn’t normal for the area and how the ecosystem responds to different conditions over time, Gooseff said. A shorter-term project might not capture some of the changes that happen from year to year.

But Antarctica itself offers a lot of lessons in resilience.

“We call Antarctica a ‘harsh environment,’” Gooseff said. “But there is a recognition that these ecosystems thrive.”

McKnight said Antarctica has taught her to be more resilient and overcome unexpected situations and challenges. She has also gotten special joy from bringing students there over the years.

“As the lead scientists, we never get jaded, because we have all this awe and wonder. But it is also rewarding to be with the graduate students who go down there, and then see how being in this challenging environment prepares them to test themselves—they think they can do anything.”

Researchers at the McMurdo Dry Valleys Long-Term Ecological Research Program have spent more than three decades studying ecosystems in one of the world’s most hostile environments.

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Satellite view of streams in the McMurdo Dry Valleys of Antarctica. (Credit: NASA)

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One of the saltiest parts of the ocean is getting fresher

Yvaine Ye — Tue, 10 Feb 2026 17:32:02 +0000

One of the saltiest parts of the ocean is getting fresher Yvaine Ye Tue, 02/10/2026 - 10:32

Yvaine Ye

The Southern Indian Ocean off the west coast of Australia is becoming less salty at an astonishing rate, largely due to climate change, new research shows.

Weiqing Han

In a study published February 3 in Nature Climate Change, �� Boulder researchers and colleagues report that over the past six decades rising temperatures have reshaped global wind patterns and ocean currents, bringing increasing amounts of fresh water into the Southern Indian Ocean. The changes could alter the interactions between the ocean and the atmosphere, disrupt major ocean circulation systems that help regulate climates around the world, and potentially affect marine ecosystems.

“We’re seeing a large-scale shift of how freshwater moves through the ocean,” said Weiqing Han, professor in the Department of Atmospheric and Oceanic Sciences in the College of Arts and Sciences. “It’s happening in a region that plays a key role in global ocean circulation,” she said.

On average, seawater has a salinity of about 3.5%, roughly equivalent to dissolving one and a half teaspoons of table salt in a cup of water. But across an expansive region stretching from the eastern Indian Ocean into the western Pacific Ocean in the Northern Hemisphere tropics, surface waters are naturally less salty. Frequent tropical rainfall brings large amounts of freshwater to the region, while evaporation is relatively low.

This area, known as the Indo-Pacific freshwater pool, is associated with a giant “conveyor belt” of ocean circulation that redistributes heat, salt and freshwater around the planet. Known as the thermohaline circulation, this system channels warm, fresh surface waters from the Indo-Pacific flow toward the Atlantic Ocean, contributing to the mild climate in western Europe. In the Northern Atlantic Ocean, the water cools, becomes saltier and denser, and eventually sinks before flowing southward in the deep ocean back to the Indian and Pacific Oceans.

A simplified illustration of the thermohaline circulation. Red shows surface currents, and blue shows deep currents. (Credit: NASA)

Over the past six decades, observational data has detected changes in salinity in the Southern Indian Ocean off the southwest coast of Australia. The area is typically dry, with evaporation largely exceeding precipitation. As a result, the seawater in the region has historically been salty.

Han and her team calculated that the area of salty seawater has decreased by 30% over the past six decades, representing the most rapid increase in fresh water observed anywhere in the Southern Hemisphere.

This freshening is equivalent to adding about 60% of Lake Tahoe's worth of freshwater to the region every year,” said first author Gengxin Chen, visiting scholar in the Department of Atmospheric and Oceanic Sciences and senior scientist at the Chinese Academy of Sciences’ South China Sea Institute of Oceanology. “To put that into perspective, the amount of freshwater flowing into this ocean area is enough to supply the entire U.S. population with drinking water for more than 380 years,” he said.

The Indo-Pacific warm pool. (Credit: NOAA)

The freshening is not a result of local precipitation changes. Using a combination of observations and computer simulations, the team found that global warming is altering surface winds over the Indian and tropical Pacific Oceans. These wind shifts are pushing ocean currents to channel more water from the Indo-Pacific freshwater pool to the Southern Indian Ocean.

As seawater becomes less salty, its density decreases. Because fresher water usually sits on top of saltier, denser water, the surface water and deep ocean water become more separated into layers. These stronger contrasts in salinity between layers reduce vertical mixing, an important process that normally allows surface waters to sink and deeper waters to rise, redistributing nutrients and heat throughout the ocean.

Previous studies have suggested that climate change could slow part of the thermohaline circulation, as melting from the Greenland Ice Sheet and Arctic sea ice adds freshwater to the North Atlantic, disrupting the salinity balance needed for the conveyor belt to keep moving. The expansion of the freshwater pool could further influence this system by transporting fresher water into the Atlantic.

Reduced mixing could also impact marine ecosystems. When nutrients from deeper waters fail to reach the sunlit surface, organisms living in shallow waters have less food. Weaker mixing also prevents excess heat in the surface waters from dissipating into deeper layers, making shallow waters even hotter for organisms already under stress from rising temperatures.

“Salinity changes could affect plankton and sea grass. These are the foundation of the marine food web. Changes in them could have far-reaching impact on the biodiversity in our oceans,” Chen said.

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Off the west coast of Australia, some seawater has lost nearly a third of its salty area in recent decades, as climate change-related current shifts push more fresh water into the region.

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Aerial view of rugged western Australian coastline. (Credit: Harrison Reilly/Pexels)

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Aerial view of rugged western Australian coastline. (Credit: Harrison Reilly/Pexels)

Breaking ice, moving earth: Greenland will release more sediment into ocean as climate warms

Megan M Rogers — Thu, 05 Feb 2026 20:28:03 +0000

Breaking ice, moving earth: Greenland will release more sediment into ocean as climate warms Megan M Rogers Thu, 02/05/2026 - 13:28

INSTAAR

A new paper from Irina Overeem and Ethan Pierce describes how icebergs export Greenlandic sediment into the Arctic Ocean—and how that process might change in the future.

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Climate & Environment

House fires release harmful compounds into the air

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Political polarization can spur CO2 emissions, stymie climate action

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Changing times

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What are other ways scientists can reach people who might only hear about climate change issues from the news?

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