Climate & Environment

'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 CU �鶹ӰԺ 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 CU �鶹ӰԺ’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 CU �鶹ӰԺ 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, CU �鶹ӰԺ 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.

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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One photo, many whales: Scholar captures research above the Arctic Circle

Megan M Rogers — Thu, 05 Feb 2026 17:02:34 +0000

One photo, many whales: Scholar captures research above the Arctic Circle Megan M Rogers Thu, 02/05/2026 - 10:02

Colorado Arts and Sciences Magazine

For CU �鶹ӰԺ ecology and evolutionary biology alum Emma Vogel, an award-winning photo captured a vital moment of research and science.

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Wildlife need social connections too

Yvaine Ye — Thu, 05 Feb 2026 16:59:12 +0000

Wildlife need social connections too Yvaine Ye Thu, 02/05/2026 - 09:59

Yvaine Ye

Imagine an asteroid striking Earth and wiping out most of the human population. Even if some lucky people survived the impact, Homo sapiens might still face extinction, because the social networks humans rely on would collapse.

This dynamic also plays out in the wild.

Social interactions are essential for many animals, helping them to locate food, spot predators and raise offspring. Without such connections, individuals can struggle to survive.

In a new CU �鶹ӰԺ study, researchers challenge a long-held assumption that social connections matter most for “highly social species”, like humans and wolves. They show that much more common “loosely social species,” those that make temporary friends rather than living in stable groups, might be more vulnerable to extinction due to population declines that limit social interactions. Deer, squirrels, chickadees and a whole host of other animals, including invertebrates, all fall into this category.

Mike Gil. (Credit: Heather Hillard)

The study was published in Trends in Ecology & Evolution.

“This finding comes at a moment when many wildlife populations are shrinking or fragmenting due to climate change, habitat loss and exploitation,” said senior author Mike Gil, assistant professor in the Department of Ecology and Evolutionary Biology in the College of Arts and Sciences. “We provide a new framework for predicting which species are most susceptible to collapse so we can better forecast risk.”

The extroverts

Nearly a century ago, American ecologist Warder Clyde Allee showed that animals often do better when they are in larger groups, a phenomenon known as an Allee effect.

Studies have since linked larger group sizes to higher reproductive success and survival in many highly social animals, which are those that live in a fixed group. For example, meerkats with more group mates tend to have more offspring, and more of those offspring survive.

Having more individuals in a group means the group members can get more help when needed, said Samantha Rothberg, the paper’s first author and a doctoral student in Gil’s lab in the Department of Ecology and Evolutionary Biology.

“We can relate to that as humans, because we can benefit a lot from the information provided by individuals around us,” she added.

While many explanations for Allee effects point to benefits from social interactions, research to date has failed to show that social behavior, or the loss of it, can tip a species’ chances of survival.

For example, in African wild dogs, larger packs often have more pups per animal. But when wild dog populations decline across the region, the remaining dogs form new social groups, allowing group sizes and overall survival rates to remain unchanged.

Confused by the inconsistency, Rothberg, Gil and Ella Henry, another doctoral student in Gil’s lab, reviewed decades of ecological theory, models and case studies on social interactions and survival.

What they found suggested that ecologists might have been looking at the wrong animals.

Samantha Rothberg. (Credit: Andy Tan)

The introverts

For decades, ecologists assumed that if social interactions are driving Allee effects, it would be the most pronounced in highly social species like meerkats and wild dogs. But those animals, Gil said, appear to have a built-in buffer against the loss of social interactions.

“It’s intuitive that we think the more social a species is, the more vulnerable it is to losing those interactions,” Gil said. But it turns out, highly social animals can actively compensate.

Much like extroverted humans who have no trouble making friends when they move to a new city, wild dogs seek out new members to restore their group size when they lose members of their pack.

Loosely social animals, by contrast, are more like introverted people. They make friends, but they don’t always have to hang out with them. These species don’t go out of their way to replace lost companions to maintain their social interactions. As a result, when their populations decline, they lose social benefits from experiencing fewer interactions.

“When you remove individuals, you're not just removing those individuals from the population, you're also removing the benefits that they conferred on surviving individuals. That creates a feedback loop,” Rothberg said.

A driver of collapse

Gil said the study highlights a glaring possibility that more species are susceptible to population collapse than previously thought.

According to the World Wildlife Fund, global wildlife populations have declined by at least 73% in the past 50 years. Many scientists have declared this period the “sixth mass extinction,” with human resource extraction wiping out species hundreds of times faster than they would otherwise disappear.

“I’m looking out my window right now, and there are a couple of birds sitting on branches. They’re being social. But those moment-to-moment interactions are easy to take for granted. We now realize that, in aggregate, they can determine whether a population survives or collapses,” Gil said.

New research reveals that "introverted" animals that don't live in stable social groups may be more vulnerable to extinction.

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Deer on CU �鶹ӰԺ campus during a snow storm. (Credit: Casey A. Cass/CU �鶹ӰԺ)

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A group of deer on CU �鶹ӰԺ campus during a snow storm. (Credit: Casey A. Cass/CU �鶹ӰԺ)

US-Greenland science partnerships are on thin ice

Yvaine Ye — Wed, 04 Feb 2026 19:40:57 +0000

US-Greenland science partnerships are on thin ice Yvaine Ye Wed, 02/04/2026 - 12:40

Yvaine Ye

After months of repeated threats to “take over” Greenland, President Trump said last week that he had reached the framework of a deal with NATO over the island’s future.

Amid the geopolitical chaos, researchers have compiled a “statement from U.S. scientists in solidarity with Greenland” to voice their support for the autonomous territory of Denmark. So far, more than 200 scientists who have conducted research in Greenland and worked with Greenlanders have signed the letter, including at least 20 from CU �鶹ӰԺ.

“We vehemently oppose President Trump’s aggressive stance regarding Greenland and reiterate – as Greenland’s leaders have clearly stated – that Greenland is not anyone’s to ‘buy’ or ‘take.’ Greenland belongs to its people,” the letter stated.

Twila Moon, deputy lead scientist at the National Snow and Ice Data Center in the Cooperative Institute for Research in Environmental Sciences (CIRES), signed the letter.

Twila Moon

“I have been studying the ice sheet and going to Greenland for more than 20 years,” said Moon. “The Greenlanders have been very generous in sharing information with us and providing resources to us. We would like to see this peaceful collaborative relationship continue.”

CU �鶹ӰԺ Today sat down with Moon to chat about the letter, the role Greenland and its people play in global research and what would be at stake if the U.S.-Greenland relationship collapses.

What is Greenland like?

I first visited the Greenland Ice Sheet in 2006 as a graduate student. I probably have been there more than a dozen times.

It is a stunningly beautiful landscape. On the west coast, you have large, smoothed-over hills and mountains, which were covered by the ice sheet at one point in history. There are huge fjords all around the coast, so there is a lot of contrast with the ocean meeting up with these big hills and mountains. As you move further inland, you run into the massive ice sheet that still covers 80% of the island.

What do you study there?

When I first began studying Greenland, I was focused on the ice sheet. I was participating in research to understand how quickly the ice sheet was retreating, or advancing, and where the edge of the ice sheet was in recent history.

Over the years, I’ve expanded my research to study how the ice sheet and the ocean interact with each other, how ecosystems are connected to ice sheet changes and how the changes are affecting communities in Greenland and communities really far from Greenland.

Why is Greenland so important in climate research?

The Greenland Ice Sheet holds enough water to raise global sea levels by roughly 24 feet. It has now lost ice every year since the late 1990s, and the rate is much faster than that of Antarctica’s.

When we think about sea level rise over the next few decades, and about changes in currents and weather driven by shifts in the Atlantic Ocean, all of these are tied back to the Greenland Ice Sheet and the very rapid, substantial changes we’re seeing there right now.

In addition to climate research, Greenland also has a wide variety of biodiversity to study. Just a few years ago, I worked with biologists to discover the world’s 20^th sub-population of polar bears in southeast Greenland. Scientists are even in Greenland to study space and astrophysics.

What do you hope to achieve by signing the letter?

We want to help people in the United States who maybe haven't been paying attention to Greenland understand that we have a really good past relationship with Greenland. The Greenlanders have been important partners in being able to understand environmental changes that impact the United States directly.

Greenlanders have been incredibly generous in getting researchers around the island and on the ice sheet, helping people understand the landscape around them, and taking care of instruments at times when international scientists can't be there.

We also wanted to tell our Greenlandic partners that we support them and stand with them.

How important is it to continue the research collaboration between Greenlanders and the United States?

Rapid changes are happening in the Arctic, and we have to run to keep pace with understanding them. I worry that if we see a decline in our relationship with Greenlanders, they might not be as open to providing information or assistance, and this would really be a challenge for U.S. researchers. I've already seen some hesitancy from Greenlanders to participate in projects that include U.S. federal funding.

Science in Greenland is really important for us in America and for all other countries of the world.

CU �鶹ӰԺ 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.

CU �鶹ӰԺ researcher Twila Moon shares what is at stake as President Trump bids for Greenland.

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A view of a small town with mountains in the background, Tasiilaq, Greenland. (Credit: Bernd/Pixabay)

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A view of a small town with mountains in the background, Tasiilaq, Greenland. (Credit: Bernd/Pixabay)

Some tropical land may experience stronger-than-expected warming under climate change

Yvaine Ye — Mon, 02 Feb 2026 16:11:07 +0000

Some tropical land may experience stronger-than-expected warming under climate change Yvaine Ye Mon, 02/02/2026 - 09:11

Yvaine Ye

Some tropical land regions may warm more dramatically than previously predicted, as climate change progresses, according to a new CU �鶹ӰԺ study that looks millions of years into Earth’s past.

Lina Pérez-Angel and her colleagues studying a sediment core from Colombia. (Credit: Maria Fernanda Almanza)

Using lake sediments from the Colombian Andes, researchers revealed that when the planet warmed millions of years ago under carbon dioxide levels similar to today’s, tropical land heated up nearly twice as much as the ocean.

The study was published February 2 in the Proceedings of the National Academy of Sciences.

“The tropics are home to about 40% of the world’s population, yet we’ve had very little direct evidence of how tropical land temperatures respond to climate change,” said lead author Lina Pérez-Angel, who conducted the study as a doctoral student at CU �鶹ӰԺ’s Institute of Arctic and Alpine Research (INSTAAR) and the Department of Geological Sciences. “If we want to study climate change to help people, we need to pay more attention to the regional changes so those living there know what to expect.”

Climate archive from sediments

�鶹ӰԺ 2.5 to 5 million years ago, giant sloths still roamed Earth. The planet was on average 2.5 to 4 °C (4.5 to 7.2°F) warmer than today, and Greenland was largely ice-free.

This period, known as Pliocene, was the last time Earth had carbon dioxide levels similar to what they are today. As such, it is one of the best analogs for what would happen if Earth’s temperatures continued to rise.

Sediment cores are one of the main tools scientists use to reconstruct Earth’s past climate. As sediments slowly accumulate layer by layer, they trap chemical signals, fossils and minerals that reflect temperature, rainfall and atmospheric conditions at the time they were deposited. By drilling and extracting a column of these sediments, scientists can retrace past climate.

Lina Pérez-Angel holding two rock samples from the sediment core that are around a million years apart. (Credit: Ellen Jorgensen)

Most of what scientists know about Earth’s ancient temperatures comes from ocean cores. This is because sediments on the seafloor build up slowly and remain largely undisturbed, whereas on land, rapid landscape changes from erosion, landslides, shifting rivers and mountain building often scramble older sediments, making continuous records hard to come by.

In 1988, a team of Dutch and Colombian scientists retrieved an impressive 580-meter (1,902 feet) long sediment core from the Bogotá basin in Colombia. Pérez-Angel grew up in the region, located at nearly 2,550 meters above sea level in the Andes. The lush high-plain basin is home to Colombia’s capital, Bogotá, South America’s second most populous city with about 11 million people.

Formed millions of years ago, the basin has preserved sediment continuously and largely undisturbed since the late Pliocene.

For the study, Pérez-Angel, senior author Julio Sepúlveda, associate professor in the Department of Geological Science, and their team analyzed a type of fat in bacteria preserved in the core. This enabled them to reconstruct a temperature record of the region from the Pliocene to the Pleistocene, or Ice Age.

They found that compared to the Holocene, which is the current epoch, this land region of the tropical Andes was about 3.7 °C (6.6°F) warmer than today, whereas the tropical sea surface was only 1.9 °C (3.4°F) warmer. This means that land temperatures in the tropics changed about 1.6 to nearly 2 times more than the tropical ocean.

Feedback loop

Pérez-Angel, now a senior research associate at Brown University, said that the Pacific Ocean had a nearly permanent El Niño condition during the late Pliocene, which in turn heated up the tropical Andes even more.

Modern El Niño events have already caused significant warming and drought in the northern Andes. The team warned the area could experience additional warming with El Niño potentially happening more frequently due to climate change.

Pérez-Angel (fourth from the left) and Sepúlveda (right) with co-authors Kathryn Snell (third from left), Peter Molnar (fifth from left) and Angélica Parrado (sixth from left), as well as colleagues at the Colombian Geological Survey. (Courtesy of Julio Sepúlveda).

“If you compare the temperature records for the past couple of decades with what climate models predicted a few decades ago, you see that all the real-world data is at the uppermost end of those predictions,” said Sepúlveda, who is also a fellow at INSTAAR. “This is partly because there are so many feedback mechanisms in nature, and crossing certain thresholds could trigger a series of cascading events that amplify changes.”

Overlooked land

The tropics don’t get as much attention as other regions in climate science, Pérez-Angel said, partly because most of the leading institutions studying climate change are located in middle and high latitude areas, like North America and Europe. The tropics are also not warming as fast as colder regions like Greenland or Antarctica.

But in a region where temperatures are already very high, any increase could push it beyond the threshold of what people and wildlife can tolerate.

“When we model climate change, we tend to focus on how temperatures are going to change globally. But people experience climate change at the regional level,” Pérez-Angel said. With only two high-income countries across the entire tropics, many communities have limited resources to adapt to climate change.

“Understanding what the future might look like for people, ecosystems and the land they depend on is very important for building resilience at a regional level,” she said.

A sediment record millions of years old revealed that the tropical Andes heated up dramatically when atmospheric CO2 levels were similar to today’s.

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Bogotá, Colombia. (Credit: Juan Felipe Ramírez/Pexels)

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Bogotá, Colombia. (Credit: Juan Felipe Ramírez/Pexels)

The pine beetles are back. Here's why—and what you can do about it

Yvaine Ye — Wed, 28 Jan 2026 16:13:55 +0000

The pine beetles are back. Here's why—and what you can do about it Yvaine Ye Wed, 01/28/2026 - 09:13

Yvaine Ye

Colorado’s warm and dry winters have tipped the balance in a long-running ecological tug-of-war.

The mountain pine beetles, native insects to the Centennial State, have recently exploded in numbers in the Front Range after a decade of relatively low populations. The mild winter temperatures have allowed more beetle larvae to survive, while the lack of water has weakened pine trees’ natural defenses against the bugs.

Already, thousands of pine trees along the U.S. 285 and I-70 corridors are turning brown. The devastation prompted Gov. Jared Polis to sign an executive order in December to slow the spread of the beetles.

“A very high level of tree mortality, especially among ponderosa pines, is likely to continue for the next decade,” the order warned.

But the insects are not the antagonists of the story, said Samuel Ramsey, assistant professor in the Department of Ecology and Evolutionary Biology and the BioFrontiers Institute.

Samuel Ramsey looking at a beehive in his lab. (Credit: Patrick Campbell/CU �鶹ӰԺ)

“They are doing exactly what evolution has primed them to do, and they are just able to do it to the maximum because of the ways that climactic contexts have shifted. That is our fault,” he said.

The impact extends beyond tree loss. For the Front Range, a densely populated region already under persistent wildfire threat, dead trees can exacerbate risk.

To unpack what’s behind the outbreak and what may come next, CU �鶹ӰԺ Today sat down with Ramsey to chat about its causes, the outlook for Colorado’s forests and steps people can take to limit the damage.

The Mountain pine beetles are native to Colorado. Why are they causing problems now?

As the climate has shifted, it has knocked the beetles out of their normal balance with the trees. Because the weather has been warm for longer stretches of time, these beetles are able to produce an additional generation of babies, in addition to the dozens of offspring they usually produce.

How do the pine beetles attack trees?

An adult mountain pine beetle. (Credit: Colorado State Forest Service)

The mountain pine beetles are smaller than a grain of rice. When a single pine beetle attacks a tree, it actually can’t do much damage. So, when a pine beetle locates a tree, it will release a smell that tells all the pine beetles in the area to come and attack it. When 1,000 pine beetles all attack the same tree, some get through and lay eggs in the tree. Once inside, the beetles will gum up the tree’s vascular system, cutting off its water and nutrient supply.

Do trees have a defense mechanism for keeping beetles out?

They did in the original climactic circumstances, such as secreting sap to push out the beetles. But when there isn't enough water, they can only produce a small amount of sap, and that is not enough to fend off thousands of beetles that just keep coming at them.

With the warm weather, pine beetles are also maturing faster. That means the trees are starting their battle against the beetles earlier than they had planned. The trees are also fighting later into the season because of the additional generation of beetles.

How bad will this round of the outbreak be?

I'm not a prognosticator, so I cannot tell you that this is going to be a terrible year. But the data is pointing in the direction. In the past, when we have had the same set of circumstances, we have had a banner year for mountain pine beetles. It is estimated that out of more than 4 million acres of pine forests across the state, more than 80% were damaged by the beetles between 1996 and 2013.

This winter has been really warm. That means that more pine beetles are going to survive the winter. So starting this year, their population will be large enough to likely overcome the defense of a lot of these trees. We could have dead stands of pine trees just sitting there ready to welcome the next wildfire.

Are mountain pine beetle outbreaks unique to Colorado?

The mountain pine beetles are distributed in many parts of North America, but Colorado kind of has a perfect storm of circumstances. We have these issues with a warmer winter. Really high winds can help these pine beetles move farther distances when they're flying. In addition, the wind can drive wildfires. Together, those factors make the risks here especially high.

Are there any actions individuals can take to reduce the damage?

There are ways that we can lean into our agency here.

If you have a pine tree in your yard, you need to make sure that it has adequate water by watering it and reducing competition for water from other plants around it.

If you are getting firewood, get it and burn it locally. It’s a really, really bad idea to move firewood, because you could inadvertently help spread the beetles.

If you're seeing mountain pine beetles in your area, and you haven't seen that before, contact your local forest service office.

The pheromone packets people used in the past might not be the best solution, because they won't stop an infestation, and sometimes they can make the problem worse by drawing more beetles to an area than would've arrived otherwise.

As the climate continues to warm, these sorts of ecological issues are going to happen more often. So we need to make sure that instead of only treating the symptoms of climate change, we are reducing the amount of carbon that is going into the atmosphere.

Mountain pine beetles are exploding in numbers again, killing ponderosa pines across large swaths of Colorado. A CU �鶹ӰԺ entomologist explains why it's happening and what it means for wildfire risk.

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A moutain pine beetle chewing on a tree. (Credit: Colorado State Forest Service)

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A moutain pine beetle chewing on a tree. (Credit: Colorado State Forest Service)

Precious waterways: How contaminated mountain streams could power American-made technology

Megan M Rogers — Mon, 22 Dec 2025 18:56:12 +0000

Precious waterways: How contaminated mountain streams could power American-made technology Megan M Rogers Mon, 12/22/2025 - 11:56

INSTAAR

Diane McKnight and Tom Marchitto are collaborators on a new project looking for a way to extract rare earth metals from contaminated Colorado streams. The goal is to improve water quality while also increasing the domestic supply of raw materials for advanced technologies.

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CUriosity: Why hasn't it snowed much this year, and what does that mean for Colorado?

Daniel William Strain — Thu, 18 Dec 2025 22:59:54 +0000

CUriosity: Why hasn't it snowed much this year, and what does that mean for Colorado? Daniel William… Thu, 12/18/2025 - 15:59

Daniel Strain

In CUriosity, experts across the CU �鶹ӰԺ campus answer questions about humans, our planet and the universe beyond.

Jennifer Kay, professor of atmospheric and oceanic sciences and fellow at the Cooperative Institute for Research in Environmental Sciences (CIRES) at CU �鶹ӰԺ, talks about why this winter has been so dry.

A deer on the CU �鶹ӰԺ campus on Dec. 3, 2025, during a short-lived dusting of snow. (Credit: Patrick Campbell/CU �鶹ӰԺ)

Jennifer Kay has a message for the skies above Colorado: “Let it snow.”

Kay is an atmospheric scientist who, in her free time, likes to go cross-country skiing in the Rocky Mountains.

But this year, the season’s typical white-out blizzards haven’t arrived.

Denver didn’t get its first snow—a wimpy dusting of just 0.2 inches—until Nov. 29, the second latest first snow on record. Temperatures around the Front Range have also been downright balmy, drawing close to or even setting record highs.

Could the late start to the winter be a bad omen for Colorado’s ski industry and its future water supplies?

Kay weighs in on the question from CU �鶹ӰԺ’s East Campus with a view of the Flatiron Mountains behind her. They’re almost completely dry, with almost none of the sprinkling of white that usually marks them this time of year.

She says it’s not time to panic—yet.

“It's also really early in the season still, so people shouldn’t be too worried about what’s going to happen with the ski season or water,” says Kay, a fellow at the Cooperative Institute for Research in Environmental Sciences (CIRES) at CU �鶹ӰԺ. “There are still a lot of different ways this season could unfold.”

In 2021, for example, Denver didn’t see its first snow until Dec. 10 (the latest on record). But snowfall totals inched closer to normal in the months that followed.

Kays says it’s not possible to predict how much snow will come to Colorado in an individual winter season months ahead of time.

A lot of that stems from a phenomenon known as the jet stream. That’s the name for a narrow band in the atmosphere above North America where winds reach tremendous speeds, sometimes over 250 miles per hour. When this band hovers above Colorado, it tends to bring big, rumbling storms to the state.

“When the jet stream brings storms to us, we get...a lot of wet, snowy days,” Kay said. “If the jet stream goes another direction, maybe to the north or south of us, we don’t get as many snowstorms.”

Previously in CUriosity

Why do so many people watch football on Thanksgiving?

Or read more CUriosity stories here

But, she adds, any number of complex factors can make the jet stream wiggle from month to month—although meteorologists can often predict what the jet stream will do several days in advance.

Recently, the jet stream has stuck mostly to the north of Colorado, crossing over states like Montana and the Dakotas.

This year’s less-than-snowy winter has Kay thinking about what the future may hold.

With warming, she says, many storms that might normally produce snow may instead bring rain. That could have a wide range of consequences for the state.

A thick blanket of snow on the ground, for example, can keep wildfires from starting and spreading. The Marshall Fire, which devastated parts of �鶹ӰԺ County in December 2021, erupted at a time when the ground was relatively dry, and winds were especially fierce.

Kay believes it’s important for Coloradans to prepare themselves for hotter and dryer weather.

She lives in �鶹ӰԺ and keeps a go-bag packed at all times, even during the winter months. It includes a change of clothes, important documents, chargers for electronic devices and contact information for her neighbors.

“I have already adapted to the reality of more fires as we get hotter and drier in Colorado,” she says. “Understanding what's happening around you and having a plan for extreme events like the strong wind events we have along the Front Range is important.”

This year, the normal blizzards haven't come to most of Colorado, but atmospheric scientist Jennifer Kay says there's still time for the season to turn around.

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