Climate Change

This summer, where there's smoke there's probably fire

Rachel Sauer — Wed, 23 Apr 2025 21:01:58 +0000

This summer, where there's smoke there's probably fire Rachel Sauer Wed, 04/23/2025 - 15:01

Laura Dee

Controlled burns reduce wildfire risk, but they require trained staff and funding—this could be a rough year

Red skies in August, longer fire seasons and checking air quality before taking my toddler to the park. This has become the new norm in the western United States as wildfires become more frequent, larger and more catastrophic.

As an ecologist at the �鶹ӰԺ, I know that fires are part of the natural processes that forests need to stay healthy. But the combined effects of a warmer and drier climate, more people living in fire-prone areas and vegetation and debris built up over years of fire suppression are leading to more severe fires that spread faster. And that’s putting humans, ecosystems and economies at risk.

To help prevent catastrophic fires, the U.S. Forest Service issued a 10-year strategy in 2022 that includes scaling up the use of controlled burns and other techniques to remove excess plant growth and dry, dead materials that fuel wildfires.

CU �鶹ӰԺ researcher Laura Dee is an associate professor of ecology and evolutionary biology.

However, the Forest Service’s wildfire management activities have been thrown into turmoil in 2025 with funding cuts and disruptions and uncertainty from the federal government.

The planet just saw its hottest year on record. If spring and summer 2025 are also dry and hot, conditions could be prime for severe fires again.

More severe fires harm forest recovery and people

Today’s severe wildfires have been pushing societies, emergency response systems and forests beyond what they have evolved to handle.

Extreme fires have burned into cities, including destroying thousands of homes in the Los Angeles area in 2025 and near �鶹ӰԺ, Colorado, in 2021. They threaten downstream public drinking water by increasing sediments and contaminants in water supplies, as well as infrastructure, air quality and rural economies. They also increase the risk of flooding and mudslides from soil erosion. And they undermine efforts to mitigate climate change by releasing carbon stored in these ecosystems.

In some cases, fires burned so hot and deep into the soil that the forests are not growing back.

While many species are adapted to survive low-level fires, severe blazes can damage the seeds and cones needed for forests to regrow. My team has seen this trend outside of Fort Collins, Colorado, where four years after the Cameron Peak fire, forests have still not come back the way ecologists would expect them to under past, less severe fires. Returning to a strategy of fire suppression − or trying to “go toe-to-toe with every fire” − will make these cases more common.

Proactive wildfire management can help reduce the risk to forests and property.

Measures such as prescribed burns have proven to be effective for maintaining healthy forests and reducing the severity of subsequent wildfires. A recent review found that selective thinning followed by prescribed fire reduced subsequent fire severity by 72% on average, and prescribed fire on its own reduced severity by 62%.

But managing forests well requires knowing how forests are changing, where trees are dying and where undergrowth has built up and increased fire hazards. And, for federal lands, these are some of the jobs that are being targeted by the Trump administration.

Parts of Cameron Peak in north-central Colorado that burned in a severe fire in 2020 showed scant evidence of recovery four years later, when this photo was taken. (Photo: Bella Olesky/CU �鶹ӰԺ)

Some of the Forest Service staff who were fired or put in limbo by the Trump administration are those who do research or collect and communicate critical data about forests and fire risk. Other fired staff provided support so crews could clear flammable debris and carry out fuel treatments such as prescribed burns, thinning forests and building fire breaks.

Losing people in these roles is like firing all primary care doctors and leaving only EMTs. Both are clearly needed. As many people know from emergency room bills, preventing emergencies is less costly than dealing with the damage later.

Logging is not a long-term fire solution

The Trump administration cited “wildfire risk reduction” when it issued an emergency order to increase logging in national forests by 25%.

But private − unregulated − forest management looks a lot different than managing forests to prevent destructive fires.

Logging, depending on the practice, can involve clear-cutting trees and other techniques that compromise soils. Exposing a forest’s soils and dead vegetation to more sunlight also dries them out, which can increase fire risk in the near term.

In general, logging that focuses on extracting the highest-value trees leaves thinner trees that are more vulnerable to fires. A study in the Pacific Northwest found that replanting logged land with the same age and size of trees can lead to more severe fires in the future.

Research and data are essential

For many people in the western U.S., these risks hit close to home.

I’ve seen neighborhoods burn and friends and family displaced, and I have contended with regular air quality warnings and red flag days signaling a high fire risk. I’ve also seen beloved landscapes, such as those on Cameron Peak, transform when conifers that once made up the forest have not regrown.

My scientific research group and collaborations with other scientists have been helping to identify cost-effective solutions. That includes which fuel-treatment methods are most effective, which types of forests and conditions they work best in and how often they are needed. We’re also planning research projects to better understand which forests are at greatest risk of not recovering after fires.

This sort of research is what robust, cost-effective land management is based on.

When careful, evidence-based forest management is replaced with a heavy emphasis on suppressing every fire or clear-cutting forests, I worry that human lives, property and economies, as well as the natural legacy of public lands left to every American, are at risk.

Laura Dee is an associate professor in the Department of Ecology and Evolutionary Biology.

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

Controlled burns reduce wildfire risk, but they require trained staff and funding—this could be a rough year.

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Top image: U.S. Fish and Wildlife Service

How we can, why we must transform food systems

Rachel Sauer — Mon, 21 Apr 2025 19:07:24 +0000

How we can, why we must transform food systems Rachel Sauer Mon, 04/21/2025 - 13:07

Laura Vang Rasmussen , Ingo Grass , Claire Kremen and Zia Mehrabi

Evidence shows that diversified farming is key

If you had to pick the single most important thing driving the overshooting of multiple planetary boundaries, it would be the food we eat and how we produce that food. The environmental grand challenges of our day—biodiversity loss, climate change, freshwater use and pollution—all tie back to our food systems.

So also do our social challenges: As of writing, one in four people around the world does not have reliable access to nutritious food. Our food systems need transformation. They must become environmentally safe and socially just.

For years, ecologists have advocated for designing our food systems to be diverse, like ecosystems, to help bring the planet into a safe operating space for humanity. And despite clear examples of both innovative farmers and more traditional ones around the world doing this in practice, governments have remained skeptical due to the opposition this idea poses to mainstream agricultural-development policy.

As we undertook our published research, we set out to explore if mainstream thinking surrounding agricultural development was wrong and, if so, what adding diversity back into agricultural systems might do to correct farming systems around the world.

We worked with more than 50 researchers, who in turn worked with thousands of farmers across 11 countries covering five continents, to test the idea. We covered vastly different food systems, from maize production in Malawi to silvopastoral cattle farming in Colombia, winter wheat production in Germany, strawberry cultivation in the United States and more.

One unique feature of our approach was that all co-authors participated actively in the study design to interweave the many data sets spread across the world. Our project was far from a standard research initiative; it was highly interdisciplinary, involving the co-production of knowledge among researchers from various fields and farmers.

Further, a stakeholder committee, including representatives from different levels of government, U.N. organizations, NGOs and various national farmers’ organizations, was involved in co-production through workshops and engagement activities.

We all worked together to answer a basic question: If more diversity is added into, or kept on, farms, what happens to the environmental and social outcomes we care about? Do we create a better world for people and nature?

CU �鶹ӰԺ scientist Zia Mehrabi and his research colleagues found that across systems, a general rule emerged: the more diversification done at a farm, the better. (Photo: California Strawberry Commission)

The outcomes we looked at were directly related to planetary boundaries on reducing environmental pollution, land use, biodiversity loss and the disruption of biogeochemical flows.

But, unlike earlier studies, we also assessed social outcomes at the same time, including human well-being, crop yields and food security. This integration allowed us to assess whether both positive environmental and social outcomes can be achieved at the same time, something that had never been done before in this way.

What we produced was novel: the first-ever cross-continental, multi-farming system and culturally contextual evidence from real food systems that diversifying agricultural systems helps move agriculture toward where we want it to be. We found that the benefits of diversification differed depending on the practices and farming systems they were tied to. But saliently, we found that across systems, a general rule emerged: the more diversification done at a farm, the better.

And even more promisingly, this was especially true when it came to improving food security and biodiversity at the same time—two outcomes that have previously been juxtaposed in policy and that need the world’s urgent attention now more than ever.

Critically, our study was not theoretical or abstract, nor was it run on field stations or in laboratories. It was conducted with farmers on real-world farms. The main effects we identified held up to a range of different analyses.

We even came up with a list and typology of on-farm interventions, all clearly defined, for practical implementation and support by governments, NGOs, research for development organizations and civil society groups. Importantly, the significance of these interventions is already recognized as a possible pathway toward change and was a key focus of the U.N. Food Systems Summit.

Our work provides robust evidence that investment in these areas will yield the desirable outcomes, bolstering ongoing initiatives by governments and the private sector to support these transformative actions.

Our research demonstrates that diversification represents a significant, tangible and policy-relevant step towards achieving more sustainable food systems globally: one not just grounded in theory or anecdotes but also supported by rich data, covering a vast range of farming systems across the world.

Other observations made during our research project include the insight that farmers in many locations have already been actively working against the odds, finding ways past barriers to diversification. We’ve found this in Malawi, Brazil and the United States, where grass-roots communities of farmers and social networks are mobilizing knowledge, land, seeds, equipment, processing infrastructure and markets to support this movement. Policymakers and practitioners can now support these groups by lowering the structural barriers that have limited their growth and the growth of diversified farming to date.

We are now at a critical juncture where agricultural-development policy requires urgent attention. While the action will be location dependent—diversifying systems that have been made far too simple to function properly and retaining diversity in systems where it is threatened—the time has come, and the options exist, to ensure that the damages and losses done in the past do not continue into the future.

Laura Vang Rasmussen is associate professor of geosciences and natural resource management at the University of Copenhagen in Denmark. Ingo Grass is professor and head of the Department of Ecology and Tropical Ecological Systems at the University of Hohenheim in Germany. Claire Kremen is the president’s excellence chair in biodiversity at the University of British Columbia in Canada. Zia Mehrabi is an associate professor of environmental studies at the �鶹ӰԺ.

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Evidence shows that diversified farming is key.

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Farm-diversification research wins high kudos

Rachel Sauer — Mon, 21 Apr 2025 19:03:22 +0000

Farm-diversification research wins high kudos Rachel Sauer Mon, 04/21/2025 - 13:03

Clint Talbott

CU �鶹ӰԺ’s Zia Mehrabi and an international group of researchers are named national champion of the Frontiers Planet Prize for research that finds environmental and social benefits of agricultural diversification

Widespread agricultural diversification could improve the health of the world’s environment and that of its people, a landmark study published last year found.

Zia Mehrabi, assistant professor of environmental studies at the �鶹ӰԺ, alongside a large group of international researchers, has been named the U.S. national champion for the Frontiers Planet Prize, the Frontiers Research Foundation announced today.

As one of 19 national champions, Mehrabi and team are in contention to be named one of three international champions, each of whom will receive $1 million in funding to advance their research. The international champions will be announced at the Frontiers Planet Prize ceremony in Switzerland in June.

Zia Mehrabi, a CU �鶹ӰԺ assistant professor of environmental studies, has been named the U.S. national champion for the Frontiers Planet Prize.

The Frontiers Planet Prize celebrates breakthroughs in Earth system and planetary science that “address these challenges and enable society to stay within the safe boundaries of the �鶹ӰԺ ecosystem.” The prize puts scientific rigor and ingenuity at its heart, helping researchers worldwide accelerate society toward a green renaissance, the Frontiers Research Foundation says.

Professor Jean-Claude Burgelman, director of the Frontiers Planet Prize, said the planet faces immense threats that require bold, transformative solutions rooted in evidence and validated by science.

“Innovative yet scalable solutions are the only way for us to ensure healthy lives on a healthy planet,” Burgelman said. “By spotlighting the most groundbreaking research, we are helping scientists bring their work to the international stage and provide the scientific consensus needed to guide our actions and policies.”

Mehrabi, who leads the Better Planet Laboratory, was recognized, alongside his co-authors, for an article published last year in the journal Science titled “Joint environmental and social benefits from diversified agriculture.”

Laura Vang Rasmussen of the University of Copenhagen in Denmark and Ingo Grass of the University of Hohenheim in Germany were lead authors of the paper, which had 58 co-authors. Claire Kremen of the University of British Columbia was a senior author and co-principal investigator on the study.

The researchers found that diversifying crops and animals and improving habitat, soil and water conservation on individual farms can improve biodiversity while improving or, at a minimum, not coming at a cost to yields. Additionally, diversified farming can yield social benefits and improve food security—showing improved food access or a reduced number of hungry months, for example, particularly in smallholder systems.

The more diversification measures farms employed, the more benefits accrued, researchers observed. Essentially, the team found evidence to move toward agriculture that more closely reflects natural systems.

“If you look at how ecosystems operate, it’s not just plants growing alone. It’s not just animals or soil,” Mehrabi said last year. “It’s all of these things working together.”

Using data from 2,655 farms across 11 countries and covering five continents, the researchers combined qualitative methods and statistical models to analyze 24 different datasets. Each dataset studied farm sites with varying levels of diversification, including farms without any diversification practices. This allowed the team to assess the effects of applying more diversification strategies.

Diversified farming differs from the dominant model of agriculture: growing single crops or one animal on large tracts of land. That efficient, “monoculture” style of farming is a hallmark of agriculture after the Green Revolution, which reduced global famine by focusing on high-yield crops that rely on fertilizers and pesticides.

“The Green Revolution did many, many great things, but it came with a lot of costs,” Mehrabi says, noting that synthetic fertilizers and pesticides harm the environment.

Also, to increase labor productivity, large farms rely on mechanization, which tends to “replace people with machines.”

“If you look at how ecosystems operate, it’s not just plants growing alone. It’s not just animals or soil. It’s all of these things working together,” says Zia Mehrabi.

“So, the idea of trying to engineer nature into our agricultural systems is somewhat antithetical to the whole way we think about agricultural development,” Mehrabi says.

Making a case for a different way of doing agriculture is one thing. Implementing it on a widespread basis is something else. The dominant view, fostered by “big ag” (short for agriculture), is that “if you want to do ag, you’ve got to do it this way,” Mehrabi says.

“Our work challenges that idea, but it’s a bit of a David-and-Goliath situation,” he adds. “We have the stone, but it hasn’t yet landed.”

But it’s necessary to confront Goliath, Mehrabi contends, noting that agriculture affects all the things people care about environmentally, including climate change, water security, biodiversity, pollution, land use and habitat destruction.

A third of the Earth’s land is used for agriculture, and about a quarter of greenhouse gas emissions stem from agriculture, he notes. Climate change has reduced agricultural yields by as much as 5% to 10% in the last four decades, research has shown.

“If we want to do something about environmental issues, agriculture is one of the big buckets that we need to really, really start in.”

Separate from the research published in Science, Mehrabi has done modeling of the future state of agriculture globally if the world continues business-as-usual farming. He found that in the next century, the number of farms is likely to be cut in half and the average size of farms would likely double.

Given that, along with what scientists know about the loss of natural ecosystems as farm sizes increase, “the future looks a little bit bleak,” Mehrabi says. But this new research shows it could be different.

Though he does not suggest that all farms must be small farms, he does advise that agriculture strive to diversify systems that have been “massively depleted and massively simplified.”

�鶹ӰԺ the Frontiers Planet Prize, Mehrabi says he’s gratified to be recognized as one of 19 national champions. Additionally, he underscores the importance of the Frontiers Research Foundation’s financial commitment to this kind of research, calling it a “signal” to other funding entities that might follow suit.

Launched by the Frontiers Research Foundation on Earth Day 2022, the prize encourages universities worldwide to nominate their top three scientists working on understanding and putting forward pathways to stay within the safe operating space of nine planetary boundaries that are outlined by the Stockholm Resilience Center.

These nominations are then vetted at the national level, and the top scientists face an independent jury of 100—a group of renowned sustainability and planetary health experts chaired by Professor Johan Rockström—who vote for the National and International Champions.

Read a guest opinion by Zia Mehrabi and co-authors at this link. See a Q&A with Mehrabi about adding carbon-footprint labels on food at this link.

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Climate change is transforming how scientists think about their roles

Rachel Sauer — Fri, 18 Apr 2025 15:08:35 +0000

Climate change is transforming how scientists think about their roles Rachel Sauer Fri, 04/18/2025 - 09:08

Sarah Kuta

CU �鶹ӰԺ researcher Pedro DiNezio emphasizes solving the problems of climate change in the here and now

When Pedro DiNezio began studying El Niño and La Niña roughly 20 years ago, human-caused climate change was still a future problem. At that time, researchers spent much of their energy trying to show that humans were, in fact, influencing the world’s climate.

Flash forward two decades, and climate change is no longer some far-off, eventual phenomenon—it’s happening now. Communities and businesses are factoring climate change into their yearly, monthly and even weekly decisions.

Against this backdrop, climate scientists are starting to transition away from purely theoretical research and pivot toward more applied work and consulting. DiNezio, a �鶹ӰԺ associate professor of atmospheric and oceanic sciences, for example, is embarking on a new partnership with WTW, a global insurance broker and risk advisor—an exciting prospect for putting research into practice.

“We can’t stop the drought and the heatwaves, but we can do things to become more resilient, so they don’t affect us as badly—at least for a while,” says Pedro DiNezio, a CU �鶹ӰԺ associate professor of atmospheric and oceanic sciences.

“I’m going through a career transformation right now because I’m more and more interested in solving problems in the here and now,” says DiNezio. “Because we now know so much about the climate system and about the impact it could have on society, many of us in academia are feeling that it’s time to act.”

Resilience is key

As global temperatures continue to rise, world leaders are taking steps to reduce greenhouse gas emissions. Whether their actions will be enough to stave off catastrophic warming remains to be seen. But, in the meantime, communities and businesses must prepare for and adapt to the unprecedented extremes caused by climate change.

Drought, heatwaves, wildfires, rising sea levels, coastal erosion and other ripple effects are already causing big problems—and scientists like DiNezio might be able to help solve them.

“We can’t stop the drought and the heatwaves, but we can do things to become more resilient, so they don’t affect us as badly—at least for a while,” DiNezio says. “And hopefully we can win that time we need to stabilize the climate.”

For example, research has linked hot weather with an increased risk of accidents and injuries in the workplace. Employees are more likely to suffer heat-related illnesses on hot days. But they’re also more likely to be involved with other seemingly unrelated accidents, too.

From an ethical perspective, companies want to keep their workers safe and healthy. But, from a business perspective, they also want to keep costs down—and workers-compensation insurance is a major expense.

“We’re only starting to learn the full extent of the impact of heatwaves and how we can mitigate them,” says DiNezio. “This is having a huge impact on businesses. So, how do we prevent these accidents?”

As the climate shifts, supply chains are also becoming increasingly vulnerable. When vital waterways like the Panama Canal’s Gatun Lake dry up during droughts, ships cannot reach their intended destinations on time. And those delays cost money.

“You cannot avoid these things, but at least you can know there’s a risk and plan an alternative shipping route,” DiNezio says.

Reinsurance companies are particularly interested in anticipating disasters because they already take a long-term, big-picture view of risk. While a company in one part of the world might be worried about drought and another might be focused on sea level rise, global reinsurance companies see what’s happening around the world and connect the dots.

“Reinsurance companies look for our knowledge because their scale makes them more sensitive to the aggregated effect of climate change over large swaths of the world,” says DiNezio. “They are some of the first businesses to think, ‘How do we anticipate this new climate that is continually changing and prepare for it?’”

Why now?

Climate science is a relatively new field. But, in recent years, it’s matured enough to allow researchers to make predictions that are applicable to communities and businesses.

When vital waterways like the Panama Canal’s Gatun Lake (above) dry up during droughts, ships cannot reach their intended destinations on time. And those delays cost money. (Photo: Valiant/Shutterstock)

“We are starting to see these climate events happening, we have the tools to better predict them, and the climate sector is recognizing this as a problem, as a need,” says DiNezio. “As academics, we cannot ignore them because this is no longer a theoretical exercise.”

Teaching has played an important role in DiNezio’s transformation. After joining the CU �鶹ӰԺ faculty four years ago, DiNezio began teaching an introductory-level class on climate change for non-science majors.

Every semester, DiNezio updated the curriculum because the climate was changing so fast. That process has been a bit of a reality check.

“When you talk about it with students, especially non-science majors, they are interested in what effect this could have on their lives and their careers,” says DiNezio. “You have to think about these things more concretely.”

Concrete problems

DiNezio, like other climate scientists who are experimenting with consulting, is approaching this new career chapter with a mix of enthusiasm and anticipation.

“I’m diving into something that I haven’t done before,” DiNezio says. “Sometimes, I describe it to my friend like I’m doing another PhD. … A lot of people in my field are going through this transformation and is entirely new.”

But, in some ways, DiNezio suspects solving real-world problems may be easier than solving theoretical ones. Either way, DiNezio is looking forward to the new challenge.

“When you move away from the purely academic, the problems become really concrete,” DiNezio says. “It’s really simple: How do you prevent heat deaths or help farmers mitigate drought? For me, the new thing is the action. The transformation is, how do we act with all this information about weather and climate? It’s very different from the academic approach. Now, we have a goal.”

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CU �鶹ӰԺ researcher Pedro DiNezio emphasizes solving the problems of climate change in the here and now.

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Picturing climate change in the West

Rachel Sauer — Wed, 02 Apr 2025 20:57:22 +0000

Picturing climate change in the West Rachel Sauer Wed, 04/02/2025 - 14:57

Rachel Sauer

What began as a hobby for CU �鶹ӰԺ economics undergrad Lucas Gauthier came together as a photographic portfolio documenting the already-evident and potential effects of climate change

Lucas Gauthier and his family moved to Colorado when he was in 6th grade, and after a decade of fairly frequent moves—both parents were in the military—this is where everything made sense: mountains for climbing, runs for skiing, trails for hiking and rivers for rafting.

They took some convincing, but eventually his parents let him venture out on his own—forays that grew longer and longer and took him farther and farther into the Colorado wilderness.

Lucas Gauthier, a senior majoring in economics, has photographically documented his adventures in western landscapes since he was in high school.

�鶹ӰԺ four or five years ago, he began taking pictures along the way, usually on his phone. The photography wasn’t the point, necessarily, “but I found that, especially in Colorado, hiking puts you in some very beautiful places,” he explains. “I hike, and the pictures happen while I’m hiking.”

A through line for what had become a large portfolio of photographs emerged in spring 2024. Gauthier, a senior majoring in economics with a focus on natural resource management, was taking ENLP 3100—Complex Leadership Challenges, a class that requires students to complete three projects during the semester.

The first two projects were more technically focused, but the third emphasized creating something of personal value. So, Gauthier thought about all the places in Colorado that he loves, scrolling through both his memories and his photos. He realized that what began as an almost offhanded hobby was actually documenting places that would be or already were altered by climate change.

From that realization was born Climate Change in the West: A Photographic Journal, a multimedia project that incorporates not only data about things like wildfire, heat wave and drought risk and their potential for significant economic impact, but makes it personal with the scenes of incomparable beauty he has witnessed and documented.

“My interest in water specifically came from my interest in hiking and skiing and an interest in all outdoor sports,” Gauthier says. “When people say there’s going to be less rain, less precipitation, that’s a big deal for me.

“I worked and lived in Breckenridge, which is a tourism-dependent area, so if there’s not enough water, that’s weeks of ski season that are lost, and there might not be a rafting season, so that’s where you start to see the overlaps between how climate change is affecting natural systems and the actual economic impacts on livelihoods.”

Capturing what he sees

“My interest in photography has been in capturing this broad swath of environments that we get to play in—as a way to memorialize the experience for myself, and also to share it with others,” Gauthier says.

He took two photography classes in high school, neither of which focused on outdoor or landscape photography, “but I do think those gave me a good idea for how to compose photos and set them up, how to look for different lighting and visual elements,” he says. “They got me in the mindset of thinking, ‘This is something that strikes me, and I’ll see if I can frame it in way that works with what I want to capture.’”

Gauthier was also in high school when he began tackling ever-more-ambitious climbs and started working his way through Colorado’s 58 fourteeners, a goal he completed over the summer. Of those 58, he climbed at least 45 solo.

“(Climbing solo) is kind of a mix of preference and necessity,” Gauthier explains. “It’s easier when the only person you have to plan for logistically is yourself. And when you’re trying to beat lighting and thunder, it’s best to move light and fast.”

However, he never moves so fast that he can’t look around and, if he’s able, to capture what he’s seeing in a photograph. And he returns to certain favorite places, enough that he can compare them season by season or year by year.

“We’ve had a mix of good and bad snow years, but it’s been very noticeable when a particular area that usually has good (snow) coverage into May or June has already melted,” he says. “And there have been times when I’ve hiked through area and a few years later it’s a burn scar, which is a very visceral sense of change in the environment.

“Then there are little things like aspens are yellowing at a different date, wildflowers are blooming and stop blooming at different times. While it’s not as black and white a change, moving those transition points is definitely something that adds up in aggregate.”

Factors of climate change

Now, as he works his way through Colorado’s 100 highest peaks—he’s summited more than 80—and completes his bachelor’s degree, he still is conceptualizing what it all means. Many climate change models are forecast to take decades—if not centuries—to happen, but Gauthier is already seeing anecdotal evidence of them. What does that mean for how he exists in the outdoors and what he’s going to do after he graduates?

“I feel like there is a lot of doom and gloom, and I definitely feel that, but at the same time I am very much a person who feels like I have to say what I’m going to do about it,” he says. “With my area of emphasis in environmental economics, it’s about acknowledging that we have these issues and asking how we address them through actual, tangible means. For me, that means engaging in actual political and broader social processes. When I’m engaged in something, I feel less powerless.

“I think the main point that I wanted to communicate with this project was emphasizing how each of these different factors of climate change are integrated,” he says. “Fires affect water quality, flooding affects agriculture and all of it impacts places that I and a lot of other people love.”

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What began as a hobby for CU �鶹ӰԺ economics undergrad Lucas Gauthier came together as a photographic portfolio documenting the already-evident and potential effects of climate change.

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Exploring selfish incentives for pursuing climate policy

Rachel Sauer — Tue, 14 Jan 2025 01:02:56 +0000

Exploring selfish incentives for pursuing climate policy Rachel Sauer Mon, 01/13/2025 - 18:02

Bradley Worrell

CU �鶹ӰԺ economist Alessandro Peri makes the case that empowering the young can meaningfully affect climate policy and climate outcomes

The consensus opinion in previous research—that future generations are the major beneficiaries of proactive climate policies—tends to emphasize the importance of intergenerational altruism. However, that perspective largely ignores the idea that selfish incentives of current young and old generations can be an important driver to undertake climate policy, says Alessandro Peri, assistant professor in the �鶹ӰԺ Department of Economics.

Recent studies indicate that peak global warming occurs within a decade of emissions. Thus, current climate policy could benefit young generations later in their lifetimes, says Peri, a macroeconomist whose research focus includes computational and environmental economics.

CU �鶹ӰԺ economist Alessandro Peri argues that selfish incentives of current young and old generations can be an important driver to undertake climate policy.

Meanwhile, climate policy may benefit the current old generations by reducing the damages associated with climate change and therefore increasing the value of their assets.

In the paper, “Selfish Incentives for Climate Policy: Empower the Young!” recently published in the Journal of the Association of Environmental and Resource Economists, Peri and his two co-authors advanced what they say is the first study to examine the direction and magnitude of the selfish incentives of young and old to undertake climate policy.

In the economic model Peri and his co-authors developed, the younger generation (ranging from infants to those aged 35) and the older generation are both part of solutions addressing the climate crisis. The older generation tends to control most of the world’s physical assets, such as factories, he notes.

“What we found after we analyzed, theoretically and quantitively, this question of selfish incentives for climate policy is that incentives of the younger generation can be an important driver for climate policy to address the challenge of global warming,” says Peri.

Abatement measures related to reduced carbon emissions can affect the asset owners’ wealth and, accordingly, the old generation’s selfish incentives to support or oppose climate policy, but the effect is quantitatively small. Hence, Peri says, the exhortation in the title: “Empower the Young!”

When climate policy is a win-win

To explore the selfish incentives for climate policy, the model Peri and his co-authors developed uses a two-generation overlapping generations model, rather than the more common infinitely lived agent model. Peri says the two-generation structure permits a clear distinction between the two types of self-interest: the younger generation’s concern for its future consumption and the older generation’s desire to protect its wealth.

For the incentives of the current young and old generations to undertake climate policy to be aligned (a win-win situation), climate policy must increase the value of the assets owned by the old generations.

“Think about it like if you own a house in front of a lake,” Peri explains. “You don't really like the lake, but someone else decides to clean the lake. Well, the value of your house close to the lake is going to increase; you’re going to benefit indirectly from the cleaning of the environment on your wealth. The (increase) of this price allows the older generations to engage in climate policy and be happy about climate policy.”

For this to happen, Peri and his co-authors created an economic model that uses endogenous asset prices, relaxing the assumption of fixed asset price adopted by most models in the climate literature.

As wealth is transferred from the older generation to the younger one, for the asset price to increase it has to be the case that current young generations want to save more.

“With the new evidence that has shown that emissions today will have an impact in our lifetime in terms of global warming, we wanted to add our new part … looking at how selfish incentives can help mitigate this great human challenge," says CU �鶹ӰԺ researcher Alessandro Peri.

“They (the young) are willing to consume a little bit less today and save for tomorrow, so that they can consume more tomorrow,” as a result of climate policy, Peri says. “And what we show is that for that to happen, it means the young have to have a high elasticity of intertemporal substitution, which is just a fancy way of saying that they are willing to transfer more consumption from today to tomorrow” as a result of the effect of climate policy on the value of consumption over time.

Still, based upon the results of computational research done for the research paper, Peri says he and his co-authors determined that selfish incentives for the younger generation proved more quantitatively important for climate policy than those of the old generation.

Goal to spur further research and discussions

Peri says he hopes the economic model for addressing climate change that he and his co-authors created will complement existing research on economic policy related to climate change, including those that rely on altruistic motivations. He says he does not expect lawmakers to adopt the model as policy, but he hopes the paper will spur further research by economists and prompt discussions among policymakers.

Discussions about combatting climate change are particularly timely now, Peri says, given that in 2024 the temperature of the earth reached 1.5 degrees Celsius hotter than in the pre-industrial era—before heat-trapping fossil fuels began accumulating in the atmosphere. The Paris Climate Accords, signed by representatives for numerous countries in 2016, aims to keep warming below that level when looking over multiple years.

“This is the great challenge we are facing nowadays, with the announcement in 2024 that we reached 1.5 degrees Celsius above pre-industrial times. So, it’s been the hottest year that we’ve observed since the pre-industrial era,” Peri says. “With the new evidence that has shown that emissions today will have an impact in our lifetime in terms of global warming, we wanted to add our new part … looking at how selfish incentives can help mitigate this great human challenge.”

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CU �鶹ӰԺ economist Alessandro Peri makes the case that empowering the young can meaningfully affect climate policy and climate outcomes.

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Racing for climate action at 18,000 feet

Rachel Sauer — Thu, 05 Dec 2024 15:14:08 +0000

Racing for climate action at 18,000 feet Rachel Sauer Thu, 12/05/2024 - 08:14

Rachel Sauer

Invited by the king of Bhutan, CU �鶹ӰԺ PhD student Clare Gallagher completed the 109-mile Snowman Race to bring attention to the realities of climate change

Usually when Clare Gallagher runs 100 miles, she does it all at once—a day that’s alternately punishing and exhilarating and at the furthest boundaries of what her body can do.

The 109-mile Snowman Race was different. It spanned five days across the Himalayas and saw 16 of the most elite ultramarathoners from around the world traversing multiple mountain passes approaching 18,000 feet.

Clare Gallagher (left) was invited by Bhutanese King Jigme Khesar Namgyel Wangchuck to run the 109-mile Snowman Race ultramarathon. (Photo: Snowman Race)

“As far as ultramarathons go, it was not that crazy a distance—we were doing about a marathon a day,” Gallagher explains. “But it took so, so long because these mountains are just so high. We started in Laya (Bhutan), which is about 13,000 feet in elevation, and went up from there.”

Gallagher, a PhD student in the �鶹ӰԺ Department of Environmental Studies and the Institute of Arctic and Alpine Research (INSTAAR), was invited by the king of Bhutan to participate in the 2024 Snowman Race held at the end of October. It was the second time the race was held—an event envisioned by Bhutanese King Jigme Khesar Namgyel Wangchuck to draw international attention to the stark realities of climate change in Bhutan and around the globe.

“Once we actually got there and were literally on top of these glaciers, I could see his point,” Gallagher says. “His goal is for international trail runners like myself to help share the story of what we saw, and what I saw is that the glaciers are melting.”

Running 100 miles

Before she vividly learned that a journey of 100 miles begins with a single step, however, Gallagher was simply a girl who liked to run. She ran track as an undergraduate at Princeton and kept running in Thailand, where she moved after graduating to teach English. While there, she signed up for the inaugural Thailand Ultramarathon almost on a whim and ended up winning.

Learn more

Read more about Clare Gallagher's experiences in Bhutan in an essay she wrote for Outside magazine.

The races she entered grew in length, and in 2016, at age 24, she ran the Leadville Trail 100 for the first time and won. “I had been reading Outside magazine, and I always looked up to some of the women who preceded me (in ultramarathons),” Gallagher says.

“I thought they were really badass, and trail running seemed a lot more interesting than track—I’d gotten really burned out in undergrad, but to race in a beautiful mountain environment, in places that are so remote, really appealed to me.”

Clare Gallagher (front row, far left in purple shirt) and 15 ultramarathon colleagues from Bhutan and around the world completed the five-day Snowman Race. (Photo: Snowman Race)

She won the 2017 Ultra-Trail du Mont-Blanc CCC, setting a course record, and went on to win the 100-mile Western States Endurance Run in 2019, the Black Canyon 100K in 2022 and the Leadville 100 again, also in 2022. She was invited to run the inaugural Snowman Race in Bhutan that year, but she’d started her PhD program, and her schedule couldn’t accommodate the training.

When she was invited to the second Snowman Race in 2024, despite still being in graduate school, she eagerly accepted. The 16 participants were evenly split between Bhutanese and international runners, “and the Bhutanese runners destroyed us,” Gallagher says with a laugh.

“The physiology of running at altitude is pretty fascinating. A lot of the literature is finding that aspects of this ability are genetic, so if you don’t live at these altitudes and if you can’t afford to be acclimating for a month, your experience is going to be really different. It’s probably the gnarliest race I’ve ever done, and I got wrecked by altitude. People thought I might do well because I’m from Colorado—and I was using an altitude tent beforehand a little bit, but I was also taking my PhD prelims and didn’t want to be sleeping in it. So, I got destroyed.”

She did, most importantly, finish the race, and the slower pace she adopted in acquiescence to the altitude allowed her more time to look around.

‘Please send our message’

The Snowman Race course follows the historic, high-altitude Snowman Trek route, beginning in Laya and ending in Chamkhar, and summitting a series of Himalayan passes—the highest of which is 17,946 feet.

"My experiences in Bhutan reminded me that I also feel a lot of hope and a lot of motivation to do what I can do, and smile while I’m at it," says Clare Gallagher (foreground, running in Bhutan), a CU �鶹ӰԺ PhD student in environmental studies. (Photo: Snowman Race)

“On day three we were up almost to 18,000 feet, and I’m walking and kind of sick with altitude, but I still had never felt the immensity of what I felt in the Himalayas,” Gallagher says. “The race route goes really close to glaciers well over 18,000 feet, and I’ve honestly never felt so scared. I could tell these glaciers were melting and the sun was so hot.

“The story of Bhutan is that these glaciers are melting at a much faster rate than predicted and are then creating these big alpine lakes that break through their levy walls or moraines and flood villages. We ran through one of these most at-risk villages—it takes seven days to get there by horse—and the people who live there don’t want to be forced to move. So, they were saying, ‘Please send our message back to your countries, we’re scared of our glaciers obliterating us.’”

And even though her PhD research focuses on plastic pollution in oceans, “even the issue of plastic pollution was apparent up there,” Gallagher says. “The interconnectedness of our world became so, so apparent up there. A piece of plastic trash up there is going to degrade really fast because of the high altitude and super harsh alpine environment, and then all those chemicals are going to go downstream. There’s not ton of trash in Bhutan, but plastic pollution is still a part of this story.”

She adds that Bhutan, like many smaller nations, is vulnerable to the impacts of climate change despite having one of the smallest carbon footprints on the planet, and she rues that it takes runners from western nations flying there—another carbon-intensive activity—to draw attention to the seriousness of climate change.

“A really surprising take-home from this journey was how spiritual the experience was,” Gallagher says. “All of my fellow Bhutanese runners were praying at mountain passes, and any time there was a meditative stupa, they were stopping and praying to the mountain deities, thanking them for safe passage.

“I really do feel there’s some connection between caring for this planet and each other and all the plants and animals on this planet. I feel like that reverence is something I’ve been missing in my work as an environmentalist. The phrase ‘climate change’ has taken on an almost corporate flavor, but in Bhutan things aren’t emails or PowerPoints or slogans, they’re real. Climate change is not just a phrase; it means melting glaciers. So, I’m interested in taking that depth and reverence for the land and living things and beings and asking, ‘OK, what are our problems here in Colorado? What are our challenges?’”

A hazard of the field in which she’s immersed is extreme climate anxiety, and Gallagher says she’s worked to focus day-to-day on “taking care of what I can take care of and acknowledging my present. My experiences in Bhutan reminded me that I also feel a lot of hope and a lot of motivation to do what I can do, and smile while I’m at it. I feel a lot of gratitude for being alive at this time in history and asking, ‘What are we going to do with this moment?’”

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Invited by the king of Bhutan, CU �鶹ӰԺ PhD student Clare Gallagher completed the 109-mile Snowman Race to bring attention to the realities of climate change.

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Top photo: Clare Gallagher runs the Snowman Race in Bhutan. (Photo: Snowman Race)

Free bus fare didn’t yield better air

Anonymous — Mon, 29 Jul 2024 06:00:00 +0000

Free bus fare didn’t yield better air Anonymous (not verified) Mon, 07/29/2024 - 00:00

Sarah Kuta

New research by CU �鶹ӰԺ PhD student Grant Webster finds that the free-fare public transit initiative didn’t reduce ground-level ozone, but may have other benefits

Grant Webster is a big fan of public transit—he takes the bus multiple times a week from his home in east �鶹ӰԺ to the CU �鶹ӰԺ campus, where he’s working on a PhD in economics.

So, two years ago, when he heard about Colorado’s new “Zero Fare for Better Air” campaign, he was intrigued.

The premise was simple: During the month of August 2022, the state’s Regional Transportation District (RTD) waived fares for all bus and train rides. With this free perk, state leaders hoped to encourage Coloradans to leave their cars at home and take public transit instead. They expected this incentive to reduce ground-level pollution during peak ozone season.

CU �鶹ӰԺ economics researcher and PhD student Grant Webster found that the "Zero Fare for Better Air” public transportation campaign did not significantly reduce ozone pollution in Colorado.

As a bus rider, Webster was optimistic, too. But as an economist, he wanted to see the data.

“When they came out with this policy, I was like, ‘Hey, I ride the bus, I think that’s a cool idea,’” he says. “But I was also curious. Has anybody studied whether these policies actually work?”

Now, he has an answer to that question. “Zero Fare for Better Air” did not significantly reduce ozone pollution in Colorado, Webster reports in a new paper published in the journal Transportation Research Part A: Policy and Practice.

Using air pollution, weather, ridership and traffic data, Webster found that public transit ridership did increase during the month of free fares—by roughly 15% to 20%. But even though bus and train travel got a boost, car traffic volumes stayed roughly the same.

“The increase in ridership doesn’t seem to be reducing the number of cars on the roads,” he says. “It might just be transit users taking more rides, or people using RTD that weren’t going to take the ride to begin with.”

Informing policy

Roughly 2% of commuters in the Denver metro area use public transit as their main daily form of transportation—and the proportion is likely even smaller in other parts of the state. So, while public transit ridership saw a sizable bump percentagewise, this bump wasn’t enough to reduce ozone pollution.

For Colorado to see a 1% decrease in ozone pollution, public transit ridership would need to increase by 74% to 192%, Webster finds.

“Even if we had this big increase in ridership, it’s still such a small proportion of commuters, in terms of total pollution contributors, that we wouldn’t expect a huge decrease in ozone pollution overall,” he says.

“The transit infrastructure, the whole environment we live in here in Colorado … people are really reliant on their cars. You’d need a much bigger switch of people’s transit behaviors for this policy to be affecting overall air pollution.”

The findings are a bit of a bummer, but Webster says they’re important nonetheless. They could help policymakers use their limited dollars in different ways—ones that might be more effective at reducing pollution.

The “Zero Fare for Better Air” campaign was funded by Colorado Senate Bill 22-180 and brought back in 2023, but axed in 2024 due to cited budget constraints.

The “Zero Fare for Better Air” campaign was funded by Colorado Senate Bill 22-180 and offered in partnership with the Colorado Energy Office. RTD brought back the campaign for a second year in 2023 and expanded it to include both July and August, while Webster’s research was still underway. But, in 2024, it axed the program, citing state budget constraints.

Webster also points out that, while the campaign didn’t reduce ozone pollution as intended, it may have had other economic benefits, such as making public transit more affordable for low-income individuals or introducing new riders to the system.

Also, his findings only apply to Colorado, where overall ridership is relatively low. The picture might look very different in cities and states with more robust transit infrastructure and a higher proportion of public transit commuters, he adds. So, policymakers elsewhere shouldn’t completely rule out similar initiatives in their locales.

“In places like New York City or Washington, D.C., this type of policy might have completely different implications,” he says.

Consider other incentives

Overall, the findings suggest that, when deciding whether to drive or take public transit, the cost of the fare is not the most important factor in commuters’ decision-making process. And that’s an important takeaway: To change commuters’ behavior, policymakers may need to consider other, more compelling incentives.

You’d need a much bigger switch of people’s transit behaviors for this policy to be affecting overall air pollution.”

“When you talk about getting to work, there are so many factors at play,” Webster says. “What’s traffic going to be like? How far away is the bus station? How long do I have to wait? Can I leave in the middle of the day to go run an errand?”

More broadly, as policymakers look for novel ways to slow or halt human-caused climate change, the study also demonstrates the value of considering possible solutions through an economic lens.

“Economics provides a lot of good tools for studying these types of environmental policies,” Webster says. “Can we incentivize people to change their behavior and, as a result, change an environmental outcome? It’s a super important time to focus on the environment and our human impacts on it. And economics can play a role in studying these issues.”

Top image: Riders board a city bus in Denver. (Photo: RTD)

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New research by CU �鶹ӰԺ PhD student Grant Webster finds that the free-fare public transit initiative didn’t reduce ground-level ozone, but may have other benefits.

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Scholar has a front-row seat to the global fight against plastic pollution

Anonymous — Tue, 28 May 2024 16:28:05 +0000

Scholar has a front-row seat to the global fight against plastic pollution Anonymous (not verified) Tue, 05/28/2024 - 10:28

Rachel Sauer

CU �鶹ӰԺ PhD student Clare Gallagher finds reason for hope amid the complexities of negotiations to craft a U.N. treaty addressing a worldwide crisis

In the past year, Clare Gallagher has gotten very interested in ghost gear, which she admits is “a really depressing Google search” if you’re not already familiar with it.

Ghost gear is the umbrella term for lost, abandoned or discarded fishing gear that contributes to the crisis of plastic pollution in Earth’s oceans and can trap fish and marine mammals, causing them to die by suffocation or exhaustion. In the upper Gulf of California, for example, abandoned gillnetting has contributed to the vaquita porpoise nearing the brink of extinction.

When Gallagher, a PhD student in the �鶹ӰԺ Department of Environmental Studies, joined an observer delegation at the fourth session of the United Nations Intergovernmental Negotiation Committee on Plastic Pollution April 23-29 in Ottawa, Canada, she learned that fishing gear is included in a proposed international treaty on plastic pollution that would be discussed at the weeklong gathering.

Clare Gallagher, a PhD student in the CU �鶹ӰԺ Department of Environmental Studies, by a sculpture outside a U.N. treaty negotiating session in Ottawa, Canada. (Photo: Clare Gallagher)

However, after attending several all-day—and sometimes into the night—negotiating sessions, “I learned that fishing gear is almost like a side note to the greater problem. Single-use plastics are so nefarious, and this is the next climate change fight,” Gallagher says.

“To be able to go sit in conference room for 14 hours a day for nine days straight—and the final meetings went until 3 a.m.—I was pretty in awe of the dedication of the people in these meetings. But then at the same time, it was also incredibly frustrating when there’s not a lot of progress made. It’s just the way of global geopolitics, and I was getting a crash course in this—there will be some countries or blocs of countries that don’t want strong treaties, like oil-producing countries, just as there are countries that have been against strong environmental treaties for the last several decades.”

The gathering Gallagher attended was the fourth session of the U.N. Intergovernmental Negotiating Committee on Plastic Pollution and focused on the marine environment. The committee’s stated goal is to have a completed treaty written by the end of the year.

For Gallagher, attending the session not only was eye-opening to the intricacies of global geopolitics, but also brought several other key insights, including:

Abandoned fishing gear is one problem of many in the crisis of plastic pollution in the world’s oceans

“Microplastics were a huge, huge topic at the treaty discussions,” Gallagher says. “From a health standpoint, I was really surprised to see so many endocrinologists there. The endocrine destruction from chemicals that are being added to plastics is linked to the obesity epidemic, to the epidemic of anxiety and depression. It’s actually pretty terrifying.”

Among the discussion topics were plastic pellets, sometimes called nurdles, which are commonly used as a raw material for making plastic products. They are frequently shipped via container, and if pellets ever spill from those containers into a marine environment, the environmental damage and harm to living creatures can be devastating.

“So, some of the discussion was about classifying them as hazardous waste,” Gallagher says.

However, abandoned fishing gear is a big problem

“Ghost gear is the colloquial term,” Gallagher explains. “The more scientific term is abandoned, lost or discarded fishing gear, or ALDFG, and it’s just a terrible thing. Let’s say you a have huge vessel that’s fishing tuna in the Pacific and use purse seines, which are these crazy kilometer-wide nets that can cinch up entire schools of tuna.

“Say that net gets lost or is intentionally cut by crew or just gets stuck on something or there’s a full-on accident. That net will continue to fish whales, dolphins, turtles, you name it after it’s lost contact with the vessel. That’s why we get term ‘ghost,’ because fishing continues to happen in a worst-case scenario.”

Gallagher notes that purse seines typically are made of nylon, which sinks in water because of its density, so they’re not a significant contributor to the Great Pacific Garbage Patch, which is now about the size of Alaska. However, lighter density nets and fishing line made of high-denisty polyethylene wash up on shorelines around the world, “so it’s pretty incredible that this treaty is trying to address fishing gear as its own plastic pollution sector because almost all commercial fishing nets and lines are made of plastic polymers, so this treaty could address industrial, global and local fishing economies.”

CU �鶹ӰԺ PhD student Clare Gallager attended the fourth session of the United Nations Intergovernmental Negotiation Committee on Plastic Pollution as an observer. (Photo: Clare Gallagher)

Many perceive plastic pollution as a symptom a bigger issue

“The biggest thing is production,” Gallagher says, “stopping primary plastic production. That’s one of the things that’s so interesting about this treaty process, because it’s almost the same story, it’s the same players, it’s the same perpetrators as the international debate over fossil fuel emissions.”

In fact, Gallagher notes, the Center for International Environmental Law analyzed the affiliations of registered attendees for the session and found almost 200 lobbyists for the fossil fuel and chemical industries were registered.

The problems of plastic pollution are daunting, but there’s room for hope

“I felt, not being a United Nations treaty expert, pretty overwhelmed by the scale at which countries around the world need to compromise and work together to create any international treaty, especially environmental treaties,” Gallagher says. “It’s pretty overwhelming to think this is how humanity governs itself at the top level.

“That being said, I have hope that the most ambitious countries will continue to push for a strong treaty on plastic pollution. I don’t know if remorse is right word, but there is sadness that many of the countries suffering the most from plastic pollution are not producing the plastic. They’re the ones that have to deal with plastic trash and plastic pollution, the ones that have to fight for a strong treaty, and there’s a real power imbalance that I find so disgusting and disturbing.”

Gallagher says one of the most impressive coalitions she observed at the session was the Pacific Small Island Developing States (PSIDS): “There was a woman from Easter Island, which, granted, is part of Chile, and she told a story about how every time her young son goes surfing, which is like every day, she has to wash his hair because there’s so much microplastic in it when he’s done.

“People from some of the smallest, poorest countries repeatedly said, ‘This is not complex. We don’t want your trash; we need to stop this.’ I think that bravery and that fight—these Davids taking on Goliaths, as seen in the Rapa Nui Declaration—is what is going to make the world a better place.”

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CU �鶹ӰԺ PhD student Clare Gallagher finds reason for hope amid the complexities of negotiations to craft a U.N. treaty addressing a worldwide crisis.

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Goodbye, El Niño, and hello, La Niña

Anonymous — Fri, 24 May 2024 18:36:15 +0000

Goodbye, El Niño, and hello, La Niña Anonymous (not verified) Fri, 05/24/2024 - 12:36

Pedro DiNezio

La Niña is coming, raising the chances of a dangerous Atlantic hurricane season–an atmospheric scientist explains this climate phenomenon

One of the big contributors to the record-breaking global temperatures over the past year—El Niño—is nearly gone, and its opposite, La Niña, is on the way.

Whether that’s a relief or not depends in part on where you live. Above-normal temperatures are still forecast across the U.S. in summer 2024. And if you live along the U.S. Atlantic or Gulf coasts, La Niña can contribute to the worst possible combination of climate conditions for fueling hurricanes.

Pedro DiNezio, a �鶹ӰԺ associate professor of atmospheric and ocean sciences who studies El Niño and La Niña, explains why and what’s ahead.

Pedro DiNezio is a �鶹ӰԺ associate professor of atmospheric and ocean sciences who studies El Niño and La Niña.

What is La Niña?

La Niña and El Niño are the two extremes of a recurring climate pattern that can affect weather around the world.

Forecasters know La Niña has arrived when temperatures in the eastern Pacific Ocean along the equator west of South America cool by at least half a degree Celsius (0.9 Fahrenheit) below normal. During El Niño, the same region warms instead.

Those temperature fluctuations might seem small, but they can affect the atmosphere in ways that ripple across the planet.

The tropics have an atmospheric circulation pattern called the Walker Circulation, named after Sir Gilbert Walker, an English physicist in the early 20th century. The Walker Circulation is basically giant loops of air rising and descending in different parts of the tropics.

Normally, air rises over the Amazon and Indonesia because moisture from the tropical forests makes the air more buoyant there, and it comes down in East Africa and the eastern Pacific. During La Niña, those loops intensify, generating stormier conditions where they rise and drier conditions where they descend. During El Niño, ocean heat in the eastern Pacific instead shifts those loops, so the eastern Pacific gets stormier.

EL Niño and La Niña also affect the jet stream, a strong current of air that blows from west to east across the U.S. and other mid-latitude regions.

During El Niño, the jet stream tends to push storms toward the subtropics, making these typically dry areas wetter. Conversely, mid-latitude regions that normally would get the storms become drier because storms shift away.

This year, forecasters expect a fast transition to La Niña – likely by late summer. After a strong El Niño, like the world saw in late 2023 and early 2024, conditions tend to swing fairly quickly to La Niña. How long it will stick around is an open question. This cycle tends to swing from extreme to extreme every three to seven years on average, but while El Niños tend to be short-lived, La Niñas can last two years or longer.

How does La Niña affect hurricanes?

Temperatures in the tropical Pacific also control wind shear over large parts of the Atlantic Ocean.

Wind shear is a difference in wind speeds at different heights or direction. Hurricanes have a harder time holding their column structure during strong wind shear because stronger winds higher up push the column apart.

La Niña produces less wind shear, removing a brake on hurricanes. That’s not good news for people living in hurricane-prone regions like Florida. In 2020, during the last La Niña, the Atlantic saw a record 30 tropical storms and 14 hurricanes, and 2021 had 21 tropical storms and seven hurricanes.

Forecasters are already warning that this year’s Atlantic storm season could rival 2021, due in large part to La Niña. The tropical Atlantic has also been exceptionally warm, with sea surface temperature-breaking records for over a year. That warmth affects the atmosphere, causing more atmospheric motion over the Atlantic, fueling hurricanes.

During La Niña, the Walker Circulation intensifies, triggering stronger storms where the air rises. (Graphic: Fiona Martin/NOAA Climate.gov)

Does La Niña mean drought returns to the US Southwest?

The U.S. Southwest’s water supplies will probably be OK for the first year of La Niña because of all the rain over the past winter. But the second year tends to become problematic. A third year, as the region saw in 2022, can lead to severe water shortages.

Drier conditions also fuel more extreme fire seasons in the West, particularly in the fall, when the winds pick up.

What happens in the Southern Hemisphere during La Niña?

The impacts of El Niño and La Niña are almost a mirror image in the Southern Hemisphere.

Chile and Argentina tend to get drought during La Niña, while the same phase leads to more rain in the Amazon. Australia had severe flooding during the last La Niña. La Niña also favors the Indian monsoon, meaning above-average rainfall. The effects aren’t immediate, however. In South Asia, for example, the changes tend to show up a few months after La Niña has officially appeared.

La Niña is quite bad for eastern Africa, where vulnerable communities are already in a long-term drought.

Is climate change affecting La Niña’s impact?

El Niño and La Niña are now happening on top of the effects of global warming. That can exacerbate temperatures, as the world saw in 2023, and precipitation can go off the charts.

Since summer 2023, the world has had 10 straight months of record-breaking global temperatures. A lot of that warmth is coming from the oceans, which are still at record-high temperatures.

La Niña should cool things a bit, but greenhouse gas emissions that drive global warming are still rising in the background. So while fluctuations between El Niño and La Niña can cause short-term temperature swings, the overall trend is toward a warming world.

Pedro DiNezio is an associate professor of atmospheric and oceanic sciences at the �鶹ӰԺ.

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

La Niña is coming, raising the chances of a dangerous Atlantic hurricane season—an atmospheric scientist explains this climate phenomenon.

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