Days with hazardous levels of air pollutants are more common due to increase in wildfires

In Western U.S., health risks from ground-level ozone and fine particulate matter continue to grow, study shows

Image of smoke from a wildfire turning the sky orange-brown in Los Angeles’ Mar Vista neighborhood.

In October 2017, smoke from a nearby wildfire turned the sky orange-brown in Los Angeles’ Mar Vista neighborhood. Photo credit: Sean Brenner

By David Colgan

After decades of air quality improvement due to the Clean Air Act of 1970 and other regulations since, the Western U.S. is experiencing an increase in the number of days with extremely high levels of two key types of air pollutants due to climate change.

From 2000 to 2020, the growing number of wildfires — made more intense by climate change — and the increasingly common presence of stagnant, hot weather patterns combined to increase the number of days with hazardous levels of ground-level ozone and fine particulate matter. Those conditions are creating health risks for people throughout the region, according to a paper published in Science Advances.

Daniel Swain, a UCLA climate scientist and co-author of the paper, said the increased pollution affects densely populated regions across a broad swath of the West, including the Los Angeles basin, Salt Lake City, Denver and Oregon’s Willamette Valley. The study found that the number of days when both pollutant levels were extremely high increased in nearly every major city from the Pacific Coast to the eastern Rocky Mountains. (The scientists judged pollution levels to be “extremely high” on days when they were in the 90th percentile of their daily average for the study’s 20-year span.)

Smoke from wildfires can travel thousands of miles, harming people who don’t live directly in wildfire-prone areas.

“When we looked at satellite imagery of the whole country this past summer, we could see smoke from Western wildfires making it all the way to New York City,” Swain said. “There could be a connection with air pollution as far away as the East Coast.”

Wildfires and stagnant, hot weather patterns increase the presence of pollution classified as PM 2.5 — particles that measure less than 2.5 microns in width, the equivalent of about three one-hundredths the width of a human hair — which can make its way deep into lungs and can cross into the bloodstream. Scientific studies have linked PM 2.5 pollution to health problems such as decreased lung function, irregular heartbeat and even premature death in people with heart or lung disease.

The combination of weather patterns and wildfires also increases the formation of ground-level ozone, another threat to respiratory health. Ground level ozone forms due to chemical reactions between oxides of nitrogen (such as nitric oxide and nitrogen dioxide) and volatile organic compounds, both of which can come from vehicles, power plants, industrial facilities and other sources.

The researchers found that the increase in extreme levels of PM 2.5 due to climate factors increased hazardous air quality conditions by an average of 25 million person-days each year of the past two decades in the Western U.S. and adjacent areas of the Great Plains, Mexico and Canada. (A person-day refers to a single day of exposure by a single person.)

The analysis is based on pollution data from U.S. Environmental Protection Agency monitoring sites, as well as atmospheric observations and data on atmospheric pressure and temperatures.

The poor air quality conditions highlighted in the paper are likely to get worse for at least the next few decades, even if drastic climate change mitigation measures are implemented, Swain said.

“It has gotten hotter, wildfire conditions have gotten worse and we’re seeing more persistent periods of high atmospheric pressure,” he said. “Each of those factors is projected to increase in the coming years.”

While mitigating emissions from wildfires and climate change will take decades, cities could still enact regulations and other programs to that would help reduce the presence of oxides of nitrogen and volatile ogranic compounds — so-called ozone precursor emissions — in the near term. Although the benefits of those changes would take years to accrue, it could be practical for cities to implement emissions-reduction measures during periods of hazardous air quality, and it would likely help reduce the dangers to human health, Swain said.

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit

UCLA-led team refines ‘kick and kill’ strategy aimed at eliminating HIV-infected cells

Study in mice could point toward method for clearing virus from people who would otherwise depend on medication
A microscope image of HIV particles

A microscope image of HIV particles. The “kick and kill” approach uses cells that are naturally produced by the immune system to kill HIV-infected cells that hide in the body. Photo credit: A. Harrison and Dr. P. Feorino/CDC

By Enrique Rivero

In a study using mice, a UCLA-led team of researchers have improved upon a method they developed in 2017 that was designed to kill HIV-infected cells. The advance could move scientists a step closer to being able to reduce the amount of virus, or even eliminate it, from infected people who are dependent on lifesaving medications to keep the virus from multiplying and illness at bay.

The strategy, described in the peer-reviewed journal Nature Communications, uses cells that are naturally produced by the immune system to kill infected cells that hide in the body, potentially eradicating them, said Dr. Jocelyn Kim, an assistant professor of medicine in the division of infectious diseases at the David Geffen School of Medicine at UCLA.

“These findings show proof-of-concept for a therapeutic strategy to potentially eliminate HIV from the body, a task that had been nearly insurmountable for many years,” said Kim, the study’s lead author. “The study opens a new paradigm for a possible HIV cure in the future.”

Worldwide, there are currently 38 million people living with HIV, and an estimated 36 million have died of HIV-related diseases in the decades since HIV began circulating, according to UNAIDS.

People with HIV take antiretroviral medication to keep the virus at bay. But HIV has the ability to elude antiretrovirals by lying dormant in cells called CD4+ T cells, which signal another type of T cell, the CD8, to destroy HIV-infected cells. When a person with HIV stops treatment, the virus emerges from those reservoirs and replicates in the body, weakening the immune system and raising the likelihood of opportunistic infections or cancers that can lead to illness or death.

The UCLA-led study continues research on a strategy called “kick and kill,” which many of the same scientists first described in a 2017 paper. The approach coaxes the dormant virus to reveal itself in infected cells, so it can then be targeted and killed. In the earlier study, the researchers gave antiretroviral drugs to mice whose immune systems had been altered to mimic those of humans, and then infected with HIV. They then administered a synthetic compound called SUW133, which was developed at Stanford University, to activate the mice’s dormant HIV. Up to 25% of the previously dormant cells that began expressing HIV died within 24 hours.

But a more effective way to kill those cells was needed.

In the new study, while the mice were receiving antiretrovirals, the researchers used SUW133 to flush HIV infected cells out of hiding. They then injected healthy natural killer cells into the mice’s blood to kill the infected cells. The combination of SUW133 and injections of healthy natural killer immune cells completely cleared the HIV in 40% of the HIV-infected mice.

The researchers also analyzed the mice’s spleens — because the spleen harbors immune cells, it’s a good place to look for latent HIV-infected cells — and did not detect the virus there, suggesting that cells harboring HIV were eliminated. In addition, the combination approach performed better than either the administration of the latency reversing agent alone or the natural killer cells alone.

Kim said the researchers’ next objective is to further refine the approach to eliminate HIV in 100% of the mice they test in future experiments. “We will also be moving this research toward preclinical studies in nonhuman primates with the ultimate goal of testing the same approach in humans,” she said.

The study was funded by the National Institutes of Health, the American Foundation for AIDS Research, the National Science Foundation, a National Center for Advancing Translational Sciences UCLA CTSI Grant and the McCarthy Family Foundation.

The study’s co-authors are Tian-Hao Zhang, Camille Carmona, Bryanna Lee, Dr. Christopher Seet, Matthew Kostelny, Nisarg Shah, Hongying Chen, Kylie Farrell, Dr. Mohamed Soliman, Melanie Dimapasoc, Michelle Sinani, Dr. Kenia Yazmin, Reyna Blanco, David Bojorquez, Hong Jiang, Yuan Shi, Yushen Du, Ren Sun and Jerome Zack of UCLA; Natalia Komarova, Dominik Wodarz and Matthew Marsden of UC Irvine; and Paul Wender of Stanford University. Sun is also a member of the faculty of the University of Hong Kong.

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit

UCLA nonviolence class connects students to Martin Luther King Jr.’s enduring legacy

The class taught by Rev. James Lawson Jr. has motivated students to carry on the fight for justice
Graphic depicting an image of Martin Luther King Jr. as well as Rev. James Lawson and UCLA students
By Citlalli Chávez-Nava

Though it’s been more than 50 years since he was killed, the teachings of civil rights leader Martin Luther King Jr. live on at UCLA, as they’re passed along from one of King’s contemporaries to today’s undergraduates.

For the past two decades, Rev. James Lawson Jr. — one of King’s close friends and fellow civil and labor rights leader, who King once referred to as “the leading strategist of nonviolence in the world” — has taught a UCLA course on King’s signature method for social reform.

Lawson, who received campus’s highest honor, the UCLA Medal, in recognition of his life’s work, co-teaches the class with Kent Wong, director of the UCLA Labor Center. “Labor Studies M173: Nonviolence and Social Movements” is part of the labor studies academic program and offered jointly with the African American studies department and the César E. Chávez Department of Chicana and Chicano and Central American Studies.

During the civil rights movement, King and Lawson embraced the philosophy of nonviolence as the most effective force to advance social, racial and economic equity in U.S. society. Together, they taught nonviolent resistance tactics to young activists, catalyzing lunch counter sit-ins, the 1961 Freedom Rides, and worker and student demonstrations that helped desegregate the South and inspired far-reaching voter mobilization efforts. In 1968, Lawson invited King to support the renowned Memphis Sanitation Strike where King was assassinated.

The class has motivated students to embrace King’s enduring legacy, while carrying on the fight for justice on campus and in the community.

“UCLA students have been inspired by Dr. King and Rev. Lawson’s teachings,” Wong said. “Many undocumented students of UCLA, in particular, have embraced the philosophy of nonviolence to win historic victories for immigrant rights, including DACA, the California Dream Act and health care access for undocumented young people.”

Students in the course examine nonviolent theory and its impact on social movements in the United States and around the globe while applying these concepts to present-day social challenges through service learning activities.

“We share a common commitment to getting the nonviolent history and theory into the public coffers where social change, personal change and the change towards equality can be made directly,” said Lawson said during a lecture last year.

Leticia Bustamante, who graduated from UCLA in 2017, said taking the class strongly influenced her academic journey and her activism. Among her most memorable class lectures was learning about King’s “Letter from a Birmingham Jail,” in which King wrote a powerful defense of a 1963 massive direct action campaign to pressure Birmingham merchants to desegregate the city during a busy shopping season. The letter is regarded as one of the most influential texts of the civil rights movement.

“For me, this letter serves as a blueprint and reference on the essentials of nonviolent action. Whether I am organizing for labor or immigration, I always keep the four [nonviolence] principles in the back of my mind,” Bustamante said. “I remind myself that the tensions we are creating are necessary. People should be made to feel uncomfortable, because progress and growth are never easy.”

Bustamante is now a master’s candidate in public policy at the UCLA Luskin School of Public Affairs and has returned to the class as a guest speaker to share her immigrant rights organizing experiences.

Last spring, when the course was moved to an online platform because of COVID-19 restrictions, Lawson and Wong identified an opportunity to share the class with a wider audience. The weekly lectures and conversations were made available in real-time and were also archived on the Labor Center’s YouTube channel.

“Rev. Lawson has deep relationships with union activists, the faith community and social justice leaders throughout the country. We thought this would be an excellent opportunity to spread his teachings on nonviolence far and wide,” Wong said.

Among other distinguished guests, the class featured labor and civil rights activist Dolores Huerta, Black Lives Matter Los Angeles co-founder Melina Abdullah, California State Senator Maria Elena Durazo and anti-apartheid leader Rev. Allan Boesak who addressed the class from his home in South Africa. Lectures offered viewers perspectives on the Delano grape strikes, the Nashville sit-ins and nonviolence movements in other countries. Students and viewers also had the opportunities to discuss Los Angeles-based movements in support of hotel worker rights and Black Lives Matter.

“Our labor studies program is proud to offer a curriculum that connects students to King’s legacy and the teachings of Rev. Lawson,” said Tobias Higbie, professor of history and labor studies faculty chair. “Lawson not only inspires our students by his long career, he also challenges each of us to live up to our potential as agents of positive social change.”

This coming spring 2022, the class will explore similar themes and students will also learn about Lawson’s teachings in a new book, “Revolutionary Nonviolence: Organizing for Freedom,” to be published by UC Press next month. Lawson and Wong hope to teach the course in-person but are prepared to offer the course virtually once again if public health restrictions persist.

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit

Reimagining the scope and approach of the UCLA Center for Early Global Studies

Zrinka Stahuljak embraces the role of ‘fixer’ as she directs the center’s transformation

By Jonathan Riggs

Photo credit: Janja Ružić

Zrinka Stahuljak in front of a 15th-century relief of the winged lion of Venice. Each quarter, she guides students through explorations of paintings, sculptures and architecture, encouraging them to find deeper meaning about the people who created them. Photo credit: Janja Ružić

Journalists, businesspeople and politicians working in foreign countries often depend on fixers — resourceful, problem-solving guides with a sophisticated grasp of local languages, cultures and customs.

Zrinka Stahuljak has long considered herself a fixer, both literally — she was a wartime interpreter in her native Croatia during the 1990s wars in the former Yugoslavia — and metaphorically, in her role at UCLA.

“I’m fascinated and inspired by the transcultural work of fixers, who ultimately help people make transformative connections,” she says.

It’s in that spirit that Stahuljak has overseen the thoughtful transformation of the UCLA Center for Medieval and Renaissance Studies into the UCLA CMRS Center for Early Global Studies. As the center’s director since 2019, Stahuljak has aimed to honor the center’s illustrious past — founded in 1963, it’s one of the oldest such centers in North America — and ensure its dynamic future.

While the center’s purview will still span the third to the 17th centuries, its new name represents an expanded focus, which now takes a global perspective extending far beyond the Eurocentric view that once defined the field. As part of its new approach, research is centered around five axes: sustainability and repurposing, fluidity and permanence, bodies and performance, conversion and mobility, and communication and archive.

“This collaborative platform allows faculty studying various parts of the globe over almost 1,500 years to exchange effectively from within their fields or work together innovatively across them,” says Stahuljak, a professor of European languages and transcultural studies and of comparative literature.

The transformation makes UCLA’s center one of the first major entities in the field to adopt the new, more inclusive approach, and to employ the new methodologies and interdisciplinary orientations that come with it.

“The key to it all is recognizing and proceeding with the knowledge that none of us is alone in this world,” she says. “That’s something the study of the past can give us: an overwhelming sense of relationality to others who have lived and who will live.”

In the wake of its relaunch, the center already has begun to forge new collaborations with partners from across campus, including scholars at the departments of anthropology, Asian languages and cultures, Near Eastern languages and cultures, and world arts and cultures/dance, the David Geffen School of Medicine at UCLA and the Charles E. Young Research Library.

It’s work worthy of a world-class fixer like Stahuljak, who recently wrote two books on fixers: “Les Fixeurs au Moyen Age: Histoire et Littérature Connectées” (“Fixers in the Middle Ages: Connected History and Literature”), which was published in September by Éditions du Seuil, and “Medieval Fixers: Translation in the Mediterranean (1250–1500),” forthcoming from the University of Chicago Press.

Stahuljak researched and wrote both volumes in 2017 and 2018, when she was a Guggenheim fellow.

Staying connected to Europe and her own past richly informs all Stahuljak does. Born to musician parents who valued education, she grew up with a gift for learning multiple languages, including the two she would later adopt professionally, French and English.

Her time as a wartime interpreter — including a frightening night navigating mountain paths alone after the Croatian–Slovenian border closed — interrupted her college education for a year, but it also taught her much about injustice and the need for an international community of scholarship. Stahuljak went on to earn her master’s degree from the University of Kansas and a doctorate from Emory University; after four years at Boston University, she joined UCLA in 2005.

To open her students’ eyes and intellects and perhaps inspire their empathy, Stahuljak starts each quarter by guiding them through explorations of paintings, sculptures and architecture, encouraging them to find deeper meaning about the people who created them and those who have absorbed them over centuries. Her goal: to help students connect with the subjects they’re studying, no matter the historical distance.

That thoughtful approach carries over to her vision for the Center for Early Global Studies. Even with the campus having resumed in-person instruction, Stahuljak plans to continue offering a range of programs online, too, to maintain the growing global audience it cultivated during the pandemic. She’s also investing in the next generation of scholars, for example by holding manuscript workshops to shepherd junior faculty through the often overwhelming process of producing their first books, and she is directing more funds to support graduate students in both traditional and underrepresented areas of study.

“As a fixer, I see my role as making this a community: a collective platform to empower UCLA’s extraordinary researchers, scholars and teachers,” she says. “My goal is to put myself out there and ask, ‘What do you want to do, and how can I help you make it happen?’”

Stahuljak sees her work relaunching the center as an opportunity to marry her rich understanding of the past with her hopeful view of a humane future for all.

“We cannot understand the present without the past — the contrast allows us to analyze differences, successes and failures and, ideally, to find innovation to build an informed and thoughtful future,” she says. “The CMRS Center for Early Global Studies has an investment in making the past contemporary. These lessons help us do what we fixers always seek to do: invent and make real change.”

This article originally appeared in the UCLA Newsroom.

For more of Our Stories at the College, click here.

A meeting between citizens and members of the municipal police in Medellín, Colombia.

In developing countries, no quick fix for strengthening police–civilian relations

Study co-led by UCLA’s Graeme Blair finds community policing did little to improve citizens’ trust of law enforcement
A meeting between citizens and members of the municipal police in Medellín, Colombia.

As part of the study, residents of Medellín, Colombia, met with members of the municipal police to share concerns about law enforcement and discuss potential solutions. Photo credit: Evidence in Governance and Politics

By Jessica Wolf

In an international study co-led by UCLA political scientist Graeme Blair, community policing efforts in six developing countries were ineffective in reducing crime or restoring civilians’ trust in law enforcement.

The practice of community policing was developed in the U.S. in the early 1990s and has since gained popularity across the world. It typically involves collaboration between police and neighborhood watch groups and introduces new mechanisms for citizens to report crimes as well as abuses of power by police.

Along with Blair, the study’s lead authors are Jeremy Weinstein of Stanford University and Fotini Christia of MIT. They and 23 other authors from five universities studied new community policing efforts in Brazil, Colombia, Liberia, the Philippines, Uganda and Pakistan.

The researchers collaborated with local police agencies to implement some common elements of community policing, including town hall meetings and so-called problem-oriented policing, which entails police and civilians identifying specific areas where specific types of crime are occurring, and working together to define solutions. The projects ran for periods ranging from six months (in Pakistan) to 17 months (in the Philippines), and researchers judged the programs’ success based on crime reports and surveys of community members and police officers.

The results, published in the journal Science, showed no evidence that the reforms reduced crime or increased civilians’ trust in police.

Blair said the findings were surprising given the increasing attention being paid to community policing in recent years. Advocates say the approach can help reduce crime while also rebuilding trust between citizens and police.

“Previous evidence from the U.S., U.K. and Australia suggested these policies were effective, and their wide adoption was driven in part by prominent success stories in Boston and Chicago,” Blair said. “But when we studied these locally adapted community policing practices in developing countries we just didn’t see any changes.”

The data showed no improvements in terms of trust in law enforcement, crime reduction or cooperation between civilians and police — the three primary benefits touted by advocates of community policing.

“There were some improvements in citizens’ attitudes toward the police in a couple of cases, but those were inconsistent across the countries we studied,” Blair said.

The study is one of the largest ever to study policy reform in partnership with governments. Researchers worked with six police agencies in six countries, implementing reforms in more than 700 localities and testing them against police beats where the reforms were not instituted. Data collection included interviews with more than 18,000 citizens and 800 officers.

MIT’s Christia said the findings suggest there is no one-size-fits-all approach to police reform.

The researchers have several theories as to why the community policing tactics were ineffective. Among them:

• Insufficient encouragement from senior law enforcement officials, who are responsible for shaping police officers’ understanding of whether and how to implement new policing practices.

• Officers’ reluctance to respond to issues concerning so-called minor crimes — including domestic abuse, harassment and fraud — raised by citizens during community meetings. Researchers observed that police leadership demanded that officers focus on higher-profile crimes, which are more likely to influence their departments’ success metrics and job promotions.

• Police officers being frequently rotated in and out of test locations, which interrupted their training in new policing practices and hampered their ability to create rapport with community members.

“While community policing strategies didn’t deliver the anticipated results on their own, the challenges in implementation point to the need for more systemic reforms that provide the necessary resources and align incentives for police to respond to citizens’ primary concerns,” said Stanford’s Weinstein.

The researchers write that the future success of community policing in developing countries might require support from each level of authority, from senior law enforcement leaders down to station commanders, in order to engender widespread adoption among police officers. Police agencies also might need to change how they measure their success, giving more attention to issues community members care about, and to rethink training and staffing practices.

“It is possible that there is a version of community policing that works in these kinds of settings, but we didn’t find it.” Blair said. “One explanation could be that it takes a long time to build trust between citizens and the police. In some places, it is being thought of as a policy that can reap quick benefits in creating a symbiotic relationship between citizens and the police, but our study shows that doesn’t seem to be broadly true.”

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit

UCLA astronomers discover more than 300 possible new exoplanets

Findings also include a distinctive planetary system with two gas giants
Rendering of the Kepler-444 planetary system.

UCLA researchers identified 366 new exoplanets using data from the Kepler Space Telescope, including 18 planetary systems similar to the one illustrated here, Kepler-444, which was previously identified using the telescope. Photo credit: Tiago Campante/Peter Devine via NASA



By Briley Lewis

UCLA astronomers have identified 366 new exoplanets, thanks in large part to an algorithm developed by a UCLA postdoctoral scholar. Among their most noteworthy findings is a planetary system that comprises a star and at least two gas giant planets, each roughly the size of Saturn and located unusually close to one another.

The discoveries are described in a paper published today in the Astronomical Journal.

The term “exoplanets” is used to describe planets outside of our own solar system. The number of exoplanets that have been identified by astronomers numbers fewer than 5,000 in all, so the identification of hundreds of new ones is a significant advance. Studying such a large new group of bodies could help scientists better understand how planets form and orbits evolve, and it could provide new insights about how unusual our solar system is.

“Discovering hundreds of new exoplanets is a significant accomplishment by itself, but what sets this work apart is how it will illuminate features of the exoplanet population as a whole,” said Erik Petigura, a UCLA astronomy professor and co-author of the research.

The paper’s lead author is Jon Zink, who earned his doctorate from UCLA in June and is currently a UCLA postdoctoral scholar. He and Petigura, as well as an international team of astronomers called the Scaling K2 project, identified the exoplanets using data from the NASA Kepler Space Telescope’s K2 mission.

The discovery was made possible by a new planet detection algorithm that Zink developed. One challenge in identifying new planets is that reductions in staller brightness may originate from the instrument or from an alternative astrophysical source that mimics a planetary signature. Teasing out which ones are which requires extra investigation, which traditionally has been extremely time consuming and can only be accomplished through visual inspection. Zink’s algorithm is able to separate which signals indicate planets and which are merely noise.

“The catalog and planet detection algorithm that Jon and the Scaling K2 team came devised is a major breakthrough in understanding the population of planets,” Petigura said. “I have no doubt they will sharpen our understanding of the physical processes by which planets form and evolve.”

Kepler’s original mission came to an unexpected end in 2013 when a mechanical failure left the spacecraft unable to precisely point at the patch of sky it had been observing for years.

But astronomers repurposed the telescope for a new mission known as K2, whose objective is to identify exoplanets near distant stars. Data from K2 is helping scientists understand how stars’ location in the galaxy influences what kind of planets are able to form around them. Unfortunately, the software used by the original Kepler mission to identify possible planets was unable to handle the complexities of the K2 mission, including the ability to determine the planets’ size and their location relative to their star.

Previous work by Zink and collaborators introduced the first fully automated pipeline for K2, with software to identify likely planets in the processed data.

For the new study, the researchers used the new software to analyze the entire dataset from K2 — about 500 terabytes of data encompassing more than 800 million images of stars — to create a “catalog” that will soon be incorporated into NASA’s master exoplanet archive. The researchers used UCLA’s Hoffman2 Cluster to process the data.

In addition to the 366 new planets the researchers identified, the catalog lists 381 other planets that had been previously identified.

Zink said the findings could be a significant step toward helping astronomers understand which types of stars are most likely to have planets orbiting them and what that indicates about the building blocks needed for successful planet formation.

“We need to look at a wide range of stars, not just ones like our sun, to understand that,” he said.

The discovery of the planetary system with two gas giant planets was also significant because it’s rare to find gas giants — like Saturn in our own solar system — as close to their host star as they were in this case. The researchers cannot yet explain why it occurred there, but Zink said that makes the finding especially useful because it could help scientists form a more accurate understanding of the parameters for how planets and planetary systems develop.

“The discovery of each new world provides a unique glimpse into the physics that play a role in planet formation,” he said.

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit

Increasingly frequent wildfires linked to human-caused climate change, UCLA-led study finds

Image of smoke from a 2019 Northern California wildfire, seen by astronauts aboard the International Space Station.

Smoke from a 2019 Northern California wildfire could be seen by astronauts aboard the International Space Station. Photo credit: NASA

By Stuart Wolpert

Research by scientists from UCLA and Lawrence Livermore National Laboratory strengthens the case that climate change has been the main cause of the growing amount of land in the western U.S. that has been destroyed by large wildfires over the past two decades.

Rong Fu, a UCLA professor of atmospheric and oceanic sciences and the study’s corresponding author, said the trend is likely to worsen in the years ahead. “I am afraid that the record fire seasons in recent years are only the beginning of what will come, due to climate change, and our society is not prepared for the rapid increase of weather contributing to wildfires in the American West.”

The dramatic increase in destruction caused by wildfires is borne out by U.S. Geological Survey data. In the 17 years from 1984 to 2000, the average burned area in 11 western states was 1.69 million acres per year. For the next 17 years, through 2018, the average burned area was approximately 3.35 million acres per year. And in 2020, according to a National Interagency Coordination Center report, the amount of land burned by wildfires in the West reached 8.8 million acres — an area larger than the state of Maryland.

But the factors that have caused that massive increase have been the subject of debate: How much of the trend was caused by human-induced climate change and how much could be explained by changing weather patterns, natural climate variation, forest management, earlier springtime snowmelt and reduced summer rain?

Image of Rong Fu, UCLA professor of atmospheric and oceanic sciences

Rong Fu, UCLA professor of atmospheric and oceanic sciences. Photo courtesy of Rong Fu

For the study, published in the Nov. 9 edition of the journal Proceedings of the National Academy of Sciences, the researchers applied artificial intelligence to climate and fire data in order to estimate the roles that climate change and other factors play in determining the key climate variable tied to wildfire risk: vapor pressure deficit.

Vapor pressure deficit measures the amount of moisture the air can hold when it is saturated minus the amount of moisture in the air. When vapor pressure deficit, or VPD, is higher, the air can draw more moisture from soil and plants. Large wildfire-burned areas, especially those not located near urban areas, tend to have high vapor pressure deficits, conditions that are associated with warm, dry air.

The study found that the 68% of the increase in vapor pressure deficit across the western U.S. between 1979 and 2020 was likely due to human-caused global warming. The remaining 32% change, the authors concluded, was likely caused by naturally occurring changes in weather patterns.

The findings suggest that human-induced climate change is the main cause for increasing fire weather in the western United States.

“And our estimates of the human-induced influence on the increase in fire weather risk are likely to be conservative,” said Fu, director of UCLA’s Joint Institute for Regional Earth System Science and Engineering, a collaboration with NASA’s Jet Propulsion Laboratory.

The researchers analyzed the so-called August Complex wildfire of 2020, which burned more than a million acres in Northern California. They concluded that human-induced warming likely explains 50% of the unprecedentedly high VPD in the region during the month the fire began.

Fu said she expects wildfires to continue to become more intense and more frequent in the western states overall, even though wetter and cooler conditions could offer brief respites. And areas where vast swaths of plant life have already been lost to fires, drought, heatwaves and the building of roads likely would not see increases in wildfires despite the increase of the vapor pressure deficit.

“Our results suggest that the western United States appears to have passed a critical threshold — that human-induced warming is now more responsible for the increase of vapor pressure deficit than natural variations in atmospheric circulation,” Fu said. “Our analysis shows this change has occurred since the beginning of the 21st century, much earlier than we anticipated.”

The paper’s lead author is Yizhou Zhuang, a UCLA postdoctoral scholar; co-authors are Alex Hall, a UCLA professor of atmospheric and oceanic sciences and director of the UCLA Center for Climate Science; Benjamin Santer, a former atmospheric scientist at Lawrence Livermore National Laboratory; and Robert Dickinson, a UCLA distinguished professor in residence of atmospheric and oceanic sciences.

The research was funded by the National Oceanic and Atmospheric Administration and the University of California.

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit

Pamela Yeh, Van Savage contribute to book about lessons from the pandemic

Image of Pamela Yeh and Van Savage

Pamela Yeh and Van Savage. Photo credit: Reed Hutchinson/UCLA (2)

By Sean Brenner

UCLA professors Pamela Yeh and Van Savage are among the contributors to a new book about lessons that can be drawn from the COVID-19 pandemic and society’s response to the crisis.

“The Complex Alternative: Complexity Scientists on the COVID-19 Pandemic” (2021, SFI Press Compass Series) includes articles by 60 leading scholars.

Yeh, an associate professor of ecology and evolutionary biology, writes about the unique opportunity to study wildlife in empty cities. Savage, a professor of ecology and of evolutionary biology and of biomathematics, explores the informational pitfalls of selective testing.

Written for a general audience, the text also delves into the wide-ranging science, public health and medical challenges and implications of the pandemic, with lessons about how to prepare for possible future pandemics.

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit

Renowned Egyptologist says it’s time to stop romanticizing ancient Egypt

By Alison Hewitt

In ‘The Good Kings,’ UCLA’s Kara Cooney draws parallels between pharaohs and present-day authoritarians
Image of UCLA's Kara Cooney alongside the cover of her book, ‘The Good Kings’

In her latest book, Kara Cooney draws parallels between the rulers of 3,000 years ago and the authoritarian leaders of today. Photo credit: Mikel Healey (Cooney)/National Geographic

Pyramids, pharaohs and ancient Egyptian gods have entranced many, but it’s time we stopped romanticizing the trappings of authoritarianism, according to UCLA’s Kara Cooney.

Cooney is a UCLA professor of Egyptology and archaeology and already a bestselling author (“The Woman Who Would Be King,” 2014, and “When Women Ruled the World,” 2019). In her latest book, she admits that her fascination with ancient Egypt has soured — so much so that she now describes herself as a “recovering Egyptologist.” The uncritical admiration of the pharaohs that has continued to the present day, she writes, is a legacy of the ancient rulers’ efforts to manipulate how they were perceived, and has even served as a narrative and cultural foundation propping up modern authoritarianism.

“How many of us have had deep obsessions with the ancient world — I just love Egyptian temples! I adore Greek mythology! — that are really symptoms of an ongoing addiction to male power that we just can’t kick?” Cooney writes.

“The Good Kings: Absolute Power in Ancient Egypt and the Modern World,” published by National Geographic, draws direct parallels between the rulers of 3,000 years ago and modern tyrants. In it, Cooney describes how the pharaohs created a compelling moral argument for power that continues to mislead people today, and which is linked directly to the current rise of authoritarianism.

Cooney explores the pitfalls of patriarchal systems that harm women and men alike, and she convincingly argues that society is duplicating the historical patterns that have repeatedly led to power collapses. Only this time, she notes, climate change has altered the rules of recovery.

Cooney is chair of UCLA’s Department of Near Eastern Languages and Cultures. In an interview with UCLA Newsroom, she talks about what lessons ancient Egyptian narratives might offer in light of the societal and social challenges the world faces in 2021.

Why are the pharaohs of ancient Egypt still so relevant thousands of years later?

Pharaohs open themselves up to social justice discussions. The hard thing is that the pharaohs were arguably the best ever at presenting an authoritarian regime as good and pure and moral. That’s the underlying idea that needs to be popped first, because we still buy into it today. Concepts of patriarchal society, extraction of natural resources for profit, exploitation, overwork, misogyny and more all came pouring out of the Egyptian narrative.

Image of Kara Cooney examining an artifact

Kara Cooney at work. “Pharaohs were arguably the best ever at presenting an authoritarian regime as good and pure and moral. That’s the underlying idea that needs to be popped first, because we still buy into it today.” Photo Courtesy of Kara Cooney

We’re still living in those narratives. We may tell ourselves we’re too smart to be fooled, but the idea of modern exceptionalism is a fake-out. We’re still just as prone to the fears of an early death or a lack of prosperity. We’re just as superstitious and god fearing.

All those vulnerabilities make us very, very easy marks for authoritarian regimes if we don’t think critically and understand the tools they are wielding over us.

What do you hope people take away from the book?

I wanted to give readers a playbook, in a sense, for what could come next from a historian’s perspective, and why the patriarchy is not the only way of running a system. The patriarchy is destroying itself. It’s happening. And we need to be there, anti-patriarchically, to rebuild something that better protects us all from the abuses of power.

You write that you see signs that the patriarchy is leading society toward a collapse, repeating a pattern that has occurred throughout history. But you also note that climate change will interrupt the cycle in a big way. What can we learn about what comes next by studying the rise and fall of ancient Egyptian regimes?

The patriarchy rises and falls in cycles, collapsing and rebuilding. But the thing that’s haunting authoritarian regimes now is that the Earth is not allowing that cycle anymore. The Earth is not allowing the ongoing extractive, consumptive, unequal hoarding that defines those regimes, because it’s unsustainable, and that unsustainability is now the undoing of the patriarchy.

We’ve had smaller-scale climate change for thousands of years; think of cities wiped away by deforestation that led to mudslides. The difference now is the scale. Now it’s global. The patriarchy sows the seeds for its own destruction again and again before coming back in a vicious cycle, but the difference this time is global climate change threatens to make this the final cycle.

I’m not a soothsayer, but from my 10,000-year view of history, I see two paths. It could be more patriarchy for another 500 years until the planet is truly dead, and then that’s it; that’s the end of the story. But I think we will flirt with patriarchy and mess with it for another 200-some years, and then we will find our way through to something sustainable and different.

This article originally appeared in the UCLA Newsroom. For more news and updates from the UCLA College, visit

Mathematician Michael Hill honored for helping solve 50-year old geometry problem

Image of Michael Hill

Michael Hill. Photo credit: UCLA

By Max Gordy

Michael Hill, professor of mathematics in the UCLA College, has received the 2022 American Mathematical Society Oswald Veblen Prize in Geometry for his paper, “On the nonexistence of elements of Kervaire invariant one,” along with his co-authors Michael Hopkins and Douglas Ravenel.

This paper solved a 50-year-old problem in geometric topology by showing that framed manifolds with Kervaire invariant one can only exist in finitely many dimensions, introducing deeply influential new ideas and techniques in algebraic topology.

“I feel profoundly honored and grateful to the AMS for this award,” Hill said. “This is the award that as a graduate student, I dreamed of someday receiving, and I am all the more delighted that it is for the theorem that I had dreamed of someday proving, working with mathematicians I so admired.

Hill is a member of the topology group, and his research focuses on algebraic topology. He co-founded the Talbot workshop series for early career researchers as well as Spectra: the Association for LGBTQ Mathematicians. Spectra works to make math more inclusive for LGBTQ people, allowing them to bring their whole selves to their mathematical lives. He received a Sloan Research Fellowship in 2010, was an invited speaker at the 2014 ICM in Seoul, South Korea, and was elected a Fellow of the American Mathematical Society in 2021.

The Oswald Veblen Prize in Geometry is awarded every three years for a notable research work in geometry or topology that has appeared in the last six years. The work must be published in a recognized, peer-reviewed venue. The 2022 prize will be presented Jan. 5 at the 2022 Joint Mathematics Meetings in Seattle.

This article originally appeared in the UCLA NewsroomFor more news and updates from the UCLA College, visit