Wildfire smoke trends worsening for Western U.S.

The warming climate has made wildfires and smoke increasingly common. Researchers in the Department of Atmospheric Sciences evaluated data from a number of sources to look at air quality trends in the West. A new paper by doctoral student Kai Wilmot with Gannet Hallar and John Lin (GCSC-affiliated faculty) and Derek Mallia (past GCSC fellow) is published in Environmental Research Letters.

 

The following was originally published in At the U:

From the Pacific Northwest to the Rocky Mountains, summers in the West are marked by wildfires and smoke. New research from the University of Utah ties the worsening trend of extreme poor air quality events in Western regions to wildfire activity, with growing trends of smoke impacting air quality clear into September. The work is published in Environmental Research Letters.

“In a big picture sense, we can expect it to get worse,” says Kai Wilmot, lead author of the study and doctoral student in the Department of Atmospheric Sciences. “We’re going to see more fire area burned in the Western U.S. between now and in 2050. If we extrapolate our trends forward, it seems to indicate that a lot of urban centers are going to have trouble in meeting air quality standards in as little time as 15 years.”

Drawing the connection

Many of the West’s inhabitants have seen smoky summer skies in recent years. Last year, dramatic images of an orange-tinted San Francisco Bay Area called attention to the far-reaching problem of wildfire smoke. Wilmot, a native of the Pacific Northwest, has seen the smoke as well and, with his colleagues, looked at trends of extreme air quality events in the West from 2000 to 2019 to see if they correlated with summer wildfires.

Using air measurements of PM2.5, or the amount of particulate matter in the air with diameters less than 2.5 microns, from the Environmental Protection Agency and the IMPROVE monitoring network, along with measurements of fire area burned and the PM2.5 emitted from those fires, the researchers found consistent trends in air quality that correlated with wildfire activity—but that had different spatial patterns in August than in September.

Trends in August and September

Over the years studied, the researchers noticed that the mean air quality was worsening in the Pacific Northwest in the average August when sensors indicated wildfire smoke events.

“That’s pretty dramatic,” Wilmot says, “that extreme events are strong enough to pull the mean up so that we’re seeing an overall increase in particulate matter during August across much of the Pacific Northwest and portions of California. The Pacific Northwest seems like it’s just really getting the brunt of it.”

The reason for that, he says, is that the regions around the Pacific Northwest, in British Columbia and Northern California, both experience wildfires around August. The mountainous Pacific Northwest, Wilmot says, sits in the middle.

But by September, the researchers found, wildfire activity slows in British Columbia and shifts to the Rocky Mountains. The smoke shifts too—the researchers saw emerging trends correlating wildfire smoke with declines in September air quality in Wyoming and Montana. “We see the PM2.5trends start to pick up a bit more in the Rockies and they become more statistically significant, a little bit stronger and more spatially coherent,” Wilmot says.

What about Utah? The study findings show that the magnitude and significance of air quality trends increases as you go from the southern states of Arizona and New Mexico toward the Pacific Northwest. In Utah, Wilmot says, air quality trends are near the edge of statistical significance, with evidence for impact from wildfires, but evidence that’s less robust than in the Pacific Northwest and California. “Thinking about events like the smoke transport from fires in the Bay Area this past summer,” Wilmot says, “I would not be surprised to see trends in Utah become increasingly convincing with additional data.”

Looking to the future

Other researchers in other studies have suggested that the future will bring more fire areas burned in the Western U.S., with an accompanying increase in wildfire smoke exposure throughout the West and the impacts of that smoke on human health.

Wilmot notes that the trends the researchers see in the Pacific Northwest in August are “pretty robust,” he says, while the September trends in Montana and Wyoming are still “emerging.”

“I think the concern is that, given more time, those emerging trends are going to start looking a lot more like what we’re seeing in August,” he says. “I hope that’s not the case, but it seems entirely within the realm of possibility.”

His next step is to develop simulation models to more precisely link wildfire emissions in urban centers to smoke source regions.

“The big picture,” he says, “is aiming to help forest management in terms of identifying wildfire emissions hotspots that are particularly relevant to air quality in the Western U.S., such that if we had funding to spend on some sort of intervention to limit wildfire emissions, we would know where to allocate those funds first to get the most out of it.”

Find the full study here.

Anderegg: Know the Risks of Investing in Forests

William Anderegg, Assistant Professor in the School of Biological Sciences, has a central research question: What is the future of ecosystems in a changing climate?

His lab studies how drought and climate change affect forest ecosystems, and seeks to gain a better mechanistic understanding of how climate change will affect forests around the world. In a new study, Anderegg and colleagues look at the risks of banking on forests to store atmospheric carbon when forests themselves face a number of risks.

Read about the study in AtTheU.

From the Science paper:

“Forests have considerable potential to help mitigate human-caused climate change and provide society with a broad range of cobenefits…Widespread climate-induced forest die-off has been observed in forests globally and creates a dangerous carbon cycle feedback, both by releasing large amounts of carbon stored in forest ecosystems to the atmosphere and by reducing the size of the future forest carbon sink. Climate-driven risks may fundamentally compromise forest carbon stocks and sinks in the 21st century. Understanding and quantifying climate-driven risks to forest stability are crucial components needed to forecast the integrity of forest carbon sinks and the extent to which they can contribute toward the Paris Agreement goal to limit warming well below 2°C. Thus, rigorous scientific assessment of the risks and limitations to widespread deployment of forests as natural climate solutions is urgently needed.”

Exploring Environmental Change in Cataract Canyon

An interdisciplinary cohort of GCSC faculty joined government researchers and community partners over Fall Break for a week-long trip down the Colorado River to explore environmental change in Cataract Canyon.  It was an exceptional immersive week integrating geology, hydrology, ecology, art, philosophy, history, policy, education, recreation, and more in Utah’s spectacular wilderness redrock river landscape.

The goals of this field trip included discussing research and educational opportunities along Cataract Canyon, exploring use of the river as an experiential classroom, promoting awareness of Colorado River issues, and collecting data that catalogues the dramatic changes occurring in Cataract Canyon.

Lake Powell flooded Glen Canyon and half of Cataract Canyon at its maximum elevation. Since 2000, lake elevation dropped 120 ft due to a complex combination of water management, drought and climate change. Low lake elevation has cascading effects, including the reemergence of rapids, the re-establishment of riparian ecosystems, and changes in sediment deposition. One goal of the trip is to help catalog ongoing environmental changes by developing repeatable measurements of change.

UU faculty and researcher participants included Wendy Wischer (Art & Art History), Bill Brazelton and Susan Bush (Biology), Sarah Hinners (City & Metropolitan Planning),  Lauren Barth-Cohen (Education), Jennifer Follstad Shah (Geography), Danya Rumore (Law), and Brenda Bowen and Pete Lippert (Geology & Geophysics).

 

researcher with instrument on canyon river bank researchers standing and crouching to survey rocky desert canyon landscape three researchers on canyon riverside looking at something in the distance

Understanding forest’s response to climate change

GCSC affiliate Dave Bowling, Professor of Biology, studies ecosystem ecology. His research focuses on how organisms in their natural habitats are affected by biological and physical factors, and how these organisms in turn modify their environment.

Bowling is part of a team whose recent study shows how satellite technology enables researchers to better measure CO2 uptake of evergreen forests. This knowledge will enable scientists to better understand how forests are responding to climate change and to better predict responses to future climate change.
Read more here https://unews.utah.edu/forest-glow/

Award to Anderegg for studying the future of forests

Bill Anderegg, GCSC affiliate and Assistant Professor in the U’s School of Biological Sciences, has been awarded a Packard Fellowship to support his research to understand the future of forests in a changing climate. He aims to use this flexible funding to conduct long-term climate change research that’s hard or nearly impossible to fund with traditional grants. Read more in U News.