New UCS Study Finds Top Fossil Fuel Companies Responsible for Over a Third of Area Burned by Wildfires Across Western North America in Last 40 Years

Published May 16, 2023

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A groundbreaking study published today in Environmental Research Letters links the area burned by forest fires and increases in drought- and fire-danger conditions to heat-trapping emissions from the largest global carbon producers.

The new analysis, led by experts at the Union of Concerned Scientists (UCS), “The Fossil Fuels behind Forest Fires,” found that 19.8 million acres burned—37% of the total area scorched by forest fires in the western United States and southwestern Canada since 1986—can be attributed to heat-trapping emissions traced to the world’s 88 largest fossil fuel producers and cement manufacturers. Emissions from these companies also contributed to nearly half of the observed increase in conditions that raise the risk of large, severe forest fires across the region since 1901, the study found. The findings provide new data that can advance efforts to hold companies accountable for past, present, and future climate damages and risks.

“Over the last several decades, human-caused climate change has turned routine Western wildfires into exceptionally destructive events. Towns are turning to ash and livelihoods are being destroyed,” said Kristina Dahl, report author and principal climate scientist at the Union of Concerned Scientists. “Our study offers scientifically backed answers to questions of who bears the responsibility for this gut-wrenching destruction. We’re hopeful that with new evidence in hand, policymakers, elected officials, and legal experts will be better equipped to truly hold fossil fuel companies accountable in public, political, and legal arenas.”

UCS scientists used vapor pressure deficit (VPD)—a measure of air’s ability to draw water out of plants and soils—to demonstrate how emissions traced to major fossil fuel producers have had a direct hand in the steep increases in the area burned by forest fires and the rise of fire-danger conditions. The authors also assessed the latest science on how changes in VPD have contributed to increases in the number of large fires, the length of the fire season, and the severity of forest fires, as well as a prolonged megadrought.

The study builds on a growing body of climate attribution studies that connect emissions from the extraction and use of fossil fuel products to increased average temperature of the Earth’s surface, global sea level rise, and ocean acidification. Using attribution research like this as a foundation, more than 30 states, cities, and counties are currently suing major oil and gas corporations to seek redress for the harm they have suffered from climate change and to limit future emissions. The novel, interdisciplinary findings in this UCS research are positioned to accelerate improved corporate accountability.

“This study represents a significant breakthrough in attribution science—directly linking wildfire destruction in a specific region to the largest global carbon producers,” said Carly Phillips, report author and research scientist for the Accountability Campaign at UCS. “This research builds on over a decade of science tracing heat-trapping emissions and impacts on a global scale to particular fossil fuel operations. More specifically, UCS’ new findings can inform on-going dialogues around the world that are focused on the responsibility of these 88 entities for past, present, and future climate risks.”

The communities, cultures, and ecosystems of the western United States and southwestern Canada evolved alongside wildfire for thousands of years. But over the past several decades, almost all aspects of wildfires have worsened across the forests of Western North America, including land in California, Canada, Colorado, Idaho, New Mexico, Oregon, Washington and Wyoming. The damages from these hazards are mounting, with impacts extending far beyond a given fire scar, harming people, economies and ecosystems.

Communities of color and low-income communities face disproportionate public health risks from wildfire due to systemic socioeconomic injustices and are less able to recover. People of color, particularly Native Americans, are also more geographically at risk of wildfires and smoke exposure.

“While the impacts of increasingly dangerous wildfires are pervasive, it’s crucial to acknowledge that the burden is not borne equally,” said José Pablo Ortiz-Partida, senior bilingual water and climate scientist at the UCS. “As we turn to solutions—both restorative and preventative—the needs of underserved and other vulnerable communities must be front and center.”

In addition to holding fossil fuel companies accountable, UCS experts recommend programs and policies that: rapidly reduce heat-trapping emissions, reduce human-ignited wildfires, increase resources for forest health, and protect community health and safety including through equitable investments in fire preparedness and recovery.