Scientists blame fossil fuel production for more than a third of Western wildfires

The world’s top fossil fuel firms may be responsible for more than a third of the acreage scorched by wildfires in Western North America over the past four decades, a new analysis has found.

About 19.8 million acres — or about 37 percent of the total area burned in the Western U.S. and Southwest Canada since 1986 — can be linked to the heat-trapping emissions released by the world’s 88 largest fossil fuel and cement producers, according to the study, published on Tuesday in Environmental Research Letters.

Emissions from these manufacturers have also contributed to nearly half of the observed growth in conditions that raise the risk of severe fires across the region since 1901, the analysis determined.

“Over the last several decades, human-caused climate change has turned routine Western wildfires into exceptionally destructive events,” first author Kristina Dahl, principal climate scientist for the Union of Concerned Scientists, said in a statement.

“Towns are turning to ash and livelihoods are being destroyed,” Dahl added.

The researchers relied on a measure called “vapor pressure deficit,” which allowed them to gauge the ability of air to draw water out of plants and soils. This gauge of atmospheric “thirst,” they explained, is a critical tool for tracking how climate change is exacerbating wildfires.

Using vapor pressure deficit allowed the authors to track how emissions linked to major fossil fuel producers have had a direct impact on the steep hikes in both the acreage burned and fire-danger conditions.

The scientists also used models to demonstrate that emissions tied to the big 88 companies are responsible for raising the global average temperature by 0.5 degrees Celsius since the beginning of the 20th century — or nearly half the observed warming during that time.

This surge in global average temperature has contributed to an 11 percent rise in the vapor pressure deficit across Western North America over the same period, according to study.

In turn, the change in vapor pressure deficit has paved the way for “a steep increase in the forest area that has burned across the region since the mid-1980s,” the authors stated.

The acreage of land burned by forest fires has risen exponentially as vapor pressure deficit has increased — meaning that a relatively small shift in that deficit can “result in large changes in burned forest area,” the scientists found.

In California alone, the authors noted, wildfires killed 186 people between 2017 and 2021 and destroyed more than 51,000 structures, the authors noted.

Meanwhile, across the West, low-income populations and communities of color — particularly Native Americans — face disproportionate health and geographical risks from wildfire and are less able to recover, the researchers stressed.

These findings, Dahl contended, provide “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,” she said.