'Time to Make Polluters Pay': Study Ties Fossil Fuel Pollution Directly to Deadly Heatwaves

A study published Wednesday in the journal Nature establishing "that the influence of climate change on heatwaves has increased, and that all carbon majors, even the smaller ones, contributed substantially to the occurrence of heatwaves," is fueling fresh calls for fossil fuel giants to pay for the deadly impacts of their products.

With previous "attribution studies," scientists have generally looked at single extreme weather events. The new study, led by Sonia Seneviratne, a professor at the Swiss university ETH Zurich, is unique for its systematic approach—but that's not all.

"Past studies have mostly looked at emissions from people and countries. This time, we're focusing on the big carbon emitters," explained lead author Yann Quilcaille, a postdoctoral researcher in Seneviratne's group, in a statement.

"We are now at the point where we recognize the serious consequences of extreme weather events for the world's economies and societies—heat-related deaths, crop failures, and much, much more," he said. "People are concerned about who contributed to these disasters."

The researchers found that climate change made 213 heatwaves from 2000–23 "more likely and more intense, to which each of the 180 carbon majors (fossil fuel and cement producers) substantially contributed." They also found that global warming since 1850-1900 made heatwaves 2000-09 about 20 times more likely, and those 2010-19 more likely.

"Overall, one-quarter of these events were virtually impossible without climate change," the paper states. "The emissions of the carbon majors contribute to half the increase in heatwave intensity since 1850-1900. Depending on the carbon major, their individual contribution is high enough to enable the occurrence of 16-53 heatwaves that would have been virtually impossible in a preindustrial climate."

While the study highlights the climate pollution of "14 top carbon majors," including the governments of the former Soviet Union, China (coal and cement), India (coal), and the companies Saudi Aramco, Gazprom, ExxonMobil, Chevron, National Iranian Oil Company, BP, Shell, Pemex, and CHN Energy, Quilcaille said that "the contributions of smaller players also play a significant role."

"These companies and corporations have also primarily pursued their economic interests, even though they have known since the 1980s that burning fossil fuels will lead to global warming," the researcher added.

In a review of the study for Nature, climate scientist Karsten Hausten from Germany's Leipzig University pointed out that "Quilcaille and colleagues' results, as well as the attribution framework that they have developed, provide a tool to continue the legal battle against individual companies and countries."

"This study is a leap forward that could be used to support future climate lawsuits and aid diplomatic negotiations," he wrote. "Finally, it is another reminder that denial and anti-science rhetoric will not make climate liability go away, nor will it reduce the ever-increasing risk to life from heatwaves across our planet."

Hausten was far from alone in recognizing how the new research could contribute to climate cases. Jessica Wentz, senior fellow at the Sabin Center for Climate Change Law at Columbia University, pointed to the International Court of Justice's landmark advisory opinion from July that countries have a legal obligation to take cooperative action against the global crisis.

"Initially, when a plaintiff needs to show that they have standing in a case, they have to allege that they have an injury that is traceable to the defendant's conduct," she told CBC, suggesting the new study will help establish that connection.

"The methodologies that underpin these types of findings can also be used in more fungible ways to look at not only the contributions of the carbon majors, but presumably you could use a similar approach to start looking at government," Wentz said.

Christopher Callahan, a scientist at Indiana University Bloomington who has published research showing that economic damages from rising extreme heat can be tied to companies such as Exxon, said that "this study adds to a growing but still small literature showing it's now possible to draw causal connections between individual emitters and the hazards from climate change."

"There is a wealth of evidence now that major fossil fuel producers were aware of climate change before the rest of the public was and used their power and profit to undermine climate action and discredit climate science," he said, adding that it is "morally appropriate" to hold companies accountable for the emissions of their products.

Callahan also gathered some of the relevant research in a series of posts on Bluesky, noting that on the same day that this new study was published, another team "quantified the thousands of heat-related deaths in Zurich, Switzerland that can be attributed to climate change—and showed that dozens of these deaths are due to the emissions from these individual firms."

"Together, this science—and the broader attribution science that preceded it—are building a clear scientific case for climate accountability," he concluded.

Several US states and municipalities in recent years have launched lawsuits and passed legislation designed to make Big Oil pay for driving the deadly climate emergency—and earlier this year, drawing on an essay in the Harvard Environmental Law Review, an American woman filed the first climate-related wrongful death suit against fossil fuel companies.

In a Wednesday statement to The Guardian about the new study, Cassidy DiPaola, a spokesperson for the Make Polluters Pay campaign, said that "we can now point to specific heatwaves and say: 'Saudi Aramco did this. ExxonMobil did this.'"

"When their emissions alone are triggering heatwaves that wouldn't have happened otherwise," she added, "we're talking about real people who died, real crops that failed, and real communities that suffered, all because of decisions made in corporate boardrooms."