A groundbreaking study published today in Nature has traced responsibility for global heatwaves back to individual fossil-fuel producers, potentially strengthening efforts to hold these companies accountable for their role in climate change. Researchers found that nearly one-quarter of the heatwaves recorded between 2000 and 2023 can be directly attributed to greenhouse-gas emissions from major energy corporations and state-owned entities.
The findings come as climate scientists shift from simply associating extreme weather with global warming to identifying causal links between specific companies and individual events. “I cannot as a scientist assign legal responsibilities for these events,” lead author Yann Quilcaille, a climate researcher at the Federal Institute of Technology in Zurich, told Nature. “What I can say is that each one of these carbon majors is contributing to heatwaves, making them more intense and also more likely.”
The study estimates that more than one-quarter of the 213 heatwaves recorded during the period would have been “virtually impossible” without human-driven warming. Emissions tied to energy giants such as ExxonMobil, BP, Shell, Saudi Aramco, Gazprom, and others increased the probability of some 53 heatwaves by a factor of more than 10,000. For example, ExxonMobil’s emissions are estimated to have made the devastating 2021 heatwave in the US Pacific Northwest over 10,000 times more likely—though uncertainties remain, with lower bounds suggesting at least a 19% increased risk.
The research team analyzed historical emissions from 180 ‘carbon majors’, which together account for 57% of global emissions, including fossil-fuel corporations, state-owned energy giants, and producers of cement and coal. Using climate models comparing a world with and without greenhouse gases, the scientists traced how specific emissions contributed to heatwave probability increases worldwide.
“This is a systematic approach to attribution which brings us to the next level in creating a chain of causality,” said Karsten Haustein, a climate scientist at the University of Leipzig. “We absolutely can allocate blame, and we absolutely should.”
Legal and Ethical Implications
The study’s findings arrive amid dozens of ongoing lawsuits against fossil-fuel companies. A county government in Oregon, for instance, recently filed a $52-billion lawsuit targeting fossil-fuel producers for their role in worsening the 2021 Pacific Northwest heatwave.
Climate legal experts argue that the new evidence could bolster cases seeking damages, though science is only one component in court battles. Jessica Wentz, a legal scholar at Columbia University’s Sabin Center for Climate Change Law, emphasized that many lawsuits focus on how fossil-fuel companies knowingly misled the public about climate risks, similar to tactics used by tobacco companies in the past.
“There is a wealth of evidence now that major fossil-fuel producers were aware of climate change before the public was and used their power and profit to undermine climate action and discredit climate science,” said Christopher Callahan, an Earth-system scientist at Indiana University. “It is morally appropriate to hold those companies accountable for the emissions of the products they sell.”
Industry Silence
Attempts to obtain comments from major oil companies including BP, Shell, Chevron, Saudi Aramco, Gazprom, National Iranian Oil Company, and Coal India were unsuccessful. None responded to requests for comment from Nature.
A Turning Point?
The new study adds momentum to the debate over corporate responsibility for climate-related disasters, especially as public awareness grows and litigation pathways develop. While uncertainties remain, scientists say that attributing extreme weather events to specific companies helps create a clearer chain of causation—and accountability.
“This research takes us one step closer to answering the question of who is responsible for climate damage,” Quilcaille said. “What we choose to do with that knowledge is a decision for courts, politicians, and society at large.”
