A groundbreaking study published in Nature on September 10, 2025, has drawn a direct line between the world’s largest fossil fuel and cement producers and the intensification of hundreds of heatwaves across the globe since the turn of the millennium. In a first-of-its-kind analysis, researchers at ETH Zurich and collaborating institutions examined 213 extreme heat events from 2000 to 2023, spanning 63 countries, and attributed their increased frequency and intensity to emissions from 180 major oil, gas, and cement companies—collectively referred to as “carbon majors.”
The study’s findings are as stark as they are sobering. According to Nature, 55 of the heatwaves analyzed over the past 25 years would have been “virtually impossible” without human-caused climate change. The researchers concluded that these events were made 10,000 times more likely than they would have been before the dawn of industrialization in the 1800s. “Many of these heat waves had very strong consequences,” said Sonia Seneviratne, a climate professor at ETH Zurich and one of the study’s contributors. She highlighted the 2022 European heatwaves, which were linked to tens of thousands of deaths, as an example of the grave impacts now being traced back to specific emitters.
Using data from the EM-DAT International Disaster Database, the researchers mapped out the fingerprints of industrial pollution on each heatwave. They found that planet-warming emissions from these 180 companies—both publicly traded and state-owned, as well as several countries with available fossil fuel production data—were responsible for 57% of all carbon dioxide released into the atmosphere from 1850 to 2023. The top 14 companies alone, including household names like Saudi Aramco, Gazprom, ExxonMobil, Chevron, BP, and Shell, individually caused over 50 heatwaves. In fact, these 14 giants generated as many emissions as all the others combined, accounting for 28% of the increase in heatwave intensity, according to the Nature report.
This attribution isn’t just an academic exercise. As Chris Callahan, a climate scientist at Indiana University who was not involved in the study, told the Associated Press, “They are drawing on a pretty well-established field of attribution science now, which has existed for about 20 years.” He added that the methodology used is appropriate and high-quality, and that the science is now robust enough to inform legal and policy debates. For the first time, said Cassidy DiPaola, spokesperson for the Make Polluters Pay campaign, “We can now point to specific heat waves and say, ‘Saudi Aramco did this. ExxonMobil did this. Shell did this.’” She continued, “When these companies’ emissions alone are triggering heatwaves that wouldn’t have happened otherwise, 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.”
The Intergovernmental Panel on Climate Change (IPCC) has long warned that human-caused climate change, primarily driven by greenhouse gases such as carbon dioxide, has increased the frequency and intensity of heatwaves since the 1950s. The new study goes a step further, quantifying the direct role of individual corporations. According to the findings, every heatwave in the world is now made stronger and more likely to happen because of human-caused climate change. The physiological dangers of heat are well documented: extreme heat undermines the body’s ability to cool itself, increasing the risk of heatstroke and other life-threatening conditions.
Half of global warming can be traced back to these 180 companies, the study found. The principal culprit is carbon dioxide, a by-product of burning fossil fuels, biomass, land-use changes, and industrial processes such as cement production. Despite decades of warnings and appeals from the scientific community, global CO2 emissions from fossil fuels have soared by more than 60% since 1990, and atmospheric concentrations of the gas are now 50% higher than before the Industrial Revolution.
The legal and political ramifications of these findings are already reverberating. Lawsuits seeking to hold fossil fuel companies accountable for their role in climate change are on the rise worldwide, especially in the United States. Vermont and New York have enacted laws aiming to hold these companies responsible for their emissions and the resulting damage. Catherine Higham, Senior Policy Fellow at the Grantham Research Institute on Climate Change, told reporters that “governments and companies are increasingly having to consider the legal ramifications of pushing ahead with oil or gas projects, as they risk being dragged through the courts.”
Adding more weight to the legal argument, the International Court of Justice (ICJ) issued a historic advisory opinion in July 2025, stating that fossil fuel production may constitute an internationally wrongful act and that victims could be entitled to reparations. For campaigners like DiPaola, the new Nature study is “the evidence courts have been waiting for.” She emphasized, “We can finally put a name and a number on who’s responsible for these disasters. The bill is coming due, and it’s time these polluters pay for the damage they’ve done.”
Beyond the courtroom, the study’s findings are fueling calls for urgent fossil fuel phaseouts and a rapid transition to renewable energy. While some countries and companies are accelerating investments in wind, solar, and grid infrastructure, others, such as India, are exploring carbon capture and storage (CCS) as a way to offset continued reliance on coal. However, critics warn that CCS may divert resources from proven clean energy solutions, and research suggests that the Earth has limited capacity for long-term carbon storage.
As the world grapples with the mounting toll of extreme heat—from lost lives and livelihoods to failed crops and strained health systems—the question of accountability is taking center stage. Justin Mankin, a Dartmouth College climate scientist not involved in the study, summed up the stakes: “As we contend with these losses, the assessment of who or what’s responsible is going to become really important. I think there are some really appropriate questions, like who pays to recoup our losses, given that we’re all being damaged by it.”
With the science now able to pinpoint the corporate fingerprints on climate disasters, the era of plausible deniability for the world’s biggest polluters may be drawing to a close. The evidence is mounting, the lawsuits are multiplying, and the demand for accountability is growing louder—one heatwave at a time.
