Heatwaves linked to emissions of individual fossil-fuel and cement producers: Need CDR!
Tom Goreau
https://www.nature.com/articles/d41586-025-02596-6
- NEWS & VIEWS FORUM
- 10 September 2025
Heatwaves linked to emissions of individual fossil-fuel and cement producers
The emissions of leading fossil-fuel and cement producers have been systematically linked to particular heatwaves. Three scientists discuss the methodology behind the result and its potential impact on climate-liability court cases.
By
THE PAPER IN BRIEF
• The field of extreme-event attribution links climate change caused by anthropogenic greenhouse-gas emissions to extreme events such as heatwaves.
• The largest entities producing cement and fossil fuels are called the carbon majors.
• Writing in Nature, Quilcaille et al.1 report a methodology that attributes specific heatwaves to emissions resulting from the fossil fuels and cement produced by individual carbon majors.
• Extreme-event-attribution studies might be used to support future court cases that seek financial liability for climate change.
KARSTEN HAUSTEIN: A systematic step forward
The groundwork for the scientific attribution of extreme events such as heatwaves was laid by the pioneering efforts of collaborations such as the World Weather Attribution initiative2. Others have begun to develop methodical frameworks for establishing the liability of top emitters for economic losses caused by climate change3. Quilcaille and colleagues1 have pushed the boundaries further in the emerging field of loss and damage attribution, systematically linking particular heatwaves to the individual emissions of 180 carbon majors. The researchers considered the emissions generated by the full life cycles of the fossil fuels or cement (or both) produced by these entities.
Read the paper: Systematic attribution of heatwaves to the emissions of carbon majors
Quilcaille and colleagues first studied how anthropogenic global warming has affected the frequency and intensity of heatwaves, examining 213 events that occurred between 2000 and 2023. They used both observational and model-derived data on global and regional temperatures to calculate how the observed heatwaves compared with a counterfactual scenario in which the climate remained in a pre-industrial (1850–1900) state.
To do this, the researchers built on existing extreme-event-attribution tools, but took a more systematic approach. Instead of manually defining individual heatwaves — a complicated challenge for attribution analysis4 — they used the International Disaster Database (EM-DAT). This resource provides a record of global disasters, including heatwaves, from 1900 to the present day, and uses a consistent methodology to define the spatio-temporal characteristics of each event.
The researchers then assessed how much the emissions of individual carbon majors contributed to the likelihood and intensity of heatwaves. They combined data on the estimated carbon dioxide and methane emissions of the carbon majors with a model of Earth’s climate. This enabled them to calculate the fraction of changes in global mean surface temperature that could be attributed to different carbon majors (Fig. 1). They then used this to calculate the fraction of the change in probability for the heatwaves that could be attributed to each carbon major.
Figure 1 | Contributions of carbon majors to climate change. Climate majors are the world’s largest cement and fossil-fuel producers. Quilcaille et al.1 used climate models and observational data to show that emissions from the fossil fuels and cement produced by the carbon majors contributed to an increase in global mean surface temperature (GMST) associated with climate change. The y axis shows the change in GMST with reference to the pre-industrial period between 1850 and 1900. The shading indicates the fraction of the change in GMST that can be attributed to different carbon majors and other actors. The red and dashed-purple lines show two data sets for GMST. (Adapted from Fig. 3 of ref. 1.)
The finding that all of the studied heatwaves were made more intense as a consequence of the collective carbon emissions comes as no surprise. More worryingly, Quilcaille et al. found that climate change made 55 of these extreme heat events at least 10,000 times more likely. But the real headline figure is that the emissions of just one carbon major would have been enough to cause several of these ‘10,000 times more likely’ events.
Climate impacts are real — denying this is self-defeating
The results show that, for the events considered, the carbon majors have contributed to an increase in heatwave intensity that ranges from 0 °C to 0.18 °C. The median contribution to the change in heatwave intensity from the 14 top carbon majors ranges from 0.01 °C to 0.09 °C, which corresponds to 28% of the overall effect of human-made warming in the 2010–19 period. About half of the increase in heatwave intensity since pre-industrial times can be attributed to these entities.
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. 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.
MICHAEL B. GERRARD & JESSICA A. WENTZ: Getting to court is the hard part
The article by Quilcaille and colleagues makes a convincing case that heatwaves around the world have been worsened by the combustion of fossil fuels produced mostly by a limited number of companies. This is the latest in a series of climate-attribution studies5 that are demonstrating — with increasing precision — the link between greenhouse-gas emissions and climate impacts.
Solving aviation’s climate-action conundrum
Such studies are essential to any effort to hold the carbon majors to account in the courtroom. Recent opinions from international and domestic courts, including the International Court of Justice (see go.nature.com/3uwkw6z) and the regional human-rights courts of Europe (go.nature.com/45vzvcl) and Latin America (go.nature.com/3urues4), have made good use of climate-attribution studies in proceedings involving government obligations. Imposing financial liability on companies for their emissions, however, poses many challenges. So far, not a single court in the world has held emitters financially liable for climate change. The problem is not the weakness of the scientific evidence, but the various legal issues that must be resolved before scientists can take the witness stand.
Lawsuits against fossil-fuel companies over their emissions began in 2004, and have been brought mostly by states, counties and cities in the United States. There have since been about 40 of them. In 2011 (see go.nature.com/47pqyzm), the Supreme Court of the United States declared invalid the principal legal basis for having these cases proceed in the federal courts (courts founded by Congress that hear mainly cases under federal law, as opposed to state-established courts that consider mainly cases under state law). Years of litigation followed over whether these cases could be brought in state courts under state law. Around 2023, it became clear that state courts were the proper forum (see go.nature.com/47p7n3m).
Projections of Earth’s health under different environmental policies
Many legal issues remain, and none of them have been definitively resolved by the Supreme Court or elsewhere. In the United States, greenhouse gases are regulated by the federal Clean Air Act, and it is not clear whether this might rule out the use of state law in this context.
Also, most greenhouse-gas emissions do not come directly from the producers of oil, natural gas and coal, but from the vehicles, power plants and factories that burn the fuel. Should fossil-fuel producers be held liable for their customers’ emissions? If courts award damages to specific plaintiffs for emissions, many other entities that experience similar harms might flood the courts. Moreover, fossil-fuel production has historically not only been allowed but encouraged and subsidized by governments around the world, which are themselves customers of major emitters. Finally, some players in the fossil-fuel industry have engaged in long campaigns of deception about the causes and impacts of climate change6,7 — how much of a legal difference should this make?
Sometimes, scientific discoveries lead quickly to legal action. In 1974, an article in Nature by Frank Sherwood Rowland and Mario Molina8 showed that chlorofluorocarbons can destroy stratospheric ozone. This led, in almost record time, to the Montreal Protocol, a global agreement signed in 1987 in which the world agreed to phase out the use of such chemicals. The basic chemistry of the greenhouse effect has been known since Svante Arrhenius put forward a model in 1896, and climate science has advanced tremendously since then. The Quilcaille et al. paper is one more building block, and a useful one, but the road to actual liability for the carbon majors is still littered with legal and evidentiary potholes.
Nature 645, 319-320 (2025)
doi: https://doi.org/10.1038/d41586-025-02596-6