According to a recent Swiss study published in early September in the scientific journal Nature, nearly one-quarter of heatwaves would have been ‘virtually impossible’ without global warming, and can be attributed to the emissions of individual energy producers. In other words, some recent heatwaves would never have occurred without the emissions of a few large fossil fuel and cement companies.

Extreme heat waves are no longer anomalies, but a recurring phenomenon in all regions of the world. They are getting more severe and more frequent, contributing to at least 500,000 heat-related deaths a year. They are usually attributed to climate change.

‘Industrial signature’

The Swiss researchers, however, analyzed the overall effect of climate change, as well as the impact of well-identified entities, including the major oil, gas, and cement companies.

“Climate change has made all these heat waves more likely and more intense,” says Yann Quilcaille, a specialist in climate extremes at ETH Zurich and lead author of the study.”What this study shows is clear: today’s heat waves are not natural; they have an industrial signature.”

Database

The scientists used the Carbon Majors database, which lists the cumulative emissions of 180 fossil fuel and cement producers since 1880. Then they cross-referenced these data with climate models to estimate the extent to which these emissions had contributed to the intensity and likelihood of the heat waves studied.

What they discovered was striking: “One producer alone can emit enough to make certain heat waves possible,” says Yann Quilcaille. Wim Thiery, a climatologist at the Vrije Universiteit Brussel and co-author of the study, confirms: “These entities account for about 60% of historical CO2 emissions, and about half of global warming. When we look at heat waves, we find this same footprint: about half of the average intensity is linked to these companies.”

For the 14 largest emitters (e.g., ExxonMobil, Saudi Aramco, Shell, China’s coal industry), emissions from each single company made 50+ heatwaves at least 10,000 times more likely than they would have been in a preindustrial climate.

Lack of scientific evidence

Until now, there has been a lack of scientific evidence establishing the causality between a company’s emissions and disasters. “But this study could definitely be used in climate lawsuits,” Quilcaille says. It could provide a quantified scientific tool, potentially decisive in court. “We can no longer analyse a current heat wave without seeing the imprint of climate change, and, therefore, of the involvement of the carbon majors,” the scientists say.

However, while the contribution of these companies is undeniable, it remains impossible to attribute responsibility for a specific climatic event to any one of them.

Other disasters

On the other hand, other disasters – such as droughts, wildfires, and floods – should also be analyzed. So, the team is already considering expanding its work to other climate extremes, which have considerable human and economic costs.

The question remains of the real impact of this research.”Companies will not change their behavior with this study alone,” admits Yann Quilcaille. But he hopes that this work, along with the work that preceded it and that which will follow, will feed a broader signal from public policies and society. And why not the courts?

Health impact

Heatwaves also have a profound impact on human health. In the UK alone, 1,147 people died this summer from climate change-driven heatwaves, leading scientists and epidemiologists have found. 

The UK saw its hottest summer on record this year. Experts found that climate change, primarily caused by the burning of fossil fuels and deforestation, increased temperatures by an average of 2.2 °C, but by as much as 3.6 °C between June and August. The heat was responsible for 68% of the 24,400 total heat deaths in 854 European cities or areas over the three months, according to the researchers.

Figures show that even a few degrees of additional heat can cause large surges in deaths when vulnerable people are exposed to temperatures beyond the limits they are used to dealing with, although other factors, such as air pollution, play a role as well.