Forty-degree heatwaves are no accident. Scientists point to the culprits

On September 10, the journal Nature published the results of a groundbreaking study that leaves no doubt: the heatwaves tormenting the world are the result of the activities of oil corporations and cement factories. The consequences are tragic – according to the World Health Organization, as many as half a million people die each year from heat.

Rising temperatures are a fact, and their consequences are deadly

A team of European scientists led by Yann Quilcaille from the Institute for Atmospheric and Climate Science in Zurich analyzed 213 episodes defined as heatwaves, recorded between 2000 and 2023. The observed temperatures were compared with those from the pre-industrial era, between 1850 and 1900, which made it possible to determine beyond doubt that hot spells are becoming more intense: temperatures rose on average by 1.4 °C in 2000–2009, 1.7 °C in 2010–2019, and 2.2 °C in 2020–2023.

This is the first study that directly links climate change to greenhouse gas emissions generated by the industrial sector. According to the researchers, there is no doubt that heatwaves have been more likely and more intense in the past quarter-century precisely because of gases released from massive chimneys.

Meanwhile, the social repercussions remain underestimated. Research from the Imperial Grantham Institute shows that a single heatwave that struck Europe between June and July 2023 caused 2,300 deaths in 12 cities – 65 percent of which were directly attributed to anthropogenic climate change. As we reported in Water Matters a month ago, lethal heat affects the poorest residents of major cities the most, as they cannot afford air conditioning and often suffer from water supply interruptions.

Who do we owe the heatwaves to?

The authors of the study did not shy away from directly pointing to the culprits – their blacklist included 180 of the largest companies in the oil and cement industries. The emissions they generated were directly responsible for increasing the intensity of heatwaves by half. The rest is primarily due to deforestation.

Taking a step further toward identifying the biggest offenders, the scientists suggest that emissions generated by the 14 largest entities alone were enough to cause 50 heatwaves. The infamous fourteen included ExxonMobil, Chevron, BP, and Shell, but also coal and cement production in China’s national economy. Their combined burden was estimated at 30 percent of all anthropogenic CO2 emissions.

What does this mean?

The new study scientifically confirms what has long been said: the oil industry and cement production are responsible for a huge share of global emissions, which in turn drive climate change. However, the collected data and calculations provide a tangible basis for holding the culprits accountable and, according to experts, may serve as a legal foundation for demanding in court that they take responsibility for their actions.

Dr. Davide Faranda of the French National Centre for Scientific Research, although not involved in the analysis, praised its potential: This study is a crucial step: it connects the dots between specific climate disasters and the companies whose emissions caused them. This connection could become a milestone for legal and policy action to hold polluters accountable.

It is worth recalling that in July, the International Court of Justice issued an unprecedented ruling on the climate responsibility of individual countries. It opens the door for the nations of the Global South, most affected by climate change, to demand compensation from the world’s most polluting economies. Everything indicates that disasters such as floods or heatwaves will finally begin to be considered in terms of culprits and victims.

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Bibliography:

Quilcaille, Y., Gudmundsson, L., Schumacher, D.L. et al. Systematic attribution of heatwaves to the emissions of carbon majors. Nature 645, 392–398 (2025). https://doi.org/10.1038/s41586-025-09450-9