Fifty-five heat waves over the past quarter-century would not have happened without human-caused climate change, according to a study published Wednesday.
Planet-warming emissions from 180 major cement, oil, and gas producers significantly contributed to all of the heat events considered in the study, which examined a set of 213 heat waves from 2000 to 2023. The polluters included both publicly traded and state-owned companies, as well as several countries where fossil fuel production data was available.
Collectively, these producers are responsible for 57% of all the carbon dioxide that was emitted from 1850 to 2023, the study found.
“It just shows that it’s not that many actors … who are responsible for a very strong fraction of all emissions,” said Sonia Seneviratne, a climate professor at the Swiss university ETH Zurich who contributed to the study.
The set of heat waves analyzed came from the EM-DAT International Disaster Database, described by researchers as the most widely used global disaster repository. The Nature study examined all appropriate heat waves in the database from 2000 to 2023.
Global warming made all 213 of the heat waves examined more likely; out of those, 55 were deemed 10,000 times more likely to have happened than they would have prior to industrialization in the 1800s. The calculation infers that those 55 heat waves “would have been virtually impossible” without human-caused climate change.
“Many of these heat waves had very strong consequences,” said Seneviratne, mentioning the series of heat waves that struck Europe in 2022, which were linked to tens of thousands of deaths.
Scientists can utilize complex computer programs and historic weather data to ascertain the connection between extreme weather events and the pollutants humans emit. Attribution studies usually focus on how climate change influences specific weather occurrences, but this Nature study uniquely centered on the extent to which cement and fossil fuel producers contribute to heat waves.
“They are drawing on a pretty well-established field of attribution science now, which has existed for about 20 years,” remarked Chris Callahan, a climate scientist at Indiana University.
The findings could impact legal cases, especially with numerous lawsuits against fossil fuel companies filed by climate activists and state governments seeking accountability for their role in climate change.
For instance, Vermont and New York have enacted legislation aimed at holding fossil fuel companies responsible for emissions and subsequent damages.
As more evidence emerges linking individual contributors to climate change impacts, experts stress the importance of who bears the costs of climate-induced damages.