Heatwaves Attributed to Emissions from Carbon Major Entities

The frequency and intensity of extreme weather events are increasing worldwide. Events once considered impossible are now happening with alarming regularity. But how much of this can be attributed to climate change?

Extreme Event Attribution (EEA) has emerged as a critical field in climate science, quantifying how climate change affects the probability and severity of events such as heatwaves, floods, and droughts.

Major emitters linked to intensifying heatwaves

A new study published in Nature on 10 September 2025, titled “Systematic attribution of heatwaves to the emissions of carbon majors”, used the Extreme Event Attribution (EEA) method developed by the World Weather Attribution (WWA) initiative to examine 213 heatwaves between 2000 and 2023.

The research confirmed that climate change has made heatwaves both more likely and more intense, with significant contributions from 180 major carbon-emitting companies, including fossil fuel and cement producers.

According to the study, since the late 19th century, heatwaves have become approximately 20 times more likely from 2000 to 2009, and 200 times more likely from 2010 to 2019. It also found that 25% of recorded heatwaves would have been nearly impossible without climate change. The authors further note that emissions from these companies account for half of the observed increase in heatwave intensity since the late 1800s.

The 13 Carbon Majors

While the impacts of these 180 carbon producers vary, the study identifies 13 “carbon majors” as the largest contributors. These include:

1. The former Soviet Union
2. The People’s Republic of China (coal)
3. Saudi Aramco
4. Gazprom
5. ExxonMobil
6. Chevron
7. National Iranian Oil Company
8. BP
9. Shell
10. India (coal)
11. Pemex
12. CHN Energy
13. The People’s Republic of China (cement)

Together, these 13 entities produce emissions equivalent to those of the remaining 166 companies combined.

The study also highlights that, while these large emitters have the most significant impact, smaller carbon producers collectively contributed to 16-53 heatwave events.

A call for accountability

The research underscores the growing role of climate change in driving extreme heat and demonstrates that both significant and minor emitters have contributed to worsening heatwaves. By establishing a direct link between corporate emissions and extreme events, the study closes a crucial evidence gap, paving the way for stronger accountability for past and future climate damage.

Read the study to learn more by visiting the link provided in the source below.