A study estimates that companies with the highest carbon emissions contributed 50% to more intense heatwaves

This is an original study, as it goes beyond previous attribution studies. Its main novelty is that it directly links large carbon emissions—focused on the world's large oil, gas and coal production companies—with the increased occurrence and intensity of heatwaves observed so far this century.

This work may open the door to others with similar methodologies—a field of research yet to be explored—which could offer new tools for negotiation at climate summits, contributing to the reduction of greenhouse gas emissions with the required urgency, effectively limiting the production of oil, gas and coal worldwide. The impact of extreme heat waves on the producing countries and major emitters themselves may be a key factor in driving mitigation.

Is the study of good quality?

‘Yes, it follows the methodologies commonly used in extreme event attribution and considers the uncertainty in each case.’

What does it add to previous research?

"The main novelty is that it links the impact of climate change with the attribution to emissions, breaking down the impact caused by the main sources of emissions (whether countries or large companies). This makes it possible to associate the emissions of a particular agent with the impact caused by them, which has consequences from the point of view of legal liability. This is something that only a few other studies had addressed, but in this one, the methodology is generalised and systematised, integrating statistical estimators with the use of models and a model of intermediate complexity.

The methodology relates the impact to the average warming of the planet compared to the pre-industrial period and then relates this warming to the emissions of each of the main emitters. To do this, simulations are run with all emitters, with all except the emitter whose impact is to be analysed, subtracting both, and, on the other hand, with none, and only with the emitter to be analysed, again analysing the difference. The contribution of that emitter is calculated as the average of both.

What are its limitations?

"The main limitations of the study, apart from uncertainty (although the methodology calculates it meticulously), lie in the uncertainties about the data. First, the emissions data are based on estimates, and although different databases have been used, there is uncertainty in their precise quantification. Secondly, and more importantly, the quantification of the impacts of a heatwave is very heterogeneous. For example, in areas of Africa or Latin America, which are frequently affected by heatwaves, there is little documentation of the impacts, so a significant portion of these remain unaccounted for and are not included in the study."

What are the implications?

‘The study opens the door to criminal proceedings against large emitters, establishing a robust relationship between their role as emitters and the impact, whether economic or in terms of personal injury, that these emissions have had.’