Esteban Rodríguez Guisado
Head of the Climate Assessment and Modelling Area at AEMET
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.’