Reacción a "Reactions: July heatwaves in Europe and North America "almost impossible" without climate change"

Heatwaves are increasingly breaking temperature records around the globe, with the concurrent heat extremes across North America, Europe and China in July 2023 adding another, and certainly not the last, chapter to this story.

The study uses a so-called rapid-attribution approach, which has been similarly applied to other recent extreme events as well. These rapid-attribution analyses can give a first-order estimate of the human contribution in altering the probability of such heat extremes, but may not be robust as it comes to processes more specific to the event and how for example specific atmospheric circulation patterns or the land surface amplified the heat.

Due to this generalised approach, I would not put too much emphasis on the specific quantification such as the event being at least 50 times more likely due to human influences. Accounting for the limitations of the method it could equally be 100 times or only 30 times more likely. But the exact numbers probably do not matter that much in this context, as the important message is that human activities are strongly increasing the probability and intensity of such heat extremes. And these extremes will further increase in the future if humans do not take consequent action to limit the further increase of Greenhouse gases from burning fossil fuels.

An important value of such rapid attribution studies is to assess the role of climate change in such extreme events while the events are still in the memory of people (or even still ongoing), which hopefully helps to raise awareness and highlights the urgency of actions to mitigate dangerous levels of global warming.