Robert Wottard, Director of the Institute Pierre-Simon Laplace (IPSL), researcher in the laboratory des sciences Weather And the environment.

Future: You are a meteorologist, meteorologist and statistician. Can we establish a causal link between extreme weather events and climate change?

Robert Vottard: Yes ! For about 5 years, we were able to tell in a few days or a few weeks A hot or cold wave, A Drought Or some rain Climate change has changed in intensity and will not increase or decrease or change.

Where we generally responded, we can now respond to a specific event in a given area. These answers allow us to imagine what we will experience tomorrow … A minimum ! IPSL was one of the forerunners of these studies.

Future: How do you do that?

Robert Vottard: We all depend Past observations That we will get. We model them statistically, which allows us to Compare with new events. For example, for an episode Heavy rainfall over the Mediterranean, We use the sum of the daily rainfall of the suspicious area during the same period. This is relevant if the data is long enough, from comparable methods, or from ways in which we can correct biases.

This first step allows us to keep up with the trend, without attributing the event to climate change. In some cases, as The wind blew In the northern hemisphere, the reason is elsewhere. To say that climate change is the cause of the trend, we compare the results of the simulations statistically. Greenhouse gas Extra.

Future: What are your margins for improvement?

Robert Vottard: Establishing a link between climate change and its impact is not always easy. We expect machine learning methods (Machine learning In English) We will help make this analysis better. This is the subject of a new European research project Syeda.

In addition, we are constantly improving our tools and trying to apply them to new phenomena Gels The late ones we just worked on. And nothing can be said about it Hurricanes Or hail because we do not have enough reliable observations or models.

Future: What do you expect from COP26?

Robert Vottard: As an author The latest IPCC report, I have a duty to reserve. But, like other contributors, I hope you will read and understand this colossal work of free and transparent global collective expertise. Politicians, They are fully aware of the results.

Climate science is particularly complex. Surely we need to improve our communication, including uncertainties. But then their decisions are up to the governments.

In my opinion, it reduces Greenhouse gas emissions The effort of all countries is required. At the same time, adapting to limiting the effects of global warming precedes local selection, such as limiting soil synthesis to mitigate impacts. Heavy rain.