Since this summer, he has been the “new Valérie Masson-Delmotte”. Elected co-president of Group I of the IPCC* last July, the French climatologist, Robert Vautard, took over from the best-known French paleoclimatologist. A position that he says he initially hesitated to apply for. But “if I hadn’t found meaning in it, I wouldn’t have done it,” he assures.
After working, from 2017 to 2021, on the coordination of the National Convention on Climate Services for the Ministry of Ecological Transition, he co-chaired, for two years, the regional group of expertise on climate change and ecological transition in Ile-de-France (Greek). He is now working, with the authors of the IPCC, on a first report on the adaptation of cities to climate change.
On the eve of the opening of COP28 in Dubai, 20 minutes went to the land of researchers, to the climate and environmental sciences laboratory (LSCE), to meet the specialist in extreme weather events, and discuss with him the major challenges to come.
In July, you succeeded Jean Jouzel and Valérie Masson-Delmotte** within the IPCC. How do you feel in their shoes?
The question is very difficult because times and times are no longer the same. Today, we have a fairly good understanding of what is happening thanks to the results of the 6th assessment cycle of the IPCC which also showed that there was urgency if we wanted to succeed in meeting the objectives of the agreement of Paris, and to make a transition to decarbonization very quickly. We will therefore have to take this into account, aggregate new knowledge, but also and above all direct it towards climate action. Because countries need information that is easier to implement.
Over the next few years, we will therefore be much more action-oriented, to face rapid transition needs which will be extremely difficult to implement. Especially since there is a risk of seeing reflexes of conservatism appear concerning the necessity or not of carrying out this “revolution”. This is already the case through the climate skeptic movements that we can observe.
A climate skeptic “wave” swept through social networks this summer and attacked several scientists, notably climatologist Christophe Cassou. Does this worry you?
On social networks, there is a lot of amplification. We don’t really know where these attacks come from. So it is very difficult to measure the true rate of climate skepticism. Are there really so many climate skeptics? I know they exist, I sometimes encounter them around me, but in the conferences I give, I don’t see any. And then we are in a period of great transition, of which the phase of denial is necessarily a part. So no, I’m not particularly worried.
COP28 begins tomorrow in Dubai, where negotiations should open on the basis of the +1.5 degree objective of the Paris agreement. Isn’t it a bit hypocritical to continue to hold up this objective which today seems untenable?
Countries agreed on this objective via an international agreement. It’s not something we can undo. And the +1.5 or +2 degrees of the Paris agreement are not absurd either. Yes, we know that we will, almost certainly, surpass them in about ten years. But the question is above all to know, then, what is the reversibility of this excess. Because in most scenarios there is what we call a overshoot. That is to say that the temperature exceeds 1.5 degrees and then drops again. Thanks to certain technologies, even if we do not necessarily master them very well, we could, in theory, go back down a little. It remains to be seen whether we will be able to deploy them on a large scale under the same economic model that would hold up.
On November 20, the UN published a report in which it warned of a warming trajectory going towards +2.5 to +2.9 degrees. We still seem a long way from the +1.5 degrees of the Paris agreement…
The +2.9 degrees mentioned in this report correspond, more or less, to what the last IPCC summary report announced, that is to say approximately +3 degrees of warming if current climate policies are implemented. But it can also go higher!
This report shows above all that there has been progress, but that it is still largely insufficient to succeed in meeting the objectives. Because even if all the negotiations go well, we will still not achieve the objectives. So we have to go even further.
The consumption and extraction of fossil fuels*** should also be part of the discussions in Dubai. A big piece that’s complicated to maneuver?
You should know that during COPs, most negotiations concern the terms used. For example, it is not the same thing to disengage from investments in fossil fuels unabated, that is to say not backed by carbon capture or storage systems, than to disengage from the extraction or production of fossil fuels altogether. The second is obviously much more restrictive.
Extreme heat wave in Brazil, record floods in Pas-de-Calais… What do you think are our greatest weaknesses in the face of these extreme phenomena amplified by global warming?
I think that we are not prepared, today, for these events which are completely unprecedented. Until now, we were used to seeing records broken by a few tenths of a degree. But there, records are broken from very far away, on a large scale, over long periods of time, and on enormous spatial scales such as, for example, the fires in Canada. We are always late because it is very difficult to envisage something that has never been seen, and it takes a lot of work to succeed in considering these “worst-case situations”.
In the short term, in the current climate, we will have to face significant flooding and extreme heat. In the longer term, we will have to prepare for the coastal issues linked to rising sea levels. We will undoubtedly also have to face major crises at the global level, with heat waves in several grain-producing regions at the same time. And I think that we are not yet prepared for that.
During her mandate, Valérie Masson-Delmotte was very active on X. Would you like to continue what she set up?
I find that there are already many very good scientists who communicate in a very precise and educational way, and I am not sure of the usefulness of doing the same thing. But communication strategy is a very important issue and I think about it a lot. I would like to find a slightly different path.
On LinkedIn, I have gotten into the habit of publishing one post per week in which I talk about what the life of an IPCC member is like. Behind the scenes, in short. Although I can’t say everything either.
I would like to make a more personal communication, targeted on the lives of climatologists. I want people to understand that we are people like others with our doubts, a daily life that is sometimes exciting and sometimes not at all, our struggles, etc. Because the credibility of science also depends on the people who do it.
Working Group I evaluates the scientific aspects of the climate system and climate change.
(**) Jean Jouzel was vice-president of the working group on the physical bases of climate change within the IPCC, from 2002 to 2015. Valérie Masson-Delmotte was co-president of group 1 of the IPCC from 2015 to 2023 .