Anticipate the evolution of the territories.

Summary Not allowing the planet to warm to a level more than 1.5 times that of the pre-industrial period is imperative in terms of the risks to the most vulnerable territories. But the possibility of achieving this is considerably more limited than it was 30 years ago, just before the Rio Earth Summit in 1992. At that time, CO emissions were 5 to 6 billion tons of carbon per year - they have doubled since then. In fact, we have already made a significant commitment to the future, as evidenced by phenomena such as the melting of glaciers and ice floes, the deep warming of the oceans, or the evolution of ecosystems. The situation is even more serious if we look to the near future: the warming of the next few decades is already strongly constrained by past emissions, and the rapid mixing of greenhouse gases by atmospheric circulation makes it a growing global problem that is binding on all. We have less and less possibility to significantly modify the local climate evolution through our own actions. It is therefore necessary to adapt progressively to developments that are both the already irremediable part of future changes and the delays or failures of international actions. In this context, the territories have a privileged role to play. It is, in fact, on their scale that the major impacts of climate change develop and that a large part of greenhouse gas emissions are produced. It is therefore at this level that strategies for co-benefits between mitigation and adaptation to climate change should be developed. And it is also where trade-offs between different land uses, different biodiversity protection strategies, or different management of vulnerable areas, such as cities, mountains or coastlines, will have to be defined. This also requires an in-depth and multidisciplinary knowledge of these territories, which are all different from one another. The example of New Aquitaine, where the Acclimaterra project has implemented a very large series of regional visits (http://www.acclimaterra.fr) shows that it is necessary to take the measure of the evolutions in progress, both by listening to the expression of the various social imperatives and by facilitating the decision making of all regional actors by "putting into narrative" the scientific diagnosis. The Acclimaterra project was also materialized by the production of two reports that brought together 400 scientists and were published in the form of carefully edited books to reach the general public. This work has shown that the regions, by taking advantage of the link that unites them with their population, can thus constitute an important link of innovation and reflection and bring important elements of solution to the climate problem.