La mer monte : impacts et stratégies

Abstract

In October 2019, AllEnvi [the French National Alliance for Environmental Research] published the findings of a foresight study on the environmental, social and economic consequences of rising sea levelsone of the direct manifestations of climate changein the years to 2100 and the way we might anticipate these consequences and prepare for them. That exercise, based on the scenario-building method, enabled eight general scenarios and three territorial focuses to be developed. Denis Lacroix and Nicolas Rocle outline its main lessons here. After first going into the framing, methodology and context involved, they present the scenarios in three family groups ('Coastal adaptation', 'Denial' and 'Fragmented World'), together with the territorial focuses relating to the Aquitaine Basin, the Netherlands and Vietnam. These scenarios reveal potential sea-level rises, the consequences for the coastline and the strategies to be adopted to mitigate the impacts and, most importantly, adapt to them. Since the conditions for a reversal of the present situation (which would require highly virtuous global policies) are hardly likely to eventuate in any near timeframe, the aim is now to prepare for the coastline to be overwhelmed by the sea. The warning is all the more serious as a growing number of our contemporaries are concentrated in such areas, not to speak of the holidaymakers who rush there and of the other consequences that may ensue, as evidenced by the most exposed territories. To keep coastal areas in a state described by the authors as lying between 'moderate' and 'serious', it is essential that decision-makers and citizens work as of now on resilience and energy saving… We shall come back to this subject, this article being the first of a series on the sea that will continue in late 2020 or in 2021. Résumé En octobre 2019, l'AllEnvi a publié les résultats d'une prospective sur les conséquences environnementales, sociales et économiques de la montée de la mer d'ici 2100une des manifestions directes du changement climatique-et la façon dont on pourrait les anticiper et s'y préparer. Cet exercice, basé sur la méthode de construction de scénarios, a permis de développer huit scénarios globaux et trois focus territoriaux. Denis Lacroix et Nicolas Rocle en livrent les principaux enseignements. Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. Après un rappel des éléments de cadrage, de la méthodologie et du contexte, ils présentent les scénarios, regroupés en trois familles (« Adaptation littorale », « Déni » et « Monde fragmenté »), ainsi que les focus territoriaux portant sur le Bassin aquitain, les Pays-Bas et le Viêt-nam. Ces scénarios révèlent combien le niveau de la mer pourrait s'élever, quelles pourraient en être les conséquences sur le littoral et quelles stratégies pourraient être adoptées pour en atténuer les impacts et, surtout, s'y adapter. En effet, les conditions d'u...