Climate Change and the Land Holdings of the Conservatoire du Littoral: Erosion and Flooding Scenario

Accelerated rate of sea level rise and increased storminess are expected in the next century due to global warming. As a result, beach and cliff erosion as well as coastal lowland flooding will increase. This is of great concern for the Conservatoire du Littoral, a governmental body in charge of acquiring and protecting natural coastal sites. In metropolitan France, the Conservatoire already owns 59 000 hectares, while the purchase of 116 000 more hectares by 2100 has already been decided. It prompts the Conservatoire to launch a research project whose main objective is to evaluate the effects of erosion and to elaborate flooding scenarios on its lands. For this study, we assumed a sea level 44 cm higher than the present, a data seen as the best estimate by the Intergovernmental Panel on Climate Change (IPCC, 2001). Results must be considered in light of possible scenarios. They indicate that beach and cliff erosion on lands already owned by the Conservatoire would produce a 647 hectares loss, which is 1,2 % of the entire land holdings. In addition, if the forthcoming coastal properties are taken into account, the loss would be 1 514 hectares, or 1 % of the entire surface area. As far as salt marshes are concerned, it appears that by 2100, 1 350 hectares, i.e. 3 %, of the present holdings, would be flooded. And, if the future property is added, these figures would be respectively 3 073 hectares and 2,6 %. However, if salt marshes and low-lying reclaimed areas are combined, the surface of potentially submerged areas increases to 5 000 hectares, or 10 % of the present property. The total is more than 30,000 hectares, 21 % of the total property, when future acquisitions are included.