Growing demands for downscaling of climate information — examples from predictions of future sea levels

Abstract

2007 marked a shift in the perception of climate change. In Sweden, a wet and stormy winter coincided with increased coverage of climate change. Among the most important ones were the Stern report, IPCC's Fourth assessment report (AR4) and the national investigation on climate and risk. During 2007, the demand for future climate information to support decision makers increased significantly. According to IPCC, the global mean sea level is predicted to rise between 18 to 59 cm, and a further increase due to regional effects should be included for the Baltic Sea. In the Bothnian Sea, the post-glacial rebound is large and will continue to outweigh or balance the sea level rise during the next 100 years. However, in the southern Baltic, the apparent land uplift is negative, and sea level rise will lead to increasing problems with flooding, erosion and rising ground water levels. SMHI water level observations show that the rate of sea level rise has increased during the last decades. Results from AR4 and four climate scenarios from the coupled Rossby center model for the Baltic Sea, RCAO, are used to provide scenarios of sea level rise in the Baltic Sea for 2071-2100. End users are local authorities in charge of land areas that will be heavily affected should sea levels rise or entrepreneurs who need background for construction design. For decision makers, continued research on the effects of climate change regarding sea level and other climate factors is important for planning purposes, and continued observational and modelling efforts should be combined with downscaling of climate model output to enable information on a local or regional scale.