This research was carried out by the World Bank in 2008. Financial support for this research was provided by the Research Department of the World Bank, and the Economics of Adaptation to Climate Change study administered by the Environment Department of the World Bank. Funding for the Economics of Adaptation to Climate Change study has been provided by the governments of the United Kingdom, the Netherlands and Switzerland. An increase in sea surface temperature is strongly evident at all latitudes and in all oceans. The scientific evidence to date indicates that increased sea surface temperature will intensify cyclone activity and heighten storm surges. These surges will, in turn, create more damaging flood conditions in coastal zones and adjoining low-lying areas. The destructive impact will generally be greater when storm surges are accompanied by strong winds and large onshore waves. In this research, we have considered the potential impact of a large (1-in-100-year) storm surge by contemporary standards, and then compared it with its 10% intensification which is expected to occur in this century. In modeling the future climate, we took account of changes in sea level rise, geological uplift and subsidence along the world’s coastlines. Geographic Information System (GIS) software has been used to overlay the best available, spatially-disaggregated global data on critical impact elements (Area, population, economic activity (GDP), agricultural land, urban areas, and wetlands), with the inundation zones projected for 84 coastal developing countries.