Many scientists think that a rise in sea levels caused by global warming will be one of the key future environmental challenges facing many low-lying coastal regions. In Indonesia, there is considerable concern about the impact this problem will have on large areas of reclaimed coastal swampland in South Kalimantan. It is thought that over 150,000 ha of this land, which is currently being farmed for rice and other food crops, are at risk, and that this will jeopardize the livelihoods of many thousands of farmers and their communities. To help decide what the best response to this unfolding crisis is, the study focuses on the province of South Kalimantan which is already experiencing salination of its freshwater due to rises in sea level, especially during the dry season. The study finds that building dikes to protect farmland is the most cost-effective response. It finds that this approach would cost society less than doing nothing and that it is a better option from an economic point of view that relocating farmers to new farmland at a higher altitude.