Sea-level rise : a world-wide cost estimate of basic coastal defence measures

The present study has yielded preliminary estimates of coastal defences and their costs world-wide. These approximations for 181 coastal nations, of both protective measures and the expenditures required if they were constructed, do not constitute recommendations. They do however, provide the international community for the first time with a general quantification of the global financial consequences of protection against sea-level rise and - equally important - with the impetus to work for further elaboration and refinement. The study shows that an estimated total of 362,400 km length of coastal defences of several categories at a total cost of US$ 488.5 billions are required "if the sea level rises by 1 metre". The standard deviation of the total cost estimate is 12 percent. The main categories of coastal "features" considered in this study, when expressed in kilometres to be protected, come to 345,300 km low coasts, 10,700 km beaches, and 6,400 km city waterfronts. Small islands, if low and flat, were considered seperately in terms of both land surface elevation and other protective measures.