Along the Atlantic Coast, the ocean has risen a foot this century, and some forecasters predict another 2-foot rise over the next 100 years. The higher sea level stems in part from the fact that the land along the East Coast has been sinking since the end of the last ice age. In addition, rising global temperatures are causing ocean water to expand and rise. Beach erosion . The contours of barrier islands that line much of the Atlantic and Gulf coasts are constantly being reshaped by the ocean's waves and currents, which steal sand from one stretch of beach to widen another.
Some places lose several feet of beach each year.
Inland flooding . The number of structures destroyed by floods has been rising sharply in recent years because of unusually bad weather and the loss of coastal wetlands that act like sponges and sop up floodwaters. FEMA says that as developers fill in wetlands, more and more structures, even those built miles from the shore, are becoming more vulnerable to storm surges. Evacuation gridlock . Disaster experts worry that as the population along the coast continues to explode, they won't be able to handle the evacuation of a populous area when the next killer storm hits.