Ice caps melt and rebuild as the seasons change, but the
erosion of permafrost is a much more lasting process.
Coastal lands in polar regions are at risk for several
reasons: the gradual rising of global temperatures melt the
mud-rich sediment and the increasing intensity of ocean
storms batter what land remains. Without sea ice to block
the coasts, incoming waves carve out the sediment and cause
floods that erode large chunks of the land.