"Some scientists predict the sea will rise one and a half meters before 2100, but rapidly melting polar ice caps could make the real amount much higher. In the coming century, intensifying storms will batter our coasts, and droughts and heat events will be annual threats. All this will occur as population grows, and declining water resources desiccate agriculture. What will happen when the United States cannot provide food or fresh water for the overheated, overcrowded cities where 80 percent of Americans currently live? The good news is that this overall decline of habitability in the mid-latitudes will be matched by increases in the carrying capacity of sparsely populated lands above the 49th parallel. This phenomenon suggests that waves of environmental refugees will travel poleward as southern conditions worsen"--Amazon.com.