As seas rise, cities retreat

Climate change is causing seas to rise -- and threatening cities along the West Coast. At the current rate of greenhouse gas emission, scientists estimate that global temperatures will increase by an average of 8 degrees Fahrenheit by the end of the century, melting polar ice sheets and upping sea levels by a meter. According to recent research from the University of Arizona, by 2100, higher tides will inundate an average of 9 percent of the land area of coastal cities in the Lower 48. In subsequent centuries, "that amount of warming will likely lock us into at least 4 to 6 meters of sea-level rise," says lead researcher Jeremy Weiss.

Lower-lying East Coast cities will be hit hardest, but some Western cities are getting ready for the deluge. Maps to the right show projected sea-level rise and note how some Western communities are responding.

At least one Alaskan town, though, isn't worried -- because the land it's on is rising, too. As the Mendenhall Glacier melts and retreats inland -- another byproduct of climate change -- the land under Juneau is actually lifting faster than the sea is rising. Most West Coast communities won't be so lucky.