Washing away Washington.

Many folks think that the West Antarctic Ice Sheet is threatened, and could melt away in a warming world. That's a lot of ice, adding a lot of water to the seas. No one is particularly fond of predictions like these, but researchers are thinking that if the West Anarctic Ice Sheet melts, it might submerge Washington D.C. "Largely underwater," they say.
"The catastrophic increase in sea level, already projected to average between 16 and 17 feet around the world, would be almost 21 feet in such places as Washington, D.C., scientists say, putting it largely underwater. Many coastal areas would be devastated. Much of Southern Florida would disappear, according to researchers at Oregon State University."
Small changes can lead to great consequences. 21 Feet is no small change.