The lowest part Washington D.C. is at sea level on the tidewater Potomac. They might be some of the first to notice if the ocean rises four feet.

The most recent ice age covered as far south as Maine with ice 1.5 - 3 miles thick. Greenland is the remnant of that ice sheet. Two miles of ice disappeared from Maine in about 11,000 years. That was a very fast global warming without the use of coal. During this ice age Europe was covred with boreal forests instead of oaks. A simple truth.

http://www.climatechange.umaine.edu/Research/news/ClimateExplanation/Cli...

An earlier ice age epoch covered North America as far south as near the Indiana-Kentucky border. Carbon dioxide alone cannot account for interglacial warming or glacial cooling. There are many moving parts in the climate model.