'Warming Hole' Delayed Climate Change Over Eastern United States

http://www.sciencedaily.com/releases/2012/04/120426155117.htm

ScienceDaily (Apr. 26, 2012) — Climate scientists at the Harvard School of Engineering and Applied Sciences (SEAS) have discovered that particulate pollution in the late 20th century created a "warming hole" over the eastern United States -- that is, a cold patch where the effects of global warming were temporarily obscured.