"More than two-thirds of Americans now believe global warming contributed to recent extreme weather disasters, according to the latest report released by the Yale Project on Climate Change Communication and George Mason University." [see (2) for original poll source]
Yes! Magazine. Fall 2012. 7.
(2) "Extreme Weather and Climate Change in the American Mind," George Mason University, September, 2012. http://environment.yale.edu/climate/files/Extreme-Weather-Public-Opinion... (pg. 3)