An increasing number of Americans indicate that there is evidence of global warming, with 67 percent now expressing a belief that the planet has warmed over the past four decades, according to a University of Michigan survey.
It marks the highest level of belief in global warming since a 72 percent-measure in 2008 and is up from 52 percent in spring 2010.
The results come from the National Surveys on Energy and Environment, a joint effort of the Center for Local, State, and Urban Policy at U-M’s Ford School of Public Policy and the Muhlenberg Institute of Public Opinion at Muhlenberg College in Allentown, Pa.
“For the first time since 2008, a majority, or 51 percent, of self-identified Republicans stated that they think global warming is occurring,” he said.
The telephone survey of 998 Americans between Nov. 26 and Dec. 5, 2012, had a margin of error of 3 percent either way.
Other findings include:
- In comparisons between surveys before and after the landfall of Superstorm Sandy in October 2012, the importance of hurricanes as a factor cited by individuals in their belief that global warming is happening rose significantly.
- More Americans than at any time since 2008 attribute increasing global temperatures entirely to the activities of man, with over 4 out of 10 individuals stating that human activity is the cause of the change.
- Among the shrinking percentage of Americans who doubt global warming’s existence, there appears to be both a decreased impact of personal experiences on their views on this subject and an increased prominence for personal religious and political factors in the determination of their doubts.