For the past decade, researchers have been studying what Americans believe about climate change.
For several years, more and more of the public has agreed that climate change is taking place. But recently, the number of people who believe climate change is happening is falling.
I talked with Barry Rabe, a professor in the Gerald R. Ford School of Public Policy at the University of Michigan.
He’s the author of a new report that draws on the latest public opinion surveys.
Here's what he had to say about the report, which found fewer people believe the Earth is warming:
"We found in the United States as well as in Michigan that there appears to be an upward trajectory of this in the past decade. Do you think global temperatures are warming, independent of the question of human causation, and other questions about perceptions of global warming consistently increasing, probably peaking in late 2008.
Since that time in the United States, we’ve seen a drop of about 18-20 percentage points on some of the very basic, standard survey questions that have been used for some time in the U.S. and really around the world.
In our latest survey which comes from November 2010, we actually see a little bit of bouncing back up again, not back to those November 2008 levels but for our purposes what this suggests is public understanding and perception of climate change is really a pretty volatile area of public opinion.
The numbers move around quite a bit from year to year, much more than we would have ever anticipated."
He thinks one main reason why belief in global warming has dropped over the past couple years is because a lot of people are affected by the weather in their own backyards.