A recent Pew Research survey showing a sharp decline in the proportion of the public saying there is solid evidence of global warming has triggered considerable speculation about why these views are changing. The poll was released a day after 18 leading scientific organizations released a letter reaffirming what they see as scientific consensus on climate change.
The survey found 57% saying there is "solid evidence that the average temperature on earth has been getting warmer over the past few decades." In April 2008, 71% said there was solid evidence of global warming, and in 2006 and 2007, 77% expressed this view.
Why do fewer Americans believe the earth is warming? No single factor emerges from Pew Research Center surveys, but rather a range of possible explanations, including a sour economy and, perhaps, a cooler than normal summer in parts of the United States.
Read the full commentary Searching For Clues in the Global Warming Puzzle on the Pew Research Center's Web site.