Global Warming and the Pollsters: Who's Right?

June 16, 2010 — -- Is the glass half empty, or half full?

Public opinion polls on global warming seem to be all over the map these days. A Gallup poll in March indicated that nearly half the people in the United States think the consequences are exaggerated and they're not particularly worried about their future. But two polls released in the last few days show that most Americans believe global warming is real, the consequences could be great, and it's largely our fault.

All three of these polls were conducted by professionals, so why do they seemingly disagree? Mainly, it's in how the questions were asked, and how the data was interpreted. On the surface, it appears that Americans are deeply divided over the issue, wafting back and forth because it was a mild winter, or it's a hot spring, neither of which have anything to do with global climate change.

"Several national surveys released during the last eight months have been interpreted as showing that fewer and fewer Americans believe that climate change is real, human-caused and threatening to people," said Jon Krosnick, a professor of communication and of political science at Stanford University. "But our new survey shows just the opposite," he said in releasing a new national poll conducted by Stanford's Woods Institute for the Environment.

The Stanford poll was conducted June 1-7, and it found that three out of four Americans believe the Earth is warming because of human activity, and they want the government to stop it. But that's down 10 percent from a Stanford poll in 2007, dropping from 84 percent to 74 percent.

Public concern is going down?

Not according to another poll released on June 8, showing that public concern is growing, not dropping. That national poll, conducted by Yale and George Mason Universities from May 14, 2009 to June 1, 2010, found that 61 percent of Americans believe global warming is real (an increase of four points since January) and 50 percent (an increase of three points) believe it is caused mostly by humans.