More Americans see climate change as cause of extreme weather — report

Posted: Wednesday, October 10, 2012

Americans have become more likely to link extreme weather events to climate change, according to a report released today by researchers at Yale and George Mason universities.

Seventy-four percent of Americans said “global warming is affecting weather in the United States,” according to a survey taken in August and September, compared with 69 percent who agreed with that statement in a March survey, the report says.

The survey of 1,061 adults has an error margin of 3 percentage points.

Those surveyed were also asked what kind of weather they have seen accelerating and whether they link it to climate change. Seventy-three percent said this summer’s record heat was worsened by climate change. Sixty-one percent said they had seen U.S. weather change for the worse over the past several years.

The report provides a regional breakdown of survey results, showing that areas that have been hit hardest with severe storms or drought were more likely to say that extreme weather was on the rise. For example, 62 percent of Northeast residents said heat waves had become more common in the past two decades, while 71 percent of Midwesterners said the same thing.

Midwesterners, whose region endured a summer drought, were more likely to say droughts were increasing in frequency than those in the Northeast, 66 percent to 40 percent.

Jon Krosnick, a communication and psychology professor at Stanford University, noted that many of the survey questions asked participants to “agree” or “disagree,” which he says skews results in favor of agreement by about 15 percentage points.

“More than 50 years of research in the sciences show that questions using the agree/disagree format introduce a well-known bias called ‘acquiescence,’” he said. It is easier for a participant to simply go along with a position that he or she perceives is held by the researcher asking the question, rather than to go through the mental exercise that would lead him or her to disagree. Some respondents will also be encouraged to say they agree out of politeness, even if they do not.

Anthony Leiserowitz, director of Yale University’s Project on Climate Change Communication and a lead author of the report, said that there is indeed a debate about whether agree/disagree questions should be used in surveys. But he said the researchers chose to use that format because it was more efficient and because it was consistent with the way questions were asked in the March survey.

The most interesting finding in this fall’s survey, he said, was that more Americans are agreeing that climate change is behind extreme weather than they were six months ago.