WASHINGTON — Americans’ belief in global warming is on the rise, along with temperatures and surprising weather changes, according to a new university poll.
The survey by the University of Michigan and Muhlenberg College says 62 percent of those asked last December think the Earth is getting warmer. That’s up from 55 percent in the spring of that year and 58 percent in December 2010. It’s the highest proportion in two years.
Nearly half the people who say they believe in global warming base that on personal observations of the weather. Climate researchers say that’s reaching the correct conclusion for reasons that aren’t quite right.
When asked an open-ended question about why they thought the Earth was warming, one-quarter of those surveyed pointed to temperatures they experience and another quarter cited other weather changes. One in 7 mentioned melting glaciers and polar sea ice, and 1 in 8 noted media coverage. Only 8 percent mentioned scientific research.
“It seems to be driven by an increased connection that the public is making between what they see in terms of weather conditions and climate change,” said Chris Borick, the director Muhlenberg College Institute of Public Opinion.
The poll was conducted from Dec. 4 to Dec. 21, after the U.S. experienced a record 14 billion-dollar weather disasters in 2011, including killer tornadoes, an unusual northeastern hurricane, a devastating southwestern drought and floods along major rivers.
At the same time, this poll was done before the official start of winter, so people were not yet affected by what has been a mild season for many regions.
Borick said that after the previous two winters, which were quite snowy, belief in global warming dropped dramatically. So he says the findings from a fresh poll to be done in upcoming weeks may again reflect views based on the latest weather trend.
Climate scientists say daily local weather isn’t evidence of climate change. But they also say long-term climate change is so dramatic that people recognize and experience it.
“I’m pleased that Americans believe in thermometers,” said University of Victoria climate scientist Andrew Weaver. “People feel confident about what they personally experience. They mix up the difference between weather and climate. It’s not unexpected. It’s human nature.”
While it is a misconception to think that every short-term extreme weather event — like a flood or drought — is caused by climate change, a warming world does make such events more frequent, Weaver said.
NASA climate scientist Gavin Schmidt called strange daily weather “the visceral experience of climate” for people.
Earlier versions of the Michigan and Muhlenberg survey showed that Americans’ belief in global warming peaked in December 2008 with 72 percent.
In the most recent survey, 78 percent of Democrats, 55 percent of independents and 47 percent of Republicans said they thought there was “solid evidence” of climate change. Of those who didn’t believe climate change was occurring, 81 percent thought that scientists were overstating the evidence for their own interest.
The survey of 887 people has a margin of error of plus or minus 3.5 percentage points.
The findings are similar to other recent polls, including a 2010 AP-Stanford University Poll showing 3 out of 4 Americans thought global temperatures were going up, said Stanford poll chief Jon Krosnick. That survey, too, indicated local weather affected people’s views about climate change.