Phil Duffy, Senior Policy Analyst and Becky Fried, Policy Analyst, Office of Science and Technology Policy, Executive Office of the President
Polling results released last week by the University of Michigan and Muhlenberg College (Pennsylvania) show that, compared to previous surveys, the largest majority of Americans in years now believe global warming is occurring. Sixty two percent of respondents to the December 2011 National Survey of American Public Opinion on Climate Change (NSAPOCC) agreed there is â€œsolid evidenceâ€ that Earth has been getting warmer over the past four decadesâ€”a marked increase from 55 percent just half a year earlier.
Notably, however, almost half of the 62 percent said their views were shaped by personal observations of temperature and weather phenomena. In narrative explanations of why they accept the reality of global warming, survey respondents indicated â€œwinters just arenâ€™t as cold as they were in the past,â€ â€œtemperatures last summer that were awful,â€ and â€œdroughts this past summer,â€ among other observations.
Those results suggest that many Americans are basing their climate change attitudes on near-term personal experiences and observations rather than the stream of scientific evidence demonstrating climate change and warmer-than-normal global temperatures due to greenhouse gas emissions. While science tells us that there are indeed links between local weather and global climate, particular weather events and short-term variations are not reliable indicators of long-term climate trends, which must be measured across decades or longer. So while more and more Americans apparently agree with the scientific consensus on climate change, many seem to be doing so for the wrong reasons.
The risk in this, of course, is that in years when short-term weather cycles are coolerâ€”as can be expected occasionally in the course of the current longer-term warming trendâ€”these people will be more likely to change their minds. Indeed, the poll found that some Americans are already making this error. In the study, among those who said they are unconvinced that global warming is happening, the most commonly cited rationales were personal observations such as â€œwinters were just as cold as when I was a kid,â€ or â€œour weather seems just as cold as in the past."
â€œPeople naturally form viewpoints and make decisions based on personal experience. Itâ€™s one reason why understanding the local-scale impacts of climate change and how they differ from weather is so critical.â€ said Tom Armstrong, Director of the U.S. Global Change Research Program. â€œCommunicating this information broadly is one of the most important ways we can ensure that people and communities are able to make informed, science-based decisions.â€
The NSAPOCC is planning a follow-up report to explore the connections between American climate change attitudes and policies.