News Release

Public agrees global warming exists, but divided over seriousness of problem

Peer-Reviewed Publication

Stanford University

A majority of Americans agree with most scientists that the Earth is getting warmer, but they are divided over the seriousness of the problem, according to surveys conducted by Jon Krosnick, professor of communication and of political science. Their uncertainty is based on a belief—shared by two-thirds of the population—that scientists themselves disagree about global warming.

"Americans are very much on the same wavelength with the scientific community about the basics of the issue," Krosnick said. "But they lack certainty" about how bad the problem really is. Krosnick blames much of this on media efforts to give equal weight to opposing sides of the debate. Despite this uncertainty, he said, public consensus is growing that society must tackle global warming. "We're moving toward a tipping point, but we're not quite there yet," he said.

Krosnick will detail his survey findings and discuss ongoing research at 8:30 a.m. Sunday, Feb. 18, at the annual meeting of the American Association for the Advancement of Science. He is one of eight speakers participating in a three-hour symposium titled "Perception, Persuasion and Climate Change: Can Science Induce Urgent Action?" Stephen Schneider, a Stanford professor of biological sciences, also will participate with a short presentation titled "Uncertainty and Future Climate Policy."

According to Krosnick's surveys, scientists are frustrated with the perception that the non-scientific community is not paying enough attention to the problem of global warming. "They've been sounding alarm bells for over a decade, saying, ‘We have a really serious problem with the environment and we're destined for a train wreck down the road. How come nobody is listening?'" Krosnick said. Scientists assume that the public doesn't understand or accept their work. "That is wrong," he said. Most Americans believe the world has been heating up, probably as a result of human activity, and that this will be bad for people. But because people lack absolute certainty, Krosnick continued, global warming does not arouse a constantly heightened level of public concern.

To take action on such a huge, complicated issue, Krosnick said, people must believe it exists and will cause severe problems if it is not addressed. But they also must be optimistic that something can be done to alleviate it. "You have to be certain of these two views," he said. "That's where the breakdown comes—certainty for Americans on these issues is either moderate or low."

Last July, Krosnick published an article in the journal Climatic Change titled "The Origins and Consequences of Democratic Citizens' Policy Agendas: A Study of Popular Concern About Global Warming." In the article, Krosnick and three colleagues discussed the impact of the media, President Bush's rhetoric and real-world experiences on public consensus on the seriousness of global warming.

"The news media have been committed to covering this story in a ‘balanced' way," he said, giving a small minority of scientists who discount the crisis equal play with the "99 percent of experts who agree we have a serious problem." Krosnick dubs the result "balance as bias," and it leads most Americans to believe that the scientific community itself is divided over this critical issue.

Ongoing surveys

In addition to these findings, Krosnick will discuss work on three surveys in progress. This includes an update to a joint ABC News, Time magazine and Stanford poll on global warming released last March, which revealed that public concern about global warming has spiked sharply over the last decade and that 70 percent of people think that global weather patterns have become more unsettled in recent years. Krosnick said the new survey results, to be released in April, will gauge how public perception on global warming has changed during the last year.

Secondly, New Scientist magazine has commissioned a survey by Stanford and Resources for the Future, a Washington, D.C.-based, nonpartisan think tank, that will assess how educating people about the cost of addressing global warming affects their support for specific solutions. "People may support ameliorative efforts until they learn that these solutions are costly, at which point their support could evaporate," Krosnick said. However, as the Stern report on global warming reported last October, the cost of doing nothing to combat global warming ultimately may be a lot more expensive for society than tackling it now, he said. Survey results will be released May 12 in New Scientist.

Finally, Stanford's Woods Institute for the Environment is funding a survey to be released this summer that will look at which effects of global warming the public is most worried about. These include both local effects, such rising sea levels and increased storm activity, and worldwide consequences, such as species extinction. According to Krosnick, the survey will gauge how media coverage that reflects the views of both scientific skeptics and believers influences public opinion about global warming versus reports that only include statements by experts convinced it is a serious problem.

Daniel Abbasi from Yale University is scheduled to moderate the symposium. Other participants include James Hansen from NASA Goddard Institute for Space Studies, Arthur Lupia from the University of Michigan, Richard Somerville from the University of California-San Diego, Jane Lubchenco from Oregon State University, Baruch Fischhoff from Carnegie Mellon University and Robert Cialdini from Arizona State University. James Jackson from the University of Michigan will act as discussant.


Jon Krosnick, Department of Communication: (650) 725-3031,

Jon Krosnick will present his research at the annual meeting of AAAS during a symposium at 8:30 a.m. Pacific Time on Sunday, Feb. 18, in Continental Ballroom 4, Hilton Hotel, San Francisco.


EMBARGOED FOR RELEASE until Sunday, Feb. 18, at 8:30 a.m. Pacific Time

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