SCOTT SIMON, host:
Not so long ago, climate change was a controversial idea. Then it became a mainstream issue.
In this installment of Climate Connections, a yearlong project with National Geographic, NPR's Eric Weiner looks into the change.
ERIC WEINER: It was the summer of 1988. Ronald Reagan was president. The L.A. Dodgers were on their way to an unexpected World Series victory, and a prophetic song by George Michael rose to the top of the charts.
(Soundbite of song "One More Try")
Mr. GEORGE MICHAEL (Singer): (Singing) I didn't feel the danger. Now I feel the heat.
WEINER: And it was hot - very hot - with record-high temperatures recorded in many parts of the country. A severe drought struck the Midwest. No one could remember anything quite like it.
On one particularly hot June day, with temperatures soaring past 100 degrees in Washington, D.C., Senator Tim Wirth convened a congressional hearing on what was then called the greenhouse effect, summoning several expert witnesses.
Professor MICHAEL OPPENHEIMER (Geosciences and International Affairs, Princeton University): I don't think I've quite seen another hearing like it.
WEINER: That's Michael Oppenheimer, now with Princeton University and one of the witnesses who testified that day. Normally, these dry scientific hearings don't get much media attention but, on this day, the room was packed with reporters.
Prof. OPPENHEIMER: And there was a dramatic sense in the hearing room, which was a standing room only audience, that something new is afoot.
WEINER: The reporters were looking for a headline and they got it, the unexpectedly blunt testimony of a young NASA climatologist named James Hansen.
Dr. JAMES HANSEN (Climatologist, NASA): Altogether, this evidence represents a very strong case, in my opinion, that the greenhouse effect has been detected and it is changing our climate now.
WEINER: That was it. Never before had a respected scientist put it so definitively and so publicly. Of course, it wasn't only what Hansen said but when he said it - in the middle of a heat wave.
Mr. CHRIS MOONEY (Author, "Storm World"): And then this blockbuster statement by Hansen saying that, you know, global warming is happening and we're probably causing it.
WEINER: Chris Mooney is author of "Storm World," a new book about global warming.
Mr. MOONEY: Suddenly, suddenly, because all these things came together, it became a political issue for the first time.
WEINER: Global warming was now on the public's radar screen but it wasn't a very large blip. Polls in the mid-1990s found that few Americans considered global warming a major environmental problem. But very recently, that has changed and changed dramatically, says John Krosnick of Stanford University.
Professor JON KROSNICK (Political Science, Stanford University): Absolutely. That the tipping point did happen, I think, during the last year, that the country did move from still wondering about whether climate change was happening to saying, okay, of course, it's happening. Now, what are we going to do about it?
WEINER: A recent Washington Post/ABC News poll found that the number of Americans who named global warming as the biggest environmental problem facing the world has doubled in the past year alone.
Why the sudden surge in public concern? There are a number of theories. First, the media. They're covering the story more extensively and aggressively. The few skeptical scientists don't receive the same airtime they once did when evidence of climate change was weaker.
Then there's what psychologists call the social amplification of risk. It's a theory that explains why we fear some things more than others.
(Soundbite of movie theme for "Jaws")
WEINER: The 1975 movie "Jaws" is a classic example. It scared off countless swimmers from the oceans even though there wasn't much to fear. Sometimes, though, popular culture amplifies a risk that we should fear.
(Soundbite of movie "The Day After Tomorrow")
WEINER: The 2004 movie "The Day After Tomorrow" was a box-office hit. The acting was bad, the science worse, but the movie did help focus public attention on the very real issue of global warming, says Anthony Leiserowitz, director of the Yale Project on Climate Change.
Dr. ANTHONY LEISEROWITZ (Director, Yale Project on Climate Change): Well, of course, this is a Hollywood blockbuster. We don't take this as literal truth. But it does get us thinking about, well, what is this thing called global warming and what might this impact actually be?
WEINER: And then, of course, there is the Al Gore factor.
Mr. AL GORE (Chairman, Alliance for Climate Protection): And that is what is at stake - our ability to live on planet Earth.
WEINER: Millions of people watched the former vice president's documentary, "An Inconvenient Truth." It clearly helped gel public concern about global warming but how much is not clear. Again, Anthony Leiserowitz.
Dr. LEISEROWITZ: You know, a lot of people think "Inconvenient Truth." "Inconvenient Truth" must have been the thing that has changed things. And I see very little evidence of that. That movie appealed to people who like Al Gore and were thus willing to go see that movie. Let's call them mostly mainstream Democrats.
WEINER: Leiserowitz and others believe that what has really sparked concern about global warming is not films or documentaries but real-world weather events.
(Soundbite of news report)
Unidentified Man: Melting roads, closed schools and packed beaches. The heat wave breaks a new record.
WEINER: In Europe, it was the heat wave of 2003, which killed tens of thousands of people. In the U.S., it was the summer of 2005.
(Soundbite of news recording)
Unidentified Woman: Coastal Louisiana and Mississippi braced for the worst. Hurricane Katrina now at category five…
WEINER: The pictures from New Orleans after Hurricane Katrina spoke volumes, and while scientists have not established a definitive link between global warming and hurricane intensity, the possibility of such a connection has made people take notice. Global warming now seems a lot less abstract. Again, Chris Mooney.
Mr. MOONEY: Carbon dioxide's invisible. It's not something that can be easily dramatized. A hurricane, especially a hurricane glimpse on a satellite image from the space, is one of the most dramatic, sublime images you can possibly imagine. It's overwhelmingly terrifying.
WEINER: So where does U.S. public opinion go from here? Is concern about global warming here to stay? Baruch Fischhoff, a professor of risk analysis at Carnegie Mellon University, says yes.
Professor BARUCH FISCHHOFF (Social and Decision Sciences and Engineering and Public Policy, Carnegie Mellon University): There will be events that happen, severe storms. There will be a drought in some region of the world, and you say, you know, there's some chance that climate change made this more likely. So my guess is that climate change will be part of our consciousness indefinitely.
WEINER: Not so fast, says Yale University's Anthony Leiserowitz. Public concern about global warming does not exist in a vacuum. It's constantly competing for attention with other issues.
Dr. LEISEROWITZ : If something happens tomorrow, if, you know, the U.S. decided to invade Iran, this story drops off the radar screen completely. I mean - so there's a moment of opportunity right now in terms of policy.
WEINER: That moment, says Leiserowitz, is one that the U.S. and the world should latch on to. Global warming's public profile may rise and fall but floods, droughts and hurricanes will continue to remind people that, as Anthony Leiserowitz puts it, nature bets(ph) last.
Eric Weiner, NPR News, Washington.