AUDIE CORNISH, HOST:
From NPR News, this is ALL THINGS CONSIDERED. I'm Audie Cornish.
During the three televised debates between President Obama and Mitt Romney, one looming issue never surfaced: climate change. Romney has a mixed public position on the issue. He says climate change is happening, but he does not agree with the scientific consensus that human beings are largely responsible for it. President Obama has accepted that as consensus, but he's also trying to avoid the issue. We'll hear more about that tomorrow.
Today, NPR's Richard Harris looks at the tightrope that Romney is walking on climate change.
RICHARD HARRIS, BYLINE: Mitt Romney rarely speaks of climate change. But he has written that he accepts that the planet is warming up. Why it's happening is another matter. Here was his position, stated at a private fundraiser early in his campaign.
MITT ROMNEY: My view is that we don't know what's causing climate change on this planet. And the idea of spending trillions and trillions of dollars to try and reduce CO2 emissions is not the right course for us.
HARRIS: In other written comments, he has since said humans play some role but he hasn't embraced the sweeping scientific consensus backed by thousands of studies and accepted by science academies around the world that humans are largely responsible. You could look at this simply as a political position to appeal to Republicans skeptical about climate change. But to a philosopher, this is also an example of faulty logic.
GARY GUTTING: The flaw in that argument is that, contrary to what he says, there is a consensus among climate scientists about the extent of human-produced warming and the degree of risk to the planet.
HARRIS: Gary Gutting is a science philosopher at the University of Notre Dame. He says, since Romney is not a climate expert, he has to make the same decision the rest of us non-experts do. Do we trust the National Academy of Sciences and other experts or not? Gutting says once you decide to trust them, you can't just bail out anywhere, as if you were in a cab.
GUTTING: You have to stay for the whole ride that the driver's taking you on. You can't accept their authority for one dimension of the discussion and then say, we'll forget about it for another dimension of the discussion.
HARRIS: Logical or not, that's exactly what a lot of Americans do. Anthony Leiserowitz, at the Yale Project on Climate Communication, finds this bit of factual cherry-picking in his polling data.
ANTHONY LEISEROWITZ: Seventy percent of Americans say that global warming is happening. But 54 percent believe that global warming is caused mostly by human activities.
HARRIS: Often, people don't even know there's a strong scientific consensus, so they aren't rejecting science here.
Dan Kahan, at the Yale Law School, says people tend to base their judgments largely on what their peers think. After all, if you decide to buy a gas guzzler because you don't accept climate change, that decision won't have big consequences for the planet.
DAN KAHAN: It's just not important enough, so it's costless, really, for them to make mistakes on that. But what they believe about climate change can make a big difference for them in their communities. If I go back to New Haven and I march around the old campus with a sign that says: Climate change is a hoax, that's not going to be very good for me in my community.
HARRIS: Kahan says it's actually rational for people to reject climate science if their peers are rejecting it.
KAHAN: That's probably not bad for them, although it's not good for society.
HARRIS: Looked at this way, it's rational for Mitt Romney to tell his conservative base what they want to hear about climate change. Leiserowitz says, at least that makes sense in the current political climate, which is a different than it was during the last election.
LEISEROWITZ: Four years ago, John McCain, the presidential nominee of the Republican party, had been the primary champion of climate change action in the U.S. Senate for over a decade.
HARRIS: Romney was strongly in that do-something camp when he was governor of Massachusetts. But he eventually changed his tune, as he eyed a 2008 run for president and staked out some more conservative positions. Yet, Leiserowitz says Romney doesn't want to alienate the majority of Americans who see climate change as a real issue. So he's shading his language.
LEISEROWITZ: And so, he's trying to, you know, walk that tightrope between those two very different positions.
HARRIS: That position paves the way for Romney to say he doesn't intend to reduce carbon emissions. The Romney campaign would not provide a spokesman for this report. But the campaign's domestic policy adviser, Oren Cass, laid that out at an event at MIT webcast by E&E TV.
OREN CASS: When Governor Romney talks about a no-regrets policy, what he means is the policies that we can pursue, that will move forward, particularly with technological innovation, to find solutions without having negative effects on our economy in the interim.
HARRIS: Research but no action other than rolling back some of the Obama administration's climate policies. That again goes against the consensus of the National Academy of Sciences, which concludes that time is rapidly running out to prevent some of the most serious consequences of climate change.
But philosopher Gary Gutting says Romney recognizes that scientists don't get the last word here.
GUTTING: He does say this. And he's right about this: In the end, policymakers and the public, and not scientists, have to decide what relative balance of risks and costs they think they can live with.
HARRIS: And that plays out in the nation's broader political debate. Richard Harris, NPR News.