ARI SHAPIRO, HOST:
Now let's dig a bit deeper into the discussion of climate change that we're likely to hear tonight. NPR's energy and environment editor Jennifer Ludden is here in the studio. Hey, Jennifer.
JENNIFER LUDDEN, BYLINE: Hey, Ari.
SHAPIRO: It's a new thing for climate to be a top issue...
SHAPIRO: ...Among primary voters and at debates. What's changed?
LUDDEN: Yeah, a lot. Yeah, last time, remember, there was not a single question in the major debates.
SHAPIRO: Right, across all the debates.
LUDDEN: No. No, not at all. This time, a lot of differences. A big one would be President Trump. I think what we're seeing is, in part, a backlash to his rejection of climate science and his real push for fossil fuels.
SHAPIRO: Pulling out of the Paris climate accord, et cetera.
LUDDEN: Among other things.
Also, we had a series of sobering scientific reports last fall just pointing out how dramatically the world needs to reduce greenhouse gas emissions that warm the climate, and pretty soon to avoid really catastrophic impacts. And, you know, just a lot of extreme weather disasters.
LUDDEN: More people are feeling them, including the candidates. They talk about it, be it fires, hurricanes, flooding. Iowa this spring - record flooding. A poll of Democratic caucus voters there found three-quarters said the candidates must treat climate change as the greatest threat to humanity.
SHAPIRO: There was a push to have one debate that was entirely devoted to climate change. Is that going to happen?
LUDDEN: So far, not. The Democratic Party has rejected it, said, we can't do this for everything. You know, there's a petition. We'll see.
But, you know, this week's debates are in Miami, and it's pretty hard to avoid the issue there. That city is seeing, you know, more and more flooding from rising sea levels. They're spending a boatload of money to address that.
You know, even Republicans in Florida have been trying to push their party to do more on this issue. Just last month, Florida's Republican governor put out a new job posting for the state's first chief resilience officer to figure this out.
SHAPIRO: A lot of the conversation among Democrats is centered around the Green New Deal, which is this sort of framework of ideas but not a lot of detailed policies. What specifically are the candidates saying they would do?
LUDDEN: The main big thing - there's this push for net-zero greenhouse gas emissions by mid-century. This is a big trend. Cities and states are saying, we're going to cut our carbon emissions down to, you know, as close as we can to zero. To make that happen, you have some candidates supporting a carbon tax or some kind of price on carbon, which economists say would be, really, the most efficient way to shift the economy away from fossil fuels.
A lot of the candidates - very big on investing in clean energy - trillions of dollars, different amounts, different candidates there. Washington Governor Jay Inslee goes the farthest. His policy would, really, call for an eventual ban on all fracking and all fossil fuel production, kind of this keep-it-in-the-ground approach you've been hearing from activists.
To keep in mind what a challenge that would be, the U.S. recently became the world's largest producer of oil and gas. And, you know, a lot of these proposals would need majority support in Congress, and the next president may not have that.
SHAPIRO: Are there any outliers in the Democratic field who don't support some big, sweeping plan to limit carbon emissions and slow climate change?
LUDDEN: OK, well, not all of them have had a climate plan so far, and, you know, some emphasize it more than others. But Colorado Governor John Hickenlooper is the most critical of the Green New Deal, saying, you know, as proposed in Congress, it kind of relies too much on government and not private industry. Colorado is a big oil and gas state. He oversaw an expansion there. But he does support a tax on carbon.
Elizabeth Warren - corruption's her main focus. And she says, look; if you're going to really make headway in this issue, the first thing you got to do is get big oil money out of politics.
SHAPIRO: And speaking of big oil money, climate change activists have called on candidates to pledge to refuse all fossil fuel money. Have they?
LUDDEN: Most of them have said they will - 19 so far - a few who still have not.
SHAPIRO: That is NPR energy and environment editor Jennifer Ludden. Thanks a lot.
LUDDEN: Thank you. Transcript provided by NPR, Copyright NPR.