ARI SHAPIRO, HOST:

In a couple of weeks the world will focus on Paris again for entirely different reasons. President Obama and representatives from nearly 200 other countries will be there trying to agree on a deal to limit carbon emissions and slow climate change. Todd Stern is the chief negotiator for the U.S., his title is Special Envoy for Climate Change, and he joins us now to preview the Paris talks.

Thanks for being here.

TODD STERN: Thank very much Ari.

SHAPIRO: This summit begins November 30. It's scheduled to last two weeks. What is at stake? Is this the last best chance for the world to act?

STERN: Well, I don't know if it's the last chance, but it's definitely the best chance. I think that the stars are more aligned to get an agreement than they've ever been in my experience - and my experience goes back a fair amount. So I think that this is very important. I think the moment is now and we have to try to seize it.

SHAPIRO: What do you expect the biggest sticking points to be?

STERN: Well, this notion of the basic divide between developed and developing countries, and who's going to do what and how that differentiation is captured in the agreement is going to be an important one. We are for differentiation, but we have proposed, for example, a structure in which countries put in nationally determined commitments or contributions. So it is differentiated across the whole spectrum of countries rather than saying all developing countries only have to do this and developed countries do that.

SHAPIRO: When you talk about nationally determined goals, you mean each country says, OK, well, we are willing to shift this much to clean energy, another country says, we're willing to preserve this much forest. Each country comes up with their own promise.

SHAPIRO: That's right. When you look at all of the commitments that countries have made so far, more than 150 countries including all the biggest global emitters have already made their pledges before Paris begins. Are you satisfied with the total? Do you think it gets the world to where we need to be?

STERN: Well, it doesn't get the world where we need to be, but it is a hugely important step. I would say that the notion that we have I think close to 160 countries who have come forward with their targets at this stage is an extraordinary thing. If - anybody who is deep into the world of climate negotiations, if you would've said a few years ago - even a year ago - that we would've been looking at 160 targets from countries, 120 of them or more developing, people never would've believed it.

SHAPIRO: The goal of this climate summit is to produce a document that nearly 200 countries around the world can agree to - ideally, a short document. There have been these huge debates over various drafts. And I've been looking at some of the debates over language here, and some of it comes down to, for example, whether countries shall do something or should do something. And it's incredible to me to think that, to some extent, the fate of the world hinges on (laughter) the difference between shall and should.

STERN: Well, that's very understandable, and that is - this isn't unique to climate change. That's the nature of international agreements. But yes, a few small words, sometimes a comma can make a tremendous amount of difference.

SHAPIRO: So is that what you're actually doing in these talks, is, oh no, we need to add a comma here, we need to take it out here, we need to change the shall to a should?

STERN: I am not only doing commas, but...

SHAPIRO: (Laughter) But you're also doing commas.

STERN: (Laughter) ...I am also doing commas, and proud of it. I mean, sometimes it's important so - no, look, you're absolutely right that sometimes you have negotiators who not only are going to miss the forest for the trees, they'll miss the forest for the bark on the trees. I mean, that does happen, and we have to keep in mind what it is that we're trying to accomplish. But the words can matter.

SHAPIRO: Congress wants to roll back the Obama administration's Clean Power Plan commitment. President Obama has threatened to veto the bill that Congress is voting on, but that raises the question of whether countries will be able to adhere to the commitments they make if there is major political change in the future.

STERN: I think you will see in general that when countries make international commitments they tend to stick by those, and that's true for the United States also. All manner of international agreements are generally followed. I mean, not in every single case, but generally that is the way it works here and it's the way it works in other countries too. And I think that's an important thing and a good thing to continue.

SHAPIRO: Your job is primarily dealing with other people who appreciate the importance of climate change. But when you look at the general public, do you find it hard to focus people's attention on the long-term gradual changes that threaten American life while in the meantime there are dramatic short-term traumas and chaos happening, as we just saw Paris this week?

STERN: Well, look, there are all sorts of impacts which are upon us now. This isn't just something that's going to happen in the distant future. It's going to get worse and worse in the future, but it is happening now. I'm not suggesting that people aren't going to be also affected and more immediately affected by events like the ones in Paris, obviously, and other things that are gripping and immediate, but when you're in the path of the fire or on the coast where Hurricane Sandy is hitting, or living through the drought in California or the Midwest from a couple of years ago, those things are affecting you pretty dramatically as well.

SHAPIRO: U.S. Special Envoy for Climate Change Todd Stern, thanks very much.

STERN: Thank you very much, I appreciate it.

SHAPIRO: And NPR News will provide special coverage of the upcoming Paris climate summit, from its opening sessions on November 30 and throughout the two weeks of negotiations. Transcript provided by NPR, Copyright NPR.

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