美国国家公共电台 NPR--People in the U.S. are suffering under intense heat warnings and heat advisories（在线收听）

People in the U.S. are suffering under intense heat warnings and heat advisories

Transcript

NPR's A Martinez talks to Michael Mann, professor of atmospheric science at Penn State, about record-high temperatures across the U.S., which climate scientists say is attributable to climate change.

A MART?NEZ, HOST:

A wildfire near Yosemite National Park has become one of California's biggest blazes of the year. It's burning a path of destruction at the same time that record high temperatures are scorching much of the country. Michael Mann is a professor of atmospheric science at Penn State and runs its Earth System Science Center. I spoke with him about the intense events we're all experiencing.

MICHAEL MANN: You know, heat and drought. It's not rocket science. You make it really hot. You make it really dry. You've got the factors that lead to these devastating wildfires that we have seen in California. We've seen more than tripling in the extent of wildfires over the past few decades out West and it's because we're warming up the planet.

MART?NEZ: And is there anything different this year or maybe even last year than, say, maybe 10 years ago?

MANN: You know, climate models have predicted for a long time that we're going to see hotter and hotter summers. We're going to see a drying in mid-latitude regions in the summer like we're seeing here in the United States, especially out West. There's an additional factor, though, in the behavior of the jet stream. It's really become obvious only, I would say, over the last five or six years where we see these high- and low-pressure systems just get stuck in place. And when you've got a high-pressure system stuck out West like we have right now, you get that heat. You get that dryness. You get the wildfires that result from that combination. And you get this stagnation. The system just sits there for day after day. And that's when you really see these most devastating consequences.

MART?NEZ: How often in the past have we seen this many people in the U.S. be affected by extreme heat all at the same time?

MANN: Yeah, I mean, right. It's more than a third or about a third of the population, more than 100 million people in a population of 270 million. I mean, we've seen it twice. We saw that back in June with the heat waves in June. And we're seeing that again now. You know, these heat waves that are just - what's so unusual is how pervasive they are. In fact, it's so pervasive that we're seeing it not just across North America, but in Eurasia as well. We're seeing record-breaking heat in Europe. We're seeing record-breaking heat over a large part of the United States.

We broke the record for the hottest temperature ever observed in the U.K. just last week. And we're threatening some of those records here back in the United States. It's the scale and the persistence of this heat which is so damaging and so dangerous. And there's literally no question that we wouldn't be seeing these sorts of extreme events in the absence of human-caused warming resulting from fossil fuel burning and the increase in carbon dioxide in the atmosphere that results from it.

MART?NEZ: Yeah. And for many, all of this is life-threatening.

MANN: That's right. I mean, you know, a decade or two ago, it was sort of an abstract concept, you know? We'd show pictures of polar bears off in the Arctic. It just seemed so distant. And now the warming has now reached the point where we're seeing the consequences play out in real-time in terms of these devastating events. And that's really worrying because it's like the tip of the iceberg. By the time you see it, you know that there's much more there. We've got to bring carbon emissions down by 50% within the next 10 years to prevent the planet from warming beyond a truly catastrophic three degrees Fahrenheit.

MART?NEZ: I got to imagine that it might be hard for you and for others to admit that maybe you even underestimated the consequences of all this.

MANN: As we see these events play out, we realize now that there were limitations in our models that probably underestimated the rate at which ice sheets can begin to collapse and contribute to global sea level rise. And the models appear to have underestimated the subtle impact that climate change can have on the behavior of the jet stream that gives us these devastating summer extreme weather events. And so that's right, if anything, the science has been overly conservative.

MART?NEZ: All right. So given, then, what we're all experiencing right now, what do local governments need to do to protect people, not just today, but in the coming weeks, months and possibly years?

MANN: Low-income communities in particular often are the most prone to these extreme events. And so, you know, we need to provide resources to front-line communities to deal with the devastating impacts. But we have to prevent this problem from getting even worse. And the only way we do that is by getting off of fossil fuels, is by decarbonizing our economy, moving as rapidly as possible away from the burning of fossil fuels. And we need politicians who will support policies to do that. There's an upcoming election, a midterm election this fall, where we can turn out and vote for policymakers who are willing to act on the defining crisis of our time, which is, in fact, the climate crisis.

MART?NEZ: A lot of times when we have these kind of conversations, Michael, we always hear dates. If we don't do this by this year, then we've gone too far. We've reached a point of no return. Have we lost the ability to limit at least some of the impacts of climate change by now?

MANN: Sometimes, you know, we frame this as if it's some sort of cliff that we go off at three degrees Fahrenheit warming or four degrees Fahrenheit warming. That's not what it is. It's a minefield. And we're walking farther and farther out onto that minefield. And the farther we walk out onto that minefield, the more danger that we are going to encounter. So at this point, it's about limiting the danger. It's about limiting the damage. We're not going to avoid dangerous climate change impacts because we're already seeing them. At this point, it's a matter of making sure that we don't let it get worse. And so there is urgency. But as I like to say, there is agency. There is still time to take the actions necessary to avert truly catastrophic, global-scale climate consequences.

MART?NEZ: Professor Michael Mann at Penn State University, author of "The New Climate War." Michael, thanks a lot.

MANN: Thank you. It was a pleasure talking with you.