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How this summer's extreme heat waves are connected to flooding, hurricanes


It's been a summer of extremes. Dozens recently died in Brazil when a cyclone dropped more than 11 inches of rain in 24 hours.


And Greece has been dealing with severe flooding. Following deadly wildfires in the Nevada desert, people got stuck in the mud at the Burning Man festival when torrential rain soaked the driest state in America. And much of the world has been baking in intense heat.

ESTRIN: What is going on? Michael Copley joins us from NPR's climate desk. Good morning.

MICHAEL COPLEY, BYLINE: Good morning, Daniel.

ESTRIN: Let's start with the heat. This summer felt hotter than usual. Is that true?

COPLEY: Well, you're right. It has been different. This summer was the hottest on record, with heat waves in places like the U.S., Europe and Japan. So what we're seeing is that heat waves are happening more and more frequently and the hot days are getting hotter. And that's mainly because we keep burning fossil fuels, which releases greenhouse gases like carbon dioxide into the atmosphere, trapping heat close to the Earth. But what's also happening right now is something called an El Nino. It's a natural weather pattern that happens periodically, and it's pushing up global temperatures. So that's amplifying the warming that we're getting from climate change.

ESTRIN: OK, and does that warming have any connection to the extreme rainfall that we've been seeing in Brazil and Greece and other places?

COPLEY: So what we know is that warmer air holds more moisture and warmer water acts like fuel for hurricanes. So what we're seeing right now in Brazil, for example, where a cyclone has caused severe flooding, is the kind of extreme event that we can expect to happen more often as the planet gets hotter. That's according to Andrew Weaver. He's a professor of Earth and ocean sciences at the University of Victoria.

ANDREW WEAVER: This year, what we've seen is remarkable ocean temperatures worldwide. And what we're seeing then as a direct consequence of that is, you know, more energy being fed into the system.

COPLEY: And when you look at the intense rain we've seen in Nevada, state officials say flooding is going to become more common there in the future. And that's because there are going to be more intense storms because hotter temperatures will mean less snow and more rain.

ESTRIN: OK, that's interesting. I hadn't connected the dots before. So hot air causes more rain. Hot air also heats oceans and fuels hurricanes. Is that it?

COPLEY: That's right.

ESTRIN: Is this the new normal?

COPLEY: You know, when I spoke to Professor Weaver, what he says is we're not necessarily going to continue seeing record-breaking heat year after year, but there's every reason to believe we will keep breaking records in the future, especially during years with an El Nino weather pattern.

WEAVER: What you're seeing - and you can see that in all the records globally - is that the lows aren't as low as they used to be and the highs are higher than they used to be. And that will continue forth.

COPLEY: Scientists say this pattern of extreme weather is going to continue until we stop emitting greenhouse gases into the atmosphere.

ESTRIN: OK. Now, this is a hypothetical question because we're nowhere near close to actually stopping greenhouse gas emissions. But let's say we stopped them tomorrow. Would that stop this extreme weather?

COPLEY: The reality is that carbon dioxide hangs around in the atmosphere for a long time, like hundreds of years. So we're going to be living with the consequences of the emissions we've already put into the atmosphere. So there's a lag.

ESTRIN: Oh, wow.

COPLEY: But there's a much bigger problem. Humans keep putting more greenhouse gases up there. World leaders have already agreed we need to keep warming below 1.5 degrees Celsius from preindustrial levels. That's about 2.7 degrees Fahrenheit. If we can keep to that goal, it would stave off some of the most dire consequences. But the reality is we're on track to exceed that mark. So the first thing to do is to start cutting emissions.

ESTRIN: All right. NPR's Michael Copley, thank you so much.

COPLEY: Thanks, Daniel. Transcript provided by NPR, Copyright NPR.

NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.

Daniel Estrin is NPR's international correspondent in Jerusalem.
Michael Copley
Michael Copley is a correspondent on NPR's Climate Desk. He covers what corporations are and are not doing in response to climate change, and how they're being impacted by rising temperatures.