MARY LOUISE KELLY, HOST:
Hurricane season starts today in the Atlantic, and it's looking like a bad one. Meanwhile, drought is gripping the West. That's leading to water restrictions and potentially a bad fire season. Coast to coast, this summer of extremes has one thing in common - hotter temperatures because climate change is accelerating. Lauren Sommer and Rebecca Hersher from NPR's climate team are here to talk about how the summer is shaping up.
Hey, you two.
REBECCA HERSHER, BYLINE: Hey there.
LAUREN SOMMER, BYLINE: Hi.
KELLY: Rebecca, you start. When we say this hurricane season is looking bad, how bad? What exactly are scientists expecting?
HERSHER: Well, it's really not great news. You know, forecasters are expecting an above average season, so that means six to 10 hurricanes and up to 20 named storms. So that includes tropical storms that can be super destructive even if they don't have really high wind speeds. And that's because they can still cause catastrophic flooding. And this is the fifth year in a row that the U.S. is expecting more storms than average. Now, part of that is the cycles that the ocean goes through, separate from climate change. But climate change also makes it worse. And as the Earth gets hotter, one of the things that's happening is that oceans are heating up. Hot ocean water helps hurricanes get big and powerful. So climate change makes above average hurricane seasons more likely.
KELLY: Although stay there for a second with above average because I'm wondering what average means. I mean, if the definition is changing as the climate changes, like, is there a new average, a new normal?
HERSHER: Yeah, exactly. The definition of normal is totally changing. In fact, the National Oceanic and Atmospheric Administration even updated its official definition to reflect the climate reality. So normal hurricane seasons in the past meant 12 tropical storms. Now, that number is 14.
KELLY: Wow.
HERSHER: And for full-blown hurricanes, the number went from six to seven. So that's a really stark example of climate change happening right now. And the other thing that's changing is scientists' understanding of what normal rainfall for a tropical storm is or even for a thunderstorm. So warmer air means storms are dumping very abnormal amounts of rain, you know, 15, 20 inches in an afternoon. So as people prepare for storms this summer, that's really something to keep in mind.
KELLY: OK. Let's shift to the Western U.S. and the drought, which seems to be intensifying. Lauren, what are we looking at there?
SOMMER: Yeah, basically, by every measure, it's bad. I mean, more than 90% of the Southwest, you know, from Colorado to California, is in drought, and a big part, an extreme drought. Soils are very dry. Reservoirs are low. I mean, you know, Lake Mead, which is just outside of Las Vegas, is expected to reach its lowest point this year since it was filled in the 1930s. And because there's millions of people in the West that depend on water from hundreds of miles away, we're already seeing cutbacks for farmers and cities.
KELLY: So, OK, so it was a dry winter, didn't see a lot of rain, didn't see a lot of snow. How is climate change playing into this, though, and making the drought worse?
SOMMER: It's playing a clear role. I mean, drought is definitely a normal occurrence in the West. The way Park Williams, professor at the University of California, Los Angeles, describes it, drought normally feels like bad luck, but climate change is making it much worse.
PARK WILLIAMS: Over the last 22 years or so, there's been quite a bit of bad luck because precipitation totals have on average been low, but the effects of those have been really amplified. The effect of that bad luck has been really amplified because of warmer temperatures.
SOMMER: So basically, you know, in a hotter climate, every raindrop and snowflake has less of a chance to make it into a reservoir for two reasons. You know, when soils are dry, like they were over the winter, they're a sponge. They soak up the moisture, so less runs off into rivers and reservoirs. And then when it's hotter, more water evaporates from plants and soils, which also reduces runoff.
KELLY: That makes sense. I'm hearing you say dry. I'm hearing you say hot. And I'm thinking wildfires. This cannot bode well for wildfire season and especially following a record-breaking year last year.
SOMMER: Yeah, exactly. I mean, at this point, the best hope is that the wildfires just aren't ignited in the first place. And the vast majority of fires are caused by human-related things like accidents and power lines. Once they are ignited, of course, the dry conditions make them just a lot more extreme.
KELLY: So both of you help me pull this together. It sounds like this summer, some parts of the country are going to have way too much water, others will have way too little. And it's - you're telling me it's climate change that causes both those things?
HERSHER: Yeah, it's counterintuitive, right? So basically, climate change, it juices the extremes, a hotter atmosphere - it can dry things out, in part because the hot air can hold more water. So the atmosphere is thirsty. A lot of dry places get drier as a result, which helps drive wildfires for all the reasons Lauren just explained. Meanwhile, places that are used to getting maybe a few big downpours every summer, instead, they're getting these deluges that overwhelm the drainage systems.
SOMMER: And, yeah, that's what's really important to remember here. All of this will test our infrastructure because it's not what it was designed for. More water from storms means you need a bigger storm pipes and higher roads and bridges. More intense drought means that this system of water rights, which is basically how we divided up the water, is going to fall short. These are fundamental issues that run a lot deeper than just one bad year.
KELLY: Thank you, you two.
HERSHER: Thanks so much.
SOMMER: Thanks.
KELLY: NPR's Lauren Sommer and Rebecca Hersher. Transcript provided by NPR, Copyright NPR.
