< Climate change is deadly. Exactly how deadly?

MICHEL MARTIN, HOST:

Every year, public health officials estimate that extreme weather events like wildfires and heat waves kill thousands of people in the U.S. But those numbers are just estimates. The exact death toll from climate-driven disasters is unknown, and it's likely higher than official counts suggest. NPR's climate team has been looking into this undercount more deeply, and reporter Rebecca Hersher is here with us to tell us more about it. Hello.

REBECCA HERSHER, BYLINE: Hi.

MARTIN: You know, this seems strange because we count everything, you know, in this country. So how is it that we don't know exactly how many people are dying in disasters? Doesn't the government keep track of who dies?

HERSHER: Yeah, it is a little strange. You know, the government does keep track of deaths in the U.S., you know, writ large. But it's not that simple for extreme weather. You know, there are multiple government agencies all counting the fatalities from storms and wildfires and heat waves. You have local health departments and emergency managers. You have the National Weather Service, and you have the U.S. Centers for Disease Control and Prevention - the CDC. And for a single weather disaster, like a flood or a hurricane, different agencies might actually come up with different numbers. Sometimes it's just a difference of a few people, but in many cases, the disparities between counts can be hundreds or even thousands.

MARTIN: So the death toll is different depending on who is counting or which agency is counting. Why is that?

HERSHER: So at the most basic level, it's not actually always obvious which deaths should be counted. And here I have to say, we are talking about ways that people actually die every year. I don't want this to be too theoretical. You know, these aren't just hypothetical examples. They represent real people who have lost their lives. So that said, imagine that there is a flash flood, and someone drowns in that flood. Was that death caused by the disaster?

MARTIN: Right. Why wouldn't it be?

HERSHER: Why wouldn't it be indeed. It's pretty clear-cut. That death was caused by the disaster, it's gonna be counted that way pretty much no matter who's doing the counting. But now let's imagine that that person has a neighbor, and that neighbor has a lung condition that requires an oxygen machine.

The flood knocks out the power for the machine for a couple of days. Neighbor initially survives, but the lack of oxygen makes their lung disease worse, and three weeks later they die. Some agencies would count that death. Others would not. And so you can see how you might end up with multiple death toll numbers. And for some types of climate-driven disasters, like heat waves, epidemiologists actually estimate that most deaths are not getting counted because they're like that.

MARTIN: How does digging into this more deeply, how does taking another look at death toll numbers help us going forward?

HERSHER: So disaster managers say that to save lives in the future - and again, climate change is causing more of these extreme events - you have to look at who died in past disasters and then do things to prevent those kinds of deaths from happening again. So for example, knowing that people die in heat waves can help you put cooling centers in the right places. So reliable numbers do save lives. And there's actually widespread acknowledgment among the people who do this work that the lack of reliable numbers is a problem.

MARTIN: So solutions, is there something that can be done to fix this?

HERSHER: You know, honestly, it's been a really tough nut to crack. In 2020, the National Academies put out a big report that called for national standards for exactly what we're talking about, you know, which deaths should be counted as disaster related. When we asked the CDC about this, they acknowledged that deaths from weather disasters are being undercounted and said that the agency is working to do more training for, you know, coroners and emergency managers. But there are no immediate plans to update the official CDC guidance about how to count these deaths. That means that we're headed into another deadly, hot, stormy, potentially wildfire-y summer here without that ability to reliably count how many people will die from that extreme weather.

MARTIN: That is NPR's Rebecca Hersher. Rebecca, thank you.

HERSHER: Thanks.

(SOUNDBITE OF EMAHOY TSEGUE-MARYAM GUEBROU'S "SONG OF ABAYI")

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