America's glaciers are disappearing

AYESHA RASCOE, HOST:

Melting glaciers have become one of the most iconic images of climate change - usually in some far-flung place. But what about glaciers of the American West? Turns out about a quarter of them have been lost since the mid-20th century. Andrew Fountain has spent his career studying glaciers as a geology professor at Portland State University in Oregon. His work was recently profiled by the Montana Free Press. Professor Fountain joins us now. Thank you so much for joining us.

ANDREW FOUNTAIN: Hi, Ayesha. Thank you for having me.

RASCOE: You know, I think there's a lot that we can learn about glaciers. There's a lot I don't know. What is the scientific definition?

FOUNTAIN: A glacier is perennial snow or ice that moves. And when I say perennial, what I mean is it's been around for a long time, and it's moving down the mountainside.

RASCOE: How did you begin this project of basically counting the glaciers of the Western U.S.? And you were comparing them to some old data that you had.

FOUNTAIN: Right. You know, years ago, we put together a database of all the glaciers that we found on the old USGS maps, and those are the maps that date to the mid-20th century. And using - what? - satellite imagery and aerial imagery, we've gone back and looked at all those glaciers and digitized the outlines and then compared what we found today to what was on the maps - what? - 50 years ago.

RASCOE: And what did you see? Did you see a lot of spaces where there had been a glacier, and there were now no more glaciers?

FOUNTAIN: Yeah, we were pretty surprised. You know, about a quarter of the glaciers are gone. And what I mean by gone is, yeah, some of them disappeared entirely. Others just became little snow patches. And then there's others that just shrank below our threshold area, which is, like, 0.01 square kilometers, which is basically a football field next to a football field. And if the feature is smaller than that, we just don't count it because we'd be spending all our time on these really dinky pieces of ice and not getting the big picture.

RASCOE: Is all of that due to climate change?

FOUNTAIN: Yeah, pretty much. Glaciers respond to how much snow they get in the winter and how much melting occurs in the summer. And even though the amount of precipitation over the long period of time has pretty much stayed the same, we're getting a little bit less snow, a little bit more rain in a lot of places. And rain doesn't help the glacier. And then, of course, you have a - warming summer air temperatures, which causes more melting, and these glaciers are shrinking. So it's just a matter of long-term climate warming.

RASCOE: So what is the impact of these disappearing glaciers across the West? Is this a big deal?

FOUNTAIN: Well, it's huge for high-alpine water resources and the ecosystems that depend on these glaciers that are melting. In the far West, here in Oregon, on the north side of Mount Hood, the apple and pear orchards rely on late-summer glacial melt for their water supply. And then up in the Cascade Mountains north of Seattle, Seattle City Light has a large reservoir that gets a lot of late-summer glacial melt, which is a significant contribution to its water balance. So there are some direct human effects, and then there's this kind of broad ecological effect as well.

RASCOE: If current trends continue, will these glaciers all disappear?

FOUNTAIN: Well, I think most of them are going to go. Yeah. We did a study on the Olympic Peninsula, which is west of Seattle right up against the ocean. And our modeling there suggests that those glaciers are going to disappear by about 2070 if we continue warming as we're continuing now. And all the other glaciers are going to pretty much follow suit after that, and we'll probably be left with just a few glaciers on the highest peaks of the West. It's just not looking good.

RASCOE: Andrew Fountain, professor emeritus of Portland State University, thank you so much for joining us, and thank you for your work.

FOUNTAIN: Well, thanks for your questions and your interest. Transcript provided by NPR, Copyright NPR.