ALINA SELYUKH, HOST:
Rock climbers are watching as their favorite mountains crumble because of climate change. While extreme heat and long-lasting drought affect everyone, they're having a unique impact on the world of outdoor recreation. Tommy Caldwell is a professional rock climber who has summited some of the most difficult mountains in the world. He joins us from Colorado. Welcome.
TOMMY CALDWELL: Great to be here.
SELYUKH: So with drier summers and warmer winters, what challenges are climbers facing out in the mountains now?
CALDWELL: I mean, I think the most obvious example is probably glaciers melting in the mountains. Like, that's the most visually obvious. We go up into the mountains, and the glaciers are receding. The mountains themselves are oftentimes melting out, which means, for ice climbers, less ice but also more rockfall. Like, these mountains that have historically been frozen together are melting out and kind of falling apart.
SELYUKH: Right. And earlier this summer, we had that incident where several people died hiking in the Dolomites in Italy when a glacier broke free. Like, is that sort of an example of these possible disasters that you're watching for out there?
CALDWELL: Yeah, so that's a pretty dramatic example. But, you know, in one of my favorite places to climb in the world, which is Patagonia in southern Argentina, we just started to notice that we're getting these really warm weather windows for weeks on end, which really didn't use to be the case down there. The weather was quite bad. And so everybody's excited because the weather is good to go climbing. If you're a rock climber, that's great. But every time there's a good weather window, somebody dies. And so I've stopped going there. You know, as a father, this - these days, myself, I've just decided it's too dangerous. It's just - which is sad. You know, it was my favorite place to go climbing in the world.
SELYUKH: And what were the conditions that are causing deaths in Patagonia?
CALDWELL: It's just rockfall - increased rockfall. So when you're climbing these very big, steep mountains, rockfall is one of the major hazards always. But just sporadic rockfall that happens without really any warning has just become just common enough that it's become way more dangerous.
SELYUKH: And are these dramatic changes that are causing issues in places like Patagonia or maybe Yosemite, or are you also thinking about changes that are more subtle?
CALDWELL: I mean, pretty dramatic. Like, the fact that I can't climb in one of my favorite places in the world is dramatic, but there's also relatively dramatic changes happening closer to home. Like, Yosemite is the place I climb at the most. And Yosemite Valley is pretty quickly turning from sort of this dense pine forest and more into this, like, open oak forest. First because all the trees - most of the pine trees died because of beetle kill. And then more recently, fires have been, you know, ripping through the area, mostly around Yosemite - a little bit in Yosemite as well. And so, yeah, the landscape has changed drastically. And we can't climb there oftentimes in the summer because they just close the park because it's too smoky or it's too unhealthy to go climbing.
SELYUKH: You know, I hear climbers are doing what's called last summits. What does that mean? Or sort of how do you think about this potential path forward in which we might not be able to enjoy certain mountains anymore because of the impact of climate change?
CALDWELL: Yeah, so I first heard of that idea of, like, last ascents from Kitty Calhoun, who did a great TED talk maybe 10 years ago about these ice climbs that were disappearing. And she was going and climbing them and thinking that she was probably the last one to be able to climb them. That is a thing. I mean, in Patagonia, another thing is that some of these big, beautiful walls that I've wanted to climb - as the glaciers recede and melt out, they tend to break up, and there's a lot of crevasses. And they sometimes are almost inaccessible for a while.
I also went to the Arctic National Wildlife Refuge a few years ago, and the polar regions and the high altitude regions, the - like, the warming effect is in your face. It's really obvious. And I had to do a lot of research ahead of time about where we could go because these glaciers that you usually just walked on previously had melted away. And now it's just loose, kind of gravelly and dangerous terrain to even travel on.
SELYUKH: You know, are there new opportunities that are opening up through all of this? Maybe places that used to be too cold for an adventure are now more available.
CALDWELL: Yeah, there are places. Like, Yosemite is a great example of a place that you used to just climb there - you know, the best free-climbing season, which is the type of climbing that I like to do, was October and April. And now you can go there and reliably climb on El Capitan all winter long, as long as the forest fire smoke doesn't get to you. So there are places that I climb where there's just these really long warm spells which can be good for rock climbing.
SELYUKH: That's professional rock climber Tommy Caldwell. Thank you so much for being here.
CALDWELL: Yeah, thank you.
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.