How climate change is making mountaineering more dangerous

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In July 2011, Arnaud Temme and three friends were climbing the Rottalgrat, a difficult route on the west side of the Jungfrau in the Bernese Oberland in Switzerland, when rocks started raining down from above. Temme, an experienced mountaineer, took a rock to the shoulder and a handful of others hit his helmet, but the team eventually completed the course unscathed.

That night, the climbers evaluated their experience in the warm comfort of the Mönchsjoch refuge. Their guide, which was a decade old, described the route as relatively safe with only minor rockfall danger. “But the most recent guidebook, which we didn’t have, said to stay away from this route because of the very high risk of rockfall,” Temme says.

The disparity struck Temme, a 37-year-old assistant professor at the Dutch University of Wageningen who is also affiliated with the Institute of Arctic and Alpine Research (INSTAAR) at the University of Colorado at Boulder. How could two guidebooks describe the same route so differently when they were written less than a decade apart? This question served as the driving force behind Temme’s three-year study of the effects of climate change on the danger of alpine climbing, the results of which were recently published in the international scientific journal Geografiska Annaler. Temme says the two are “most likely related.”

Rising temperatures and higher freezing altitudes on mountains are major rockfall hazard factors, as is shifting permafrost, or the subterranean layer that has remained frozen for years but is now melting at higher altitudes. bass. According to a recently published article by the Swiss Alpine Club, more permafrost melted last year in Switzerland than in any other year in recorded history. This phenomenon, like increasing freezing levels and even an upward migration of alpine plants in the region, is the result of climate change, which is why Temme believes the danger of rockfall will continue to grow.

“It’s going to get worse,” Temme says. “Ice and snow are melting and rocks are waiting to fall. I don’t see a mechanism that would stop this and reduce the levels again.

“Seven of the 63 routes I studied are now completely removed from all guides, as if they never existed, because they are too dangerous due to falling rocks.”

Temme used a unique strategy to undertake his study, something he half-jokingly calls “fossil crowdsourcing”: He went to a library in Zurich that archives old guidebooks and looked at 17 editions that cover the alpine routes of the Bernese Oberland. From the guidebooks, which dated as far back as 1864, he extracted detailed information on 63 routes on five mountains – the Jungfrau, Eiger, Moench, Finsteraarhorn and Schreckhorn. He chose the most popular routes – thousands of people climb these places each year – because their descriptions included more detail and regular updates than less frequently climbed routes.

“I selected any type of information that said something about the danger of rockfall,” says Temme. “It could just be, ‘It’s dangerous here’, or ‘The rock here is weak’ or ‘Don’t go there anymore. I put it all together and watched the development over time.

Temme found that hazard warnings started appearing in guidebooks around 1960 and became much more pronounced in the 1990s and 2000s. About half of the 63 routes changed for the worse. “You really see that progression,” Temme says. “Seven of the 63 are now completely removed from all guides, as if they never existed, because they are too dangerous.”

Temme is not the first to study this – Ludovic Ravanel of the University of Savoie Mont Blanc, France, has studied rockfall by comparing old photographs in the French Alps – but his findings have resonated with climbers and Oberland guides. Freddy Grossniklaus, an international mountain guide born and raised in Beatenberg, a village that looks out over the Eiger, Moench and Jungfrau, says the increased danger of rockfall has changed the way he guides.

“It’s not just the snow that disappears, it’s the rocks; some standard routes or north faces, you can no longer do it safely in the summer,” says Grossniklaus, owner of Swiss Guides LLC and climbing in the area since 1975. “Because the freezing level is too high. Today it is often above 13,000 feet, or higher than the highest peaks in the area. “You can’t even beat it starting very early in the morning.”

This phenomenon was hammered home one day last August. Grossniklaus was leading a hike on the Aletsch Glacier. He stopped to share information with his seven guests when a piece of ice broke off from the Moench above them. A few minutes later, a huge section of ledge broke away from a nearby ridgeline. “I had never seen a cornice break there,” Grossniklaus says.

He and his party descended on foot, where they found a pile of boulders that had tumbled a mile and a half down the south face of the Trugberg that morning. “It was something incredible,” says Grossniklaus. “This glue [the permafrost] left.”

While Grossniklaus once guided the Eiger North Face in summer, he says he will never do so again. It also canceled a once-standard Gruenhorn saddle recall due to the danger of falling rocks.

Temme points out that many routes he has studied have not changed significantly over time. “I’m not advocating a halt to escalation or anything like that,” he says. But it plans more real-time information sharing online as a way to tackle the heightened danger of rockfalls. “It’s going to be much more powerful in the years to come,” he says. “Perhaps even more powerful than these guides, which may become less relevant.”