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Green Line: Climate Change in the Alpine Means Shorter Seasons and Increased Risks

As temperatures warm, iconic routes are melting away and becoming more dangerous—even seeing their final ascents

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Green Line is a new, science-driven column by Ula Chrobak on environmental issues and how they affect climbers.

The Moose’s Tooth in Denali National Park, like many alpine objectives, has seen less and less ice over previous decades due to climate change.U.S. Department of Agriculture/Flickr; CC BY 2.0

Conditions should have been perfect. Irina Overeem, a longtime rock and ice climber and a climate scientist at the University of Colorado, Boulder, and her climbing partner Sarah Fritz had consulted a guidebook that was only a few years old to determine the right time to climb Ham and Eggs on the Moose’s Tooth in Denali National Park, a classic ice route originally ascended by Jon Krakauer and Nate Zissner in 1975. The guidebook said April to May was the best window, and historically the route had even been climbed in July.

The two were there in April 2009—right at the perfect time—but the ice, however, was bad. “[The ice] was really thin and it was really warm,” says Overeem, “What would have been normal, good timing was [now] too late in the season.” To protect the route, Overeem and her partner had to use rock gear instead of ice screws. That method worked for them, but another climber below them took a 60-footer after his rock protection pulled during a fall. Overeem and Fritz went down to rescue the man, who had fractured his left leg, using buddy rappels to get him back to the base where he could be airlifted to a hospital. They returned to summit the route the next day.

Overeem recalls the incident as an example of how the frozen parts of the world are changing quickly—and sometimes surprising climbers like her with bad and even dangerous conditions. While scientists warn of the dangers of a 2° C rise in temperature globally—and recommend keeping warming within 1.5° C—some of the poleward and high-elevation parts of the world have already warmed by that much. This rapid warming is melting away classic routes and presenting new hazards for climbers. In a survey conducted this spring, the American Alpine Club found that 78 percent of climbers “feel that climate change will make outdoor activities like climbing, skiing, and mountaineering more dangerous.” And 64 percent of climbers reported that they had seen the effects of a changing climate in the mountains they visit.

Arctic and high-mountain areas are warming more quickly than the rest of the world. When ice melts, it often reveals rock, soil, or ocean beneath it—all of which absorb heat rather than reflect it, as ice does. This in turn leads to greater surface warming, creating more ice melt, which leads to more warming, and on and on.

This is bad news for recreating in the snowy and icy parts of the world, according to the International Panel on Climate Change’s recent report on the ocean and cryosphere, which references almost 7,000 scientific publications. If emissions continue to rise at a similar rate as today’s, the globe’s glaciers could lose 80 percent of their mass by 2100. Meanwhile, snow depth at lower elevations will decrease and permafrost will thaw, introducing difficulties for those traversing and climbing in those areas. “In several regions, worsening route safety has reduced mountaineering opportunities,” the report concludes. And, as more people summit peaks while routes crumble, we can expect more of these climbers to be at risk of increased hazards.

“We’ve already seen changes on Everest, rockfall in the Alps, and changes in snowpack,” says Taylor Luneau, policy manager at the American Alpine Club. “All of this will change how we interact with these places. With shifting climates, it just makes everything less of a sure bet.”

These changes are well-documented in the Alps. While on average the world has warmed by 1.1 º C above pre-industrial times, these mountains hit 2º C around the start of the twenty-first century. As once-permanent layers of ice—permafrost—in high mountains thaw, brittle surrounding rock loses its “glue” and comes loose. Additionally, the water in cracks and crevices that was once frozen now alternates between liquid and solid, expanding and contracting, slowly prying away loose rock from the spires.

The region has thus seen more rockfall in recent years. In 2005, for example, the Petit Dru lost a classic route, the Bonatti Pillar, as rock sloughed off the peak. In following years, a rash of rockfalls has chipped away at other facets of the spire.

The west and south-west faces of the Petit Dru in May, 2006, displaying scars from the 2005 rockfall via the gray portion of the face.Eltouristo/Wikipedia; CC BY-SA 3.0

This has come as a cost to climbing in the region, and at least two studies have tried to quantify these impacts. In 2011, rocks rained down on Arnaud Temme, a geomorphologist at Kansas State University, and his climbing party during an ascent of the Jungfrau in the Swiss Alps. While the older guidebook they had consulted hadn’t mentioned rockfall, they later saw that a newer description discouraged attempting the route they were trying— the Rottalgrat—due to that hazard. That incident inspired Temme to use climbing guidebooks as a record for how routes have changed across the years. Thanks to the region’s rich history of climbing—it’s known as the birthplace of mountaineering—he had 146 years of guidebook entries to go by. For 63 routes of the Grindelwald region of the Bernese Alps, he tracked how mentions of rockfall hazards or rock quality had changed over time. According to those descriptions, rockfall risks have increased, especially since 2000. Some routes were even omitted from guidebooks in recent years, as they’ve just grown too dangerous.

And this year, Jacques Mourey, climber and geomorphologist at the University of Savoie Mont Blanc, published his findings tracking 40 years of change on routes detailed in the 1973 guide The Mont Blanc Massif: The 100 Finest Routes. He talked to 31 climbing guides, trail managers, guidebook editors, and first ascensionists about how conditions on 95 routes in the book had evolved. Of those, according to his sources, 93 had changed as temperatures increased—and of those 93, 26 had been “greatly affected,” which meant that those routes can no longer be climbed in summer, and had grown more dangerous and technically difficult. And three routes just don’t exist anymore. Shrinking glaciers, loss of snow and ice cover, and melting permafrost contributed to those increased hazards. Mourey concludes in the study that “periods during which these [routes] can be climbed in good conditions in summer have tended to become less predictable and periods of optimal conditions have shifted toward spring and fall, because the [routes] have become more dangerous and technically more challenging.”

So far, no one’s performed such detailed assessments for routes in the States. But longtime climbers and guides say conditions are changing here too, potentially adding new dangers. The Black Ice Couloir, on the Enclosure in Grand Teton National Park, is one name-brand classic that’s changed. Typically, the eight-pitch route features 1,200 feet of permanent alpine ice. But in recent years, the route’s occasionally melted away and become unclimbable. “In the time since I started climbing to the turn of the century, [the route] was more or less there,” says Andrew Carson, owner of Jackson Hole Mountain Guides. “But in the last 20 or so years it has melted out—there was nothing there.” Overeem says there have been more rocks tumbling down from Middle Teton in recent years, too, according to the park’s climbing rangers, who warned her of the dangers during a recent trip.

Chuck Crago exiting the crux of the Black Ice Couloir in September of ~1990. The route has melted out in recent years.Andrew Carson

Simeon Caskey, acting chief of science and resource management at Grand Teton, says that while traversing the park’s glaciers—some of which have lost up to 50 percent of their extent—has certainly changed with their melting, rockfall and other processes are harder to measure. He’s working on building a citizen-science database of rockfall incidents in the park, but says that so far the accounts about increasing hazards are hard to attribute definitively to climate change. “A lot of the information we have on these areas is anecdotal,” says Caskey. “Without that quantitative information, it’s hard to speculate whether or not there was an increase in geohazards or recreational hazards in Grand Teton National Park.”

There’s less permafrost on the peaks of the Lower 48, says Overeem, but some areas with relatively high precipitation could face similar risks as those in the Alps. She notes that you’d expect similar hazards in the Pacific Northwest. A September article in the REI Co-op Journal describes some of the changes to the glaciated volcano Mount Rainier due to warming. In the article, guidebook author Mike Gauthier says that rockfall dangers on the iconic Liberty Ridge, which features in the book Fifty Classic Climbs, have increased: “I have definitely noticed there is more rock exposed, less snow and ice, and warmer summers, and that leads to more rockfall.”

Also in the Pacific Northwest, this summer was hard for guides at Mount Baker. Kitty Calhoun, co-owner of Chicks Climbing and Skiing, says that she and others weren’t able to guide up the Coleman-Deming glacier route after a big crevasse opened up, taking with it the ice bridges that typically allow people to access that side of the mountain. Calhoun adds that climate change may have played a role in the death of Craig Luebben in North Cascades National Park in 2009. Luebben, a seasoned all-round climber and rock guide, lost his life after a block of ice he was climbing on Washington State’s Mt. Torment in the North Cascades calved free and took him with it.

Across decades of climbing, Calhoun’s watched glaciers melt around the world, including in the Himalayas. “In terms of alpine climbing, [climate change] shrunk the season,” she says. “That means more people on fewer routes in a shorter season.”

The dangers are certainly alarming, but Temme says that climbers shouldn’t necessarily stay home. Instead, the shifting climbing seasons and conditions in the mountains mean alpinists need to do more research before getting out. “Conditions have changed; make sure you get the latest information,” says Temme. “We just have to be careful in a different way.”