To the untrained eye, the view from the Yanapaqcha glacier, some 17,000ft above sea level in the heart of the Peruvian Andes, represents nature at her most sublime. Sheer, snowcapped peaks stretch to the horizon while, through the clouds below, fertile ravines drain into perfect turquoise lakes.

The changing face of Andean glaciers

But as our crampons crunch into the hard ice, it quickly becomes apparent that not all is well in this spectacular wilderness. “The glacier looks like a patient dying of a virus,” says Richard Hidalgo, arguably Peru’s foremost mountaineer. “The disease is eating it away from the inside.” Climate change is tightening its grip.

The statistics for glacier retreat in the Cordillera Blanca – or White Range, as this stretch of the Andes is known – are well documented: The average annual figure per glacier was seven meters in the 1970s, 20 meters in the 1980s, 24 meters in the 1990s and 25 meters in the 2000s. But, as Richard explains, the ravaging of the glaciers is about far more than shrinking snouts.

As we tour Yanapaqcha, his concern becomes palpable. A huge expanse of the lower part of the glacier is riddled with dark stains, slushy puddles, ponds that freeze every evening only to thaw out again each afternoon, and enormous sinkholes. Long sections of Yanapaqcha appear as concave hollows as the river of ice beneath the compressed snow gradually melts and buckles.

“These current conditions are scarier. You have to be even more careful,” says Richard, acknowledging how mountaineering, one of the world’s more dangerous sports, just became riskier still. He should know. An internationally-certified guide, Richard, 42, is headed this month to Nepal to tackle Manaslu, the world’s eighth-highest peak and the third of the 14 mountains over 8,000 meters that he will have summitted.

Indeed, last year a colleague and climbing partner of Richard’s, the experienced American guide Tyler Anderson, died just a few hundred feet above where we are standing – the first mountaineer, Richard believes, to perish in the Cordillera Blanca as a result of climate change. It is notable that the accident happened as Anderson was guiding clients up a mountain that he knew well and was, for a climber of his abilities, little more than an energetic stroll.

No one knows for sure but Anderson, 37, appears to have succumbed as a huge area of the glacier around a crevasse spontaneously collapsed. He fell 60ft and suffered massive injuries including a broken neck. “That crevasse was not normal,” says Richard, who participated in the recovery of his friend’s body. “There was a labyrinth of holes within the glacier. I have never seen anything like that before.”

Yet the dangers of the Cordillera Blanca’s shifting landscape potentially affect far more than the climbing community. As they melt, glaciers lose their traction with the mountainside, increasing the risk of massive, unnatural avalanches. Meanwhile, the increasing run-off is forming vast alpine lakes in danger of catastrophically bursting their banks high above towns and villages along the valley floor. The risk is heightened by the possibility of an avalanche or rock-fall into the lakes. It bears remembering that the region is highly seismic.

One lake, Palcacocha, threatens the regional capital of Huaraz, with a population of 120,000. Its current volume of 17 million cubic meters is 34 times greater than in the 1970s and officials have since 2009 continuously categorized Palcacocha as being at “high risk” of overflowing. That threat arouses powerful emotions in a region that still vividly recalls how a 1970 quake triggered a massive slide of rocks and ice that wiped out the town of Yungay, killing a mind-boggling 25,000 people.

As we slowly move upwards, the glacier appears to recover. Eventually, most of its surface is a uniform expanse of white, broken only by the barely visible long, thin crevasses that occur normally as Yanapaqcha inches its way down the mountain. But even here, there appear occasional, incongruous sinkholes randomly scattered around the glacier.

Above us rises the imposing granite face of the southern peak of Huascaran, Peru’s highest summit at 22,205ft. But again, things are not as they seem. Richard notes how, just three years ago, the face was almost entirely covered by deep snow and ice. Climate change has now made this steep wall too slippery for snow to accumulate.

The shifts in the landscape are now coming so quickly that Richard sees them from one season to another. “I cannot even imagine how the Cordillera Blanca will be in 10 years time,” he says. Although Huascaran’s two summits and the vast col between them, at 20,000ft, remain blanketed, scientists believe that the mountain may be snow-free by mid-century. If that happens, then the White Range will suffer the final indignity of its name becoming nothing more than an antiquated misnomer.