Experienced mountaineers agree that the Alps, and winter climbing generally, are becoming more dangerous as rising temperatures make ice layers thinner and shorten the season when climbs are "in condition".
Last week the mountain guide David "Smiler" Cuthbertson told the High Court that climatic change had, in effect, forced him to hurry across an ice slope without setting a solid anchor for his climbing partner, Gerald Hedley.
"It was the hottest I had ever known it, even though it was only 8.30 in the morning," Mr Cuthbertson said. "I was extremely concerned about the danger of rocks falling. Since the 1960s, global warming has affected the Alps badly. They are far more treacherous now."
While he was trying to reach safety across the slope, the ice gave way underneath him. He fell 150 feet, pulling with him Mr Hedley, who was killed.
Andy McNae, who has been going to the Alps for 13 years, said: "It's changing the character of climbing, and making classic climbs of 20 or 30 years ago more hazardous. Glaciers are retreating all over the world; and that means that on some parts of the Alps where the ice used to reach the bottom of glaciers, now it's common to have bare rock at the base of the faces."
The vast majority of classic Alpine routes are on the north faces of mountains, because that allows ice to form. But where the temperature is too high, the ice cannot last through the day and rocks trapped in it will loosen and fall as the ice melts.
"Whether it's global warming or what, there's no shadow of doubt that in the Alps there has been a series of long, hot summers," said Sir Chris Bonington, 62, who first went to the area in 1958. "All over the world, you can see glaciers retreating and the ice coverage thinning out. It's obviously associated."
Doug Scott, another famous British climber who has been travelling to mountains all over the world since 1954, said: "The ice everywhere is retreating, apart from a couple of glaciers in New Zealand. I don't know whether it's global warming - these things may be cyclical - but the Alps in summer have obviously been affected, as has Mount Kenya in Africa."
The question is: if the lack of ice is caused by global warming, what will mountaineers do?
It may be no accident that one of the fastest-moving areas of the winter sport is "mixed" climbing, which comprises routes of both ice and rock. Might it be that climbers in future will find themselves vying to reach Everest's summit across ice-free rock?Reuse content