Seven of us are roped in a line, with hiking poles in our hands and crampons on our boots. Led by our guide, David, we take it in turns to step from rock into the marbled grey ice beyond. I hesitate before taking my step; the act feels oddly disrespectful. It takes a few minutes to trust that the spikes will hold their grip, but I get used to the crunching rhythm and the occasional tug of the rope. The summer sunshine is warm but a coldness radiates from below. It is a six-hour hike to the hut we will sleep in tonight.
This is the Aletsch glacier in Switzerland’s Bernese Alps. It is 15 miles long and up to 800 metres deep, the largest and longest glacier in the Alps. From above, its mass looked uniform, but up close it is creased and contorted, speckled with browns, blacks and greys, and glimpses into its deep crevasses reveal a startling turquoise. Two gritty parallel lines follow its long curve downhill, moraines that act as conveyor belts bearing rocks and rubble. As David reminds us, the ice is not static but a dynamic system, a frozen river in a constant state of (very slow) motion.
All morning we follow that river upstream. No previous mountaineering experience is required to walk on Aletsch, but we can only be here as part of a guided tour – partly for the glacier’s protection but mostly for our own. It’s an almost imperceptible climb, but the monotony of the trudge, and the tricks that the enormity of the whiteness plays with my sense of perspective, combine to make the journey unexpectedly gruelling. We stop briefly for lunch, freed from the rope, and eat bread and cheese in the midday sun on the edge of a crevasse.
At one point everyone jumps at a sudden, fearsome roar emanating from somewhere beneath our feet. This, says David, is simply chunks of ice shifting inside a crevasse, but local people knew these noises as arme Seelen (poor souls), evildoers whose souls were condemned to entombment within the glacier. “They live during the day in crevasses, at midnight they come out,” he says, smiling. “When they touch you, it means you are going to die.”
Eleven thousand years ago this glacier was so deep that only the tips of the mountains around us protruded from the ice. In the 17th century, during the cold snap known as the little ice age, its advance threatened destruction for farms in the Upper Rhône valley below. German-speaking Catholics from the village of Fiesch, where we caught the cable car this morning, began an annual pilgrimage to beg God to turn the glacier back. It might have taken 300 years, but today their prayers seem to have worked …
Since the late 19th century Aletsch has lost almost two miles of its length, and by 2100 it is predicted to shrink by eight miles more, reducing it to a tenth of the mass it is today. Of course, it is not alone: nine in 10 glaciers in the Alps will disappear by the end of this century. Throughout the morning, David has pointed out marks on the valley walls that indicate the extent of the ice in 1850, or 1950, a grubby brown stain like the residue on the side of a draining bathtub. The scale of what has already been lost is incomprehensible, let alone the greater loss to come.
In 2009, the pilgrims of Fiesch sought papal permission to change the wording of their prayer, beseeching God’s intervention again – this time to protect the glacier. That prayer has come too late.
Everyone else in the group is Swiss, and all have grown up with glaciers as their neighbours, and whose steady disappearance they have witnessed in their lifetimes. The woman roped in front of me was born in 1995, and talks of the Morteratsch glacier near her family’s summer house: “We’ve grown up together, but in different directions. I can measure the years of my life by the glacier’s retreat.”
As well as regulating local climates and providing year-round reservoirs of water, glaciers are an important part of Switzerland’s culture and identity. “It is hard to imagine our country without them. I wonder what we will become?” she asks.
It’s hard to escape the troubling thought that this hike is a form of “last-chance tourism”: like taking a cruise ship to the Antarctic or flying to see the Great Barrier Reef, which often does greater damage to already endangered places. Does the act of walking on Aletsch hasten its demise? According to Dr Matthias Huss, a glaciologist who measures its rate of ablation every year: “Touristic hikes on the glacier do not have any direct impact on the melt rate. Other sources of heat are more important, including carbon dioxide emissions due to travelling there.”
For people in Europe, Aletsch is easily accessible by train – I got to Switzerland eight hours after leaving St Pancras station in London – but flying halfway around the world to marvel at the ice you are helping to melt would be, to put it mildly, problematic. The impact of crampons, and even polluting microfibres from mountaineers’ jackets, is negligible compared with the disaster of climate crisis, says Huss.
At last we reach Konkordiaplatz, the highest and thickest part of Aletsch’s body. This region is a labyrinth of crevasses that looks unnavigable, though David deftly finds a way through; for the first time the ropes are not an encumbrance but a reassurance. This is where, in 1926, four young climbers seemingly vanished, only for their shattered bones to emerge in 2012 (along with their boots, binoculars, walking sticks and other items) six miles further down the valley, having travelled under the ice for 86 years. Perhaps the legends of “poor souls” have their origins in such losses.
We leave the glacier and clamber up the valley wall on a rickety metal staircase bolted to the rock. We reach Konkordia Hut, which is run by the Swiss Alpine Club, for salty pumpkin soup, spaghetti, and chocolate cake, rounded off with steins of beer and schnapps coffee. The atmosphere is convivial, as other hikers and climbers arrive, banging the ice off their boots and trading mountain stories. The sun goes down on the sea of ice that stretches far to the south, turning it electric blue, framed by the peaks of the Eiger, Mönch and Jungfrau. In this moment it’s impossible to think all this could ever vanish.
The next day’s hike, retracing our steps back down the ice to where we began, starts in rain, continues in sleet and finishes in a blizzard. It feels reassuring to see snow fall on the glacier, turning its grubby grey to white: an illusion, however transitory, of permanence and renewal. But future travellers here – poor souls – will walk in a valley of rock.
Glacier tours with Aletsch Arena range from a one-day circular hike for CHF99 (£88.50) to CHF370 (£330) for a two-day hike, including a night in Konkordia Hut. The season runs until 7 October