Collapsing Swiss glaciers aren’t the ones to worry about

By David Fickling

The sight of a Swiss village obliterated in seconds by a flood of ice and rock is a grim reminder of how a changing climate puts the societies we have built in jeopardy.

The worst effects of such disasters will happen not in villages like Blatten, whose population of 300 was evacuated after landslides gave an early warning of the imminent collapse that destroyed the settlement last week. Instead, they will be visited upon the millions of people living in the shadow of melting glaciers who don’t reside in Switzerland, one of the wealthiest countries on the planet.

The risks are greatest in the poor and fragile states that ring the Himalayas, whose ice packs feed many of the world’s largest and most economically important rivers: the Indus, Ganges-Brahmaputra, Mekong, Yangtze, and Yellow. Pakistan alone has more than 7,000 glaciers, the largest collection outside the polar regions. Kyrgyzstan, Afghanistan, Nepal and India are home to tens of thousands more.

These reserves of frozen water are shrinking rapidly as the planet warms. Ice loss in 2023 was the fastest in five decades, Sulagna Mishra, a hydrology expert at the World Meteorological Office, told an online seminar earlier this year.

The damage from this great melting can come in many forms. Highland landscapes are often held together by ice, with glaciers, permafrost, mountainsides and deposited sediments creating a fragile stability that can last for millennia. When this equilibrium is disrupted, the change can be as sudden as snow sliding off a chalet roof in spring — especially if, as in the Alps, Himalayas, Andes and Rockies, the region is seismically active. In Switzerland, a succession of mild winters and warm summers has caused glacial mass to decline by about 10% in the last three years alone, according to Mishra.

The most serious threat is not from landslides like the one that destroyed Blatten, but flooding. The melting of a glacier can at first feel like a bounty in an underdeveloped country, creating high-altitude lakes that feed river systems and encourage agriculture, hydroelectric dams, and scenic tourism. The volume of such glacial lakes globally has increased by about half since 1990, drawing people to the valleys just downstream. The population of Gilgit-Baltisan, Pakistan’s most mountainous region, has more than doubled since the late 1990s to about 1.7 million.

It’s a fatal temptation. The same almost imperceptible changes that caused Blatten’s stable glacier to turn into a wave of mud can lead such glacial lakes to burst through the ice and rock that hold them in place, swamping communities downstream. Heavy rainfall and the melting of the Chorabari glacier caused a lake near the Indian pilgrimage town of Kedarnath to burst its banks in June 2013. The deluge that resulted killed more than 6,000 people, one of India’s most devastating natural disasters. Such glacial lake outburst floods increased six-fold over the course of the 20th century, and now threaten about 15 million people globally.

It’s possible to make predictions of where glaciers are most at risk, but Himalayan countries are starting from a position of enormous disadvantage. Switzerland has been measuring the position of over a hundred of its glaciers for more than a century, giving it the most comprehensive understanding anywhere in the world. In Pakistan, just 12 such datasets are available, dating back for an average of 31 years.

While some information can be gleaned from aerial and satellite photography, on-the-ground measurements are still the gold standard. That’s a challenge in an area as remote as the Himalayas, especially when the tense ceasefire lines separating India, Pakistan, and China run through some of the most at-risk areas. Even where solar-powered early warning systems have been set up to detect the first signs of flooding, in poor and isolated regions they often break down due to lack of maintenance.

The advantages from redressing this imbalance are immense. A recent United Nations-backed program to build 50 warning systems in northern Pakistan cost less than $40 million and directly benefited 700,000 people at risk. But rich countries are less and less willing to provide the funds needed.

Much of the money for initiatives to help mountain communities adapt to climate change, for instance, has come from the US Agency for International Development, currently in the process of being closed down after an executive order by President Donald Trump. Even when cases against companies contributing to this environmental degradation make it to court, success is never guaranteed. Within hours of the Blatten landslide, a Peruvian farmer, who has spent a decade suing German coal-fired utility RWE AG to help build protections against glacial flooding, had his case dismissed by a German court.

As the climate warms, the Global North is doing what it can to protect itself against the worst effects of collapsing glaciers. The Global South is being left to fend for itself.