Scientists are sounding the alarm that rapidly intensifying climate change in the world’s mountain regions is driving a dramatic rise in destructive floods and other hazards, threatening billions of people who rely on high-altitude ecosystems.

A sweeping new analysis by the University of Portsmouth shows that temperature, rainfall, and snowfall patterns in ranges such as the Alps, Andes, Rocky Mountains, and the Tibetan Plateau are shifting at an “accelerated rate", with far-reaching consequences.

The findings highlight the escalating risks facing more than one billion people who depend on mountain glaciers and seasonal snowpack for their water supply, and the growing likelihood of “devastating floods” and widespread biodiversity loss.

Climate change in the mountains

Published in Nature, the study explores “elevation-dependent climate change” (EDCC), a phenomenon in which environmental changes intensify with altitude.

Researchers found that from 1980 to 2020, mountain regions warmed an average of 0.21°C per decade faster than nearby lowlands. These areas are also experiencing more erratic rainfall patterns and a pronounced shift from snow to rain.

“Mountains share many characteristics with Arctic regions and are experiencing similarly rapid changes,” said lead author Dr. Nick Pepin. “This is because both environments are losing snow and ice rapidly and are seeing profound changes in ecosystems. What’s less well known is that as you go higher into the mountains, the rate of climate change can become even more intense.”

‘Devastating’ consequences

The impacts of these rapid changes extend “far beyond” mountain communities themselves. More than one billion people, including the populations of China and India, depend on water originating in the Himalayas.

As Himalayan ice retreat accelerates, the threat of “devastating” floods is expected to grow, with scientists warning that extreme hazardous events will become more frequent. This year alone, flash floods in Pakistan, situated at the western edge of the range, killed more than 1,000 people and affected nearly seven million.

Rising temperatures are also forcing trees, plants, and animals to migrate upslope. Eventually, many species will reach a point where they have “nowhere left to go.”

“With nowhere left to go, species may be lost and ecosystems fundamentally changed,” Dr. Pepin warned.

The new study builds on a 2015 review by the same team, which identified key drivers of mountain climate change, including snow and ice loss, rising atmospheric moisture, and aerosol pollution. A decade later, Dr. Pepin says these challenges remain unresolved. “We can’t just tackle mountain climate change independently of the broader issue of climate change,” he noted.

Shrinking glaciers

In Switzerland, glaciers are undergoing “enormous” melt this year, losing around three percent of their total volume, the fourth-largest annual decline ever recorded.

That drop contributes to a staggering overall loss: Switzerland’s glaciers have shed roughly one-quarter of their ice mass in the past decade.

“Glaciers are clearly retreating because of anthropogenic global warming,” said Matthias Huss, head of GLAMOS, referring to human-driven climate change.

Swiss authorities have been on heightened alert after a massive chunk of rock and ice collapsed from a glacier in May, burying much of the southern village of Blatten. A 64-year-old shepherd was killed, and the community was left in ruins.

Major obstacle

Scientists warn that a lack of weather stations and climate data in many mountain regions is hindering efforts to accurately measure the speed of these changes, meaning current models may be underestimating temperature increases.

Most models track climate patterns at scales of several kilometers, but conditions can differ dramatically from one slope to the next.

Dr. Emily Potter of the University of Sheffield stressed the urgency of scaling up both climate action and monitoring systems. She called for “significantly improved monitoring infrastructure in these vulnerable mountain regions.”