Mountain climate changes outpace predictions as review highlights billions at risk

by Sophie Jenkins
London, UK (SPX) Nov 26, 2025

A global review of mountain regions over the last four decades finds accelerated shifts in temperature, rainfall, and snowfall. Researchers report that over one billion people rely on these regions for water, including China and India. As higher temperatures cause snowfall to become rain, the result is less mountain snow, greater rainfall unpredictability, and a higher likelihood of flooding.

The review, led by Dr Nick Pepin at the University of Portsmouth, examined elevation-dependent climate change - where environmental shifts increase at higher altitude - using global datasets and mountain range case studies such as the Rocky Mountains, Alps, Andes, and Tibetan Plateau.

Data from 1980 to 2020 show temperatures in mountain areas rising 0.21 degrees Celsius per century faster than lowlands. The transition from snow to rain, as the climate warms, has increased the risk of devastating floods and made hazardous events more extreme.

"Mountains share many characteristics with Arctic regions and are experiencing similarly rapid changes," said Dr 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."

As mountain temperatures rise, species including trees and animals have migrated to higher altitudes in search of cooler conditions, according to Dr Pepin, but some may run out of habitat entirely. "With nowhere left to go, species may be lost and ecosystems fundamentally changed."

The review also highlights the Himalayan ice decline, noting that decreased snowfall and increased rain elevate flood risks for downstream populations. Events in regions such as Pakistan, where extreme mountain rainfall recently resulted in the deaths of over 1,000 people, underscore the growing severity of such hazards.

The study builds on a 2015 Nature Climate Change paper that first gathered evidence for greater mountain warming at higher altitudes and identified contributing factors like snow and ice loss and atmospheric changes. Science has advanced since then, but Dr Pepin emphasized that "the issue of climate change has not gone away. We can't just tackle mountain climate change independently of the broader issue of climate change."

Limited weather station data in mountainous areas remains an obstacle to understanding the full extent of these changes. Dr Nadine Salzmann of the WSL Institute for Snow and Avalanche Research SLF said, "Mountains are harsh environments, remote, and hard to get to. Therefore, maintaining weather and climate stations in these environments remains challenging."

With sparse observations, scientists may underestimate the speed of warming and snow loss. The authors call for improved computer models and monitoring infrastructure, as noted by Dr Emily Potter from the University of Sheffield, who said, "The good news is that computer models are improving. But better technology alone isn't enough - we need urgent action on climate commitments and significantly improved monitoring infrastructure in these vulnerable mountain regions."

Research Report:Elevation-dependent climate change in mountain environments