The world’s mountains are warming faster than anyone expected

The international study, published in Nature Reviews Earth & Environment, focuses on a process scientists call "elevation-dependent climate change" (EDCC), which describes how environmental changes can speed up as altitude increases. The review brings together the most comprehensive evidence so far showing how mountain climates are changing worldwide.

A Global Look at Rising Temperatures and Shifting Snow

The research team, led by Associate Professor Dr. Nick Pepin of the University of Portsmouth, analyzed information from global climate datasets along with detailed case studies from major mountain regions. These included the Rocky Mountains, the Alps, the Andes, and the Tibetan Plateau, offering a broad picture of how conditions are evolving across different continents.

Their analysis reveals troubling trends between 1980 and 2020:

• Temperature: Mountain regions are warming on average 0.21°C per century faster than surrounding lowlands
• Precipitation and snow: Rainfall patterns are becoming more erratic, and snowfall is increasingly being replaced by rain

"Mountains share many characteristics with Arctic regions and are experiencing similarly rapid changes," said Dr. Pepin from the University of Portsmouth's Institute of the Earth and Environment. "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."

Why Mountain Warming Affects the Whole World

The consequences of these changes extend far beyond high-altitude communities. More than one billion people depend on mountain snow and glaciers as a critical source of freshwater. This includes large populations in China and India -- the world's two largest countries by population -- which receive much of their water from the Himalayas.

Dr. Pepin emphasized the growing risks linked to these shifts: "The Himalayan ice is decreasing more rapidly than we thought. When you transition from snowfall to rain because it has become warmer, you're more likely to get devastating floods. Hazardous events also become more extreme."

Rising temperatures are also forcing plants and animals to move higher up mountain slopes in search of cooler conditions. "As temperatures rise, trees and animals are moving higher up the mountains, chasing cooler conditions. But eventually in some cases they'll run out of mountain and be pushed off the top. With nowhere left to go, species may be lost and ecosystems fundamentally changed."

Extreme Weather Signals Growing Danger

Recent disasters highlight how urgent the situation has become. Dr. Pepin pointed to events in Pakistan this summer, when intense monsoon storms combined with extreme mountain rainfall. These cloudbursts led to deadly flooding that killed more than 1,000 people, underscoring how rapidly changing mountain weather can amplify natural hazards.

Building on a Decade of Climate Research

The new review builds on the research team's 2015 paper in Nature Climate Change, which first provided strong evidence that warming increases with elevation. That earlier study identified several key drivers, including shrinking snow and ice cover, rising atmospheric moisture, and the influence of aerosol pollutants.

Ten years later, scientists have a clearer understanding of the mechanisms behind these changes and their consequences. Still, the core challenge remains. "The issue of climate change has not gone away," Dr. Pepin said. "We can't just tackle mountain climate change independently of the broader issue of climate change."

Data Gaps and the Need for Better Monitoring

One of the biggest challenges is the lack of reliable weather observations in mountain regions. "Mountains are harsh environments, remote, and hard to get to," said Dr. Nadine Salzmann from the WSL Institute for Snow and Avalanche Research SLF in Davos, Switzerland. "Therefore, maintaining weather and climate stations in these environments remains challenging."

Because of these gaps, scientists may be underestimating how quickly mountain temperatures are rising and how fast snow and ice could disappear. The review also calls for improved climate models with much finer spatial detail. Many current models track changes only every few kilometers, even though conditions can vary dramatically between slopes just meters apart.

Dr. Emily Potter of the University of Sheffield noted that progress is being made but warned it is not enough on its own. "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."