Mountain Regions Warming 50% Faster Than Global Average: Alarming Implications for Water Resources and Ecosystems

The findings were published in the journal Nature Reviews Earth and Environment.

New Delhi:

According to a recent study, warming at high elevations in mountains, including the Himalayas, has been occurring approximately 50 percent faster than the global average since 1950. This accelerated warming could have devastating consequences for over a billion people who depend on these mountain regions.

Research published in the journal Nature Reviews Earth and Environment shows that mountains globally experienced enhanced warming of 0.21 degrees Celsius per century during 1980-2020 compared to lowlands. Additionally, mountains faced enhanced drying of 11.5 millimeters per century and accelerated snow melting of 25.6 millimeters per century.

An international research team led by scientists from the UK's University of Portsmouth investigated 'elevation-dependent climate change' - a phenomenon where environmental changes accelerate at higher altitudes. This phenomenon is driven by multiple factors including surface albedo (the ratio of reflected radiation to incident radiation), specific humidity, and aerosol concentrations in the atmosphere.

"Mountains share many characteristics with Arctic regions and are experiencing similarly rapid changes," explained lead researcher Nick 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."

However, Pepin clarified that the relationship between elevation and climate sensitivity is complex: "Although on average climate change is accelerating at higher elevations, there is lots of regional variation. In lots of cases, loss of snow is an important driving factor, so it is those intermediate elevations where the snow has receded (imagine the snowline is going up) that are changing most quickly."

Aerosols released from lowland areas in countries like India and China represent another significant factor. These pollutants can travel upward onto mountain snow and ice, causing accelerated melting and loss in high-altitude environments.

The research team, which included scientists from India's Uttaranchal and Jawaharlal Nehru universities, analyzed global datasets and reviewed evidence from case studies across various mountain ranges including the Alps, Tibetan Plateau, and High-Mountains Asia.

"On a global scale, differences between mountain and lowland trends for temperature, precipitation and snowfall are 0.21 degrees Celsius per century (enhanced mountain warming), (minus) 11.5 millimetres per century (enhanced mountain drying) and (minus) 25.6 millimetres per century (enhanced mountain snow loss), respectively, for 1980-2020," the authors reported.

"Such positive elevation-dependent warming (EDW) is evident at historical and longer timescales, and despite much variation according to time of day, season and location, the mean warming at high elevations is nearly 50 percent faster than the global mean since 1950," the team noted.

Most climate models predict continued warming of 0.13 degrees Celsius per century in mountain regions throughout the twenty-first century, although precipitation changes remain less certain.

The implications of these findings extend far beyond mountain communities themselves. Over one billion people worldwide depend on mountain snow and glaciers for water resources, particularly in China and India, which receive water from the Himalayan region.

"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," warned Pepin.

The lead researcher further explained the ecological impacts: "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."