The worst kept secret is out; scientists have identified climate change as having played a key role in the recent Nepal disaster.
Climatic drivers, piggybacking geological factors, played a key role to trigger the August 26 monstrous avalanche that devastated Nepal, finds a rapid scientific analysis by World Weather Attribution (WWA) scientists and international glaciologists that has been released early morning on September 17.
Earlier few researchers expressed that it was difficult to conclusively link a fast-moving, localized rock-ice avalanche to global warming. The massive rock and ice collapse on the country’s northern border swept away entire communities and localities. Over 1,300 people were killed and more than 5,000 are still missing in the high-altitude landscape. A part of overhanging glacier and rock in Langtang Lirung mountain had collapsed on August 26, causing a gigantic, killer flood of water, ice and debris that swept downstream causing the destruction.
World Weather Attribution is a global science research organisation that identifies the role of different phenomenon in environment events, and an international team of glaciologists and climate scientists, the Nepal catastrophe was influenced by several climatic and geological factors, most of which were exacerbated by the impact of longterm climate change.
“The science is now unambiguous: fossil-fuelled warming thinned the glaciers and thawed the permafrost that held the mountain together. Nepal did nothing to cause this, yet its people are paying with their lives. This is climate injustice — and the Loss and Damage Fund must deliver now, not as charity, but as compensation and reparations,” claimed Harjeet Singh, Global Convenor, Fill the Fund campaign, and Founding Director, Satat Sampada Climate Foundation
Factors played in tandem with climate change at centre
Scientists feel that the disaster resulted from a number of factors working together, with climate change playing a crucial role. They have pointed at decades of atmospheric warming, caused mainly by the burning of fossil fuels, having melted the glacier and pushed the freezing threshold line (0°C isotherm) upward by around 100 metres of altitude per decade, says a World Weather Attribution statement.
This has resulted in glacier recession and thawing in permafrost within rock fractures that have historically held high mountain walls together. The thawing has made them unstable.
The 2015 earthquake preconditioned the slope to collapse
A massive earthquake that had occurred in the region in 2015 may have preconditioned the slope for the collapse. “Scientists have pointed at the impact of compound preconditioning … Its contribution to this disaster cannot be confirmed, but the 7.8 magnitude earthquake in 2015 may have further contributed to the slope failure,” reads the report.
“This disaster was not an extreme weather event, but the fingerprints of climate change are still clear to see in long-term changes,” said Ben Clarke, extreme weather and climate change researcher, Imperial College, London. “We found that climate change is transforming the high mountain environment influencing many of the possible drivers of this collapse. This increases the risk in a region that is already exposed to high seismic activity,” the expert added.
Key factors includes rapid local warming preceding disasters
The analysis came up with several key findings, among them glacier thinning, permafrost thaw, compound conditioning and temperature rise.
Global warming has led to substantial glacier recession, removing ice from around the collapse site and contributing meltwater, says the analysis.
At the same time, continuous warming has raised the altitude of the freezing threshold on the high Himalayas, exposing ice and permafrost deep in the bedrock to higher and longer thaw temperatures, weakening mountain slopes.
Climate conditions in the immediately preceding months are being factored in. High temperatures and increased melt water between July and August were the warmest on record locally. High snowfall in October and November 2025 added huge quantities of melt water in the months preceding the collapse.
The analysis says that climate change has caused about 1.5°C of warming since pre-industrial times in the collapse region in July and August. Climate change has pushed up temperatures by about 2°C to date annually.
The analysis added that though Nepal has early warning systems, the scale of this tragedy exceeded physical adaptation limits. This highlights the difficulty of adapting to escalating disasters and risk for greater loss and damage.
Experts refer irreversible shift in Himalayas
“We are witnessing fundamental, irreversible shifts in Himalayan mountain environments. Climate change from the burning of fossil fuels is pushing the freezing line – the zero-degree isotherm – upward by roughly 100 metres per decade, exposing perennially frozen ground and bedrock to thaw conditions that are longer and warmer than before,” said Walter Immerzeel, mountain hydrologist, Utrecht University.
“The Bhote Koshi catastrophe is a stark warning of the growing risks people are facing with the rapidly warming Himalaya. Scientific evidence is clear that rising temperatures are transforming glaciers, snow, permafrost and the wider mountain environment, creating increasingly complex and cascading hazards,” pointed out Manjeet Dhakal, director of climate analytics South Asia.