Climate change significantly increased the likelihood of the catastrophic glacier and rock collapse that devastated Nepal last month, according to a new analysis released by the World Weather Attribution. The August 26 disaster killed more than 1,300 people and left over 5,000 missing after a massive section of rock and overlying glacier collapsed near Nepal's border with China, unleashing a torrent of water, ice, boulders and sediment through communities along the Trishuli River corridor.

While researchers cautioned that climate change was not the sole cause of the disaster, they found clear evidence that warming played a destabilizing role. A large 2015 Nepal earthquake may have weakened the rock years before the collapse, but multiple climate-driven processes made the slope progressively less stable over decades.

How Is Climate Change Destabilizing Himalayan Mountains?

The analysis identified several interconnected mechanisms through which warming temperatures are weakening mountain stability in the Himalayas:

• Permafrost Thawing: Rising temperatures have pushed the altitude at which ground remains consistently frozen upward by roughly 100 meters per decade, exposing rock at increasingly high elevations to longer periods above freezing and causing cracks within the ice that weaken rock faces.
• Glacier Retreat: Glaciers in the region have been losing mass for decades at a rate equivalent to more than half a meter of thinning each year, with the Langtang Lirung glacier retreating about half a kilometer since the 1990s and exposing rock once covered by ice.
• Pressure Loss: As glaciers shrink, they remove pressure that helped support adjoining rock walls while simultaneously producing additional meltwater that can destabilize slopes.

A geoscientist who has worked in the Himalayan region since 2006 noted the severity of these changes. "This means that the ground that was sitting below ice for hundreds and thousands of years is now becoming exposed," explained Jakob Steiner, a geoscientist at the University of Graz, referring to monitoring instruments around 5,000 meters that now show some rock and ground no longer remain frozen throughout the year.

What Makes the Himalayan Region Particularly Vulnerable?

The Himalayan region contains the largest volume of snow and ice outside the polar regions, with more than 63,000 glaciers feeding at least 10 major Asian river systems and supporting the food, water, energy and livelihood security of billions of people. However, various studies have found that around 78 percent of the glacier area, located between 4,500 and 6,000 meters above sea level, is highly exposed to warming.

Between 2000 and 2019, glaciers in the region lost 267 billion tons of ice per year, roughly equivalent to the mass of 46,500 Great Pyramids of Giza. The weeks before the August 26 collapse were also unusually warm, with July and August 2026 being the warmest such months recorded locally.

"Other than the potential geological factors like earthquakes that are weakening the bedrock, all these other factors are made worse by human-induced climate change," said Friederike Otto, a climate scientist at Imperial College London and one of the report's authors.

Friederike Otto, Climate Scientist at Imperial College London

Why Are Early Warning Systems Insufficient?

Nepal has developed disaster risk reduction plans and warning systems, but researchers said the size and speed of the collapse overwhelmed those defenses. Unlike a flood caused by rainfall, which can sometimes be forecast hours or days ahead, catastrophic slope failures in remote high mountains can occur suddenly and remain extremely difficult to predict.

The report cautioned that the catastrophe demonstrates how some climate-related risks in the world's highest mountains may exceed the protection that early warning systems and other adaptation measures can provide. Better high-altitude monitoring, earth observation and warning systems could reduce some risks, but researchers warned there are limits to adaptation in Himalayan valleys where settlements, roads, hydropower projects and other infrastructure are concentrated along rivers.

"Small changes in temperatures affect the stability of the land itself," noted Friederike Otto, emphasizing that mountain ecosystems and societies are more vulnerable to climate impacts than those living in the plains.

Friederike Otto, Climate Scientist at Imperial College London

Since glaciers and permafrost respond to temperature changes over decades, some mountain destabilization caused by warming has already been set in motion. Researchers stressed that the most important step to minimize risk in the region is to rapidly stop using fossil fuels that lead to increasing global temperatures.

"All these drivers that we've talked about, permafrost melting, glacial melting, etc., will just become worse. And that means that events like this become more frequent," Otto warned.

Friederike Otto, Climate Scientist at Imperial College London

The analysis underscores a critical challenge facing mountain communities worldwide: as climate change accelerates, the physical stability of the terrain itself becomes increasingly uncertain, creating hazards that traditional disaster preparedness may not be equipped to handle.