The first scientific attribution analysis of the August 26 glacier collapse that killed more than 1,300 people in Nepal and Tibet has identified climate change as a destabilizing factor in the disaster. Researchers at Imperial College London, working with the World Weather Attribution collaboration, published findings showing unusually warm conditions preceded the collapse of a roughly 200,000-square-metre section of glacier and rock from Langtang Lirung mountain. The mass dropped about 1,400 metres and slammed into the valley floor with such intensity that it registered as an earthquake.

The avalanche sent 110 million cubic metres of snow and ice into the valley, liquidising ice and sparking a freezing flood that moved downriver at speeds exceeding 110 mph, the study said. The flood of water, ice, rock and sediment swept away families, homes, settlements, roads, bridges and other infrastructure, leaving survivors stranded and cut off.

More than 1,300 people were killed and more than 5,000 remain missing from the disaster. The flooding hit communities downstream in Nepal and Tibet without warning.

The study marks a departure from prior World Weather Attribution analyses, which have typically ascribed climate breakdown’s role to a single weather event. In this case, the researchers characterized the disaster as a compound crisis in which decades of atmospheric heating from greenhouse gas pollution worsened multiple contributing factors.

Dr Friederike Otto, a climate science professor at Imperial College London, said communities in Nepal are “paying with their lives for a crisis driven by fossil fuel emissions thousands of miles away.” She added that warming was destabilizing the “roof of the world” and that “without much faster action to transition to zero fossil fuel emissions we will inevitably see more disasters of this scale occurring in the years to come.”

Dr Ben Clarke, who researches extreme weather and climate change at Imperial, said the “fingerprints of climate change” were clear in the long-term changes that occurred around the glacier before its collapse. Clarke said: “We found that climate change is transforming the high mountain environment, influencing many of the possible drivers of this collapse.”

Specific findings the researchers documented include roughly 2°C of warming in the collapse region since pre-industrial times, with about 1.5°C of that warming occurring in July and August specifically; July and August 2026 as the warmest on record locally, reaching 5°C above the 30-year average in the days before the collapse; the freezing threshold in the Himalayas rising by about 100 metres per decade since the 1980s, which the researchers said had weakened mountain slopes shaped by permafrost; and substantial glacier recession that had already removed stabilising ice from around the collapse site, contributing meltwater to the system.

The study also found that a 7.8 magnitude earthquake in Nepal in 2015 further contributed to slope failure, though the researchers said they could not confirm the earthquake’s specific contribution to the August disaster. They noted that rock avalanches of the size observed are rare, with annual frequency estimates of approximately one event this size every 1,000 to 10,000 years.

The researchers framed their findings carefully, saying the study did not directly ascribe climate breakdown as the fundamental cause of the catastrophe but rather as a destabilizing factor on the existing geology. The study concluded that “this event shows that limits to adaptation are already being reached.”

Nepal has filed a formal request with the UN loss and damage fund for financial support to address the destruction from the flood, a process that requires documentation of a link to the climate crisis. Foreign Minister Shisir Khanal has demanded that top-emitting nations including China and India “wake up” and accept shared responsibility for the disaster.

Madhab Uprety, senior technical advisor for the Red Cross Red Crescent Climate Centre, which is part of World Weather Attribution, said only aggressive cuts to global emissions could begin to address the “losses and damages faced by vulnerable frontline communities.” Uprety said: “In addition to the human tragedy on an unimaginable scale, the cost of recovery for this disaster is substantial. For a nation that’s done virtually nothing to contribute to this problem, it underlines the need to find fairness in helping climate vulnerable nations cope with the problems they have not unleashed.”