The climate crisis is the most likely cause of the glacier that collapsed and caused catastrophic floods with hundreds of deaths in Nepal and Tibet, according to the first scientific study of the disaster.
Researchers at Imperial College, London, identified unusually warm conditions before the glacier’s destruction.
Over 1,400 people were killed – and more than 5,000 remain missing – after a massive section of overhanging glacier and rock fell from Langtang Lirung mountain in Nepal on 26 August 2026.
The collapse caused an enormous flood of water, ice and debris that swept downstream, resulting in catastrophic damage.
Rather than a single extreme weather event, scientists found that the disaster happened as a compound crisis.
Decades of atmospheric warming – caused primarily by the burning of fossil fuels – have melted the glacier and pushed the freezing threshold line (0°C isotherm) upward by around 100 metres of altitude per decade.
This has caused glacier recession and thawing in permafrost within rock fractures that historically hold high mountain walls together, rendering them unstable. A massive 2015 earthquake is likely to have also further preconditioned the slope for collapse.
‘Communities in Nepal are paying with their lives for a crisis driven by fossil fuel emissions thousands of miles away,’ said Dr Friederike Otto, a climate science professor at the college.
‘When warming destabilises the roof of the world, no amount of local adaptation can fully shield vulnerable people downstream from this scale of destruction’
Dr Friederike Otto, Imperial College, London,
‘When warming destabilises the roof of the world, no amount of local adaptation can fully shield vulnerable people downstream from this scale of destruction.
‘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.’
The rock and ice dropped about 1,400m and hit the valley floor with such intensity that it registered as an earthquake, liquidising ice and causing a freezing flood which raced through the landscape at speeds in excess of 150 km/h, carrying debris up to 240km from the original disaster.
‘Rock avalanches of this size are rare, with annual frequency estimates of approximately one event this size every 1,000–10,000 years,’ the study said. ‘This event shows that limits to adaptation are already being reached.’
Otto and her team at World Weather Attribution (WWA) – a collaborative project between Imperial and other climate specialists worldwide – found the disaster was the result of a number of factors made worse by decades of atmospheric heating as a result of greenhouse gas pollution.
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 happened around the glacier before its catastrophic collapse.
In the region where the collapse took place, climate breakdown has caused about 2C of warming since pre-industrial times, and about 1.5C of warming in July and August specifically.
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 Friederike Otto, Imperial College, London,
July and August 2026 were the warmest on record locally, reaching 5C above the 30-year average in the days before the collapse;
The freezing threshold in the Himalayas has risen by about 100 metres per decade since the 1980s, with higher and longer thaw temperatures weakening mountain slopes shaped by permafrost.
The warming temperature had already driven substantial glacier recession, removing stabilising ice from around the site where the collapse occurred and contributing meltwater;
Clarke said: ‘We found that climate change is transforming the high mountain environment, influencing many of the possible drivers of this collapse.’
Nepal has filed a formal request with the UN loss and damage fund for financial support to address the destruction caused by the flood, a process that requires proof of a link to the climate crisis.
Madhab Uprety, senior technical advisor for the Red Cross Red Crescent Climate Centre, which is part of WWA, said only large scale cuts to global emissions could begin to address the ‘losses and damages faced by vulnerable frontline communities”.
He added: ‘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.’
Scientists are predicting long-term impact on conditions in mountainous areas as the Earth warms.
Professor Walter Immerzeel, Mountain Hydrologist at Utrecht University, said: ‘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.
‘When you combine high–elevation permafrost degradation with glacier retreat and record summer heat, the structural integrity of these mountain walls is compromised.
‘The catastrophic impacts of what can then happen are clear for all to see.’
