A new scientific study has found that climate change likely weakened the glacier involved in the catastrophic collapse that triggered deadly floods across Nepal and Tibet last month.
Researchers identified unusually warm conditions before the glacier collapse, which sent around 110 million cubic metres of snow and ice crashing into the valley below. The collapse triggered massive flash floods that struck downstream communities with little warning.
Scientists Identify Climate Change Factors
Researchers from World Weather Attribution (WWA), a climate research collaboration involving experts from Imperial College London and other institutions, found that the disaster was not caused by a single weather event but by a combination of factors intensified by decades of global warming.
Dr Friederike Otto, a climate science professor at Imperial College London, said the disaster showed how rising temperatures are increasing risks in vulnerable mountain regions.
“When warming destabilises the roof of the world, no amount of local adaptation can fully shield vulnerable people downstream from this scale of destruction,” Otto said.
The researchers noted that climate change should not be considered the direct cause of the collapse, but rather a major destabilising factor that increased the likelihood of such a disaster occurring.
Deadly Glacier Collapse in the Himalayas
More than 1,300 people were killed and more than 5,000 remain missing after a massive section of glacier and rock, measuring approximately 200,000 square metres, collapsed from Langtang Lirung mountain on August 26.
The falling mass dropped about 1,400 metres before striking the valley floor with enough force to register as an earthquake. The impact transformed ice, rock and sediment into a destructive flood that moved downstream at speeds exceeding 110 mph.
The resulting flood destroyed homes, roads, bridges and entire settlements, leaving many communities isolated and without immediate access to assistance.
Researchers described rock avalanches of this size as extremely rare, with estimates suggesting events of this magnitude typically occur only once every 1,000 to 10,000 years.
Rising Temperatures Changed Himalayan Conditions
The study identified several long-term climate changes that contributed to the instability of the mountain environment.
- The region has experienced around 2°C of warming since pre-industrial times, including approximately 1.5°C of warming during July and August.
- July and August 2026 were the warmest on record locally, with temperatures reaching 5°C above the 30-year average shortly before the collapse.
- The freezing threshold in the Himalayas has risen by about 100 metres per decade since the 1980s, exposing mountain slopes shaped by permafrost to longer periods of thawing.
- Glacier retreat removed stabilising ice around the collapse site and increased meltwater levels.
- The 2015 magnitude 7.8 earthquake in Nepal may have contributed to slope instability, although researchers could not confirm its exact role in the disaster.
Climate Risks Increase in Mountain Regions
Dr Ben Clarke, a researcher specialising in extreme weather and climate change at Imperial College London, said the long-term impacts of climate change were visible in the changing Himalayan environment before the collapse.
“Climate change is transforming the high mountain environment, influencing many of the possible drivers of this collapse,” Clarke said.
The researchers warned that communities living below glaciers and unstable mountain slopes are facing increasing risks as temperatures continue to rise.
Nepal Seeks Climate Support After Disaster
Nepal has submitted a request to the United Nations loss and damage fund for financial assistance to help address destruction caused by the floods.
The country’s foreign minister, Shisir Khanal, has called on major emitting nations to recognise shared responsibility for climate-related disasters affecting vulnerable countries.
Madhab Uprety, senior technical advisor at the Red Cross Red Crescent Climate Centre, said reducing global emissions remains essential to limiting future losses.
“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,” Uprety said.
