Climate change was a core contributing factor in the August 26 collapse of rock and glacier from Nepal’s Langtang Lirung mountain, scientists said, as a flood of water, ice and debris swept downstream through parts of Nepal and Tibet. The disaster has killed 1,446 people and left at least 6,669 missing, according to figures cited by disaster authorities and state media.
Researchers from the World Weather Attribution group described the event as a “compound crisis” shaped by long-term warming, glacier retreat, permafrost thaw and geological instability rather than by one extreme weather event.
Why researchers linked the collapse to warming
The WWA report, titled “Rapid Warming in the Himalaya Exacerbates Geohazard Cascades Beyond Adaptation Limits”, said relentless warming had raised the altitude of the freezing threshold in the high Himalaya. That exposed ice and permafrost in the bedrock to higher and longer thaw temperatures, weakening mountain slopes. Read the context: Study links warming to glacier collapse behind deadly Nepal-Tibet floods.
July and August were the warmest locally recorded months, with temperatures about 5 degrees Celsius above normal. Heavy snowfall in late 2025 also contributed to increased meltwater before the collapse. A magnitude 7.8 earthquake in Nepal in 2015 may have further weakened the slope, although the report said its precise role remains uncertain.
The toll and the rebuilding challenge
Nepal’s disaster authority said 6,150 people were considered missing after data collection and verification in affected districts. It reported that 1,403 bodies had been retrieved, including 105 that had been identified. In China, state media reported 43 dead and 519 missing.
Nepal estimates that rebuilding after the flood will cost $4.78bn. The disaster has also raised concerns about the limits of adaptation in a largely rural country of 30 million people that contributes a fraction of the greenhouse gas emissions produced by industrialised nations.
Friederike Otto, a climate science professor at Imperial College London, said climate change was one of the drivers and should therefore be discussed in the context of loss and damage. Walter Immerzeel, a mountain hydrologist at Utrecht University and report co-author, said glacier retreat and permafrost degradation were undermining mountain stability.
What happens next
Prime Minister Balendra Shah is expected to address the United Nations General Assembly on the issue next week, in his first foreign trip as Nepal’s leader.
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