A scientific analysis released on September 17 has concluded that climate change likely contributed to the catastrophic collapse of a glacier in Nepal last month, which triggered deadly flash floods and left more than 5,000 people missing.
The World Weather Attribution (WWA) group, an international team of climate researchers, found that rapidly warming temperatures in the Himalayas weakened the Langtang Lirung glacier and surrounding permafrost, increasing the likelihood of the August 26 disaster. The collapse sent 110 million cubic meters of ice, rock, and debris cascading into the Trishuli River valley, killing at least 1,300 people and destroying infrastructure across Nepal and Tibet.
Immediate Impact and Official Findings
The study determined that human-induced climate change played a role in preconditioning the disaster through permafrost thawing, glacier thinning, and increased rainfall instead of snowfall in the region. Researchers noted that temperatures in the Himalayas have risen faster than the global average, accelerating ice loss.
Friederike Otto, a climatologist at Imperial College London and co-author of the report, stated: "There's absolutely no doubt that human-induced climate change played a role here in the preconditioning of the disaster through permafrost thawing, through thinning of the glaciers, through having more rainfall instead of snow."
The disaster was not classified as a single extreme weather event but rather a compound crisis, with multiple contributing factors. A 2015 earthquake in Nepal was also cited as a possible preconditioning factor that weakened the mountain slope years before the collapse.
Long-Term Climate Trends and Future Risks
The WWA report highlighted that glacier thinning in the Himalayas has lifted the freezing threshold by approximately 100 meters per decade, exposing previously stable permafrost and ice to higher temperatures. This process destabilized mountain slopes over time, increasing the risk of similar events.
Ben Clarke, a climate researcher at Imperial College London, emphasized: "This disaster was not an extreme weather event, but the fingerprints of climate change are still clear to see in long-term changes." He added that while the earthquake may have weakened the slope, climate change amplified the risks.
Human and Economic Toll
The collapse of the 2 square kilometer section of rock and ice from Langtang Lirung mountain sent a debris-laden flood racing downstream at speeds exceeding 110 mph (177 km/h). Entire villages, roads, and bridges were swept away, leaving survivors stranded and cut off from aid.
More than 5,000 people remain missing, and the economic damage is estimated in the billions of dollars, according to local officials. The disaster has raised urgent questions about preparedness and adaptation in high-risk mountain regions.
Calls for Urgent Climate Action
Researchers warned that similar disasters are likely to become more frequent unless global emissions are drastically reduced. Otto stressed that without faster action to transition to zero fossil fuel emissions, such events will be inevitable.
The study underscores the global implications of Himalayan glacier loss, which not only threatens local communities but also regional water security and downstream ecosystems.
Scientific Consensus and Methodology
The WWA team used climate models and historical data to assess the role of climate change in the disaster. While they could not attribute the collapse entirely to climate change, they concluded that warming trends significantly increased the likelihood of such an event.
The report aligns with broader scientific consensus that Himalayan glaciers are retreating at an accelerating rate, with potential long-term consequences for billions of people who depend on glacial meltwater for drinking and agriculture.