New Delhi: Human-induced climate change may have thawed permafrost contributing to the instability of the rock wall that gave way in Rasuwa in Nepal and triggering flash floods downstream, according to a report released on September 17. The catastrophic floods have killed over 1,300 people and left 5,000 missing. Thawing ice, more rainAccording to the report released by World Weather Attribution (WWA), a global collective of scientists who analyse the role of climate change in extreme weather events, warmer temperatures caused by human-caused climate change possibly thawed ice and weakened the rock wall in Rasuwa, causing slope instability that led to the ice-rock avalanche that triggered the floods.The resulting mixture of sediment, ice, and rock led to the formation of deadly debris, which ravaged families, homes, and nearly all existing infrastructure it encountered. This bulwark moved at rapid speed, reaching the Rasuwagadhi border in seven minutes. It took another half an hour for it to reach the Trishuli Valley. In under seven hours, the flood travelled 200 kilometres, wreaking devastation. The report suggests that while climate change was not the “fundamental cause” it acted as a “significant destabilising force.” What this means, effectively, is that climate change can not only dramatically alter weather patterns, but remake the mountains themselves. The report also noted that another contributing factor that caused the slope failure on the Langtang-Lirung glacier could have been an earthquake of magnitude 7.8 on the Richter Scale, in 2015 in the area, which could have weakened the rock below:“Subsequent monitoring shows persistently elevated and, at high elevations, increased landslide activity, suggesting that earthquake shaking may have weakened the underlying rock mass over the long term. Although its specific contribution to the 2026 failure cannot yet be confirmed, the earthquake may have preconditioned the slope for failure, alongside geological and climatic factors.”The Langtang-Lirung glacier, which collapsed on the morning of August 26, setting the disaster in motion, has retreated about a half a kilometre since the 1990s. The recession of glaciers weakens existing fractures and increases slope instability, the WWF highlights. Moreover, Nepal saw unusually warm temperatures from September 2025 to August 2026, which means that the increased quantities of melting ice and precipitation fell not as snow, but as rain, the report said. Fingerprints of climate change “This disaster was not an extreme weather event, but the fingerprints of climate change are still clear to see in long-term changes. While this is a complex event, our analysis brings together scientists with a diverse range of expertise to set out the factors that likely contributed to this catastrophe. We found that climate change is transforming the high mountain environment influencing many of the possible drivers of this collapse. This increases the risk in a region that is already exposed to high seismic activity,” said Ben Clarke, researcher, Extreme Weather and Climate Change at the Imperial College London.Also read: The Report We Buried While Arguing About AI: The Climate Reality We Refuse to See“The new analysis removes any doubt about the fingerprint of climate change on Nepal’s catastrophe and confirms this was a compound disaster, decades in the making. The science is now unambiguous: the burning of fossil fuels helped bring that mountainside down,” said Harjeet Singh, global convenor, Fill the Fund campaign, and founding director, Satat Sampada Climate Foundation.Nepal has established early-warning systems, such as cross-border engagement with Chinese scientists to monitor Himalayan Glacial Lake Outburst Floods (GLOFs). But, the analysis says, this event was far beyond the domain of any existing early warning system and could not have been prevented. “In a rapidly warming Himalaya, increasingly extreme and complex hazards are exceeding adaptation capacity, resulting in loss and damage,” it reads. While the WWA hasn’t studied whether this specific avalanche would have occurred in a world that wasn’t warming, steadily rising temperatures definitely contribute to frequency and severity, it said.Moving away from fossil fuels In context of the floods and similar events that have decimated parts of several poorer nations, experts and activists have consistently pointed out: the countries that suffer the most from ensuing climate change, have contributed the least. Nepal has emitted 0.01% of global emissions since 1751. Those who reside in mountainous regions, whose lives and livelihoods are framed by these ecosystems, are more vulnerable to the effects of a changing climate. Ideas of climate justice, climate finance policies, and a significant portion of what transpires during COP summits, are situated in this gulf. Also read: Three Questions, With Clear Answers, About the Nepal Disaster“Responsibility must now follow the evidence. Developed countries, whose historical emissions drove this warming, have a clear and unavoidable role to play,” said Singh. “The Loss and Damage Fund was created for precisely this moment, and it must come forward and support Nepal without delay. Let us be honest about what this support is: not aid, not charity, but compensation and reparation – an obligation owed by those most responsible to those bearing the consequences.” The WWA analysis is unequivocal in stating what is required to minimise risk – a swift transition away from fossil fuels and the execution of climate finance commitments. “Minimising future risk requires a rapid transition away from fossil fuel use and delivering on climate finance commitments for adaptation,” the report read. “This is particularly important in the Himalaya and other high mountains, where glacier decline and permafrost degradation are expected to continue even without further warming, meaning that some of the impacts of past warming have yet to fully emerge.”