Three weeks after a mountain collapsed on the Nepal-Tibet border, scientists have reached their first verdict on what primed the disaster. A new analysis by researchers at Imperial College London and the World Weather Attribution project concludes that human-caused warming destabilised the rock-and-ice slope whose failure triggered the August 26 Nepal glacier collapse, which has now killed at least 1,410 people in Nepal and left more than 6,000 missing. Nepal plans to take the findings to the United Nations next week as it asks a global climate fund to help pay for the recovery.

According to Nepal's National Disaster Risk Reduction and Management Authority, the official toll reached 1,410 deaths by the evening of September 18, with 6,055 people still missing and 13,756 rescued. Eighteen survivors were receiving treatment in six hospitals, while security forces had provided medical care to nearly 10,000 people, the authority reported. In China's Xizang Autonomous Region, known as Tibet, the reported toll stood at 43 dead and 519 missing, including 261 foreign nationals.

Warming thinned the ice and thawed the permafrost

The study describes the Nepal glacier collapse as a cascading disaster rather than a conventional flood. Roughly two square kilometres of rock wall and glacier ice sheared off Langtang Lirung at an altitude of about 5,150 metres, plunged nearly 1,400 metres, and turned into a debris flood that covered the 22 kilometres to the border town of Rasuwagadhi in seven minutes, leaving downstream settlements almost no warning, the researchers found.

Decades of atmospheric warming had been quietly preparing the slope. Researchers reported that thawing permafrost loosened the frozen material binding the steep rock, thinning glaciers removed ice that had buttressed the wall, and more precipitation fell as rain instead of snow. The freezing level in the Himalayas has been rising by roughly 100 metres of altitude per decade, exposing deep permafrost to longer and warmer thaws, according to the World Weather Attribution analysis, as reported by 7Globe. July and August were exceptionally warm, with the team estimating that human-caused climate change added around 1.5 degrees Celsius to temperatures, while heavy snowfall in late 2025 may have supplied extra meltwater.

Friederike Otto, a climatologist at Imperial College London and a co-author of the study, said the fingerprints of climate change were clear in the long-term transformation of the mountain environment, even though the warming was not the sole trigger. Ben Clarke, an extreme weather researcher at Imperial, added that the disaster showed the limits of adaptation were already being reached in vulnerable mountain communities. The researchers also noted that a magnitude-7.8 earthquake in 2015 may have further weakened the slope, though its exact contribution could not be quantified. Events of this scale are estimated to occur only once every 1,000 to 10,000 years.

Nepal takes its case to the UN General Assembly

Kathmandu intends to use the study as scientific weight behind a formal request to the UN Fund for Responding to Loss and Damage, the pool created to help developing countries pay for climate-driven destruction. Foreign Minister Shisir Khanal said the country would seek $20 million toward an estimated $5 billion rebuilding cost, which includes replacing up to 20,000 destroyed homes.

The arithmetic of that fund shows how hard the road ahead will be. The fund currently holds an estimated $400 million, while nearly 120 countries have submitted claims totalling almost $3 billion, according to reporting by UK Pulse. Nepal's leaders argue the claim is a matter of fairness: the country is estimated to account for less than 0.1 percent of global greenhouse gas emissions, yet its mountains are absorbing some of the heaviest costs.

Prime Minister Balendra Shah will travel to New York from September 22 to 26 for the UN General Assembly, his first foreign trip since taking office, where his government says he will highlight the disaster, Nepal's Himalayan vulnerability, and demand greater climate justice and financing for countries carrying disproportionate losses. The government has also called on major emitters, including China and India, to recognise a shared responsibility for the risks facing climate-vulnerable nations.

On the ground, the rescue effort remains one of the largest in the country's history. More than 20,900 security personnel have been mobilised, the Nepal Army has flown 1,651 helicopter sorties and the Armed Police Force another 320, reaching areas cut off by destroyed roads and bridges. Rescue teams recovered four bodies from a tunnel connected to one of 13 damaged hydropower plants this week, with searches of those tunnels continuing.

Neighbouring countries have joined the relief operation. India dispatched another 11 tonnes of supplies on September 19, including medicines, forensic kits, tents and sleeping bags, while China informed foreign embassies of DNA-collection procedures for the relatives of missing foreign nationals and sent forensic experts to Nepal to assist with victim identification. Among the missing are 587 foreign tourists.

The findings shift the conversation beyond the immediate collapse. Madhab Uprety, senior technical adviser for the Red Cross Red Crescent Climate Centre, said the scale of the human and economic losses underlined the need for major emissions cuts and greater support for vulnerable countries. Independent researchers say Himalayan preparedness can no longer focus only on rainfall and conventional flood forecasts; it will require integrated monitoring of glaciers, permafrost, slopes and rivers together. For more coverage of the climate crisis, see GenZ Newz's climate coverage.