As Nepal Prime Minister Balendra Shah prepares to address the United Nations General Assembly on September 24, fresh scientific assessments have put the Himalayan climate crisis and its economic consequences in sharp focus, warning that rapid warming is destabilising glaciers, permafrost and mountain slopes and pushing disasters beyond the limits of existing adaptation systems.
Shah is scheduled to address the general debate of the 81st UN General Assembly in New York. Nepal’s Foreign Ministry has said the August 26 disaster in Rasuwa, which caused extensive loss of life and property, has reinforced the country’s position as being on the frontline of the climate crisis.
The timing of the address comes as the Prosperous and Resilient Himalayas report, prepared by Systemiq and the Integrated Mountain Initiative (IMI), with the GB Pant National Institute of Himalayan Environment as a key knowledge partner, warns that the Himalayas underpin 21.5% of India’s GDP, equivalent to `64.8 lakh crore. The report says the figure represents economic activity directly and indirectly dependent on Himalayan water, rather than an estimate of ecosystem-service value or climate damage.
The report makes the case that the Himalayas need to be treated as national economic infrastructure because rivers originating in the mountains support wheat and rice production across the Indo-Gangetic plains, tea production in Assam and Bengal, hydropower in the Northeast and downstream pilgrimage economies. It estimates that the Himalayan states themselves capture only about 5% of the GDP ultimately underpinned by the mountain system, with roughly 15 percentage points accruing downstream.
“The Himalayan region is critical to India’s water, biodiversity, climate, and ecological security,” said Dr Indra D Bhatt, Director of the GB Pant National Institute of Himalayan Environment and Sustainable Development, in the report. He said protecting the fragile mountain ecosystems through science, innovation and community participation was essential for a resilient and sustainable future.
The economic dependence, however, is increasingly being accompanied by escalating physical risks. The report says the Himalayas constitute about 18% of India’s land area but account for around 35% of its disasters. It cites the 2013 Uttarakhand disaster, the 2021 Chamoli disaster and the 2023 Sikkim glacial lake outburst flood, while noting that India now has 56 glacial lakes classified as very high risk. The August 26 Nepal disaster comes as a striking example of how these risks can cascade.
A new analysis by the World Weather Attribution (WWA), released on September 17, says the disaster was not a single extreme-weather event but a compound geological and climate-sensitive crisis. A large rock wall collapse beneath the Langtang-Lirung glacier triggered a rock-ice avalanche, which rapidly transformed into a debris flood and then a water-dominated flash flood. The WWA analysis says the collapse involved roughly two sq km of rock wall and glacier ice, falling about 1,400 metres from an elevation of around 5,150 metres to the valley floor. The resulting flood travelled downstream at extraordinary speed, carrying rock, ice, sediment and water.
The scientists are careful not to attribute the physical collapse solely to climate change. Instead, they identify climate change as a destabilising factor acting on a pre-existing geological weakness. Long-term warming, glacier retreat and permafrost degradation can weaken ice-filled fractures and rock-ice contacts, while increased meltwater can raise water pressure inside fractures. The WWA says the 2015 magnitude 7.8 earthquake may also have preconditioned the slope, although its specific contribution to the 2026 failure cannot yet be confirmed.
The strongest evidence of the climate signal comes from the changing thermal environment. The WWA analysis found that temperatures during July and August 2026 were unusually high at the location of the failure and across the wider Himalayan region. At the failure elevation, temperatures in the days immediately before the collapse remained substantially above the 2016-25 average.
Climate change increased July-August temperatures in the region by about 1.5 degree Celsius, according to the analysis, while the annual attributable warming is around 2 degree Celsius. The height of the 0 degree Celsius freezing threshold has also been rising by about 100 metres per decade in recent decades during the monsoon and post-monsoon seasons. “This disaster was not an extreme weather event, but the fingerprints of climate change are still clear to see in long-term changes,” said Dr Ben Clarke, an extreme weather and climate change researcher at Imperial College London. “We found that climate change is transforming the high mountain environment influencing many of the possible drivers of this collapse,” he said. Professor Walter Immerzeel, a mountain hydrologist at Utrecht University, said the Himalayas were undergoing “fundamental, irreversible shifts”, with the upward movement of the freezing line exposing perennially frozen ground and bedrock to longer and warmer thaw conditions.
The WWA report also found substantial long-term glacier change around Langtang-Lirung. The glacier lost 41% of its area since the end of the Little Ice Age, while recession accelerated significantly after 2000. The retreat left parts of the rocky slope increasingly exposed and removed ice that had helped shape the mechanical conditions of the mountain.
Importantly, the WWA found that exceptional rainfall was not the main causal factor. Precipitation during the 2026 monsoon was broadly within historical variability. However, exceptionally high precipitation in October-November 2025, much of it falling as snow at high elevations, may have contributed to subsequent meltwater availability. The researchers also point to a shift from snowfall towards rainfall at high elevations as temperatures rise. The human cost has been enormous. The Nepal government records more than 1,300 confirmed deaths and over 6,000 people missing as of mid-September. Nepal’s rapid damage assessment has estimated the disaster’s economic impact at $2.7 billion, with recovery and reconstruction needs of about $4.8 billion, equivalent to 11.8% of national GDP.
For India, the implications extend well beyond the immediate Himalayan states.
The GB Pant-backed report says glaciers, springsheds and forests underpin water security for more than 40% of India’s population. Yet only around 0.1% of the estimated 40,000 Himalayan glaciers are currently monitored, highlighting the gap between the scale of the risks and the available scientific observation network. It also calls for the revival of the NITI Aayog Himalayan Council and the creation of a dedicated Himalayan institution covering conservation, disaster resilience and sustainable growth. India, Nepal and Bhutan are urged to deepen cooperation on shared hazard data, early warnings and natural capital.
(This reporter is a resident fellow of the Climate Change Media Hub at the Asian College of Journalism. The programme is supported by Interlink Academy Germany)