The Himalaya Is Sending Us a Warning We Cannot Afford to Ignore
The Himalaya is not merely a spectacular landscape or a distant source of rivers. It is a living, changing system on which millions of people across South Asia depend.
The catastrophic disaster in Nepal on 26 August has now acquired another, deeply worrying dimension. A rapid attribution analysis by World Weather Attribution, involving researchers from Imperial College London and institutions across several countries, describes the Langtang Lirungcollapse as a complex cascade of geological and climate-related processes. Its message is clear: climate change may not have been the fundamental cause of the collapse, but it has increasingly become a destabilising force in an already fragile high-mountain environment.
The scale of the tragedy is difficult to comprehend. More than 1,300 people had been confirmed dead by mid-September, with more than 5,000 still missing, according to the WWA assessment. The collapse of a huge rock wall and overlying glacier generated an avalanche that transformed into a debris flood and then a devastating flash flood. The resulting flow travelled at an average speed of about 188 km per hour, reaching settlements and infrastructure downstream with extraordinary speed.
What makes this particularly disturbing is not simply the magnitude of the event, but what happened before it.
The Himalayan region has been warming rapidly. WWA estimates that annual warming around the site is about 2°C attributable to human-caused climate change, while July-August temperatures have increased by about 1.5°C. The freezing threshold has also been moving upwards by roughly 100 metres per decade in recent decades during the monsoon and post-monsoon seasons. These changes matter enormously in a landscape where ice and permafrost act as part of the mountain’s structural system.
The Langtang Lirung glacier has also been thinning and retreating for decades. WWA notes that glacier thinning and retreat can reduce buttressing and alter stresses within adjacent rock walls. Permafrost degradation can weaken ice-filled fractures, while meltwater can increase pressure within those fractures. Add the legacy of the 2015 earthquake, changing precipitation from snow to rain and unusually warm conditions, and the result is not one isolated climate hazard but a compound geohazard cascade.
This is where the Nepal disaster offers a lesson far beyond Nepal.
We have become accustomed to preparing for hazards that announce themselves: cyclones have tracks, heatwaves can be forecast, heavy rainfall can trigger warnings. But a mountain slope weakened over decades by warming, permafrost thaw, glacier retreat and changing water dynamics does not necessarily provide such a clear warning.
The signals, however, are measurable. The challenge is whether we are monitoring them systematically enough.
High Himalayan regions need sustained observation of glaciers, permafrost, unstable slopes and glacial lakes, combining satellite observation with ground-based monitoring. Risk maps need to be continuously updated. Data must reach disaster-management agencies and communities downstream. And because rivers, hazards and mountain systems do not respect political boundaries, transboundary sharing of data and warnings must become standard practice.
The World Meteorological Organization says it’s Global Cryosphere Watch already provides an institutional framework for strengthening coordinated observations of glaciers, snow, ice and permafrost through in-situ, airborne and space-based systems. The WMO has also been working towards standardised permafrost measurements – precisely the kind of long-term observation needed to understand a rapidly changing cryosphere.
But monitoring alone will not be enough. The WWA assessment makes an uncomfortable point: the August disaster was beyond the predictive and design limits of existing risk-reduction measures. In high mountain valleys, where habitable land is limited and communities and economic activities are concentrated along rivers, completely eliminating exposure may be socially and economically impossible.
This is where the language of loss and damage becomes important.
Nepal has already approached the UN Loss and Damage Fund following the disaster, seeking international support. The UN has described the catastrophe as a stark illustration of the losses and damages increasingly faced by climate-vulnerable countries. Nepal has reportedly sought an initial $20 million from the Fund for the Rasuwa disaster.
Attribution science therefore matters not only to scientists. It matters to communities seeking accountability, to governments planning adaptation, and to countries seeking international support for losses they had little role in creating. The Himalaya is not merely a spectacular landscape or a distant source of rivers. It is a living, changing system on which millions of people across South Asia depend.
The Langtang Lirung disaster should therefore not be remembered only as another tragic flood or landslide. It should become a turning point in how we understand mountain risk.
We cannot prevent every mountain from collapsing. But we can monitor the mountains, understand the warning signals, prepare the valleys and invest in the people who live below them. And where adaptation reaches its limits, the world must be prepared to respond with climate justice – not merely sympathy.
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