Nepal Floods Expose Gaps in Himalayan Glacial Hazard Preparedness

The Himalayas are among the world's youngest and most tectonically active mountain systems. Their steep slopes, fractured rock, and vast glacial cover create conditions where small triggers can release enormous destructive energy. Nepal and Sikkim both sit within this zone of structural vulnerability. Nepal is a mountainous, landlocked country with steep river gradients, contributing less than 0.1 per cent of global greenhouse gas emissions yet absorbing a disproportionate share of climate-driven disaster risk. The Himalayan region is warming at roughly twice the global average rate, destabilising glaciers and expanding glacial lakes across Nepal, Bhutan, northern India, and Tibet. Upper tributaries of the Ganges, including the Bhote Koshi, Karnali, and Trishuli, originate on the Tibetan Plateau and flow through Nepal before entering India, making Nepal a critical transit zone for Himalayan hydrology. Upstream disasters in Nepal therefore become direct downstream threats for Indian states such as Uttarakhand, Bihar, and West Bengal.

The equity framework governing international climate obligations is the principle of Common But Differentiated Responsibilities and Respective Capabilities (CBDR-RC), enshrined in the UNFCCC (1992). It holds that developed countries, which are historically responsible for the bulk of cumulative greenhouse gas emissions, must take the lead in mitigation and support developing countries through finance and technology. The Paris Agreement (2015) reaffirmed CBDR-RC and explicitly acknowledged the special vulnerability of mountainous states. The Loss and Damage mechanism, operationalised at COP27 (2022) and further developed at COP28 (2023), was created for irreversible harm suffered by vulnerable nations that cannot be addressed through adaptation alone. India has consistently invoked CBDR-RC to resist binding emission-reduction targets that treat all large emitters equally regardless of historical contribution or per-capita emissions.

Glacial lakes form when meltwater accumulates in depressions left behind by retreating glaciers, often held in place by a moraine dam, a natural barrier of loose rock and debris. These dams are inherently unstable. An earthquake, a landslide into the lake, or a rapid inflow of meltwater can breach the dam almost instantaneously. The resulting glacial lake outburst flood (GLOF) sends a wall of water, mud, and debris downstream at speeds that leave little time for warning or evacuation.