Expanding Glacial Lakes Pose Growing Threat in the Himalayas

Given Nepal’s extreme climatic conditions, fragile geography, and susceptibility to seismic hazards, these beautiful glacial lakes could turn into "water time bombs" in the near future if timely risk reduction measures are not taken. The risks are too significant to ignore.

Several imagery analyses reveal a concerning trend of steadily expanding glacial lakes in the Himalayan region, a consequence of the accelerated glacial melting observed in recent years. This rapid pace of glacial retreat has led to the formation of new lakes and the expansion of existing ones, many of which are on the brink of bursting. The Glacial Lake Outburst Flood (GLOF) event on August 16 in Thame Village of Pasang Lhamu Rural Municipality in the Solukhumbu district, exemplifies the growing threat that lies ahead. The flash flood in Thame was triggered by the breach of upstream glacial lakes, resulting in a cascading chain reaction that devastated downstream areas. Preliminary assessments indicate that 20 houses, schools, and clinics were damaged while displacing 135 people. Meanwhile, the consequences that Thame GLOF has brought to tourism, culture, ecosystems,and beyond are yet to be documented.

Thame’s GLOF is not an isolated event. Nepal has experienced over 26 devastating GLOFs since the 1970s. These incidents have resulted in substantial loss of life and property damage, including the destruction of critical infrastructure. The Dig Tsho GLOF in 1985, for example, caused an estimated US$1.5 million in damage to the Namche small hydroelectric plant and destroyed many connecting bridges. Most recently in 2016, the Upper Bhote Koshi River experienced massive GLOF originating from China, resulting in significant damage to the hydropower sector.

An assessment by the International Centre for Integrated Mountain Development indicates Nepal is home to over 2,000 glacial lakes, with over 1400 of over 0.02 km2 large enough to trigger a GLOF, and 47 out of them identified as potentially dangerous. Climate projections suggest that Nepal could experience warming by 1.2°C to 4.2°C by 2080 under RCP 8.5 scenarios. This warming trend is expected to accelerate glacier retreat, permafrost melting, avalanche, and glacial lake expansion, further increasing the risk of GLOFs and other glacial hazards and thus impacting the availability of water resources, energy production, and distributing agricultural and food security and tourism. Taking an example of Nepal’s hydropower sector, with over 42 GW of economically feasible hydropower potential, Nepal aims to be the regional hub for exporting hydroelectricity. However, these ambitions could be jeopardized, amidst existing multi-hazard risks of both climatic and non-climatic hazards. 

Given Nepal’s extreme climatic conditions, fragile geography, and susceptibility to seismic hazards, these beautiful glacial lakes could turn into "water time bombs" in the near future if timely risk reduction measures are not taken. The risks are too significant to ignore.

Efforts to mitigate GLOF risks have seen some success in Nepal. Tsho Rolpa glacial lake lowering project in 2000 and Imja Lake in 2016 were able to reduce the risk to downstream communities, ecosystems, and infrastructure. Early Warning Systems have also proven their value, as evidenced by their role in reducing the impact of the Thame and Mahendranagar floods.However, with the number of potentially dangerous lakes continuing to grow, these efforts must be scaled up and prioritized. The targets set in plans and policies of the government including the National Adaptation Plan, Disaster Risk Reduction National Strategic Plan of Action, and Nationally Determined Contributions are largely conditional. Over-reliance on external agencies might lead to little, delayed, or no actions, hence it is crucial that governments should prioritize mitigating such risk by actually allocating adequate internal funds and mobilizing local resources. Not just the federal government, sub-national governments are equally important and critical to reducing such risk. The recent gesture by Kathmandu Metropolitan City, which provided NPR 2 million to support Thame’s recovery, is commendable. Much more such cooperation is needed among local governments to build resilience and prepare for future events. It is also imperative that governments closely monitor adaptation projects to avoid duplication and ensure the effectiveness of risk reduction. 

The Thame GLOF has rung several alarm bells, serving as a critical wake-up call. It is very high time for Nepal to champion highlighting the impacts of climate change in the mountainous country at the international level. With the establishment of the Loss and Damage Fund, Nepal also has an opportunity to scientifically document the economic as well as the non-economic loss and damage caused by the Thame GLOF and play a critical role in shaping the architecture of the Loss and Damage Fund.

 
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