Act now on climate

As early as 2007, the Intergovernmental Panel on Climate Change (IPCC) in its fourth assessment report confirmed that the receding and thinning of Himalayan glaciers could be attributed primarily to global warming caused by the human-driven emissions of greenhouse gases. 

The 2014 IPCC fifth assessment report further confirmed that the Himalaya is experiencing some of the fastest rates of glacial retreat globally, contributing to the increased size and number of glacial lakes.

Above the village of Thame in Khumbu lie new glacial lakes. Five of them are located at about 4,760m elevation. Just after noon on 16 August, two of the lower lakes burst, triggering a massive flood. 

Debris, including rocks and ice, were pushed downstream to Thame village, located about 960m below, destroying 20 houses, an elementary school, and damaging a 650KW hydropower station. It displaced 135 people, who have been evacuated to temporary shelters.

The IPCC projects that snow cover, glaciers, and permafrost will continue to diminish in almost all regions throughout the 21st century. These changes will likely trigger landslides, floods, and cascading events in areas where such disasters were previously unheard of. 

Glacial lake outburst floods (GLOFs) are a regular occurrence in the Nepal Himalaya, and 26 such events have been recorded in the recent past. In fact, Thame was already hit in 1985 when the Dig Tso glacial lake burst on 4 August 1985 destroying the nearly completed Thame hydropower plant. 

There are more than 3,800 glaciers in Nepal, and they are vital for sustaining river flows, supporting agriculture, promoting tourism, and generating hydropower. Various studies and glacier inventories have identified nearly 2,500 glacial lakes in Nepal, of which 330 of them are expanding steadily.

A 2020 study by ICIMOD and UNDP of glacial lakes in the wider Himalaya region revealed that 1,400 of these lakes are bigger than or equal to 0.02 km², making them large enough to cause floods from overflow. Among these, 47 glacial lakes were identified as potentially dangerous, with 21 located in Nepal. There have been some attempts to respond to the impact of glacial lake floods. For instance, the water level of Tso Rolpa in Nepal was lowered by more than 3m in 2000, and Imja Tso by 3.4m in 2016. However, the estimated monetary value of the responses is enormous and far exceeds Nepal’s regular development budget. This highlights the critical role of the international community to step in and ensure that countries like Nepal do not have to divert resources allocated for health, education, and poverty eradication.

This week’s flood in Thame could have threatened five major hydropower projects downstream on the Bhote Kosi, Dudh Kosi and Sun Kosi Rivers, seriously impacting energy security in the region.

The increased frequency and intensity of glacial lake floods in the Himalaya in recent decades have caused significant economic and non-economic losses, including infrastructure damage, community displacement, loss of cultural heritage, and ecosystem degradation.

If climate change continues at its current pace, the rates of glacier mass loss, shrinkage, and the formation and expansion of glacial lakes will lead to more frequent GLOFs and other glacial hazards – impacting on water availability on which millions of people downstream depend.

Despite ongoing efforts, there are limits to adaptation. Some impacts of climate change, such as the loss of glacial ice and the resulting long-term changes in water availability for agriculture and hydropower, are irreversible. These scenarios lead to loss and damage that require measures beyond traditional adaptation strategies.

As the Loss and Damage Fund begins its operation, events like the Thame disaster should inform its design. It must be tailored to address extreme events, where the conventional approach of adapting through a lengthy funding proposal process may not be effective or timely.

Countries must remain committed to curb global average temperature rise by reducing fossil fuel emissions, and mobilise adequate finance for vulnerable countries like Nepal. Building on the existing recognition of mountains in multilateral processes, it is crucial to advance mountain priorities to address the needs of vulnerable communities on the frontlines of the climate crisis.

Nepal itself must establish systems for regularly monitoring glacial lakes, particularly those identified as potentially dangerous, and keep communities informed about their status. A robust mechanism must also be in place to provide immediate response, coupled with a longer-term plan to help affected communities.

The Thame disaster serves as a stark reminder of the urgent need for global action as vulnerable communities continue to bear the brunt of climate extremes. It is imperative that the international community commit to even stronger climate action aligned to the 1.5°C target, ensure sufficient climate finance for the most vulnerable, and protect the lives and livelihoods of those most at risk.

Manjeet Dhakal, is Head of the LDC Support Team and Director of Climate Analytics South Asia.