As glacial lakes flood, the effect can be devastating

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Tsho Rolpa Glacial Lake in Gaurishankar VDC, Dolakha district, Nepal. © Deepak KC/UNDP Nepal

13 Oct 2015 by Rajeev Issar, Policy Specialist, Disaster & Climate Risk Governance, UNDP

Rajeev Issar is a Policy Specialist in Disaster & Climate Risk Governance at UNDP.

In this blog series, UNDP experts and practitioners share their perspective on issues of climate change, in the lead up to COP21 in December.

Golf, yes. But GLOF? What is that?

The increasingly apparent impacts of climate change have introduced this new term—an abbreviation for “glacial lake outburst flood”—to the world’s vocabulary.

When glaciers melt, they sometimes form lakes on mountaintops. The water in these glacial lakes accumulates behind loose “dams” made of ice, sand, pebbles and ice residue. But these dams are inherently unstable and avalanches, falling boulders, earthquakes, or even simply the accumulation of too much water can unleash sudden, potentially disastrous floods in nearby communities.

GLOFs come up often for those of us who work on disaster and climate risk management in South Asia. They are becoming increasingly common, and can have devastating impacts on lives, livelihoods, and mountain ecosystems, as well as on critical assets and infrastructure such as roads or hospitals.

Satellite imagery has shown that, due to the melting of Himalayan glaciers at the rate of 30-60 meters per decade, existing glacial lakes have been expanding while new glacial lakes are being formed at a disconcertingly fast rate. A study of the recorded incidents across South Asia found that, in the second half of the 20th century, the occurrence of GLOFs increased from once a decade to every 2-3 years by the 1990s.

Seeing the tell-tale signs of the devastation left by GLOFs has given me a better understanding of the extent and magnitude of the challenge. A trek to one of the glacial lakes was truly eye opening. A vast body of water was held back by a loose and unstable “dam” comprised of ice, boulders and sand, and it was painfully clear just how much damage the millions of cubic meters of water could inflict on downstream communities that have no mitigation or disaster risk reduction and preparedness measures in place.

UNDP’s Regional GLOF Risk Reduction Project in the South Asian region conducted an assessment of the disaster risk mitigation measures used to protect communities against GLOFs and found that most measures focused on cost-intensive “structural” or engineering-based interventions. The need to complement these measures with non-structural solutions such as disaster preparedness and contingency planning, as well as involve local administrators, communities, and other stakeholders became evident.

The findings, combined with our visits to the glacial lakes, made it clear that we needed to increase our focus on community preparedness, early warning systems, evacuation and search and rescue training. One of the mitigation measures we introduced was planting fruit-bearing trees along the banks of mountain rivers in order to protect human habitations and livelihoods.

The idea was to create a locally-sourced, “natural” barrier that would weaken the force of outburst waters and reduce the impact of boulders and rocks. The selection of tree varieties like bamboo and other fruit-bearing trees was done in consultation with the local agricultural institute and administration—the tree varieties would not only protect communities, but also diversify livelihood options.

The experience of addressing this relatively new hazard gave me a glimpse of the real-time impacts brought about by climate change. It became apparent that the challenges posed by climate change are not somewhere in the distant future, but are in fact unfolding here and now. Our solutions lie not just in integrated disaster risk reduction and climate adaptation-based risk management measures, but also in ensuring that mankind adopts more environmentally friendly and risk-informed development solutions.

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