Bursting glacial lakes in Nepal

For the people of Nepal, the threats of global warming are not something they fear for the future, but something they face right now.

“Glaciers are rivers frozen in time and time is running out for Nepal's glaciers”, says Ang Tshering Sherpa, the president of the Nepal Mountaineering Association and the Union of Asian Alpine Associations. He is trying to turn the world’s attention to his country’s glacial lakes, which are threatening to burst and destroy everything on its way, including the trail to Mount Everest.

Glacial lakes are a normal feature of mountain geography, formed by melting ice. In the last decades though, there has become a lot more of them. Speaking at a mountain environment conference in Matsumoto, Japan, Ang Tshering told his audience that there are over 3000 glaciers in the high Himalayas and in the last 40 years almost as many glacial lakes have formed.

In 1985 one such lake, the Dig Tsho in the Khumbu Region burst its natural dam after an ice avalanche hit the lake. A five meter high wave overtopped the moraine dam and the lake, which measured roughly 1500 by 300m and was 18m deep, drained almost completely within 4-6 hours. The flood caused drowning deaths and destroyed homes and infrastructure.

Today there are several other unstable glacial lakes in Nepal. Their walls can break at any time if there is an avalanche, landslide, heavy snowfall, earthquake, or even an accelerated melting of the glacier. One of them, the Imja Tsho lake, is nearly five times as big as Dig Tsho. When Ang Tshering was a child, this lake didn’t even exist, it first appeared in 1962 as a small pond. As the glacier has melted the lake has grown and it is now posing a danger to the people, buildings and landscape below the glacier.

Imja Tsho is directly above the Everest Trail, used by expeditions and trekkers every year. “When Lake Imja Tsho decides to burst, it will be a vertical Tsunami” says Ang Tshering, who also runs a mountain tourism business. Tourism and visiting climbers are vitally important to Nepal’s economy and should the Everest trail be washed away, or visitors scared by a glacial lake outburst flooding, the country’s income might be dramatically reduced.

The long term solution to the threat of glacial lakes is to slow down human-made global warming. In the meantime Nepal needs a more pragmatic approach. Ang Tshering suggests draining the lakes slowly, to reduce the stress on the dams. Another proposal is to relocate people so they would live above the flood zone.

The UN is working to implement early warning systems, so people can be evacuated before the lakes brake. Still, it is also necessary to improve emergency response capability. The problem with Nepal’s geography, explains Ang Tshering, is that in the event of a disaster, mountains are hard to access and it is difficult to bring in help. Therefore it also takes longer for the local community to recover.

“Since 1922, Sherpa people have been helping the world climb Everest”, says Ang Tshering, “but now we need to work together to overcome the next great challenge: global warming, climate change and the melting of our glaciers.”

Sherpas and other mountain people, whose minimal CO2 emissions have caused so little of the problem, are facing the consequences of climate change. “The poorest will pay for global warming with everything they have,” says Ang Tshering.

Additional sources:  www.germanwatch.org