Monday, October 26, 2009

When the Ice Melts: Bhutan, Asian Countries Under Multiple Threats

One of the types of stories that we post here are "impacts of unsustainability" stories -- stories about all the bad things that the solutions we write about will help us avoid.

The prestigious journal, Nature, has an eye-opening piece about the multiple threats that global warming is posing to Himalayan countries such as Bhutan.

It's not just the scary thought of losing their drinking and agricultural water supplies -- a story that we have covered in several posts.

There is also the alarming threat to public safety and economy posed by the formation of glacial lakes behind ice dams -- and the collapse of those dams:

Every country within the Himalayan region has suffered a glacial outburst flood at some point3, and Bhutan is no exception. The only scientifically documented glacial flood in Bhutan's history came from a lake at the bottom of Luggye glacier, on Thorthormi's eastern margin, 15 years ago.

On 7 October 1994, the glacier's moraine broke and released an estimated 18 million cubic metres of water and debris down the Pho river, killing 21 people and razing fields and settlements downstream with a jumble of uprooted trees, boulders and mud.

Memories of that flood still haunt Dawa Gyeltshen, a herder who lives in the village of Taksho, beside the Pho river around 20 kilometres downstream of Luggye. He remembers being woken by a thunderous noise early that morning. For hours he raced around outside his house in the dark, terrified as the river rose.

It wasn't until dawn that Gyeltshen saw the extent of the damage. The forested river valley and a large portion of the fields in front of his house had been washed away and in their place were mounds of boulders and glacial silt. .

A combined flood from Thorthormi and Rapstreng lakes (whose dams are in danger of collapsing as early as 2010) could cause at least ten times the damage and fatalities of the 1994 event4.

It was in part because of the 1994 disaster that Bhutan became a leader in adapting to climate change.

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