Geology And Geophysics

Could Melting Glaciers Form a Himalayan Tsunami



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Alarming new information from the International Centre for Integrated Mountain Development (ICIMOD) suggests that a major disaster in the Himalayas is waiting to happen. According to data compiled by the Kathmandu-based organization, a number of glacial lakes in the region are at risk of bursting through their restraining walls and causing flash floods. So large are some of these glacial lakes that any outburst would have the impact of a tsunami.

ICIMOD program co-ordinator Pradeep Mool has told Time magazine that in the Hindu Kush region of the Himalayas, glaciers are melting at an alarming rate. The area, which stretches from Afghanistan to Burma, is home to about 20,000 glacial lakes, and several may soon come under extreme pressure from additional melting. When the water pressure builds up sufficiently, or when natural erosion or an earthquake weakens the rocky deposits which are holding back the waters, the lakes can release millions of cubic meters of water in a matter of minutes.

The problem seems to be as a result of climate change. Since 1992, average pre-monsoon and winter temperatures in the Himalayas have risen by 0.6 degrees, which does not sound particularly extreme, but is nonetheless capable of causing profound changes to the region’s glaciers and snow-line. Recent data released by a team from the University of Milan suggests that the snow-line has risen about 180m since the 1960s, and that glaciers in the proximity of Everest have shrunk by 13 percent over the same period.

Glacial lakes are caused by melted ice filling up troughs created by retreating glaciers, and under normal circumstances, the lateral and terminal moraines form a natural barrier to stop the water escaping. There are hundreds of thousands of glacial lakes around the world which bear witness to past ice ages, including the Great Lakes of America and Britain’s idyllic Lake District, and more are created every year. The latest evidence, however, suggests that many in the ravines that mark the Himalayan foothills will soon be vulnerable.

In the Dudh Koshi region of Eastern Nepal, for instance, “almost all the glaciers are retreating at rates of 10 to 59 m annually,” according to Pradeep Mool, and the rate for some “has accelerated during the last half-decade to 74 m annually.” This alarming retreat has created 24 new glacial lakes in the area, and at least ten of them are potential hazards.

If that’s not bad enough, any serious earthquake could cause multiple outbursts, leading to widespread inundation and major loss of life. Although many local villages have access to text messages warning of impending floods, they would only have minutes to evacuate should an outburst occur.

The uncommonly rapid glacial melt has potentially catastrophic consequences, not only for the thousands of hardy souls that inhabit the region, but also for millions of farmers throughout lands that rely on mighty rivers like the Indus and Ganges for irrigation. The New Indian Express reports that this documented climate change will not only affect the levels of these life-giving rivers and their tributaries, but also possibly lead to increased sea levels. The resulting influx of sea water could destroy vast expanses of fertile land, affecting the lives of almost 1.5 billion people in South East Asia.

 Anyone with a TV is aware of the incredible devastation that a tsunami can cause, and certainly, the prospect of one developing from an over-gorged glacial lake is a terrifying thought. And yet, incredible as it may sound, such an event – which now seems an inevitability – may only be the herald of a worse disaster yet to come.

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ARTICLE SOURCES AND CITATIONS
  • InfoBoxCallToAction ActionArrowhttp://www.icimod.org/
  • InfoBoxCallToAction ActionArrowhttp://world.time.com/2013/05/27/fears-grow-of-a-himalayan-tsunami-as-glaciers-melt/
  • InfoBoxCallToAction ActionArrowhttp://education.nationalgeographic.com/education/encyclopedia/moraine/?ar_a=1
  • InfoBoxCallToAction ActionArrowhttp://newindianexpress.com/editorials/Act-now-to-save-melting-Himalayan-glaciers/2013/05/17/article1593113.ece1