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Heavy snowfall in late winters has failed to check the increasing rate of melting of Himalayan glaciers but has ensured more water for plains during summers, says a new study, to be published shortly in the International Journal of Glaciology.

In a study spanning over four years from 2002, School of Environment Sciences, Jawahar Lal Nehru University, Great Ice of France and Remote Sensing Division of Government of India, joined hands to study the mass balance of Choota Shigri glacier in Himachal Pradesh, internationally accepted as benchmark to study glaciers in western Himalayan region.

The monitoring found that the glacier was receding at a rate of 0.7 metres to 0.85 metres in length and depth. Professor Syed Iqbal Husnain of JNU says the continuous negative mass balance indicates at the fast rate of glacier melting. “We cannot say whether the depleting rate has increased as there is no data to compare the findings,” he said.

Although global warming has been blamed for negative mass balance, the study also indicates at the relation between local climate changes and the melting of glaciers. Husnain says it takes at least three to four months for snowflakes to re-crystallise into solid ice. But, in recent years, including 2007, the Himalayan region is witnessing majority of snowfall during late winters. “The glaciers are warm because of high aerosol content and westerly disturbances increases heat resulting in quick melting of flakes. Moreover, the snow does not get the gestation period to solidify as summer are close by,” Husnain explained, saying the recent snowfall is not helpful for the cause of receding glaciers. 

This snow will at least help some, as Husnain admits, that the heat in the glaciers will cause faster melting of the snow, resulting in more water flow to plain areas in the months of April and May. 

Choota Shigri is not an isolated case in point. The study of 466 Himalayan glaciers through remote sensing indicate that there had been deglaciation of these glaciers by up to 21 per cent since 1962, meaning annual receding rate of 0.7 to 0.85 metres. “The deglaciation in Choota Shigri is similar to these remote sending studies,” says lead author, Patrick Wagnon of Great Ice, in the study.

Terming the study as a wake-up call for the government, Husnain wants the Centre and the state governments to set up monitoring stations in glaciers to record data to help governments in formulating policies to check the melting rate of glaciers.
 
Email author: chetan@hindustantimes.com