Saturday, July 18, 2009

Himalayan glaciers have shrunk by 38% in 40 years

Himalayan glaciers are going through a phase of retreat, with some glaciers in specific basins having shrunk by up to an alarming 38% 40 years while at the same time satellite mapping has not shown any accleration of the process even as the rate of Gangotri's shrinkage has slowed.

The overall process of shrinking is leading glaciers to fragment and, therefore, paradoxically enough, the total number of glaciers in the Himalayas is increasing. These were some of the conclusions ISRO scientists drew up during a presentation at a meeting -- organised by the ministry of environment -- of all institutions and experts in glaciology.

The ministry has decided to support ISRO and the department of science and technology to undertake long-term and extensive glacial surveys across the eastern and western Himalayas. Environment and forests minister Jairam Ramesh told TOI, "We will institutionalize scientific studies of not only glaciers but also studies on terrestrial hydrology and agriculture as well as measurement of green house gases along with the department of science and technology and ISRO."

Scientists at the meeting recorded there is no evidence yet to claim the rate of retreat of glaciers, ranging from a few cms to couple of metres a year, has accelerated in the recent past. Scientists from the Geological Survey of India noted that the rate of recession of the Gangotri glacier has actually reduced in recent years.

The scientific community also observed that the process of retreat and advance of the glaciers was a natural process and that at present there was no evidence to prove that the current glacial recession phase is a consequence of climate change.

But scientists did express concern about the health of the glaciers pointing to the evidence of debris accumulation at the snouts in some glaciers. At present, the worst impact is seen in the Suru basin, with glaciers recorded a 38% shrinkage between 1969 and 2004. The Chandra, Bhaga, Parbati and Warwan basins are the other four recording the worst recessionary trends over the same period.

The meeting also noted that currently most of the automated weather stations are located in Jammu and Kashmir and serve the Army. These should be extended to Arunachal Pradesh,Himachal Pradesh and Uttarakhand in order to record data across the Himalayas

Link TOI

No comments: