Mother Nature never sleeps. She works constantly and continuously. That is why our planet has seen the worst warming and cooling episodes. Fortunately we were not there then. The present global warming is hyped more because the present rulers of the planet, the humans are most affected. The warming episodes affect all forms of life, including the humans. Though, it is a different matter that life proliferates in warmth only. Cold climate means a lifeless planet.
For sustenance life needs an optimum temperature, oxygen to breath in and water to drink. The Himalayas are a major source of water as well as climate controllers of Asia. Glaciers are one of the major factors for both of these. In the last 5000 years glaciers have been retreating gradually and most of them are now situated at almost inaccessible remote places. It is well established that our planet has undergone warm and cool phases since it came into being. The last cooling episode ended about 18,000 years before present. Since then the earth has been gradually warming.
Global warming is the contemporary hot topic. Conjectures from submergence of coastal areas to spread of pandemics are galore as the consequences of global warming. It is being claimed that glaciers are melting faster. Rapid melting of ice means more water in the Himalayan Rivers. The rock material (moraine) carried by a glacier is left as the glacier melts/retreats. Once free from the 'grip' of the glacier this material can at times roll down the slope and block the streams. Such accidents have often taken place in the past and when the temporary blockade gives way, flash floods occur, causing misery to the population downstream. Rapid melting of glaciers thus has lots of hazardous possibilities.
Are the glaciers really melting faster than they should or it is just a hype created to draw public attention by few is a thought that is haunts the glaciologists in the country. Based on remote sensing data Anil V. Kulkarni, I.M. Bahuguna, B.P. Rathore and S.K. Singh of Marine and Water Resources Group, Space Application Centre, Indian Space Research Organization Ahmedabad; S.S. Randhawa and R.K. Sood of Himachal Pradesh Remote Sensing Cell, Shimla and Sunil Dhar of Department of Geology, Government College, Dharamshala, H.P. studied glaciers in Chenab, Parbati and Baspa basins in Himachal Pradesh. They published their results in the Current Science.
Kulkarni and his co-researchers selected Baspa, Parbati and Chenab basins as their area of study. They state to have monitored 466 glaciers in these basins from 1962 onwards with the help of remote sensing data. In addition they undertook expeditions to Chota Shigri, Patsio and Samundar Tapu glaciers in Chenab basin; Parbati glacier in Parbati basin and Shaune Garang glacier in Baspa basin.
Based on their data they have claimed that the glaciers studied have shown a reduction in area from 2077 sq. km. in 1962 to 1628 sq. km. at present. In other words it means an overall deglaciation of 21%. Kulkarni claims that due to heavy melting many glaciers have been defragmented, thereby the number of glaciers have increased, though the total quantity of ice carried by them has reduced. Glaciers with less than one sq. km. area have shown a retreat of more than 38% says Kulkarni.
Geological Survey of India (GSI) has done some pioneering work in the field of glaciology. They have carried out Mass Balance studies of all the major glaciers in all the basins in general. The glaciers studied by Kulkarni and his co-workers have been under the scanner of the GSI, say Dr. Deepak Srivastava, Deputy Director General and an eminent glaciologist and C.V. Sangewar, Director, Glaciology. Forty glaciers were monitored physically by GSI in Chenab basin alone. The observations of GSI are somewhat different than those of Kulkarni and his co-workers. Average recession is seven to eight metres says Sangewar in the above area, with the exception of Barashigri glacier, which showed a retreat of 29 metres till 2005. Much hyped Chota Shigri glacier has shown a near positive mass balance in 2004-2005 Hydrologic year (October 1 to September 30), as published by Science Reporter and also confirmed by GSI.
'Yes glaciers are melting fast in other parts of the Globe' says Dr. Deepak Srivastava, but our glaciers, fortunately are located above 3500 metre altitude. Our glaciers too are melting but there is a conflict of information on rate of melting. Geological Survey of India's data is based on ground realities and meticulously collected by detailed surveying. He also agrees that the climate has changed in the sense there are unexpected events, like heavy snowfall in the months of November and December. The accumulated snow in these months does not melt, he says, it adds to the glacier mass.
Similarly Gangotri glacier about which alarming reports are published in the media has shown a decline in recession in the past decade, reported by other Institutions and physically confirmed by the GSI says Sangewar.
The glacier inventory of GSI however, tallies with the observations of Kulkarni. There is an increase in the number of glaciers of the Himalayas within the territory of the country. Now their number stands at 9575.
Our Planet is not an isolated landmass in the Universe. It is part of the planetary system and gets the energy from the Sun. The orbital cycles of the earth around the Sun vary and these can cause upto 10% of incoming solar radiation. Such periodic changes in the radiation (amount of Sunlight) reaching the earth could have caused repeated glaciations reports Kulkarni.
Industrial development is being blamed for any change in the climate or even melting of the glaciers. Yes it does affect the environment, but millions of years ago when we were not born, who was adding to the carbon or greenhouse content of the atmosphere? Those days volcanoes were fiercer and they added to the Carbon Dioxide content.
Some paleoclimatologists opine that with man turning from gatherer, hunter to farmer some 11,000 years ago, forests must have been hacked and rice cultivation might have abetted green house emissions. However, it is well established that the Industrial revolution which took off in 1850 accelerated the green house emissions and by 1900 there was a temperature rise of 60 C ?0.20C. Quoting an article in 'Science' Kulkarni says 'recent development in climate modeling suggests that the existing green house gases and aerosols have led to the absorption of 0.85 ? 0.15 Watts/Sq.m. more energy by the earth than emitted to space. This means an additional global warming of 0.60C has occurred without further change in atmospheric condition.
In a nutshell the current global warming is affecting the mass balance of the Himalayan glaciers according to Kulkarni.
There is a dispute in figures of retreat of glaciers in the past four decades based on actual field measurements and Remote Sensed information. Those who have done the leg work claim that glaciers are not retreating as much as claimed by some with the help of satellite imageries. But the fact remains that the glaciers are retreating, there is no dispute about that. The panic of retreat of glaciers is such that each individual seems to be pointing finger at the other. The retreat of glaciers in inevitable as presently we are in the 'warmer phase' of the earth's geological cycle. But yes the rate of retreat can be reduced by curbing the green house emissions. Question is can we do it?