Dakshin Gangotri in Antarctica is disappearing
Scientists from Geological Survey of India (GSI) have been monitoring the changes in DG glacier snout since the beginning of Indian Antarctic Expedition in 1983
The Dakshin Gangotri (DG) glacier snout that forms a part of the East Antarctica ice sheet (EAIS) is fast melting away because of rise in global temperatures, says a paper in the first volume of Antarctic research by India published in the Proceedings of the Indian National Science Academy.
Scientists from Geological Survey of India (GSI) have been monitoring the changes in DG glacier snout since the beginning of Indian Antarctic Expedition in 1983.
Monitoring changes of the ice sheet is important since Antarctica carries 70% of total fresh water of the planet. Scientists said if all ice from Antarctica melts, it will raise sea levels by about 60m across the globe, submerging most of the modern day coastal cities.
For three decades, Indian scientists have been monitoring recession in the DG snout – it forms the main snout occupying the valley region – and the western wall which includes approximately 7 km-long ice front (including ice wall and ramps) of the western flank of the DG snout.
The analysis found that the shrinking of the DG snout between 1996 and 2011 has cleared 4800 square metres (m2) area. This figure increases by about 10 times after including the vacated area by Western wall, the study said.
The Russian Novolazarevskaya research station has estimated that since 1996, average surface air temperature varies between -9.2 degree Celsius and -11.1 degrees Celsius.
The present calculation indicates the disappearance of ice from the snout of Dakshin Gangotri glacier, which is a part of East Antarctic Ice Sheet is related to the meteorological parameters such as increase in surface air temperature, ground temperature and wind speed. But a perfect correlation does not exist between recession and local meteorological parameters, indicating existence of complex system between recession and natural parameters.
The observation shows that the decline in ice mass is more pronounced at the western wall that lies at a higher elevation and therefore receives more solar radiation. In contrast, the snout of the DG glacier that rests in a small valley and protected from direct solar radiation for longer duration.
Between 2001 and 2016, the cumulative recession of the ice at the western wall is 21.73 metres – that’s an average recession of 1.44 metres every year. With an average recession at the snout of the DG glacier of around 0.6 to 0.7 metres every year, the total recession of ice between 1996 and 2016 is 14.38 m.
During the period 2001 to 2016, the recession of ice in the western wall saw two peaks – that of 10.96m in 2002-2003 and 10.45m in 2012-2013. At 1.31 metres, the decline in ice at the DG snout glacier was the highest in 2014-15 followed by 1.21m (2002-03), 1.10m (2007-08 and 2008-09) and 1.01m (1997-98).
Antarctica and Greenland hold 90% of the total ice of the earth. The Antarctic environment also controls many ocean circulations which is essential to marine life, and is directly related to our existence.
Every year, Antarctic loses huge volumes of ice in the form of icebergs. Some of the largest Antarctic icebergs are capable of providing water to some of the major rivers of India for many years.