The Gurudongmar glacier in Sikkim — the source of one of iconic lakes in the world by same name — has receded one-fourth since 1989, a new study has found, implying down-stream impact on hydro-power projects and livelihood of people in Bengal and Bangladesh.
The Gurudongmar lake, named after founder of Tibetan Buddhism in the 8th century Guru Rinpoche, is the main source for Teesta river that flows from Himalayas in Sikkim to Bangladesh.
The sharing of Teesta river water is a contentious issue between India and Bangladesh with Bengal chief minister Mamata Banerjee refusing to provide even “single drop of extra water” to the neigbouring country where it is main source of irrigation. The river has major hydel potential for Sikkim with projects over 5,000 MW either proposed or under construction.
A new study published in American Geophysical Union this week says the Gurudongmar glacier retreat has increased by nearly four times between 1965 and 1989.
“Between 1989 and 2016, the size of Gurudongmar lake has grown by one-sixth of its size in 1989,” said Mauri S Pelto, professor of environmental studies at Nichols College in Dudley, Massachusetts, in a study on Sikkim glaciers.
The study found that terminus of the glacier has retreated by about 600 meters (one-fourth of the total length) since 1987 and the lake has moved upwards. “The retreat distance is substantial given the length of the glacier is 25% of the 1996 glacier length of 2.4 km,” the study based on satellite images of the glacier in the last 20 years found.
Gurudongmar like all glaciers in the region is different from other winter accumulating Himalayan snow-sheets. It is summer accumulation type which receives 80% of its snowfall during monsoon months between July and September.
“Following the summer monsoon which ends in early September there is a transition period with some colder storm events where the snowline drops. Than November-February is the dry winter monsoon with limited precipitation,” the study says.
The study also said between 2003 and 2012 the glacier lakes in higher reaches of Sikkim has increased with 85 new one detected in addition to existing 320.
Increase in lakes indicates faster melting and fragmentation of glaciers, a sign of climate change impact on the Indian sub-conditions biggest water source.
