‘Himalayan glaciers losing mass due to climate crisis’

MONITORING OF TWO GLACIERS IN HIMACHAL PRADESH AND LADAKH HAVE FOUND THAT IN THE 2000S, GLACIER MASS LOSS WAS SIGNIFICANTLY HIGHER THAN IN LATE 20TH CEN

NEWDELHI: Climate change is having a discernible impact on glaciers in the Western Himalayan region, studies by Jawaharlal Nehru University’s glaciology unit in the School of Environmental Sciences have found.

Long-term monitoring of two glaciers, based on observational data and modelling exercises, in Himachal Pradesh and Ladakh have found that in the 2000s, glacier mass loss was significantly higher than in late 20th century.

While the glaciers will not disappear in the coming decades, the authors said, negative mass balance (glaciers losing more mass than they gain) of glaciers is likely to have a profound impact on water availability for local communities, authors of the studies said.

They also said that mass loss in glaciers in the region was mainly linked to rising temperatures and diminishing snowfall.

For Ladakh’s Stok glacier study, published in the Journal of Glaciology on May 18, the team found that the glacier is facing as much mass loss as other Western Himalayan glaciers despite being in a higher altitude zone between the Himalayas and Karakoram.

The Stok glacier was in a balanced condition during the late 20th century (1980s) due to sufficient winter precipitation or snowfall. It was followed by a severe loss during the early 21st century (before 2009) and a moderate loss after 2011.

“This is mainly because of reducing winter snowfall in the arid Himalayan region. This must be also affecting water availability in Stok’s villages and Indus river which needs to be studied,” said AL Ramanathan, JNU professor and corresponding author of the paper.

The paper projects that a 27% increase in snow or rain is required to compensate for the mass loss due to 1 degree C rise in temperature over pre-industrial levels.

“Accelerated temperature rise over the Western Himalayas has significantly reduced the amount of snowfall received and hence aggravated glacier mass loss,” added Ramanathan.

Another paper published in the same journal on June 23 is a study of the Chhota Shigri glacier in Himachal Pradesh from the 2002 to 2019 period. The team found that over the past two decades, on average a half meter water equivalent of ice has been drained from this glacier in the Indus River. The glacier is in an imbalanced condition—more glacial melt than gain, the paper said.

“Overall, the air temperature change is controlling the river runoff, which means a warmer world is likely to be associated with higher water in the Himalayan rivers till the 2050’s which other studies have also observed. There might be a seasonal shift in glacier runoff also,” Ramanthan said.

India’s first national climate change assessment by ministry of earth sciences published earlier this month also flagged these concerns. The entire Hindu Kush Himalayas (HKH) experienced a temperature rise of about 1.3 degrees C during 1951–2014 compared to an average temperature rise of .7 degree over India 1901 onwards. Several areas of HKH have experienced a declining trend in snowfall and also retreat of glaciers in recent decades.