Climate change leads to 18.52% decrease in snow cover in Himachal: Study

Express News Service

CHANDIGARH: Due to climate change, there is an overall decrease in snow cover in Himachal Pradesh by 18.52% in just one year.

A study titled Assessment of Spatial Distribution of Seasonal Snow Cover during the Year 2020-21 in Himachal Pradesh Using AWIFS Satellite Data’ carried out by the Centre on Climate Change of the Himachal Pradesh Council for Science Technology and Environment (HIMCOSTE) and Space Applications Centre, Ahmedabad, from October 2020 to May 2021 found that 23,542 square kilometre was under snow cover in 2019-20 which now come down to 19,183 square kilometres in 2020-21, a drop of 3,404 square kilometres in area.

Based on the analysis, it was observed that there is an overall decrease in area under the snow during the 2020-21 winter. While the Chenab basin witnessed a 9% decrease in snow cover, the Beas basin saw a 19% decrease. Similarly, the Ravi and Satluj basins witnessed 23% and 23% decrease in the snowfall. This reflects less snow-clad areas in 2020-21 (October to May) in comparison to the same period in 2019-20. Overall, there was a decrease in total area under snow by about 18.5% in Himachal Pradesh on 2020-21 winters in comparison to the total area during 2019-20, states the study. 

Talking to The New Indian Express, Nishant Thakur, Joint Member Secretary of HIMCOSTE says, “Snowfall is related to climate and weather changes. The rise in temperature and greenhouses gases affect the snowfall pattern. Thus, snow cover is less. Also, there are local phenomena such as urbanization and more tourist influx in uncharted territories, but these activities have very minimal effect on overall temperature changes. Also overall, there has been a rise in macro temperature. Various studies have also found that the temperature of the higher Himalayan region has increased by one degree as compared to the lower region.”

SS Randhawa, the principal scientist of HIMCOSTE, who headed the study team, said: “The data analysis of all four major river basins — Ravi, Sutlej, Chenab and Beas — pointed out that the total negative trend in 2020-21 winters and also seasonal snowfall pattern has extended even up to May this year which is collaborated by the data showing a positive trend in Chenab and Sutlej basis even in May whereas Ravi and Beas’s basins showed a negative trend. “Also winter last year was comparatively warmer. It has also been observed that there has been a shift in the snowfall pattern in the last few years due to less snow cover and less melting of snow in the river basins. This might have implications on water availability in the coming years.”

The study further revealed that all these rivers basins saw a fall in the snow cover area in 2020-21 in comparison to 2019-20. 

The snow cover in the Chenab basin reduced from 7,154.12 square kilometres in 2019-20 to 6,515.92 square kilometres in 2020-21 — a reduction of 638.2 square kilometres. The snow cover shrunk by 2,777 square kilometres in the Sutlej basin — from 11823.28 sq km in 2019-20 to 9,045.51 sq km this year.

The Beas basin too witnessed a decrease of about 19% with its average snow cover area. The snow-clad area of the river basin decreased from 2457.68 square kilometres to 2002.04 square kilometres.

The Ravi basin saw an overall reduction of 23% in the total area under snow cover. This year, the snow cover in the river basin was of 1,619.83 sq km compared to 2,108 sq km last winter thus. The reduction in terms of area under snow cover was 488 sq km.

Further analysis of the data reveals that the total maximum and minimum area under snow from October to May during 2020-21 that could be mapped varies from about 98% in January and about 21% in October. In the case of the Chenab basin, about 61% in January and about 10% in October and in the case of Beas, about 64% in January and about 3% in October, according to the study.