The trend of gradual reduction in snow cover in ecologically fragile Himachal Pradesh continues to haunt the hill State — also the mean maximum and minimum average temperature is on the rise in the Himalayan region.
In the past decade, Himachal Pradesh has been witnessing an erratic, inconsistent, and decreasing trend of snowfall, besides a shift in the pattern of snowfall and precipitation, triggered by climate change.
The depleting snow cover is an immediate concern in the mountain environment as it could have a devastating impact on hydropower, water sources, people, livestock, forests, farms, and infrastructure.
In the 2022-23 winter period (October-April), there was an overall reduction of about 14.05 % in the total area under snow cover in Himachal Pradesh in comparison to 2021-22.
This has been revealed in the latest scientific report conducted jointly by the Himachal Pradesh’s State Centre on Climate Change (HIMCOSTE) and Geo-Sciences, Hydrology, Cryosphere Sciences and Applications Group (GHCAG) and Space Applications Centre (SAC-ISRO).
Rivers’ discharge dependability
Himachal Pradesh receives winter precipitation in the form of snow at the higher altitudes. About one-third of the total geographical area of the State remains under thick snow cover during the winter season. Most of the major rivers like Chenab, Beas, Parvati, Baspa, Spiti, Ravi, Satluj, and their perennial tributaries originating from the Himalayas, depend upon the seasonal snow cover for their discharge dependability.
Given the importance of seasonal snow cover as a major input in controlling the hydrology of the river basins, seasonal snow cover assessment in terms of its spatial distribution was carried out in different river basins during the winter season of 2022-23 from October to April. The total area under snow cover was estimated using Advanced Wide Field Sensor (AWIFS) satellite data during 2022-23.
The study completed by using Advanced Wide Field Sensor (AWiFS) satellite under the title — ‘Seasonal Snow Cover Variations in Himachal during 2022-23 and its comparative analysis with reference to 2021-22’ — showed that during 2022-23, there was early snowfall in the month of October and November, resulting in positive trends in some basins.
However, during the peak winter months (December-February), all four basins — Chenab, Beas, Ravi and Satluj had negative trends in comparison to the last winter period.
The total area under snow during 2022-23 (October-April) slightly increased in the early half (October-November) in some basins, whereas in the peak winter (December–February), there was a drastic reduction in the area under snow. The late snowfall, that extended to April this year, resulted in an increase in the area under snow, but the snowfall during this period may not be much use as the rising temperature from April onwards may enhance the melting rate thereby affecting the discharge dependability of the major rivers that relied on the seasonal snow cover besides the glacier melt during the peak summer time, it said.
The study added that the temperature trend analysis was also carried out from 2018-23, mean maximum and minimum average temperature showed an increasing trend in almost all the river basins.
Environmentalists, scientists, and officials have expressed concern over the reducing precipitation trend in the ecologically fragile hill State. S.S. Randhawa, co-author of the study, told The Hindu, “Glaciers in the Himalayas have been reported to be retreating, and these retreating glaciers, depleting snow cover and Glacial Lake Outburst Floods (GLOFs) are of immediate concern in the mountain environment as GLOFs can have a devastating impact on hydropower, water sources, people, livestock, forests, farms, and infrastructure. Decreases in snow accumulation and glacial retreat might lead to acute water shortages in the future.”
Mr. Randhawa added that the scientific analysis for the past decade showed that the snowfall trend by and large had been negative (reducing) in the State, except for a year or so.
Expressing concern over the reduction in snow cover in the long run, horticulture scientist and a former joint director with the University of Horticulture and Forestry, Nauni, S.P. Bhardwaj said that apple, which was the most important fruit crop of Himachal Pradesh, could face trouble.
“This trend is a warning sign, if snow cover is reducing it’s not good for the apple. Snow is responsible for inducing low temperatures. If there’s less snow cover, then eventually temperature will rise, which will impact the entire crop cycle. The ‘chilling hours’ requirement for Apple would not be met. With the rise in temperature, the incidence of pests and weeds would also increase, and eventually in the long run, apple crop’s productivity and production will suffer. Growers would have to opt for newer varieties and replace the existing ones. All this would impact them economically,” he said.
The people associated with the tourism sector are also worried. Shimla, the capital of Himachal Pradesh, this year hardly received a snowfall, which according to the hospitality sector leaders is not a healthy sign for the business. Rajesh Sharma, who runs a budget hotel in Totu sub-urban area of Shimla, said snow was the greatest attraction for those visiting Shimla in the winter season. “Shimla would lose its ‘best charm’ if snowfall keeps evading this hill station,” he added.
Himachal Pradesh Chief Secretary, Prabodh Saxena said, “We have also seen the rising temperature effects during winters this time in Shimla as there was no snowfall in Shimla, which seems to be a major change in the weather patterns and if this continues, we have to think upon as we may have a shortage of water in the coming years. I am hopeful that the steps like the introduction of e-vehicles, shifting to renewable energy etc. taken by the State government would definitely help in reducing the GHGs emissions so that the rise in temperatures could be checked even at micro-scale as well,” he said.
“Shimla would lose its ‘best charm’ if snowfall keeps evading this hill station”Rajesh SharmaHotelier