DEHRADUN: A recent study, led by Wadia Institute of Himalayan Geology, Dehradun about Nanda Devi and central Himalayan regions, revealed that the glaciers have significantly receded in their areal extent during the past 37 years (1980–2017).
Dr Manish Mehta, a scientist who was part of the study which has appeared in an international journal said, "The study was conducted using satellite imagery as well as extensive field surveys. The results will help us understand behaviour of glaciers."
The total loss of area of the glaciated region in the catchment during the period is 26 sq km or 10 per cent of the total area and equilibrium line altitude (ELA) shifted between 36 and 96 m. The equilibrium-line altitude (ELA) on glaciers is the average elevation of the zone where accumulation equals ablation (removal of snow for various reasons) over a one-year period.
According to the study, the analysis of the data showed that recession rate of the glaciers has increased after the 1990s. However, the sensitivity of the glaciers in the upper Rishi Ganga catchment have suggested that the glaciers might have responded likely due to decreased precipitation rather than rise in temperature.
Rishi Ganga is a river flowing through Nanda Devi National Park. Other institutions involved in the study include Hemwanti Nandan Bahuguna Garhwal University, Srinagar, Uttarakhand Space Application Center, Dehradun and Indian Institute of Technology, Kanpur.
Concluding the correlation between glacial behaviour with climatic changes, the study stated that the dynamic response of glaciers to climate is strongly dependent on the glacier size and geometry. "It can be suggested that besides global warming, the local climate and non-climatic factors like aspect and slope etc. play an important role in variable loss and dynamics of glacier snouts even in the same valley," said the study.
The study further added that based on the variability in the recession rate, ELA shift, percentage of area loss etc, it can be concluded that the glacier regime has appeared as one of the complex systems which has responded both for precipitation and temperature.
The role of topographical factors (slope, aspect, hypsometry etc.) and local climatic components (precipitation and temperature) on glacier dynamics needs to be studied precisely with respect to un-
derstand the response of the glaciers to ongoing changes in climatic parameters, the study asserted.
The experts also concluded that a more definitive connection between glacier recession and recent climate requires regional-scale study. "However, an assessment of multiple glacier parameters help in building a more holistic picture of the status of glaciers. Detailed quantitative case studies are required in order to reduce the uncertainty of the Himalayan glacier change. Moreover, long-term measurements like field-based and multi-temporal satellite images are useful to predict future scenarios," the study concluded.
