“The Gangotri glacier is retreating like other glaciers in the Himalayas and its volume and size are shrinking as well,” a report, titled ‘Estimation of retreat rate of Gangotri glacier using rapid static and kinematic GPS survey’, by scientists from the Almora-based G.B. Pant Institute of Himalayan Environment and Development has stated.
The institute has been monitoring the Himalayan glaciers, particularly the Gangotri, since 1999. According to the report, “Recessional moraines and broad glacial terrace-like features provide sufficient evidences of shrinking of the glacier in the recent past between Gaumukh and Bhojbasa.”
The Gangotri, one of the largest Himalayan glaciers, is in Uttarkashi district. Originating at about 7,100m above sea level, the glacier is 30.2km long and has a width that varies between 0.5 and 2.5km. The Bhagirathi, one of the main tributaries of the Ganga, originates from the glacier, which has retreated more than 1,500 metres in the last 70 years.
Post-1971, the rate of retreat of the glacier has declined. “ 2000 onwards, the average rate of retreat of the glacier per year has been about 12 to 13 metres,” said Dr. Kireet Kumar of the G.B. Pant Institute.
A fluctuation in the recession rate of glaciers has engendered widespread discussion on the effects of global warming. “The Gangotri glacier is a big glacial body so its glacial response is slow. Also, global warming is not the only factor resulting in glacial retreat. However, it might be one of the factors,” Dr. Kumar said, adding: “The retreat in the past decade was higher than it is in this decade. However, there is some disintegration in the upper regions of the glacier which shows that some tectonic activities are going on in the region. This might be alarming but it is under study.”