Gangotri glacier retreated by 0.23 sq km between 2001-16, Centre informs Rajya Sabha

New Delhi, Mar 25: The retreat of the Gangotri glacier has caused it to lose approximately 0.23 square kilometre area in 15 years from 2001 to 2016, the government told the Rajya Sabha on Thursday.

Responding to a query in the Rajya Sabha on whether the presence of black carbon, a climate pollutant, is melting the Gangotri glacier, Union Environment Minister Bhupender Yadav said its impact on Himalayan glaciers is not of substantial magnitude. In a written response, Yadav said the concentration of black carbon is highly variable in the Himalayas.

"According to information received from the Indian Space Research Organization (ISRO), in-situ measurements show the black carbon concentration over the Himalayan region is highly variable with very low values over the western Himalayas, moderate values over the eastern Himalayas and high values over the foothills of the Himalayas," he said.

Black carbon is a short-lived climate pollutant with a lifetime of only days to weeks after release in the atmosphere, especially over the Himalayas which experience periodic snowfall, the minister said.

"Moreover, Himalayan glaciers have a high concentration of debris on ice and dust on snow, significantly reducing the effect of the changing reflectance of snow and ice on the glaciers. "Because of this, the impact of black carbon on Himalayan glaciers is not of a substantial magnitude," he told the House.

The ISRO is monitoring the changes observed over the Gangotri glacier using Indian Remote Sensing Satellite data. "As per information received from ISRO, it has been observed that Gangotri glacier has lost approximately 0.23 square kilometre area due to retreat of the glacier in the 15 years' time frame from 2001 to 2016," Yadav said.

The literature suggests that the Himalayan region has experienced the presence of black carbon. However, its effect on mass loss and the retreat of the Gangotri glacier has not been studied, the minister added.