A recent study by the Dehradun-based Wadia Institute of Himalayan Geology (WIHG) has found that black carbon travelling from Mediterranean countries during the western disturbance (which brings winter rains to India) may be one of the contributing factors leading to the receding snowline in the Himalayas. Black carbon is formed through the incomplete combustion of fossil fuels, biofuel etc and has an adverse effect on human health.

The study recorded data for 12 months from January to December 2016 at Gangotri Glacier Valley in Chirbasa at an altitude of 3600 meters above sea level. Scientists involved in the study found that black carbon concentration at the site was high even in winter months like January (659 nanogram per cubic metre) and February (531 nanogram per cubic metre) although the area did not have any marked human activity like burning of fossil fuels or influx of tourists which could have contributed to the pollution. “The high concentration of black carbon in January and February is not originating from local sources because life remains near standstill as almost the entire population in these areas migrates to the plains for the winter. This led us to deduce that black carbon aerosols were being transported during western disturbances and wind trajectories.” said PS Negi, senior scientist, WIHG, Dehradun. an extratropical storm originating from the Mediterranean region that brings sudden winter rain to the northwestern parts of the Indian subcontinent.” “The material present in the atmosphere also gets transported during the western disturbance and this is what is impacting the environment and ecology of Himalayas.”

The study found that the concentration of black carbon in the area during the months of January and February was in fact fourth and fifth highest respectively in the chronology of all the 12 months recorded. According to Negi, aerosols like black carbon have been recognised as “the second most important anthropogenic agent for climate change and the primary tracer for adverse health effects caused by air pollution.” “Increased black carbon will have effects like decreased snow cover area near the snowline as well as vanishing of valuable medicinal herbs,” he said.

Incidentally, studies had earlier found a co-relation between black carbon concentration and melting of glaciers. But the recent analysis by scientists reveals that it is not just local factors but global causes, too, which are having an impact on the fragile ecology of the Himalayas.

Source: September 13, 2018, The Times of India