Forest fires causing Gangotri Glacier to melt faster: Study
DEHRADUN: The black carbon concentration that contributes to faster melting of glaciers has almost doubled on the Gangotri Glacier, where the Ganga drains out of in Uttarakhand, over the past few years primarily because of the forest fires, a study by Dehradun-based Wadia Institute of Himalayan Geology (WIHG) has found.
PS Negi, a WIHG scientist, said black carbon is a kind of an aerosol (fine solid particles or liquid droplets). “Among aerosols, black carbon has been recognised as the second most important anthropogenic agent for climate change and the primary marker to understand the adverse effects caused by air pollution,” he said. Negi said they have been monitoring black carbon through two weather stations on the route to Gangotri glaciers at Chirbasa (3,600 m), and Bhojbasa (3,800 m) for the last few years.
“Analysis of the data from these weather stations in realtime has helped us to know about black carbon concentrations and seasonal variations in the higher Himalayas.
We have found that the concentration of black carbon increases in summer months due to varied factors. We have found that a range of black carbon up to 4.62 micrograms per cubic metre,” said Negi.
In summer, the concentration comes down to about 2 micrograms per cubic metre of air indicating that forest fires and tourism activities in the state contribute to higher concentration of black carbon on glaciers, he added.
“Period from April to June showed a remarkable increase in black carbon concentration primarily due to direct and indirect activities related to tourism. Also, forest fires contribute to increasing black carbon concentration,’’ said Negi. He added they found high black carbon concentration during September and October. “The lowest black carbon concentration has been recorded during August followed by December, likely due to the absence of tourist activities and forest fire incidences.”
Negi said the main local sources of black carbon observed during field study include forest fires, domestic and commercial fuel woodburning and seasonal burning of crop residue.
According to Forest Survey of India, forest fires are generally reported in Uttarakhand from February to June. Besides man-made reasons, other causes of fires include lightning. Over 44,554 hectares of the forest area was damaged in forest fires in Uttarakhand since 2000, according to the state data.
Negi said black materials absorb more light and emit infrared radiation, which increases the temperature. “So effectively, when there is an increase in black carbon in the higher Himalayas, it will contribute to faster melting of the Himalayan glaciers.” Developmental activities, pollution from local, regional and global sources accumulate over the Himalayan region and increase the concentration of black carbon.