india

Updated: Feb 04, 2020 05:34 IST

The concentration of black carbon on Gangotri glacier has almost doubled in the past few years primarily because of the raging forest fires, said a research done by Dehradun-based Wadia Institute of Himalayan Geology.

PS Negi, a scientist at Wadia’s research group on ‘Geomorphology and Environmental Geology’ said they have been monitoring black carbon through two weather stations on way to Gangotri glaciers - namely Chirbasa station at a height of 3,600 m, and Bhojbasa station at a height of 3,800 m - for the last few years.

“Analysis of the data from these weather stations in real time has helped us to know about black carbon concentrations and seasonal variations in the higher Himalayas. We have found that the concentration of the black carbon increases in summer months due to varied factors. We have found a range of black carbon up to 4.62 micrograms per cubic metre,” he said.

In the non-summer months, the concentration comes down to about 2 micrograms per cubic metre of air indicating that forest fires and tourism activities in Uttarakhand contribute to higher concentration of black carbon on glaciers.

“Period from April to June showed remarkable increase in black carbon concentration primarily due to direct and indirect activities related to tourism. Also, forest fires contribute in increasing black carbon concentration. Also we 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 during these months,” he said.

On the sources of black carbon, Negi said the main local sources of black carbon observed during field study include forest fires, domestic and commercial fuel wood burning and seasonal burning of crop residue.

According to Forest Survey of India, the forest fire activity is generally reported in Uttarakhand from February to June, with a peak in fire incidences in May and June. Besides man made, other reasons for forest fires in the state include lightning, friction of falling rocks and monkeys accidentally throwing stones that create sparks leading to forest fires. Over 44,554 hectares of forest area has been damaged in forest fires in Uttarakhand since its formation in 2000, according to the state forest department data.

On possible impact of the black carbon on Himalayan glaciers, Negi said, black materials absorb more light and emit infra-red 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,” he said.

Negi said black carbon is a kind of an aerosol (an aerosol is a suspension of fine solid particles or liquid droplets). “Among aerosols, black carbon (BC) has been recognized 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.

On the source of the black carbon in Himalayas, Negi said developmental activities, pollution from local, regional and global sources accumulate over the Himalayan region and increase the concentration of black carbon.

“Their presence in atmosphere also causes changes in weather pattern such as rain and snow precipitation pattern and local ecosystem and weather cycles. In the longer run, the changes in the atmospheric composition of the high Himalayan will affect the weather pattern, and accordingly natural resources and socio-economic activities of Himalayan communities”, he said.

Scientists at Dehradun-based Wadia Institute of Himalayan Geology monitor black carbon aerosol on real time basis through its monitoring stations and studies its impact on glaciers. The Central government institute also studies the impact of climate change on Himalayan glaciers in north-west India.