India — KOLKATA: Black carbon generated from forest fires could be leading to faster melting of Himalayan glaciers and affect flow of snow-fed rivers, warns a new study.
“The mass balance of numerous glaciers located in the lower ranges of the Himalayas, such as Pir Panjal and Greater Himalayas, could be significantly affected due to deposition of black carbon on the accumulation area in addition to changes in temperature and precipitation,” says a report by scientists of Divecha Center for Climate Change at the Indian Institute of Science in Bangalore.
During their investigation, they analysed the change in ‘reflectance’ in the accumulation area of Baspa basin in Himachal Pradesh for the year 2009, as the region has experienced extensive forest fires along with northern Indian biomass burning.
Their report shows that the drop in ‘reflectance’ in the visible region from April to May in the accumulation area was significantly higher in 2009 than in any other year from 2000 to 2012.
The number of forest fires in the summer of 2009 was substantially higher than in any other year between 2001 and 2010.
“This can only be explained by the deposition of black carbon. The study suggests that a change in snow albedo in the accumulation area due to the deposition of black carbon from anthropogenic and natural causes can influence the mass balance of the glaciers in the Baspa basin, Himachal Pradesh, India,” says scientist A V Kulkarni.
A number of Indian states such as Jammu and Kashmir, Himachal Pradesh and Uttarakhand, located in the western and central Himalayan region, experience large forest fires in the months of May and June.
In addition, adjacent regions on the Indo-Gangetic plains also experience large agricultural fires.
This can generate a large number of black carbon particles which may be transported into the glaciated terrain of the lower Himalayan mountain ranges due to a southerly wind, says the report.
“It can significantly affect the albedo of seasonal snow and on the accumulation areas of glaciers, as black carbon absorbs substantially more radiation than mineral dust,” say the scientists.
The loss in mass for many small glaciers located in a low altitude range could be as high as 1 metre per year in thickness.
This is a substantial loss considering that the mean depth of small glaciers could be between 30 and 50 m.
Earlier some studies have suggested that the glaciers are losing an average of 0.4 per cent area per year.
“These small glaciers and ice fields are an important source of water for many mountain communities. By considering small volume and large mass loss, this source of water could be significantly influenced in the near future and could affect the sustainability of many mountain communities,” warns the study.