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Saturday, November 14, 2009

Black carbon - more responsible for the melting of Himalyan glaciers than carbon dioxide


Reports though unconfirmed, reveal that a number of glaciers located at a height of about 18,380 feet have already been receded over the years. Scientists like Professor Syed Iqbal Hasnain, a leading glaciologist and a senior fellow at The Energy and Resources Institute (TERI) is of the opinion that the regional rate of melting of Himalyan glaciers is hard to study due to absence of any benchmark glacial studies and data in the last 60 years. Any fruitful study on melting of ice and receding Himalyan glaciers can be done only after developing benchmark and the contribution of melting of glaciers to the water flow in the rivers.




Scientists have selected four glaciers for a benchmark study. These glaciers are located in Zanskar, Kashmir valley, Himachal Pradesh, and Sikkim respectively. This selection for the benchmark study has been done on the basis of advice received from the World Glacial Monitoring Station located at Zurich.

Prof. Hasnain is studying on the Himalyan Ice Climate and Black Carbon Aerosol Impacts on water resources. His study is reported to be inspired by the study of Prof. V. Ramanathan’s study on Atmospheric brown clouds and the role of black carbon.

Scientists have started measuring the black carbon in the Himalyan atmosphere t5hrough the application of aethalometer installed at East Rathong glacier at 4,700m. It is the opinion of scientists that the concentration of black carbon is high in the Western Himalyas which is basically due to the emissions from the transport sector. It has been reported that diesel when adulterated with kerosene accelerates the emission of black carbon which poses a major threat to the fragile environment at high altitudes.

The Union Environment Minister, Government of India has asked Prof. Hasnain to submit a project to measure yearly carbon emission – reports The Hindu in its issue of 12 November. The black carbon is considered as an important pollution to accelerate global warming and speeding up the climate change. Hence, some policy commitment is needed before COP 15 in Copenhagen – as per the minister.

Scientists at WWF and BIT extension centre, Jaipur have reported through their studies –“Witnessing change: Glaciers in the Indian Himalyas” that smaller glaciers in Kumaon region are retreating at faster rate. Gangotri the larger glacier has been reported to show “continuous recessionary trend in recent years, as reported by Singh et al., 2006. According to Dr. Rajesh Kumar of BIT extension Centre Jaipur, there is a sharp retreating trend and the latest figure of retreat for the Gangotri glacier is 17.19m per year. It has already been reported through another study that Gangotri glacier has already retreated 20m so far. The current status of the glacier has been assessed to be 29.5 km long. Environmentalists are of the opinion that the current trend of retreating glaciers due to the deposition of black carbon is a bad sign for glaciers of Himalyas and needs detailed study. These studies are to be based on more and more satellite imageries and ground research.

Since it is mentioned that the black carbon is the main factor responsible for retreating glaciers, some information about it is needed to be given here. What is black carbon? Well, black carbon is the particulate pollutant formed through incomplete combustion of fossil fuels, biofuels, and biomass. It is emitted in both the anthropogenic and naturally occurring soot. The rising concentration of black carbon in the Himalyan atmosphere warms the region by absorbing solar heat and also by reducing the albedo or the ability of ice to reflect the sunlight when deposited on snow and ice. Though the life of the black carbon in the atmosphere is lesser (1 week) as compared to that of carbon dioxide (more than 100 years), the deposition of black carbon on ice and snow enables these to absorb sunlight and cause ice-melts(V.Ramanathan and G. Carmichael,2008.)