From UPSC perspective, the following things are important :
Prelims level : Black Carbon Aerosols
Mains level : Not Much
Black carbon aerosols have indirectly affected the mass gain of the Tibetan Plateau glaciers by changing long-range water vapour transport from the South Asian monsoon region, a study has found.
What are Black Carbon Aerosols?
- Black Carbon (BC) aerosol, often called soot, is the dominant form of light absorbing particulate matter in the atmosphere.
- They are emitted by incomplete combustion processes, both human (e.g., diesel engines) and natural (e.g., wildfire).
- Its ability to absorb visible and infrared radiation means BC can heat the atmosphere and darken surfaces, specifically snow and ice.
- These effects have important consequences on earth’s climate and climate change.
- BC may also have adverse impacts on human health. Unlike long-lived greenhouse gases such as carbon dioxide, BC is removed from the atmosphere in 1-2 weeks, so its impacts tend to be more regional rather than global.
Deposition over Himalayas
- The South Asia region adjacent to the Tibetan Plateau has among the highest levels of black carbon emission in the world.
- Many studies have emphasised black carbon aerosols from South Asia can be transported across the Himalayas to the inland region of the Tibetan Plateau.
Impact on glaciers melting
- Black carbon deposition in snow reduces the albedo of surfaces — a measure of how much of Sun’s radiations are reflected.
- This accelerates the melting of glaciers and snow cover, thus changing the hydrological process and water resources in the region.
- They heat up the middle and upper atmosphere, thus increasing the North-South temperature gradient.
- As a result, precipitation in the central and the southern Tibetan Plateau decreases during the monsoon, especially in the southern Tibetan Plateau.
- The decrease in precipitation further leads to a decrease of mass gain of glaciers.
- From 2007 to 2016, the reduced mass gain by precipitation decrease accounted for 11% of the average glacier mass loss on the Tibetan Plateau and 22.1% in the Himalayas.
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