Accurate estimation of Black Carbon over Himalaya

• Accurate estimation of black carbon (BC), the second most important global warming pollutant after CO­2, will now be possible using optical instruments in the Himalayan region.
• Thanks to a parameter called the mass absorption cross-section (MAC) specific to the Himalayan region that scientists have estimated. It will also improve the performance of numerical weather prediction and climate models.
• Scientists at the Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous institute under the Department of Science & Technology (DST), Govt. of India, in collaboration with scientists from the University of Delhi, IIT Kanpur and Space Physics Laboratory, ISRO have made extensive observations of black carbon and elemental carbon and estimated monthly and wavelength-dependent values of MAC over the central Himalayan region for the first time.
• The researchers have derived the values of MAC – an essential parameter which is used for obtaining Black Carbon mass concentrations.

About Black Carbon

• Black Carbon (BC) =It is a Pollutant as well as a GHG. It is a solid particle or aerosol & a component of Particulate Matter.
• Black carbon consists of pure carbon in several linked forms.
• It is formed through the incomplete combustion of fossil fuels, biofuel, and biomass (like soot & dust), and is emitted in both anthropogenic and naturally occurring soot.

• It is short lived. It is the strongest absorber of sunlight and heats the atmosphere directly. It can upset the monsoon system and disrupt cloudiness.
• Black Carbon Study by Wadia Institute of Himalayan Geology (WIHG), Dehradun: It is not the local sources that are the reason for pollution and receding snowline of the Himalayas but the reason is Black Carbon (Because of Western disturbances). If deposited on snow, it reduces the albedo and accelerates the heating of snow and quicken the melting of glaciers.

Health Impacts

• Black carbon (BC) is a pollutant known to aggravate breathing disorders.
• According to a recent study published, BC particles emitted by the vehicular exhaust and coal-fired power plants, have been detected on the fetus-facing side of the placenta. This is expected to affect the overall development of the unborn baby.

What is the news?

• World Bank released a report on Black Carbon titled “Glaciers of the Himalayas, Climate Change, Black Carbon and Regional Resilience”.
• Black carbon (BC) deposits produced by human activity which accelerate the pace of glacier and snow melt in the Himalayan region can be sharply reduced through new, currently feasible policies by an additional 50% from current levels, a study by World Bank (WB) specialists has said.
• The research covers the Himalaya, Karakoram and Hindu Kush (HKHK) mountain ranges, where, the report says, glaciers are melting faster than the global average ice mass.
• The rate of retreat of HKHK glaciers is estimated to be 0.3 metres per year in the west to 1.0 metre per year in the east. BC adds to the impact of climate change.
• Full implementation of current policies to mitigate BC can achieve a 23% reduction but enacting new policies and incorporating them through regional cooperation among countries can achieve enhanced benefits, the WB said in the report titled “Glaciers of the Himalayas, Climate Change, Black Carbon and Regional Resilience”.
• BC is a short-lived pollutant that is the second-largest contributor to warming the planet behind carbon dioxide (CO2). Unlike other greenhouse gas emissions, BC is quickly washed out and can be eliminated from the atmosphere if emissions stop.
• Unlike historical carbon emissions, it is also a localised source with greater local impact.
• Some of the ongoing policy measures to cut BC emissions are
  1. Enhancing fuel efficiency standards for vehicles,
  2. Phasing out diesel vehicles and promoting electric vehicles,
  3. Accelerating the use of liquefied petroleum gas for cooking and through clean cookstove programmes, as well as
  4. Upgrading brick kiln technologies.
• However, with all existing measures, water from glacier melt is still projected to increase in absolute volume by 2040, with impacts on downstream activities and communities.
• Glacier melt produces flash floods, landslips, soil erosion, and glacial lake outburst floods.
• Deposits of BC act in two ways hastening the pace of glacier melt:
  1. By decreasing surface reflectance of sunlight and
  2. By raising air temperature, the researchers point out.
• Specifically, in the Himalayas, reducing black carbon emissions from cookstoves, diesel engines, and open burning would have the greatest impact and could significantly reduce radiative forcing and help to maintain a greater portion of Himalayan glacier systems. More detailed modelling at a higher spatial resolution is needed to expand on the work already completed.
• Industry [primarily brick kilns] and residential burning of solid fuel together account for 45–66% of regional anthropogenic [man-made] BC deposition, followed by on-road diesel fuels (7–18%) and open burning (less than 3% in all seasons)” in the region.