A new study revealed about existence of Brown Carbon “Tarballs” in Himalayan atmosphere that may trig Melting of Glaciers.
• Himalaya-Tibetan Plateau is well known as the “third pole” because the region has the largest reserve of glacial snow and ice outside of the north and south poles.
• The glaciers, which are extremely sensitive to climate change and human influence, have been retreating over the past decade.
“Tarballs” most commonly invoke the image of oil “blobs” in bodies of water. They can also appear at the Himalaya–Tibetan Plateau, which has an average elevation that exceeds 4,500 meters.
Unlike aquatic environments where tarballs mostly form due to oil spills, burning biomass or fossil fuels releases light-absorbing Brown Carbon “Tarballs”, and these carbonaceous particles can deposit on snow and ice.
Individual aerosol particles in brown carbon tarballs, consist primarily of carbon and oxygen, with smaller amounts of nitrogen, sulfur and potassium.
Relationship of Burning and ‘Tarball’
Primary brown carbon co-emitted with black carbon (BC) from biomass burning is an important light-absorbing carbonaceous aerosol.
Black carbon from the Indo-Gangetic Plain can reach the Himalaya region and influence glacial melting and climatic change.
Till now, there was no direct evidence for primary brown carbon in the Himalayan atmosphere.
Now, light-absorbing tarballs at microscopic scale collected on the northern slope of the Himalayas. Around 28% of thousands of individual particles were detected as tarballs.
The median sizes of externally mixed tarballs and internally mixed tarballs were 213 and 348 nm, respectively.
Air mass trajectories, satellite detection, and Weather Research and Forecasting model coupled to Chemistry (WRF-Chem) simulations all indicated that these tarballs were emitted from biomass burning in the Indo-Gangetic Plain.
Furthermore, data shows that a thick air pollutant layer containing large amounts of smoke aerosols from the Indo-Gangetic Plain climbed along the south ridge of the Himalayas into the Tibetan plateau following the elevated air masses.
The peak high pollution time lines up with the large-scale wheat residue burning that occurs annually after the wheat crops are harvested in April-May in the Indo-Gangetic Plain.
Additionally, Wind patterns and satellite data revealed that southwestern winds in the afternoon of heat day were at fault for bringing high concentrations of air pollutants from the Indo-Gangetic Plain to the south of the Himalayas during both April and May.
A climate model simulation shows a significant heating effect of the tarballs in the Himalayan atmosphere.
It is being concluded that the tarballs from long-range transport can be an important factor in the climatic effect and would correspond to a substantial influence on glacial melting in the Himalaya region.
The increasing percentage of tarballs due to peak pollution level, could contribute to Global warming. This phenomenon can make the climate change more complex and unprecedented. And thus the mitigation could be even more complex.
Climate change externalities have severe impact on agriculture practices, soil composition, and pattern of vegetation and health impacts. A more prudent way is needed at national as well as at global level.
The existence of a large amount of tarballs is highly concerning due to the area’s “extreme sensitivity to climate change and anthropogenic influence. The Himalaya region is the most vulnerable region on the planet aside from the south and north poles. Compared with other places in the world, anthropogenic aerosols from outside the Himalaya region could trigger various climate and environment problems.
To counter the anthropogenic emissions, there is dire need to adopt climate centric polices aligned in more sustainable way.
Government should strive to provide institutional remedy for crop burning-which is cited as biggest reason for atmospheric ‘tarball’. Crop residuals are needed to be managed in more sustainable ways. Government and farmers both have to play a serious role in order to cope with the issue of ‘anthropogenic led emission’.
Climate models need to consider the long-range transport of primary tarballs on a regional scale in the future.