Glaciers are known to store freshwater reserves, especially in high-altitude mountains.  Gangotri glacier is one of the longest glaciers stretching at a length of 30.2 km and covering an area of approximately 143.6 sq. km. Yet, today it stands polluted due to several pollution-based activities. Detailed study done by Dehradun based Wadia Institute of Himalayan Geology has raised alarming concerns with respect to environmental degradation of Gangotri glacier.

Aerosols play a vital role in the process of climate change. Out of the various aerosols that exist, black carbon is considered to be the second most important anthropogenic agent for climate change, and it holds the ability to trace adverse health effects caused by air pollution.

The Equivalent Black Carbon (EBC) aerosols can absorb light, and therefore give rise to unnatural weather change. Their existence in ecologically sensitive zones, such as the Himalayan glacier valleys, is a cause for great concern and should be constantly monitored. However, information on black carbon is limited and quite difficult to access.

Wadia Institute of Himalayan Geology’s research on ‘Geomorphology and Environmental Geology’ has been closely tracking black carbon through two weather stations, both found on the way to the Gangotri glaciers. The first, named Chirbasa, is at a height of 3,600 m and the second, Bhojbasa, is at a height of 3,800 m. The research found that a recession of 1519.33 meters took place at the glacier, between the years 1935 to 2004. In the years that followed, the rate of retreat varied from 30 meters per year to 5 meters per year.

Stretching over 100 years (1901 – 2001), an increasing trend in mean temperatures in the post-monsoon and winter seasons can be witnessed in the study. Agricultural burning, especially in the western region of India, forest fires along the Himalayan slopes and the addition of pollutants in the winter are the major driving factors behind the settling of black carbon.

The study further warns that as summer approaches, the continuation of forest fires and agricultural burning could trigger massive glacial melting in the Gangotri glacier. Moreover, researchers at Wadia Institute found a significant increase in the amount of black carbon in the atmosphere near the pilgrim town of Gangotri, Uttarakhand. This was witnessed during the two annual tourist seasons of April to June and September to October. Although tourism positively impacts the Himalayan economy, the trade-off lies in the fact that that it leads to the deterioration of the glacier’s wonder and beauty.

When the tourist season in May 2016 began, more than 87 thousand pilgrims visited the Gangotri Temple within the first 14 days. Additionally, the ongoing forest fires in the summer tourist season were active contributors to the rise of black carbon. The autumn tourist months of September and October reported the second-highest black carbon concentration while the lowest black carbon concentration was recorded during August, and then in December. The lack of observable tourist activities and forest fires during these months led to a lower black carbon concentration in the atmosphere.

As a result of biomass burning, the black carbon concentration was as high as 1,889 nanograms per cu.m (cubic meter). Automobiles and other sources also constituted for 1,180 nanograms per cu.m. This amount was 10 times larger than the concentrations of 168 nanograms per cu.m and 123 nanograms per cu.m that were reported during Augst, wherein black carbon concentration in the atmosphere was at a minimal level.

Why Black Carbon is bad? 

Black carbon is determinantal for our environment because it absorbs solar energy and in turn, warms the atmosphere. When black carbon falls to earth, mixed between rain, it blackens the surface of snow and ice, reducing their albedo (the reflecting power of a surface), and consequently warms the snow and catalyzes its melting.

The alarming rise of black carbon in the atmosphere is now receiving its due concern, especially from the Himalayan glaciated region that has a biologically sensitive ecosystem. The region comprises of different natural resources such as ice sheets, day off and alpine greenery that are all crucial for various environmental functioning, including the reviving of water bodies. Undoubtedly, any change in the atmosphere of the glacial Himalayan region, either due to black carbon or aerosols is bound to impact the natural resources their related functioning and purpose.

(Author is working with Research and Communications team at SDC Foundation. He tweets at AadarshAnand3)