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The glaciers in the western Himalayas, source of water for Jammu, Kashmir and Ladakh, have been melting at a significant rate due to the growing amount of black carbon aerosol and greenhouse gases, which is leading to the darkening of the region’s snowpack, researchers have found in various studies.

In a recent study, around 77 glaciers in the Drass basin of the Ladakh region were evaluated using satellite data. The study was used to investigate the shrinkage, snout retreat, ice thickness changes, mass loss and velocity changes of these glaciers between 2000 to 2020.

The findings indicated that glaciers in the Drass region have thinned by 1.27 metres between 2000-2020. Besides soaring regional temperatures, research indicates that the region’s black carbon (or soot, a component of particulates) increased from 330 nanograms to 680 nanograms from 1984-2020.

Around 77 glaciers in the Drass basin of the Ladakh region were evaluated using satellite data. The findings indicate that the glaciers have thinned by 1.27 metres between 2000 and 2020. Credit: Shakil A Romshoo via Mongabay.

Earth Scientist and glaciologist, Shakil Ahmad Romshoo, who has co-authored this study, said that there is a direct link between black carbon and the melting of glaciers.

“Climate change has two components — one is natural and another is anthropogenic. Broadly, anthropogenic climate change is all about increasing greenhouse gases and pollutants the world over,” Romshoo said. Through this study, “we have tried to establish a link between greenhouse gases, black carbon and increased glacial melt in the Himalayas,” he said.

“Black carbon deposition on glaciers decreases the reflectivity of ice surface resulting in faster ice melt. Likewise, increasing black carbon concentration in the atmosphere, increases radiative forcing and upon deposition on glaciers absorbs solar radiation, ultimately playing a part in fast-melting of snow cover and glaciers in the mountains,” he said.

Romshoo emphasised that the proximity of the glaciers to the National Highway, in the Drass region of the Himalayas in Ladakh, is another factor for the increased melting of the glaciers as there is an increasing concentration of black carbon from vehicular emissions.

“In Kashmir, a major factor for the increase in black carbon is the burning of pruned branches of orchard trees in autumn and woody biomass for heating in winter mainly driven by economic considerations as the horticulture sector gives five-six times more monetary benefits to farmers than paddy cultivation,” he said.

According to Department of Horticulture, Jammu and Kashmir data, the area under the horticulture sector has increased by over 400% in the valley since 1974. Figures accessed by this correspondent revealed that in 1974-’75, the area under horticulture cultivation was 82,486 hectares in the Union Territory. It increased to 2,19,039 hectares in 2001. In 2020, the area under horticulture jumped to 3,30,956 hectares.

Irfan Rashid, Coordinator, Department of Geoinformatics, University of Kashmir, also echoed the views of professor Romshoo. He said, “Science funders, including the Department of Science and Technology, Ministry of Earth Sciences and MoEF&CC, should launch comprehensive coordinated programs aimed at establishing ambient black carbon observatories near glacier sites across the Indian Himalayan region with contrasting topography, diverse climates and varying anthropogenic footprint.”

He added, “despite improvements in our understanding of the behaviour of Himalayan glaciers to changes in environmental factors, key knowledge about black carbon concentration in glacier ice or influences from microbial life on glaciers remains elusive”.

A 2021 paper estimated the particulate matter, or PM, data for five years (2012-’17) at Srinagar, Kashmir, to examine the temporal variability, meteorological impacts and potential source regions of particulate matter, a mixture of solid particles and liquid droplets found in the air. It includes inhalable PM10, with diametres that are generally 10 microns and smaller, and finer PM2.5.

The study stressed that Srinagar has the highest concentration of PM compared to other Himalayan states. “Further, according to the study, the annual PM10 and PM2.5 concentrations were two to three times higher than India’s annual National Ambient Air Quality Standards (PM10 = 60 μg/m3 and PM2.5 = 40 μg/m3) in autumn and winter.”

Romshoo said that Kashmir has a valley-like setup surrounded by mountains on all sides. “As a result, haze develops in autumn and winters, in the lower troposphere over the Kashmir valley that restricts the vertical dispersion of pollutants. Besides, mostly biomass burning of the predominantly pruned branches from orchards takes place at this time. The haze can settle on the glaciers and can exacerbate glacier melt,” Romshoo added.

Glacier water flows in Ladakh's Markha Valley. Chris Hunkeler from Carlsbad, California, USA, CC BY-SA 2.0, via Wikimedia Commons.

He pointed out that the pruned branches of orchard trees can be converted into high calorific wood pellets, which would help to meet the demand for wood for heating during harsh winters when the temperature dips to several degrees below zero in the valley.

The wood pellets will lessen the burning impacts and can also be used in hamams, a room within a home that serves as a traditional space heating arrangement in Kashmir. “The heating value of pellets is more and could be an efficient way to reduce deforestation and emission of black carbon,” Romshoo said.

The long-term consequences of shrinking glaciers, Romshoo said, will affect the downstream community in the Indus basin, which encompasses the Union Territory of Jammu and Kashmir, states Himachal Pradesh, Punjab and a part of Rajasthan, Haryana, and Union Territory of Chandigarh, having an area of 3,21,289 square kilometres, nearly 9.8% of the total geographical area of the country. The Indus is the westernmost river system in the subcontinent. Jhelum, Chenab, Ravi, Beas and Satluj are its main tributaries.

“Most importantly, we have more than 12,000 glaciers in the Jammu, Kashmir and Ladakh region, which forms the Upper Indus Basin [UIB]. The melt waters, emanating from these glaciers in the UIB meet about 80% water demands of neighbouring Pakistan. Therefore, the melting glaciers, if the causes are not understood in the right perspective, might affect the security situation in South Asia because of the transboundary nature of the rivers,” said Romshoo.

Anil V Kulkarni, a distinguished visiting scientist at Divecha Centre for Climate Change, Indian Institute of Science, Bengaluru, said that the ability of the snow to reflect solar radiation is very high. “When the pollutants fall on the snow, that ability is significantly reduced. That means snow will start to melt very fast.”

“On top of that,” Kulkarni said, “climate change, particularly the faster rise in winter temperatures and high particulate load force early snow melt.” Once it melts early, he emphasised that it has many implications on the ecology and community of the region.

“One major factor is that the mountain springs start to dry up early. We have a perfect balance in the Himalayas where in wintertime, we have snowfall and in springtime, it melts, and the water percolates in the ground. After that, the monsoon comes. So there is a gap between the departure of snow and the arrival of the monsoon. Because of increasing air pollution, two things happen – mountain springs dry early and creates scarcity for communities that are living in the mountains. Second thing, it also dries up mountain forests resulting in the early arrival of forest fire season,” he added.

He said early snowmelt will have a profound impact on communities living, particularly in the mountain of the Indus basin. “It has many facets. There will be a change in seasonality and availability of water, and how it will affect the agricultural practices needs to be seen,” Kulkarni said.

Hydrologist Sharad Jain said that rising air pollution and aerosols in the western Himalayas are likely to impact precipitation and, thereby, river flows, hydropower development, agriculture, and other sectors.

Glaciers in the Drass region. Credit: Shakil A Romshoo via Mongabay.

“Due to faster snow/glacier melt caused by global warming, we might witness high flows in the near future. Unless properly harnessed, higher flows may cause more flood damages,” said Jain, former director, National Institute of Hydrology, Roorkee, India, and currently a visiting professor at the Indian Institute of Technology in Roorkee.

But, as the glaciers recede, after some time, the river flows may decline, leading to falling hydropower generation, crop production, and so on. Rising rainfall intensities will lead to increased sediment movement in rivers. This, in turn, may damage hydropower plants; river beds will be affected by higher sediment deposition,” he said.

Kulkarni said the communication between the scientific community and policymakers is very limited. “We need to redefine the research goals where the socially relevant issues can be taken and should try to do the research in that direction. Also, the snow and glaciers studies need to be fully institutionalised, and funding should be increased.”

Jain stressed that the development and timely implementation of policies remains a challenge. “The connection between policy and actual groundwork is not very strong. There are many opportunities to construct small hydro-projects on various rivers of Jammu and Kashmir and generate electricity. It would help to engage stakeholders more closely in decision-making. Also, increased scientific efforts are needed to monitor the glaciers and rivers in J&K and understand their hydrologic behaviour.”

This article was first published on Mongabay.