Black carbon deposits coming from industries, vehicles, and cooking practices aggravate climate change’s adverse impacts to accelerate the melting of glaciers in the Himalayas, the Hindu Kush, and the Karakorum (HKHK) ranges, a new World Bank report has concluded.

As countries around the globe mark ‘World Environment Day’ on Saturday, the findings come as another warning for Nepal and other countries of the HKHK mountain ranges, where impacts of climate change are becoming more visible in recent years.

The HKHK region spans 2,400 kilometres across six nations—Afghanistan, Bhutan, China, India, Nepal, and Pakistan.

The report, ‘Glaciers of the Himalayas: Climate Change, Black Carbon and Regional Resilience’, states that along with rising temperatures and changing rainfall patterns, black carbon deposits—air-borne particles generated by incomplete combustion from brick kilns, diesel exhaust, and the burning of biomass—are speeding up glacier and snowmelt in these ranges.

“Rising temperature has already been contributing to faster melting of glaciers in the mountain. Even various studies have shown the global temperature rise will be much higher in the Himalayan region,” Arun Prakash Bhatta, an undersecretary with the Ministry of Forests and Environment, told the Post. “Besides, black carbon, which absorbs radiation and converts to heat, as shown by the study, adds another challenge for us.”

The impacts of global warming and climate change already witnessed on the region’s mountains are further multiplied by black carbon emissions, which is the second most significant anthropogenic agent of climate change.

Studies have shown that black carbon can have a greenhouse effect two-thirds that of carbon dioxide (CO2), and greater than methane. Black carbon or soot is a short-lived pollutant and the second-largest contributor to warming the planet.

Black carbon is an essential contributor to warming because it effectively absorbs light and heats its surroundings. As per estimates, black carbon has a warming impact on climate that is several hundred times stronger than CO2.

In terms of its effects on mountains, black carbon can increase glacial melt by decreasing surface reflectance of radiation and increasing air temperature.

Once black carbon is deposited on the surface of snow and ice, it increases the absorption of solar radiation by decreasing the surface albedo (the ability to reflect sunlight) of the glacier surface. As the area heats up, snow melts faster.

Likewise, circulating black carbon raises air temperatures before it is deposited, ultimately playing a part in fast-melting snow cover in the mountains.

Such a trend can spell negative consequences to the region and hundreds of millions of people dependent upon these mountain ranges for their needs, the study has warned.

Glaciers have been crucial to the balance of the ecosystem and ensuring ecosystem services to the people living downstream.

“Glaciers help to moderate flows in the region’s major rivers by providing a source of meltwater in hot, dry years and storing water during colder, wetter years,” read the report. “Himalaya, Karakoram, and Hindu Kush mountain ranges of South Asia, which contain almost 55,000 glaciers, store more freshwater than anywhere but the North and South Poles.”

According to the study, melting glaciers and loss of seasonal snow pose significant risks not just to the people who live in the mountains but also to the stability of water resources in the South Asia region more broadly.

It is estimated that more than 750 million people depend on the glacier and snow-fed Indus, Ganges, and Brahmaputra rivers for freshwater. The report warns that changes in the volume and timing of flows could have crucial economic and social implications for the people of the region.

“Melting of glaciers at an accelerated rate is perhaps the biggest threat for countries like Nepal. Black carbon covering all over these snow-capped mountains will be disastrous for us,” said Bhatta, the official at the Climate Change Management Division of the Environment Ministry. “Such melting of glaciers will not only threaten our water security with the decline in the volume of water stored in these mountains but also lead to various disasters like floods and landslides.”

A 2019 study, which assessed the world’s 78 mountain glacier-based water systems for the first time and ranked their significance to the downstream communities and their vulnerabilities in terms of various factors, including future changes, concluded that over 1.9 billion people could face water shortage in future.

People relying on mountains for meeting their water needs would face an acute shortage of water because water stored in those water towers is quickly disappearing due to rising demands and excessive melting of glaciers accelerated by climate change, the study had concluded.

According to the World Resources Institute, from 1.5 billion to 1.7 billion people or 70–81 percent of the population in South Asia are projected to be exposed to water scarcity by 2050.

Another World Bank report in 2018 estimated that rising temperatures and changing patterns of monsoon rainfall due to climate change could lower the living standards of half the regional population by 2050.

Besides the scarcity of water, the latest study warns that the melting of glaciers threatens both local glacier-related tourism and infrastructure that facilitates tourism as well as other physical infrastructure.

The rapid shrinking and retreating of glaciers influence the formation and expansion of glacial lakes, multiplying the risk of glacial lake outburst floods (GLOFs).

The region where dangerous glacial lakes have been identified and are ticking like a time bomb can cause massive damage to physical infrastructure and cause loss of human lives and livelihoods downstream.

A decade-old study had estimated the damages from potential GLOFs for three major glacier lakes in Nepal ranging from US$2.2 billion to US$8.98 billion.

These consequences will only get worse unless greater efforts are made to curb black carbon deposits that are accelerating melting, according to the study.

“Recent devastating flash floods attributed to a collapsing glacier in the Himalayas were a sobering reminder of the sometimes disastrous effects of climate change and the dangers we have to protect against,” Hartwig Schafer, World Bank vice president for South Asia, was quoted as saying in its press release. “As glaciers shrink, the lives and livelihoods of many people downstream are affected by changes in the water supply. We can slow glacier melt by collectively acting to curb the black carbon deposits that are speeding the thinning of the ice.”

Unlike other climate-warming greenhouse gas emissions, black carbon is quickly washed out and can be eliminated from the atmosphere if its emissions stop, giving hope for limiting its impacts on mountains. Lower emissions of black carbon can also improve human health around the world.

But, the business-as-usual practices would not make any difference but rather speed up glacier melt, with harmful implications for the health and well-being of people in the region, the study cautioned.

“Regional cooperation to protect these resources will pay important dividends for the health and well-being of the people in the region,” said Schafer.

The major finding of the Glaciers of the Himalayas report is that fully implementing current black carbon emissions policies in South Asia can reduce its deposition in the region by almost one quarter.

Existing policies to limit black carbon emissions—through enhancing fuel-efficiency standards, phasing out diesel vehicles and promoting electric cars—although laudable, are not enough to prevent an acceleration of water releases from glacier melt in the region.

An additional 50 percent emission of black carbon can be reduced by enacting and putting in place new policies that are currently economically and technically feasible, said the report.

“The mountain region also has two biggest emitters India and China. Countries need to adopt a clean development mechanism and clean energy resources for reducing the emission of greenhouse gases like black carbon,” said Bhatta.

Improving the efficiency of brick kilns, which account for roughly half of black carbon emissions, would reduce melt-accelerating deposits. Cleaner cookstoves and cleaner fuels are another key way to reduce black carbon emissions, suggested the study. Likewise, incentivising households to switch from biomass or coal to liquefied petroleum gas (LPG), and, in the long run, to solar energy could help the region cut down black carbon emission.

What makes it more urgent for countries in the region to act quickly is not only they are mountainous countries battling impacts of climate change, but also the fact that South Asia is at the global epicentre of the generation and adverse impacts of air pollution.

The study has pointed out that regional cooperation will be necessary for fully addressing the challenges associated with the melting glaciers of the Himalayas, which is a transboundary task and goes beyond the scope of a single country’s policymakers.

“Water resource management policies must evolve because the trends we are observing point to a different and more challenging future,” said Muthukumara Mani, lead economist in the World Bank’s South Asia region and a lead author of the report. “Success will require an active and agile cooperation between researchers and policymakers so both groups can continue to learn about the problems at hand.”