Black Carbon: The Super Pollutant Erasing Asia's Glaciers

W. Syaban

March 29, 2025

Although CO2 receives most of the attention, black carbon's powerful but brief warming impact is causing Asian glaciers to surpass their critical thresholds.

A nearly invisible black dust is accelerating the melting of glaciers ranging from the Himalayas to the Arctic. This substance, known as black carbon—a “super pollutant” with significantly greater heat-trapping ability than carbon dioxide—is posing a severe threat to Earth’s water systems, with Asia being particularly affected.

PM2.5 contains tiny particles so small they can deeply infiltrate the lungs, causing significant harm to human health; among these, black carbon stands out for its high-efficiency ability to absorb sunlight lethally. Upon landing on snow and ice, this substance tints their surface darker, which increases heat uptake and prompts quicker glacier melting.

"Accelerated melting of glaciers leads to increased risks of flooding, water scarcity, and various environmental issues," said Khushboo Sharma, an air pollution analyst working with the International Centre for Integrated Mountain Development (ICIMOD) based in Kathmandu, during an interview with This Week in Asia.

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A fresh report released by the international charitable organization known as the Clean Air Fund has identified China and India As the globe’s biggest producers of black carbon, their power plants, steel and cement facilities, brick kilns, along with rice mills and sugar refineries, are releasing vast quantities of this contaminant. However, an additional source stands out as more significant.

The report stated that the residential sector is the main contributor to black carbon emissions in both China and India due to the extensive usage of conventional fuels for cooking and heating, which leads to significant pollution. It also noted that wildfires account for the majority of such emissions in Russia, whereas transportation is the leading cause in the United States.

In contrast to carbon dioxide, which remains in the atmosphere for hundreds of years, black carbon has a short existence lasting only days to weeks. Despite this brief period, its effects are severe. It contributes not only to glacier melt but also interferes with monsoons, intensifies extreme temperatures, and exacerbates floods.

The severity of this crisis is nowhere more pronounced than in the Hindu Kush Himalaya area, home to approximately 240 million individuals who rely on the glaciers for essential resources such as water, sustenance, and power. Spanning eight countries like China and India, these glaciers supply water to Asia’s ten major rivers, ranging from the Ganges to the Mekong. However, the ice is melting at an alarming pace never seen before.

The rising levels of black carbon, mainly due to vehicle exhausts, biomass combustion, and industrial processes, are causing these disturbances to occur more often and with greater intensity," Sharma stated. She noted that systematic tracking of black carbon remains inadequate; however, ICIMOD has assisted nations in gathering "data on black carbon from both city centers and mountainous regions.

Experts caution that the Hindu Kush Himalayan region might lose about half of its ice by 2100, with up to 70 to 80 percent of its glaciers disappearing if global temperatures exceed 2 degrees Celsius (3.6 degrees Fahrenheit) due to climate change.

According to Kang Shichang, who leads China's Institute of Mountain Hazards and Environment, an uptick of just 2 degrees makes conditions "far too warm for the glaciers." He stated, "[While we can’t halt glacial melting], we can decelerate it by cutting down on emissions." In an interview with This Week in Asia, he also emphasized that the opportunity for intervention is rapidly diminishing.

Asia is 'most vulnerable'

The outcomes of failing to act are severe. In only thirty years, global warming has caused the melting of approximately 14 trillion metric tons (13.8 trillion short tons) of ice, as stated in a factsheet published by the Hong Kong-based nonprofit organization CWR on March 21 to observe the World Day for Glaciers. The report highlighted that Asia faces the highest risk from increasing sea levels.

If emissions continue unabated, sea levels might rise by one meter (3.3 feet) by 2070, posing risks to major cities like Mumbai, Shanghai, Bangkok, and Hong Kong.

In the meantime, glacial lake outburst floods — which occur when full-to-bursting lakes break through their frozen confines — are happening more often. For instance, this occurred in August. Nepal 'Thyangbo glacier lake released a surge that engulfed settlements in the Khumbu area. A year earlier, South Lhonak glacier lake had caused flooding in India's Teesta River. killing 77 people and destroying communities in Sikkim.

Sudden outbursts of water from glacial lakes, along with destruction resulting from melting permafrost, are expected to intensify in the future," cautioned Miriam Jackson, who serves as the Eurasia and Nordic director for the International Cryosphere Climate Initiative. "These issues may render certain communities unlivable; however, some places are already facing this reality.

Chinese researchers stated earlier this year that all glaciers below 0.5 square kilometers (0.2 square miles) in size in northwestern China will vanish by mid-century. Recent data indicates that over the last six decades, the country’s overall glacier coverage has decreased by 26 percent.

According to the Global Glacier Casualty List project, glaciers across 19 nations, such as China and Nepal, have been categorized as either critically endangered, vanishing, or completely melted away.

Several nations are adopting innovative strategies to protect the remaining ice masses. In China, experiments involving thermal blankets have been conducted; these reflective covers minimize solar radiation and decrease glacial thawing. According to reports from 2020 to 2021, the use of these blankets decreased the melting pace of the Dagu Glacier by approximately 34%. However, scientists like Kang argue that such approaches offer only short-term solutions.

Dr. C.T. Low, who leads geospatial and scientific efforts at CWR, stated, " numerous nations in Southeast Asia have never witnessed ice sheets and glaciers, hence they may not fully grasp issues such as melting-related concerns, particularly rising sea levels."

The previous year marked the highest temperatures ever recorded globally, surpassing 1.5 degrees Celsius (2.7 degrees Fahrenheit) over pre-industrial averages. Although the Paris Accord set a target to limit warming to 1.5 degrees, the United Nations Environment Programme has cautioned that achieving this objective may be unattainable. Scientists assert that unless substantial reductions in emissions occur—decreasing them by 42% by 2030 and by 57% by 2035—we might face irreparable harm.

Jackson stated that the objective of limiting global warming to 1.5 degrees remains "certainly attainable" over the longer term, though this would necessitate both political commitment and efforts towards reducing carbon emissions.

The price of not meeting the objective continues to rise, and it will only increase further with time," she stated. "It’s crucial for governments worldwide to take greater steps towards addressing climate change. They must understand that this challenge belongs to them regardless of their location.