Levels of black carbon — ultra-fine particles of carbon that come from autos, stoves and wood-fire — within the Himalayas have been rising for many of the previous 20 years, in accordance with a examine by the think-tank Climate Trends. This is contributing to hotter snow, rising the chance of unseasonal flooding by glacier-fed rivers, it mentioned.
While not a peer-reviewed evaluation, the examine analysed satellite-based measurements of black carbon and adjustments within the temperature of snow between 2000 and 2023. Climate science says that aerosols — particulate matter emissions from quite a lot of sources, from fertiliser to automobile exhaust — clog the environment, deflecting daylight away from the carbon and are identified to masks the heating impact of greenhouse gases.
Black carbon is totally different, in that it absorbs daylight and if it settles on the floor can thus warmth the bottom. This is one purpose climatologists think about black carbon as a catalyst to world warming, regardless that it’s comparatively short-lived within the environment in contrast to carbon dioxide, probably the most pervasive greenhouse gasoline.
Reduces daylight reflection
“The snow surface temperature in the Himalayas has shown a consistent warming trend over the past two decades, which may have serious implications for snow and glacier stability,” the examine notes. The common snow-surface temperature has elevated from -11.27°C from 2000–2009 to -7.13°C throughout 2020–2023, with an total imply of -8.57°C for the 23-year interval.
Among the three main areas, the Eastern Himalayas report the warmest snow surfaces, adopted by the Central and Western Himalayas. This warming was “likely driven,” the examine surmised, partially by the deposition of light-absorbing particles like black carbon, which lowers snow albedo — the power to replicate daylight — and accelerates floor heating. The decadal common for 2010–2019 confirmed the best warming within the Eastern Himalayas at -5.69°C.
Accelerating glacier soften
“Continued temperature rise in snow-covered areas can shorten snow season duration and advance melting onset, impacting hydrological systems and water security for millions downstream. Thus, temperature increases, in conjunction with [black carbon] BC presence, are significantly altering the snow thermal regime in the Himalayas,” the examine underlined.
“Glacier melt is accelerating, threatening freshwater resources to nearly two billion people downstream,” Palak Baliyan, lead writer of the examine, mentioned in an announcement.
Snow depth rises
There is not any direct correlation between black carbon concentrations and ‘snow depth’, a measure of the thickness of snow. In reality, this truly elevated throughout the examine interval, with spatial and temporal variability. The imply snow depth elevated from 0.059 m throughout 2000–2009 to 0.117 m throughout 2020–2023, leading to a 23-year common of 0.076 m.
“The increase in snow depth despite rising temperatures could be attributed to factors like increased snowfall events, seasonal precipitation changes, or measurement uncertainties due to surface snow redistribution by wind. The Western Himalaya exhibited the highest snow depths, possibly due to its higher elevations and greater exposure to western disturbances that bring winter precipitation. Meanwhile, the Eastern and Central Himalayas, closer to BC sources, showed lower snow depths. This variability in snow depth highlights the complex interplay of climatic and atmospheric factors influencing snow-pack dynamics across the Himalayan arc,” the examine notes.
The main mills of black carbon embody biomass combustion, fossil gasoline use, and open burning, significantly within the Indo-Gangetic plain, which acts as a hotspot for emissions. Previous research have reported that biofuel use alone accounts for almost 42% of black carbon emissions in India, with States like Madhya Pradesh and Maharashtra contributing considerably via forest and agricultural fires, in accordance with the examine.
Published – May 31, 2025 02:50 am IST
