A study has found that black carbon aerosols indirectly affect the mass gain of Tibetan Plateau glaciers by altering long-range Water vapor transport from the South Asian monsoon region.
The South Asia region adjacent to the Tibetan Plateau has the highest levels of black carbon emissions in the world, the researchers said.
Black carbon aerosols originate from the incomplete combustion of fossil fuels and biomass and are characterized by strong light absorption.
Several studies have emphasized that black carbon aerosols from South Asia may be transported across the Himalayas to the inland region of the Tibetan Plateau.
The accumulation of black carbon in ice lowers the albedo of surfaces – how much of the Sun’s radiation is reflected – which can accelerate the melting of glaciers and ice caps, thus affecting hydrological processes and climate change in the region, the researchers said. Can replace water resources.
The study, published in Nature Communications, found that since the 21st century, South Asian black carbon aerosols have indirectly affected the mass gain of Tibetan Plateau glaciers by altering long-range Water vapor transport from the South Asian monsoon region.
“Black carbon aerosols over South Asia warm the middle and upper atmosphere, increasing the north-south temperature gradient,” said Kang Shichang, a professor at the Chinese Academy of Sciences (CAS).
“Accordingly, convective activity increases over South Asia, which causes Water vapor to converge over South Asia. Meanwhile, black carbon also increases the number of cloud condensation nuclei in the atmosphere,” Shichang said.
These changes in meteorological conditions caused black carbon aerosols to create more water vapor as precipitation over South Asia and the northward transport to the Tibetan Plateau was weakened, the researchers said.
As a result, rainfall is reduced in the central and southern Tibetan Plateau during the monsoon, especially in the southern Tibetan Plateau, he said.
The reduction in precipitation leads to a reduction in the mass gain of glaciers.
From 2007 to 2016, 11 per cent of the average glacier mass loss on the Tibetan Plateau and 22.1 per cent in the Himalayas were largely due to a decrease in precipitation.
“Transboundary transport and deposition of black carbon aerosols from South Asia accelerate glacier ablation on the Tibetan Plateau.
“Meanwhile, the reduction in summer precipitation over the Tibetan Plateau will reduce the mass gain of plateau glaciers, leading to a reduction in glacier mass,” Shichang said.