Black carbon aerosols, products of fossil fuel and biomass incomplete combustion, possess strong light-absorbing properties, ranking second only to carbon dioxide as a major atmospheric warming climate forcing agent. Deposition of black carbon onto snow and ice surfaces reduces reflectivity, accelerating the melting of glaciers and snow, thereby altering regional hydrological processes and water resource availability. The Tibetan Plateau harbors some of China's most extensive frozen regions, and under global warming, many glaciers on the plateau are undergoing accelerated retreat, with the influence of light-absorbing impurities such as black carbon being significant.
Recently, significant progress has been made by the research team at the Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, in studying the sources and impacts of black carbon aerosols in the southeastern Tibetan Plateau. This finding holds vital importance for a deeper understanding of glacier melting phenomena on the Tibetan Plateau and global climate change. The relevant paper was published in the Science of the Total Environment journal.
The research team conducted intensified monitoring of black carbon aerosols in the Mingyong Glacier region of the Meili Snow Mountain and quantitatively analyzed the sources and climatic effects of black carbon aerosols using the regional climate-chemistry coupled model WRF-Chem. It was found that the annual average concentration of black carbon aerosols in the Mingyong Glacier region is much higher than that in the inland Tibetan Plateau (415 ± 372 ng m-3), showing significant seasonal variations, reaching peak values in April (monthly average: 930 ± 484 ng m-3). Black carbon aerosols exhibit a bimodal diurnal variation pattern, with the most pronounced changes occurring in spring, indicating significant influences of climate conditions on the sources, transport, and boundary layer thickness of black carbon aerosols.
It is noteworthy that South Asia and Southeast Asia, adjacent to the Tibetan Plateau, are among the globally high-emission regions of black carbon. Researchers introduced that black carbon aerosols emitted from these regions can cross the Himalayas and be transported over long distances to the inland Tibetan Plateau, contributing over 60% to the black carbon aerosols on the plateau, primarily affecting the southern and central regions of the plateau. This finding offers a new perspective on understanding the sources of black carbon aerosols on the Tibetan Plateau.
Furthermore, black carbon aerosols emitted from South Asia and Southeast Asia generate positive radiative forcing in the atmosphere of the Tibetan Plateau, further exacerbating the warming effect in the region. The seasonal variations of this radiative forcing were also revealed in the study, with significant values observed in winter and summer.
The research results not only deepen our understanding of the content, variations, sources, and impacts of black carbon aerosols in typical glacier regions of the Tibetan Plateau but also provide valuable references for further exploring the climatic effects of light-absorbing impurities such as black carbon and international cooperation on black carbon emission reduction. Against the backdrop of global efforts to combat climate change, this discovery holds significant implications for promoting international cooperation, jointly reducing black carbon emissions, and protecting the Tibetan Plateau, known as the "Asian Water Tower."
Related paper information:
https://doi.org/10.1016/j.scitotenv.2024.172262
Cross-border input of black carbon contributes to radiative forcing in the atmosphere of the research area. Image courtesy of Northwest Institute of Eco-Environment and Resources.
