Researchers report a 200-year record of atmospheric sulfur cycling in the Himalayas. Increasing aerosol concentrations over the Himalayas and Tibetan Plateau (HTP) have affected the regional climate, which in turn affects water supply and quality for more than 1 billion people. A shortage of data has led to uncertainty in the sources of these aerosols. Mang Lin and colleagues analyzed sulfur isotopes in a 200-year sediment core from a Himalayan lake. The core showed that atmospheric sulfate concentrations began steadily increasing at the end of the Second Industrial Revolution in the early 20th century. Post-1930 sulfur isotope ratios indicated that the increased sulfate did not originate directly from combustion emissions or from stratospheric photochemical reactions. Instead, it likely formed through oxidation of anthropogenic sulfur dioxide on the surface of mineral dust, anthropogenic dust emissions, or climate-induced enhancements in weathering and erosion. According to the authors, the results carry implications for understanding climate change in the HTP region. Sulfur isotope ratios from the 19th century, which likely reflect extensive biomass burning, resembled those observed in 3.6-3.2 billion-year-old Archean barite, thereby shedding light on atmospheric chemistry during the period when life first emerged, according to the authors.
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Article #18-01935: "Atmospheric sulfur isotopic anomalies recorded at Mt. Everest across the Anthropocene," by Mang Lin et al.
MEDIA CONTACT: Mang Lin, Tokyo Institute of Technology, JAPAN; tel: +86-13570398203; e-mail: m6lin@ucsd.edu; Mark H. Thiemens, University of California, San Diego, La Jolla, CA; tel: 858-534-6882, 858-344-3084; e-mail: mthiemens@ucsd.edu
Journal
Proceedings of the National Academy of Sciences