Publications by authors named "Poonam Thapa"

To achieve the Paris Agreement, China pledged to become "Carbon Neutral" by the 2060s. In addition to massive decarbonization, this would require significant changes in ecosystems toward negative CO emissions. The ability of coastal blue carbon ecosystems (BCEs), including mangrove, salt marsh, and seagrass meadows, to sequester large amounts of CO makes their conservation and restoration an important "nature-based solution (NbS)" for climate adaptation and mitigation.

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The recent substantial expansion of human activities in northeast (NE) China has resulted in increased emission of environmental pollutants. Longer-term records of such environmental pollutants provide a benchmark against which it is possible to evaluate the nature, extent and timing of anthropogenic environmental changes. Based on measurements of mercury (Hg) concentrations and accumulation rates in 11 lake sediment cores from the Songnen Plain in NE China, we here present a reconstruction of the historical deposition of Hg as an indicator of the changing scale of human impact.

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Tibetan Plateau (TP) is an important geographical region for investigating the long-range transport of pollutants as limited emission sources exist in this region. In this study, based on analysis of 61 surface samples, we report the spatial distribution and concentrations of BC, Hg, total organic carbon (TOC) and inorganic carbon (IC) in surface sediments of Selin Co, the largest lake in central Tibet. The mean BC and Hg concentrations were 0.

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Recent studies have revealed the abundance of dissolved organic matter (DOM) in snow/glaciers of the Tibetan Plateau (TP). Here, we present a comprehensive study on the chemical compositions of snowpit samples collected from widely distributed eight glaciers in the western China (six from the TP) to investigate the spatial variation of deposited atmospheric aerosols. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to chemically characterize the DOM in snow samples which can offer chemical properties of DOM.

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Article Synopsis
  • Black carbon (BC) is a significant factor in climate change, and measuring its presence in environments like the Himalayan-Tibetan Plateau (HTP) is essential for understanding historical trends.
  • Analysis of BC concentration from six lake sediments in the HTP reveals a notable increase in BC deposition, particularly since the 1950s, aligning with the rise in human activities during industrialization.
  • The primary source of BC is identified as biomass burning, supported by evidence of open-fire events, and the trend shows that BC emissions are continuing to rise, especially from South Asia.
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