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  • 1
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    Geosciences, Vol. 9, Pages 232: Permafrost Degradation within Eastern Chukotka CALM Sites in the 21st Century Based on CMIP5 Climate Models (2019)
    MDPI
    Details
    Publication Date: 2019
    Description: Permafrost degradation caused by contemporary climate change significantly affects arctic regions. Active layer thickening combined with the thaw subsidence of ice-rich sediments leads to irreversible transformation of permafrost conditions and activation of exogenous processes, such as active layer detachment, thermokarst and thermal erosion. Climatic and permafrost models combined with a field monitoring dataset enable the provision of predicted estimations of the active layer and permafrost characteristics. In this paper, we present the projections of active layer thickness and thaw subsidence values for two Circumpolar Active Layer Monitoring (CALM) sites of Eastern Chukotka coastal plains. The calculated parameters were used for estimation of permafrost degradation rates in this region for the 21st century under various IPCC climate change scenarios. According to the studies, by the end of the century, the active layer will be 6–13% thicker than current values under the RCP (Representative Concentration Pathway) 2.6 climate scenario and 43–87% under RCP 8.5. This process will be accompanied by thaw subsidence with the rates of 0.4–3.7 cm∙a−1. Summarized surface level lowering will have reached up to 5 times more than current active layer thickness. Total permafrost table lowering by the end of the century will be from 150 to 310 cm; however, it will not lead to non-merging permafrost formation.
    Electronic ISSN: 2076-3263
    Topics: Geosciences
    Published by MDPI
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  • 2
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    Geosciences, Vol. 9, Pages 67: Methane in Gas Shows from Boreholes in Epigenetic Permafrost of Siberian Arctic (2019)
    MDPI
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    Publication Date: 2019
    Description: The gas shows in the permafrost zone represent a hazard for exploration, form the surface features, and are improperly estimated in the global methane budget. They contain methane of either surficial or deep-Earth origin accumulated earlier in the form of gas or gas hydrates in lithological traps in permafrost. From these traps, it rises through conduits, which have tectonic origin or are associated with permafrost degradation. We report methane fluxes from 20-m to 30-m deep boreholes, which are the artificial conduits for gas from permafrost in Siberia. The dynamics of degassing the traps was studied using static chambers, and compared to the concentration of methane in permafrost as analyzed by the headspace method and gas chromatography. More than 53 g of CH4 could be released to the atmosphere at rates exceeding 9 g of CH4 m−2 s−1 from a trap in epigenetic permafrost disconnected from traditional geological sources over a period from a few hours to several days. The amount of methane released from a borehole exceeded the amount of the gas that was enclosed in large volumes of permafrost within a diameter up to 5 meters around the borehole. Such gas shows could be by mistake assumed as permanent gas seeps, which leads to the overestimation of the role of permafrost in global warming.
    Electronic ISSN: 2076-3263
    Topics: Geosciences
    Published by MDPI
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  • 3
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    Atmosphere, Vol. 8, Pages 105: Cryogenic Displacement and Accumulation of Biogenic Methane in Frozen Soils (2017)
    MDPI Publishing
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    Publication Date: 2017-06-16
    Description: Evidences of highly localized methane fluxes are reported from the Arctic shelf, hot spots of methane emissions in thermokarst lakes, and are believed to evolve to features like Yamal crater on land. The origin of large methane outbursts is problematic. Here we show, that the biogenic methane (13C ≤ −71‰) which formed before and during soil freezing is presently held in the permafrost. Field and experimental observations show that methane tends to accumulate at the permafrost table or in the coarse-grained lithological pockets surrounded by the sediments less-permeable for gas. Our field observations, radiocarbon dating, laboratory tests and theory all suggest that depending on the soil structure and freezing dynamics, this methane may have been displaced downwards tens of meters during freezing and has accumulated in the lithological pockets. The initial flux of methane from the one pocket disclosed by drilling was at a rate of more than 2.5 kg C(CH4) m−2 h−1. The age of the methane was 8–18 thousand years younger than the age of the sediments, suggesting that it was displaced tens of meters during freezing. The theoretical background provided the insight on the cryogenic displacement of methane in support of the field and experimental data. Upon freezing of sediments, methane follows water migration and either dissipates in the freezing soils or concentrates at certain places controlled by the freezing rate, initial methane distribution and soil structure.
    Electronic ISSN: 2073-4433
    Topics: Geosciences
    Published by MDPI Publishing
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  • 4
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    Estimation and Sensitivity of Carbon Storage in Permafrost of North-Eastern Yakutia (2017)
    Wiley
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    Publication Date: 2017-01-11
    Description: Organic carbon derived from permafrost can provide a substrate for greenhouse gas production where the buried carbon pool thaws and mobilizes into biogeochemical cycles. Much attention has focused on the permafrost carbon of the Yedoma region of Siberia due to the wide distribution of organic and ice-rich deposits. Here, we present a new estimation of carbon storage in the upper 25 m of permafrost in north-eastern Yakutia based on a novel database of total carbon (TC) content, bulk density and ice content of permafrost, and a new map of Quaternary deposits derived from drilling data. The stratigraphic units contain 0.6–2.1% TC, with the highest concentrations in the Holocene cover layer and Late Pleistocene Yedoma superhorizon. The largest carbon pool is found in the Pliocene/Middle Pleistocene Olyor superhorizon. The TC pool of Yedoma is estimated to be 1.5–2 times less than that calculated previously. The TC pool of the study area is 31.2 ± 15.2 Pg C spread across 88 000 km 2 , with a mean specific carbon content of approximately 14.3 kg C m −3 . Carbon storage is estimated excluding the ice-wedge volume and, due to the limited data for Yedoma and Alas deposits, we present a maximal assessment of the carbon pool for the Yedoma region. Refinement of the size of the Yedoma TC pool is critical for quantifying the scale of permafrost feedback to the carbon cycle. Copyright © 2017 John Wiley & Sons, Ltd.
    Print ISSN: 1045-6740
    Electronic ISSN: 1099-1530
    Topics: Geography , Geosciences
    Published by Wiley
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  • 5
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    CACCON and Partner Knowledge Networks: Arctic Coastal Engagement Network of Future Earth Coasts (2016)
    In:  EPIC3Arctic Science Summit Week 2016 ASSW, Fairbanks, Alaska, USA, 2016-03-12-2016-03-18
    Details
    Publication Date: 2018-08-24
    Description: The Circumpolar Arctic Coastal Communities Observatory Network (CACCON) functions as the Arctic Regional Engagement Network for Future Earth Coasts. In partnership with other Arctic knowledge networks and programs, including the Exchange for Local Observations and Knowledge of the Arctic (ELOKA) and Arctic-COAST, CACCON promotes consensus and collaboration to advance local knowledge availability and accessibility for adaptation planning and sustainable development in Arctic coastal communities and regions. Components of the CACCON agenda include: integrative analyses of sustainability challenges in Arctic coastal communities using co-developed situational and sustainability indicators; solutions-oriented research for actionable, proactive adaptation policies in Arctic coastal communities; sharing insights among existing community-based research and resilience programs; responding to community-based agendas and building resilience by growing local and regional knowledge co-production and dissemination capacity. These activities support the Global Coastal Futures initiative of Future Earth Coasts, rooted in the Future Earth principles of co-design and co-production of knowledge involving a broad cross-section of stakeholders and consensus-building on pathways for transformation to more sustainable strategies for enhanced present and future well-being on Arctic coasts.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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