B027-08
Subsea Permafrost Carbon Stocks and Climate Change Sensitivity Estimated by Expert Assessment
Tuesday, 8 December 2020: 17:58
Virtual
Sayedeh Sara Sayedi1, Benjamin W Abbott1, Brett Thornton2, Jennifer Mary Frederick3, Jorien Vonk4, Paul Overduin5, Christina Schaedel6, Edward Schuur7, Annie Bourbonnais8, Nikita Demidov9, Anatoly Gavrilov10, Shengping He11, Gustaf Hugelius12, Martin Jakobsson13, Miriam Jones14, DongJoo Joung15, Gleb Kraev16, Robie W Macdonald17, Anthony David McGuire18, Mu Cuicui19, Matt O'Regan13, Kathryn M Schreiner20, Christian Stranne13, Elena Pizhankova21, Alexander Vasiliev22, Sebastian Westermann23, Jay P Zarnetske24, Tingjun Zhang25, Mehran Ghandehari26, Sarah Baeumler27, Brian Brown1 and Rebecca Josephine Frei28, (1)Brigham Young University, Provo, UT, United States, (2)Stockholm University, Stockholm, Sweden, (3)Sandia National Laboratories, Albuquerque, NM, United States, (4)Vrije Universiteit Amsterdam, Amsterdam, Netherlands, (5)Alfred Wegener Institute Hemlholtz Centre for Polar and Marine Research, Potsdam, Potsdam, Germany, (6)Northern Arizona University, Flagstaff, AZ, United States, (7)Northern Arizona University, Center for Ecosystem Science and Society, Flagstaff, AZ, United States, (8)University of South Carolina, School of the Earth, Ocean & Environment, Columbia, SC, United States, (9)Arctic and Antarctic Research Institute, St. Petersburg, Russia, St. Petersburg, Russia, (10)Lomonosov Moscow State University, faculty of geology, Moscow, Russia, Moscow,, Russia, (11)University of Bergen, Department of Geoscience, The Faculty of Mathematics and Natural Sxiences, Norway, Bergen, Norway, (12)Stockholm University, Department of Physical Geography, Stockholm, Sweden, (13)Stockholm University, Department of Geological Sciences, Stockholm, Sweden, (14)U.S. Geological Survey., Reston, VA, United States, (15)University of Rochester, Dept of Earth & Environmental Sciences, Rochester, NY, Rochester, United States, (16)Russian Academy of Sciences, Institute of Physicochemical and Biological Problems of Soil Science, Moscow, Russia, Soil Cryology, Pushchino, Russia, (17)Inst Ocean Sciences, Sidney, BC, Canada, (18)Univ Alaska Fairbanks, Fairbanks, AK, United States, (19)Lanzhou University, College of Earth and Environmental Sciences, Gansu, China, Gansu, China, (20)University of Minnesota Duluth, Large Lakes Observatory, Duluth, MN, United States, (21)Lomonosov Moscow State University, faculty of geology, Moscow, Russia, Moscow, Russia, (22)Tyumen Scientific Center, Institute of Earth Cryosphere, Tyumen, Russia, (23)University of Oslo, Department of Geosciences, Oslo, Norway, (24)Michigan State University, Department of Earth and Environmental Sciences, East Lansing, MI, United States, (25)National Snow and Ice Data Center - Cooperative Institute for Research in Environmental Sciences, University of Colorado, USA, Colorado, United States, (26)Medici Land Governance, Utah, USA, Utah, United States, (27)Ludwig Maximilians Universität, München, Germany, München, Germany, (28)University of Alberta, Department of Renewable Resources, Edmonton, AB, Canada
Abstract:
The continental shelves of the Arctic Ocean and surrounding seas contain large stocks of organic matter and methane (CH4), representing a potential ecosystem feedback to climate change not included in international climate agreements. We combined estimates from 25 permafrost researchers, to approximate that the subsea permafrost domain contains ~550 gigatons carbon (GtC; 170–740, 90% confidence interval) in organic matter and 45 GtC (10–110) in CH4. Current fluxes of CH4 and CO2 to the water column were estimated at 18 (2–34) and 38 (13–110) megatons C yr-1, respectively. Under Representative Concentration Pathway RCP8.5, the subsea permafrost domain could release 50 Gt CO2-equivalent by 2100 (14–140) and 240 Gt CO2-equivalent by 2300 (42–730), with ~40% less emissions increase under RCP2.6. The range of uncertainty demonstrates a serious knowledge gap but provides initial estimates of the magnitude and timing of the subsea permafrost climate feedback. Together, these results suggest that this climate feedback is less sensitive to anthropogenic warming than the terrestrial permafrost climate feedback, but potentially similar in magnitude.
