Articles | Volume 11, issue 23
Biogeosciences, 11, 6573–6593, 2014
Biogeosciences, 11, 6573–6593, 2014

Research article 01 Dec 2014

Research article | 01 Dec 2014

Estimated stocks of circumpolar permafrost carbon with quantified uncertainty ranges and identified data gaps

G. Hugelius1, J. Strauss2, S. Zubrzycki3, J. W. Harden4, E. A. G. Schuur5,6,7, C.-L. Ping8, L. Schirrmeister2, G. Grosse2, G. J. Michaelson8, C. D. Koven9, J. A. O'Donnell10, B. Elberling11, U. Mishra12, P. Camill13, Z. Yu14, J. Palmtag1, and P. Kuhry1 G. Hugelius et al.
  • 1Department of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm, Sweden
  • 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit Potsdam, Telegrafenberg A43, 14473 Potsdam, Germany
  • 3Institute of Soil Science, Center for Earth System Research and Sustainability (CEN), Universität Hamburg, Allende-Platz 2, 20146 Hamburg, Germany
  • 4U.S. Geological Survey, Menlo Park, CA 94025, USA
  • 5Department of Biology, University of Florida, Gainesville, FL 32611, USA
  • 6Center for Ecosystem Science & Society, Northern Arizona University, Flagstaff, AZ 86001, USA
  • 7Biological Sciences, Northern Arizona University, Flagstaff, AZ 86001, USA
  • 8Palmer Research Center, University of Alaska Fairbanks, 1509 S. Georgeson Drive, Palmer, AK 99645, USA
  • 9Lawrence Berkeley National Lab, Berkeley, CA, USA
  • 10Arctic Network, National Park Service, 4175 Geist Rd. Fairbanks, AK 99709, USA
  • 11CENPERM (Center for Permafrost), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen, Denmark
  • 12Environmental Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
  • 13Earth and Oceanographic Science Department and Environmental Studies Program, Bowdoin College, Brunswick, ME 04011, USA
  • 14Department of Earth and Environmental Sciences, Lehigh University, 1 West Packer Avenue, Bethlehem, PA 18015, USA

Abstract. Soils and other unconsolidated deposits in the northern circumpolar permafrost region store large amounts of soil organic carbon (SOC). This SOC is potentially vulnerable to remobilization following soil warming and permafrost thaw, but SOC stock estimates were poorly constrained and quantitative error estimates were lacking. This study presents revised estimates of permafrost SOC stocks, including quantitative uncertainty estimates, in the 0–3 m depth range in soils as well as for sediments deeper than 3 m in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska. Revised estimates are based on significantly larger databases compared to previous studies. Despite this there is evidence of significant remaining regional data gaps. Estimates remain particularly poorly constrained for soils in the High Arctic region and physiographic regions with thin sedimentary overburden (mountains, highlands and plateaus) as well as for deposits below 3 m depth in deltas and the Yedoma region. While some components of the revised SOC stocks are similar in magnitude to those previously reported for this region, there are substantial differences in other components, including the fraction of perennially frozen SOC. Upscaled based on regional soil maps, estimated permafrost region SOC stocks are 217 ± 12 and 472 ± 27 Pg for the 0–0.3 and 0–1 m soil depths, respectively (±95% confidence intervals). Storage of SOC in 0–3 m of soils is estimated to 1035 ± 150 Pg. Of this, 34 ± 16 Pg C is stored in poorly developed soils of the High Arctic. Based on generalized calculations, storage of SOC below 3 m of surface soils in deltaic alluvium of major Arctic rivers is estimated as 91 ± 52 Pg. In the Yedoma region, estimated SOC stocks below 3 m depth are 181 ± 54 Pg, of which 74 ± 20 Pg is stored in intact Yedoma (late Pleistocene ice- and organic-rich silty sediments) with the remainder in refrozen thermokarst deposits. Total estimated SOC storage for the permafrost region is ∼1300 Pg with an uncertainty range of ∼1100 to 1500 Pg. Of this, ∼500 Pg is in non-permafrost soils, seasonally thawed in the active layer or in deeper taliks, while ∼800 Pg is perennially frozen. This represents a substantial ∼300 Pg lowering of the estimated perennially frozen SOC stock compared to previous estimates.

Short summary
This study provides an updated estimate of organic carbon stored in the northern permafrost region. The study includes estimates for carbon in soils (0 to 3 m depth) and deeper sediments in river deltas and the Yedoma region. We find that field data is still scarce from many regions. Total estimated carbon storage is ~1300 Pg with an uncertainty range of between 1100 and 1500 Pg. Around 800 Pg carbon is perennially frozen, equivalent to all carbon dioxide currently in the Earth's atmosphere.
Final-revised paper