Improved Estimates Show Large Circumpolar Stocks of Permafrost Carbon While Quantifying Substantial Uncertainty Ranges and Identifying Remaining Data Gaps

Wednesday, 17 December 2014
Gustaf Hugelius1, Jens Strauss2, Sebastian Zubrzycki3, Jennifer W Harden4, Edward A G Schuur5, Chien-Lu Ping6, Lutz Schirrmeister2, Guido Grosse2, Gary J Michaelson6, Charles D Koven7, Jonathan A ODonnell8, Bo Elberling9, Umakant Mishra10, Philip Camill11, Zicheng Yu12, Juri Palmtag1 and Peter Kuhry1, (1)Stockholm University, Stockholm, Sweden, (2)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Potsdam, Potsdam, Germany, (3)University of Hamburg, Hamburg, Germany, (4)USGS California Water Science Center Menlo Park, Menlo Park, CA, United States, (5)Univ Florida, Gainesville, FL, United States, (6)University of Alaska Fairbanks, Anchorage, AK, United States, (7)Lawrence Berkeley National Laboratory, Berkeley, CA, United States, (8)National Park Service Fairbanks, Fairbanks, AK, United States, (9)University of Copenhagen, Copenhagen, Denmark, (10)Argonne National Laboratory, Argonne, IL, United States, (11)Bowdoin College, Brunswick, ME, United States, (12)Lehigh University, Department of Earth and Environmental Sciences, Bethlehem, PA, United States
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 stock estimates are poorly constrained and quantitative error estimates were lacking. This study presents revised estimates of the permafrost SOC pool, including quantitative uncertainty estimates, in the 0–3 m depth range in soils as well as for deeper sediments (> 3 m) in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska. The revised estimates are based on significantly larger databases compared to previous studies. Compared to previous studies, the number of individual sites/pedons has increased by a factor ×8–11 for 1–3 m soils, a factor ×8 for deltaic alluvium and a factor ×5 for Yedoma region deposits.

A total estimated mean storage for the permafrost region of ca. 1300–1400 Pg with an uncertainty range of 1050–1650 Pg encompasses the revised estimates. Of this, ≤900 Pg is perennially frozen. While some components of the revised SOC stocks are similar in magnitude to those previously reported for this region, there are also substantial differences in individual components.

There is evidence of substantial 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 >3 m depth deposits in deltas and the Yedoma region.