Search

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 ± 16PgC 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 3mdepth 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. [ABSTRACT FROM AUTHOR]

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 0-3m 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 x 8-11 for soils in the 1-3 m depth range,, a factor x 8 for deltaic alluvium and a factor x 5 for Yedoma region deposits. Upscaled based on regional soil maps, estimated permafrost region SOC stocks are 217 ± 15 and 472 ± 34 Pg for the 0-0.3 m and 0-1 m soil depths, respectively (±95% confidence intervals). Depending on the regional subdivision used to upscale 1-3 m soils (following physiography or continents), estimated 0-3 m SOC storage is 1034 ± 183 Pg or 1104 ± 133 Pg. Of this, 34 ± 16 Pg C is stored in thin soils of the High Arctic. Based on generalised calculations, storage of SOC in deep deltaic alluvium (>3m to ≤60 m depth) of major Arctic rivers is estimated to 91 ± 39 Pg (of which 69 ± 34 Pg is in permafrost). In the Yedoma region, estimated >3m SOC stocks are 178+140/-146 Pg, of which 74+54/-57 Pg is stored in intact, frozen Yedoma (late Pleistocene ice- and organic-rich silty sediments) with the remainder in refrozen thermokarst deposits (±16/84th percentiles of bootstrapped estimates). A total estimated mean storage for the permafrost region of ca. 1300-1370 Pg with an uncertainty range of 930-1690 Pg encompasses the combined revised estimates. Of this, ≤819-836 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 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 >3m depth deposits in deltas and the Yedoma region. [ABSTRACT FROM AUTHOR]

The article presents research on a data set for the estimation of organic carbon storage in soils up to a depth of three meters in the northern circumpolar permafrost region. Topics include the role of high-latitude terrestrial ecosystems in the global carbon cycle, the use of the Northern Circumpolar Soil Carbon Database (NCSCD) geographical information system (GIS) to quantify soil organic carbon (SOC) levels, and soil classification through GIS mapping.

The article discusses research on high latitude terrestrial ecosystems and their role in the global carbon cycle, with a focus on the development of a dataset to estimate organic carbon storage in soils of the northern circumpolar permafrost region. Topics include the Northern Circumpolar Soil Carbon Database (NCSCD), the use of regional soil classification maps to determine quantities of soil organic carbon (SOC), and the application of NCSCD in spatial analysis.