Amplified carbon release from vast West Siberian peatlands by 2100

• Published in: Geophysical Research Letters
• Main Authors: Frey, Karen E., Smith, Laurence C.
• Format: Text
• Language: unknown
• Published: Clark Digital Commons 2005
• Subjects: Siberia; permafrost; carbon; Arctic Ocean; Geography; Social and Behavioral Sciences; Arctic
• Online Access: https://commons.clarku.edu/faculty_geography/249; https://doi.org/10.1029/2004GL022025; https://commons.clarku.edu/context/faculty_geography/article/1248/viewcontent/GeogFacWorks_Frey_Amplifiedcarbon_2005.pdf

Extensive new data from previously unstudied Siberian streams and rivers suggest that mobilization of currently frozen, high-latitude soil carbon is likely over the next century in response to predicted Arctic warming. We present dissolved organic carbon (DOC) measurements from ninety-six watersheds in West Siberia, a region that contains the world's largest stores of peat carbon, exports massive volumes of freshwater and DOC to the Arctic Ocean, and is warming faster than the Arctic as a whole. The sample sites span ∼106 km2 over a large climatic gradient (∼55-68°N), providing data on a much broader spatial scale than previous studies and for the first time explicitly examining stream DOC in permafrost peatland environments. Our results show that cold, permafrost-influenced watersheds release little DOC to streams, regardless of the extent of peatland cover. However, we find considerably higher concentrations in warm, permafrost-free watersheds, rising sharply as a function of peatland cover. The two regimes are demarcated by the position of the -2°C mean annual air temperature (MAAT) isotherm, which is also approximately coincident with the permafrost limit. Climate model simulations for the next century predict near-doubling of West Siberian land surface areas with a MAAT warmer than -2°C, suggesting up to ∼700% increases in stream DOC concentrations and ∼2.7-4.3 Tg yr-1 (∼29-46%) increases in DOC flux to the Arctic Ocean. Copyright 2005 by the American Geophysical Union.