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PAST, PRESENT, AND FUTURE PEATLAND CARBON BALANCE: AN EMPIRICAL MODEL BASED ON 210 Pb‐DATED CORES
Author(s) -
Wieder R. Kelman
Publication year - 2001
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1890/1051-0761(2001)011[0327:ppafpc]2.0.co;2
Subject(s) - peat , boreal , primary production , subarctic climate , environmental science , sink (geography) , climate change , carbon sink , atmospheric sciences , taiga , physical geography , climatology , ecosystem , ecology , geography , geology , biology , cartography
Boreal and subarctic peatlands today represent a large global carbon (C) reservoir. Existing models that describe organic matter accumulation in peatlands over thousands of years are inadequate for predicting short‐term responses to changing climate. This paper develops a new, empirically based model that estimates net primary production (NPP) and depth‐dependent decay rates (exponential decay k values) of near‐surface peat. Application of the model to three sites in boreal Alberta indicates that today the sites are net sinks for atmospheric C at rates of 34–52 g C·m −2 ·yr −1 . Even without climate change, within 80–160 years, these sites will attain steady‐state conditions with no further net C accumulation. Climate change scenarios in which NPP or k values are allowed to change gradually and linearly (at 0.1% per year) affect net C sequestration. Any scenario of decreasing NPP or increasing k values results in the peatlands switching from net sinks to net sources of atmospheric C within the next 20–62 years. Regional C balance of the peatlands in boreal, continental, western Canada will at best diminish in terms of strength of an atmospheric C sink and may well shift to becoming a source of atmospheric C. Shifts from sinks to sources of atmospheric C may occur within time frames that are similar in magnitude to the anticipated doubling of atmospheric CO 2 by the middle of the 21st century.