TY - JOUR
T1 - Resolving the Carbon-Climate Feedback Potential of Wetland CO2 and CH4 Fluxes in Alaska
AU - Ma, Shuang
AU - Bloom, A. Anthony
AU - Watts, Jennifer D.
AU - Quetin, Gregory R.
AU - Donatella, Zona
AU - Euskirchen, Eugénie S.
AU - Norton, Alexander J.
AU - Yin, Yi
AU - Levine, Paul A.
AU - Braghiere, Renato K.
AU - Parazoo, Nicholas C.
AU - Worden, John R.
AU - Schimel, David S.
AU - Miller, Charles E.
N1 - Publisher Copyright:
© 2023 Jet Propulsion Laboratory, California Institute of Technology and The Authors. Government sponsorship acknowledged.
PY - 2023/9
Y1 - 2023/9
N2 - Boreal-Arctic regions are key stores of organic carbon (C) and play a major role in the greenhouse gas balance of high-latitude ecosystems. The carbon-climate (C-climate) feedback potential of northern high-latitude ecosystems remains poorly understood due to uncertainty in temperature and precipitation controls on carbon dioxide (CO2) uptake and the decomposition of soil C into CO2 and methane (CH4) fluxes. While CH4 fluxes account for a smaller component of the C balance, the climatic impact of CH4 outweighs CO2 (28–34 times larger global warming potential on a 100-year scale), highlighting the need to jointly resolve the climatic sensitivities of both CO2 and CH4. Here, we jointly constrain a terrestrial biosphere model with in situ CO2 and CH4 flux observations at seven eddy covariance sites using a data-model integration approach to resolve the integrated environmental controls on land-atmosphere CO2 and CH4 exchanges in Alaska. Based on the combined CO2 and CH4 flux responses to climate variables, we find that 1970-present climate trends will induce positive C-climate feedback at all tundra sites, and negative C-climate feedback at the boreal and shrub fen sites. The positive C-climate feedback at the tundra sites is predominantly driven by increased CH4 emissions while the negative C-climate feedback at the boreal site is predominantly driven by increased CO2 uptake (80% from decreased heterotrophic respiration, and 20% from increased photosynthesis). Our study demonstrates the need for joint observational constraints on CO2 and CH4 biogeochemical processes—and their associated climatic sensitivities—for resolving the sign and magnitude of high-latitude ecosystem C-climate feedback in the coming decades.
AB - Boreal-Arctic regions are key stores of organic carbon (C) and play a major role in the greenhouse gas balance of high-latitude ecosystems. The carbon-climate (C-climate) feedback potential of northern high-latitude ecosystems remains poorly understood due to uncertainty in temperature and precipitation controls on carbon dioxide (CO2) uptake and the decomposition of soil C into CO2 and methane (CH4) fluxes. While CH4 fluxes account for a smaller component of the C balance, the climatic impact of CH4 outweighs CO2 (28–34 times larger global warming potential on a 100-year scale), highlighting the need to jointly resolve the climatic sensitivities of both CO2 and CH4. Here, we jointly constrain a terrestrial biosphere model with in situ CO2 and CH4 flux observations at seven eddy covariance sites using a data-model integration approach to resolve the integrated environmental controls on land-atmosphere CO2 and CH4 exchanges in Alaska. Based on the combined CO2 and CH4 flux responses to climate variables, we find that 1970-present climate trends will induce positive C-climate feedback at all tundra sites, and negative C-climate feedback at the boreal and shrub fen sites. The positive C-climate feedback at the tundra sites is predominantly driven by increased CH4 emissions while the negative C-climate feedback at the boreal site is predominantly driven by increased CO2 uptake (80% from decreased heterotrophic respiration, and 20% from increased photosynthesis). Our study demonstrates the need for joint observational constraints on CO2 and CH4 biogeochemical processes—and their associated climatic sensitivities—for resolving the sign and magnitude of high-latitude ecosystem C-climate feedback in the coming decades.
KW - CH
KW - CO
KW - carbon-climate feedback
KW - climatic sensitivities
KW - global warming potential
KW - northern high latitude
UR - http://www.scopus.com/inward/record.url?scp=85171369550&partnerID=8YFLogxK
U2 - 10.1029/2022GB007524
DO - 10.1029/2022GB007524
M3 - Article
SN - 0886-6236
VL - 37
JO - Global Biogeochemical Cycles
JF - Global Biogeochemical Cycles
IS - 9
M1 - e2022GB007524
ER -