Recent trends and drivers of regional sources and sinks of carbon dioxide
The land and ocean absorb on average just over half of the anthropogenic emissions of carbon dioxide (CO<sub>2</sub>) every year. These CO<sub>2</sub> "sinks" are modulated by climate change and variability. Here we use a suite of nine dynamic global vegetation mode...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-02-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/12/653/2015/bg-12-653-2015.pdf |
| _version_ | 1828820594301337600 |
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| author | S. Sitch P. Friedlingstein N. Gruber S. D. Jones G. Murray-Tortarolo A. Ahlström S. C. Doney H. Graven C. Heinze C. Huntingford S. Levis P. E. Levy M. Lomas B. Poulter N. Viovy S. Zaehle N. Zeng A. Arneth G. Bonan L. Bopp J. G. Canadell F. Chevallier P. Ciais R. Ellis M. Gloor P. Peylin S. L. Piao C. Le Quéré B. Smith Z. Zhu R. Myneni |
| author_facet | S. Sitch P. Friedlingstein N. Gruber S. D. Jones G. Murray-Tortarolo A. Ahlström S. C. Doney H. Graven C. Heinze C. Huntingford S. Levis P. E. Levy M. Lomas B. Poulter N. Viovy S. Zaehle N. Zeng A. Arneth G. Bonan L. Bopp J. G. Canadell F. Chevallier P. Ciais R. Ellis M. Gloor P. Peylin S. L. Piao C. Le Quéré B. Smith Z. Zhu R. Myneni |
| author_sort | S. Sitch |
| collection | DOAJ |
| description | The land and ocean absorb on average just over half of the anthropogenic
emissions of carbon dioxide (CO<sub>2</sub>) every year. These CO<sub>2</sub> "sinks"
are modulated by climate change and variability. Here we use a suite of nine
dynamic global vegetation models (DGVMs) and four ocean biogeochemical
general circulation models (OBGCMs) to estimate trends driven by global and regional
climate and atmospheric CO<sub>2</sub> in land and oceanic
CO<sub>2</sub> exchanges with the atmosphere over the period 1990–2009, to attribute
these trends to underlying processes in the models, and to quantify the
uncertainty and level of inter-model agreement. The models were forced with
reconstructed climate fields and observed global atmospheric CO<sub>2</sub>; land
use and land cover changes are not included for the DGVMs. Over the period
1990–2009, the DGVMs simulate a mean global land carbon sink of −2.4 ± 0.7 Pg C yr<sup>−1</sup>
with a small significant trend of −0.06 ± 0.03 Pg C yr<sup>−2</sup> (increasing sink). Over the more limited period 1990–2004, the
ocean models simulate a mean ocean sink of −2.2 ± 0.2 Pg C yr<sup>−1</sup>
with a trend in the net C uptake that is indistinguishable from zero (−0.01 ± 0.02 Pg C yr<sup>−2</sup>). The two ocean models that extended the
simulations until 2009 suggest a slightly stronger, but still small, trend of
−0.02 ± 0.01 Pg C yr<sup>−2</sup>. Trends from land and ocean models compare
favourably to the land greenness trends from remote sensing, atmospheric
inversion results, and the residual land sink required to close the global
carbon budget. Trends in the land sink are driven by increasing net primary
production (NPP), whose statistically significant trend of 0.22 ± 0.08 Pg C yr<sup>−2</sup> exceeds a significant trend in heterotrophic respiration of
0.16 ± 0.05 Pg C yr<sup>−2</sup> – primarily as a consequence of
widespread CO<sub>2</sub> fertilisation of plant production. Most of the
land-based trend in simulated net carbon uptake originates from natural
ecosystems in the tropics (−0.04 ± 0.01 Pg C yr<sup>−2</sup>), with almost no
trend over the northern land region, where recent warming and reduced
rainfall offsets the positive impact of elevated atmospheric CO<sub>2</sub> and
changes in growing season length on carbon storage. The small uptake trend
in the ocean models emerges because climate variability and change, and in
particular increasing sea surface temperatures, tend to counter\-act the trend
in ocean uptake driven by the increase in atmospheric CO<sub>2</sub>. Large
uncertainty remains in the magnitude and sign of modelled carbon trends in
several regions, as well as regarding the influence of land use and land cover changes on
regional trends. |
| first_indexed | 2024-12-12T12:36:51Z |
| format | Article |
| id | doaj.art-b31bb438c7074087bd8385a8e89e4dad |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-12T12:36:51Z |
| publishDate | 2015-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-b31bb438c7074087bd8385a8e89e4dad2022-12-22T00:24:19ZengCopernicus PublicationsBiogeosciences1726-41701726-41892015-02-0112365367910.5194/bg-12-653-2015Recent trends and drivers of regional sources and sinks of carbon dioxideS. Sitch0P. Friedlingstein1N. Gruber2S. D. Jones3G. Murray-Tortarolo4A. Ahlström5S. C. Doney6H. Graven7C. Heinze8C. Huntingford9S. Levis10P. E. Levy11M. Lomas12B. Poulter13N. Viovy14S. Zaehle15N. Zeng16A. Arneth17G. Bonan18L. Bopp19J. G. Canadell20F. Chevallier21P. Ciais22R. Ellis23M. Gloor24P. Peylin25S. L. Piao26C. Le Quéré27B. Smith28Z. Zhu29R. Myneni30University of Exeter, Exeter EX4 4QF, UKUniversity of Exeter, Exeter EX4 4QF, UKInstitute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, SwitzerlandTyndall Centre for Climate Change Research, University of East Anglia, Norwich NR4 7TJ, UKUniversity of Exeter, Exeter EX4 4QF, UKLund University, Department of Physical Geography and Ecosystem Science, Sölvegatan 12, 223 62 Lund, SwedenMarine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543, USADepartment of Physics and Grantham Institute for Climate Change, Imperial College London, London SW7 2AZ, UKGeophysical Institute, University of Bergen, Bergen, NorwayCentre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UKNational Center for Atmospheric Research, Boulder, Colorado, USACentre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UKDepartment of Animal {&} Plant Sciences, University of Sheffield, Sheffield S10 2TN, UKInstitute on Ecosystems and Department of Ecology, Montana State University, Bozeman, MT 59717, USALaboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, FranceBiogeochemical Integration Department, Max Planck Institute for Biogeochemistry, P.O. Box 10 01 64, 07701 Jena, GermanyDepartment of Atmospheric and Oceanic Science, University of Maryland, College Park, MD 20740, USAKarlsruhe Institute of Technology, Garmisch-Partenkirchen, GermanyNational Center for Atmospheric Research, Boulder, Colorado, USALaboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, FranceGlobal Carbon Project, CSIRO Oceans and Atmosphere Flagship, Canberra, AustraliaLaboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, FranceLaboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, FranceCentre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UKUniversity of Leeds, School of Geography, Woodhouse Lane, Leeds LS9 2JT, UKLaboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, FranceCollege of Urban and Environmental Sciences, Peking University, Beijing 100871, ChinaTyndall Centre for Climate Change Research, University of East Anglia, Norwich NR4 7TJ, UKLund University, Department of Physical Geography and Ecosystem Science, Sölvegatan 12, 223 62 Lund, SwedenState Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, ChinaDepartment of Geography and Environment, Boston University, 675 Commonwealth Avenue, Boston, MA 02215, USAThe land and ocean absorb on average just over half of the anthropogenic emissions of carbon dioxide (CO<sub>2</sub>) every year. These CO<sub>2</sub> "sinks" are modulated by climate change and variability. Here we use a suite of nine dynamic global vegetation models (DGVMs) and four ocean biogeochemical general circulation models (OBGCMs) to estimate trends driven by global and regional climate and atmospheric CO<sub>2</sub> in land and oceanic CO<sub>2</sub> exchanges with the atmosphere over the period 1990–2009, to attribute these trends to underlying processes in the models, and to quantify the uncertainty and level of inter-model agreement. The models were forced with reconstructed climate fields and observed global atmospheric CO<sub>2</sub>; land use and land cover changes are not included for the DGVMs. Over the period 1990–2009, the DGVMs simulate a mean global land carbon sink of −2.4 ± 0.7 Pg C yr<sup>−1</sup> with a small significant trend of −0.06 ± 0.03 Pg C yr<sup>−2</sup> (increasing sink). Over the more limited period 1990–2004, the ocean models simulate a mean ocean sink of −2.2 ± 0.2 Pg C yr<sup>−1</sup> with a trend in the net C uptake that is indistinguishable from zero (−0.01 ± 0.02 Pg C yr<sup>−2</sup>). The two ocean models that extended the simulations until 2009 suggest a slightly stronger, but still small, trend of −0.02 ± 0.01 Pg C yr<sup>−2</sup>. Trends from land and ocean models compare favourably to the land greenness trends from remote sensing, atmospheric inversion results, and the residual land sink required to close the global carbon budget. Trends in the land sink are driven by increasing net primary production (NPP), whose statistically significant trend of 0.22 ± 0.08 Pg C yr<sup>−2</sup> exceeds a significant trend in heterotrophic respiration of 0.16 ± 0.05 Pg C yr<sup>−2</sup> – primarily as a consequence of widespread CO<sub>2</sub> fertilisation of plant production. Most of the land-based trend in simulated net carbon uptake originates from natural ecosystems in the tropics (−0.04 ± 0.01 Pg C yr<sup>−2</sup>), with almost no trend over the northern land region, where recent warming and reduced rainfall offsets the positive impact of elevated atmospheric CO<sub>2</sub> and changes in growing season length on carbon storage. The small uptake trend in the ocean models emerges because climate variability and change, and in particular increasing sea surface temperatures, tend to counter\-act the trend in ocean uptake driven by the increase in atmospheric CO<sub>2</sub>. Large uncertainty remains in the magnitude and sign of modelled carbon trends in several regions, as well as regarding the influence of land use and land cover changes on regional trends.http://www.biogeosciences.net/12/653/2015/bg-12-653-2015.pdf |
| spellingShingle | S. Sitch P. Friedlingstein N. Gruber S. D. Jones G. Murray-Tortarolo A. Ahlström S. C. Doney H. Graven C. Heinze C. Huntingford S. Levis P. E. Levy M. Lomas B. Poulter N. Viovy S. Zaehle N. Zeng A. Arneth G. Bonan L. Bopp J. G. Canadell F. Chevallier P. Ciais R. Ellis M. Gloor P. Peylin S. L. Piao C. Le Quéré B. Smith Z. Zhu R. Myneni Recent trends and drivers of regional sources and sinks of carbon dioxide Biogeosciences |
| title | Recent trends and drivers of regional sources and sinks of carbon dioxide |
| title_full | Recent trends and drivers of regional sources and sinks of carbon dioxide |
| title_fullStr | Recent trends and drivers of regional sources and sinks of carbon dioxide |
| title_full_unstemmed | Recent trends and drivers of regional sources and sinks of carbon dioxide |
| title_short | Recent trends and drivers of regional sources and sinks of carbon dioxide |
| title_sort | recent trends and drivers of regional sources and sinks of carbon dioxide |
| url | http://www.biogeosciences.net/12/653/2015/bg-12-653-2015.pdf |
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