Global ocean carbon uptake: magnitude, variability and trends

Type Article
Date 2013
Language English
Author(s) Wanninkhof R.1, Park G. -H.1, 2, Takahashi T.3, Sweeney C.4, 16, Feely R.5, Nojiri Y.6, Gruber N.7, Doney S. C.8, McKinley G. A.9, Lenton A.10, Le Quere C.11, Heinze C.12, 13, 14, Schwinger J.12, 13, Graven H.7, 15, Khatiwala S.3
Affiliation(s) 1 : NOAA, Ocean Chem Div, AOML, Miami, FL 33149 USA.
2 : Univ Miami, Cooperat Inst Marine & Atmospher Studies, Miami, FL 33149 USA.
3 : Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA.
4 : NOAA, ESRL Carbon Cycle Grp Aircraft Project, Boulder, CO 80304 USA.
5 : NOAA, Ocean Climate Res Div, PMEL, Seattle, WA 98115 USA.
6 : Natl Inst Environm Studies, Ctr Global Environm Res, Tsukuba, Ibaraki 3058506, Japan.
7 : ETH, Environm Phys Grp, Inst Biogeochem & Pollutant Dynam, CH-8092 Zurich, Switzerland.
8 : Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA.
9 : Univ Wisconsin, Ctr Climat Res, Madison, WI 53706 USA.
10 : CSIRO Marine & Atmospher Res, Hobart, Tas, Australia.
11 : Univ E Anglia, Tyndall Ctr Climate Change Res, Norwich NR4 7TJ, Norfolk, England.
12 : Univ Bergen, Inst Geophys, N-5007 Bergen, Norway.
13 : Bjerknes Ctr Climate Res, Bergen, Norway.
14 : Uni Res, Uni Bjerknes Ctr, Bergen, Norway.
15 : Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA.
16 : Univ Colorado, CIRES, Boulder, CO 80304 USA.
Source Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2013 , Vol. 10 , N. 3 , P. 1983-2000
DOI 10.5194/bg-10-1983-2013
WOS© Times Cited 262
Abstract Estimates of the anthropogenic global-integrated sea-air carbon dioxide (CO2) flux from 1990 to 2009, based on different models and measurements, range from –1.4 to –2.6 Pg C yr–1. The median values of anthropogenic CO2 for each method show better agreement and are: −1.9 for Pg C yr−1 for numerical ocean general circulation hind cast models (OGCMs) with parameterized biogeochemistry; –2.1 Pg C yr–1 for atmospheric inverse models; –1.9 Pg C yr–1 for global atmospheric constraints based on O2 / N2 ratios for 1990–2000; and –2.4 Pg C yr–1 for oceanic inverse models. An updated estimate of this anthropogenic CO2 flux based on a climatology of sea-air partial pressure of CO2 differences (ΔpCO2) (Takahashi et al., 2009) and a bulk formulation of gas transfer with wind speed for year 2000 is –2.0 Pg C yr–1. Using this ΔpCO2 climatology and empirical relationships of pCO2 with sea-surface temperature (SST) anomalies (Park et al., 2010a), the interannual variability of the contemporary CO2 flux is estimated to be 0.20 Pg C yr–1 (1σ) from 1990 through 2009. This is similar to the variability estimated by the OGCMs of 0.16 Pg C yr–1 but smaller than the interannual variability from atmospheric inverse estimates of 0.40 Pg C yr–1. The variability is largely driven by large-scale climate re-organizations. The decadal trends for different methods range from –0.13 (Pg C yr–1) decade–1 to –0.50 (Pg C yr−1) decade−1. The OGCMs and the data based sea-air CO2 flux estimates show smaller uptakes and appreciably smaller decadal trends than estimates based on changes in carbon inventory suggesting that methods capable of resolving shorter timescales are showing a slowing of the rate of ocean CO2 uptake. It is not clear if this large difference in trend is a methodological issue or a real natural feedback.
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Wanninkhof R., Park G. -H., Takahashi T., Sweeney C., Feely R., Nojiri Y., Gruber N., Doney S. C., McKinley G. A., Lenton A., Le Quere C., Heinze C., Schwinger J., Graven H., Khatiwala S. (2013). Global ocean carbon uptake: magnitude, variability and trends. Biogeosciences, 10(3), 1983-2000. Publisher's official version : https://doi.org/10.5194/bg-10-1983-2013 , Open Access version : https://archimer.ifremer.fr/doc/00141/25179/