Strengthening seasonal marine CO2 variations due to increasing atmospheric CO2

Type Article
Date 2018-02
Language English
Author(s) Landschutzer PeterORCID1, Gruber NicolasORCID2, Bakker Dorothee C. E.3, Stemmler Irene1, Six Katharina D.1
Affiliation(s) 1 : Max Planck Inst Meteorol, Hamburg, Germany.
2 : Swiss Fed Inst Technol, Inst Biogeochem & Pollutant Dynam, Environm Phys, Zurich, Switzerland.
3 : Univ East Anglia, Sch Environm Sci, Ctr Ocean & Atmospher Sci, Norwich, Norfolk, England.
Source Nature Climate Change (1758-678X) (Nature Publishing Group), 2018-02 , Vol. 8 , N. 2 , P. 146-150
DOI 10.1038/s41558-017-0057-x
WOS© Times Cited 92

The increase of atmospheric CO2 (ref. (1)) has been predicted to impact the seasonal cycle of inorganic carbon in the global ocean(2,3), yet the observational evidence to verify this prediction has been missing. Here, using an observation-based product of the oceanic partial pressure of CO2 (p(CO2)) covering the past 34 years, we find that the winter-to-summer difference of the p(CO2) has increased on average by 2.2 +/- 0.4 mu atm per decade from 1982 to 2015 poleward of 10 degrees latitude. This is largely in agreement with the trend expected from thermodynamic considerations. Most of the increase stems from the seasonality of the drivers acting on an increasing oceanic p(CO2) caused by the uptake of anthropogenic CO2 from the atmosphere. In the high latitudes, the concurrent ocean-acidification-induced changes in the buffer capacity of the ocean enhance this effect. This strengthening of the seasonal winter-to-summer difference pushes the global ocean towards critical thresholds earlier, inducing stress to ocean ecosystems and fisheries(4). Our study provides observational evidence for this strengthening seasonal difference in the oceanic carbon cycle on a global scale, illustrating the inevitable consequences of anthropogenic CO2 emissions.

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Supplementary Notes, Supplementary Table 1, Supplementary Figures 1–9 and Supplementary References 21 1 MB Open access
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