Warnsignal Klima: DIE MEERE / ÄNDERUNGEN & RISIKEN
Kap.3 Auswirkungen des Klimawandels auf die Meere
Birgit Schneider (Institut für Geowissenschaften, Universität Kiel)
CO2-uptake by the ocean: The ocean has played a dominant role in glacial-interglacial CO2 variability and it will be the major sink for anthropogenic CO2 in the future. The uptake is mainly driven by a positive gradient of the CO2 partial pressure (pCO2) between atmosphere and ocean. Until today, the ocean has taken up almost 50% of the total anthropogenic CO2 emissions since the industrialisation began. However, due to non-linear effects of the marine carbonate system and a reduced CO2 solubility as a consequence of climate change the rate of uptake relative to emissions will decrease in the future. This decreasing sink behaviour constitutes a positive feedback on the atmospheric CO2, amplifying climate change. On multi-milennial time scales the capacity of the oceanic CO2-sink will be increased by dissolution of CaCO3 from marine sediments, so that only about 10% of the anthropogenic perturbation will remain in the atmosphere after 10 kyrs.