Response of the global carbon cycle to human-induced changes in Southern Hemisphere winds

摘要

An Earth System model is used to explore the response of the oceanic and terrestrial carbon sinks to strengthening and poleward shifting of the extratropical Southern Hemisphere winds, which is a robust feature of climate models' response to greenhouse gas forcing through the 20th and 21st centuries. We find that under time-varying CO2 emissions poleward intensifying Southern Hemisphere winds act on average to slightly enhance the efficacy of both the oceanic and terrestrial carbon sinks, thus providing a small negative feedback on the atmospheric CO2 concentration. Regionally, the effects of the changing winds on oceanic and terrestrial carbon uptake are more pronounced and partly of opposite sign. We further show that the magnitude and sign of global oceanic CO2 uptake is also controlled by changes in mesoscale eddy activity, which has been suggested to increase in response to intensifying Southern Hemisphere winds.