Sensitivity experiments

A positive climate feedback is associated with the carbon cycle (Klepper and deHaan, 1995) due to a different response of ocean and land CO2 uptake when the climate warms A large uncertainty exists about the rate of this feedback (20 to 200 ppm among CGCM, Friedlingstein et al., 2006) Oceanic uptake reduction in warmer condition is due to the decrease of CO2 solubility related with SST increase and modification in mixed layer depth as from changes in circulation Thermohaline circulation (THC) weakening will participate to the reduction in oceanic carbon uptake via the reduction in deep ocean ventilation Investigate if changes in THC can effectively affect CO2 uptake under global warming conditions in a coupled GCM Quantify the effect of various modifications of ocean due to THC weakening 1.Overturning circulation and biology production decrease due to THC weakening tend to reduce the oceanic CO2 uptake 2.SST decrease, SSS decrease and sea-ice cover increase due to a THC weakening tend to increase the oceanic CO2 uptake Aim of this work Table 2.: Effect of changes in SST, SSS, sea-ice cover and circulation+biology due to THC reductio