1. Arne Winguth University of Wisconsin-Madison, USA Uwe Mikolajewicz, Matthias Gröger, Ernst Maier-Reimer, Guy Schurgers, Miren Vizcaíno Max-Planck-Institut für Meteorologie, Germany The work is supported by the EU, BMBF-DEKLIM, UW Gradschool, NASA CARBON CYCLE SCIENCE CO 2 Uptake of the biosphere: Feedbacks between the carbon cycle and climate using a dynamic earth system model

2. MOTIVATION How will polar fresh water input by integrated changes in surface circulation, continental ice sheets, and enhanced precipitation affect the thermohaline circulation on decadal-to-centennial time scales? How may these changes in the ocean circulation affect carbon uptake in the ocean and on land?

4. Control simulation CO 2 concentration increased from preindustrial (280 ppm) to 2 x, 3 x, or 4 x pre-industrial concentration with an increase of 1% per year 3x and 4x CO 2 simulation where atmospheric radiation is calculated with a pCO 2 of 280 ppm (NO_FEED) Simulations where freshwater input from ice sheet is not considered (NOICE) Publication: Winguth et al., GRL, accepted. Future Climate Change Simulations Control 2 x CO 2 3 x CO 2 4 x CO 2 time (yr) pCO 2 (ppm)

5. ice sheet feedback No ice sheet feedback

6. precipitation ice sheets

8.  pCO 2 OCEAN-ATMOSPHERE DIFFERENCE 3 x CO 2 - CONTROL Mean 900-1000 CUMULATIVE CO 2 UPTAKE (kg C/m 2 )

9. Export Production mol C m -2 yr -1 PO 4 anomaly mmol m -3 Central Pacific 3 x CO 2 - CONTROL Vertical Velocity [10 -6 m s -1 ]

11. pH VALUE ANOMALY (3 x CO 2 - CTRL) W. Atlantic Riebesell et al. Nature (2001); Engel et al. Limnol. Oceanogr. (2005) Scanning electron micrographs under conditions of 300 (top) and 780 - 850 ppm (bottom) pCO 2 showing malformed coccospheres at the higher CO 2 levels.

12. CO 2 EMISSION SCENARIOS 1750-2000: fossil fuel emissions and land use data from CDIAC 2000-2100: IPCC RES scenarios 2100-3000: C 2100 EXP(  -1 *(t-2100))

13. ANOMALY OF AIR SURFACE TEMPERATURE [K] A1BB1 A2 Mean 2800-3000

14. ANOMALY OF AIR SURFACE TEMPERATURE [K] MERIDIONAL OVERTURNING CIRCULATION [Sv]

15. precipitation ice sheets ANOMALY Of NET FRESHWATER INPUT [Sv] North Atlantic Change in Sealevel Equivalent [m] GREENLANDANTARCTICA

16. Export Production Pg C yr -1

17. Change in carbon uptake

18. Conclusions In 1000-year future climate simulations changes of freshwater input by ice sheets are significantly smaller than changes by precipitation. Overall, consideration of both marine and terrestrial carbon cycle feedbacks with climate significantly affects the CO 2 radiative forcing due to a total decrease in the carbon uptake by ~24-28%.

19. Climate-Carbon Cycle Feedbacks

20. OXYGEN (3 x CO2) [  mol/L] mean 900-1000 Central Pacific