1. How will rising CO2 affect vegetation in the Sahel?
Sebastian Bathiany, Martin Claussen, Victor Brovkin
Max Planck Institute for Meteorology

2. Petit-Maire, 1990:
Sahel

3. Plants need food and water
CO2 (physiological)

4. Plants need food and water
CO2 (physiological)
Climate
(most important:
rainfall)

5. Model description
MPI-ESM-LR
HadGEM2-ES
MIROC-ESM

6. 21st century
Change in vegetation cover fraction (abs. %)

7. 21st century
Change in vegetation cover fraction (abs. %)

8. 21st century
22-23rd century
Change in vegetation cover fraction (abs. %)

9. Separation of effects Radphys Rad Phys Experiment
Plants see climate change
Plants see CO2 change
Radphys
Rad
Phys

10. Separation of effects Radphys Rad Phys
Change in vegetation cover fraction (abs. %)

11. Separation of effects Radphys Rad Phys
Change in vegetation cover fraction (abs. %)

12. Separation of effects Radphys Rad Phys
Change in vegetation cover fraction (abs. %)

13. Plants need food and water
CO2 (physiological)
Climate
(most important:
precipitation)

14. Darker surface warms…

15. but transpiration cools…

18. vegFrac [abs %]

19. vegFrac [abs %]

20. Summary
Vegetation cover change in the Sahel depends on the time horizon.
Reasons for vegetation cover change are different in each model. Uncertain effects oppose each other.
In the Sahel, vegetation expansion could cool High resolution is necessary.