Climatic Change, DOI 10.1007/s10584-008-9396-y.
International Research Institute for Climate and Society, Earth Institute at Columbia University, Palisades, NY
Lamont-Doherty Earth Observatory, Earth Institute at Columbia University, Palisades, NY
Isaac M. Held
Geophysical Fluid Dynamics Laboratory, Princeton, NJ
Adam H. Sobel
Department of Applied Physics and Applied Mathematics and Department of Earth and Environmental Sciences, Columbia University, New York, NY.
We review recent advances and current challenges in African climate research and offer a global climate context in which to interpret African environmental change. We classify the various mechanisms that have been proposed as relevant for understanding variations in African rainfall, emphasizing a ``tropospheric stabilization'' mechanism that is of importance on interannual time scales as well as for the future response to warming oceans.
We show that the latest generation of climate models captures in part the recent African drying trend, attributing it to the combination of anthropogenic emissions of aerosols and greenhouse gases, the relative contribution of which is difficult to quantify with the existing model archive. The same climate models fail to reach a robust agreement regarding the 21st century outlook for African rainfall, in a future with increasing greenhouse gases and decreasing aerosol loadings.
We argue that consideration of African environments in a global climate context is indispensable if we are to exploit advances in our physical understanding of recent variability and trends to shape our outlook on future climate change, to inform the debate between proponents of mitigation v. adaptation strategies, and to plan and implement well-informed policymaking action at national, regional and continental scales.