88th Annual Meeting (20-24 January 2008)

Monday, 21 January 2008: 9:30 AM
Regional projections of future changes in climate in tropical Africa under greenhouse gas forcing and land cover changes
217-218 (Ernest N. Morial Convention Center)
Heiko Paeth, University of Würzburg, Würzburg, Germany; and M. Christoph and A. H. Fink
Most investigations on future pathways of West African climate have been carried out with state-of-the-art global circulation models (GCMs) taking into account only the effect of increasing greenhouse gas concentrations and thus the effect of warmer tropical oceans. A number of GCMs predict a northward extension of moisture advection into the Sahel and more humid conditions. In this paper a multi-ensemble run of a long-term transient climate change experiment with the regional climate model REMO is presented to assess regional aspects of the future pathway of climate in tropical Africa. The simulations are not only forced by increasing greenhouse gas concentrations according to the IPCC-SRES, but also by land-cover changes until the year 2050 according to the FAO. We find a prominent surface heating and a significant reduction in annual rainfall amount over most of tropical Africa, resulting in enhanced heat stress and extended dry spells. The degradation of the vegetation cover accounts for about half of the surface warming signal and about two thirds of the drying trend in West Africa.

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