Page 173 - Climate Change and Food Systems

chapter 5: climate change impact on key crops in africa: using crop models and general equilibrium models to bound the predictions
table 3
Top five crops per region, ranked by harvested area (ha), mean 2006-2008
East Africa
Southern Africa
West Africa
Crop
Hectares
Crop
Hectares
Crop
Hectares
Sorghum
Maize
Millet
Beans
Cassava
9 893 208
9 367 883
3 622 654
3 512 688
3 474 208
Maize
Cassava
Groundnuts
Millet
Sorghum
Africa as well as moving towards
Botswana. High rainfall areas are
the tropical forests of the Democratic Republic
of Congo, the eastern coast of Madagascar, and several coastal locations in Central Africa and West Africa.
In the three monographs on agriculture and climate change in Africa, the authors used climate data from GCMs that had been produced for the IPCC AR4. Figure 3 shows changes in annual precipitation as projected by the four GCMs used in these studies (CNRM, CSIRO, ECHAM, and MIROC). These GCMs reflect assumptions of the IPCC’s A1B scenario for GHG emissions (see notes for Figure).Table 4 augments the maps in Figure 3, tabulating the mean changes for each country and region by GCM.
According to the CNRM GCM, a few locations should expect a significant reduction in rainfall (a noteworthy exception being the southern half of Madagascar) but the Horn of Africa and much of coastal Central Africa should anticipate significant increases in rainfall. This is in contrast to the CSIRO GCM, which shows very few locations experiencing significant increases in rainfall. Much of the Atlantic coast of Africa is projected to become significantly drier.
The ECHAM GCM projects that most of Southern Africa will become significantly drier under climate change. At the same time, much of Central Africa and parts of the interior of East Africa are projected to become wetter. Some of
9 199 950
2 015 384
1 073 603
988 690
848 518
Millet
Sorghum
Cow peas
Maize
Rice
figure 2
Mean annual precipitation (mm), 1950-2000
16 002 237
14 288 715
10 297 759
7 747 435
5 725 947
Source: FAOSTAT (FAO 2010)
the coast of noted among
Source: WorldClim version 1.4 (Hijmans et al., 2005)
the steepest declines in rainfall are projected by the MIROC GCM. These occur in coastal portions of central Africa and the southern coast of West Africa.
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