According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, warming in Sub-Saharan Africa (SSA) is expected to be greater than the global average, and rainfall will decline in certain areas. Global circulation models (GCMs), which provide an understanding of climate and project climate change, tend to agree that temperatures are increasing across the region, but models vary widely regarding predicted changes in precipitation—with the exception of some agreement that precipitation decreases from June to August in southern Africa and increases from December to February in eastern Africa. Whether the Sahel will be more or less wet in the future remains uncertain. Given the limited agreement of GCMs, the University of Illinois and the International Food Policy Research Institute (IFPRI) developed a global comprehensive climate change scenario combining 17 models selected for their past performance in predicting temperature and precipitation.
This brief is based on a study that integrates these results with a process-based crop simulation model and IFPRI’s International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) to assess climate change outcomes for SSA. The modeling approach employed for the study considered three possible climate change impacts on crop production: (1) direct effects on rainfed yields through changes in temperature and precipitation, (2) indirect effects on irrigated yields from changes in temperature and available irrigation water (including precipitation), and (3) autonomous adjustments to area and yield due to price effects and changes in trade flows. Overall, results indicate that climate change impacts, as evidenced by declining crop yields, are less severe in SSA compared with other regions like Asia because yield levels are much lower to start with, and fertilizer application is limited. These same conditions make SSA much more vulnerable to climate change, particularly because low yield levels and limited agricultural inputs are combined with a high dependence on rainfed agriculture and high poverty levels.