The changes in the effects of temperature and rainfall on cereal crop yields in Sub-Saharan Africa: a country level panel data study,1989 to 2004

The harsh agro-climatic endowment is among a host of factors underlying the absence of a Green Revolution in Sub- Saharan Africa (SSA) since high-yielding agricultural technologies tend to be resource-demanding and thus applicable only to agro-ecologically favorable production environments. While in Asia some empirical studies indicate that the climate sensitivity of major cereal crops has begun to be mitigated and there are now both resource-demanding and resource-efficient types of technologies adopted, in SSA almost no such evidence has empirically been reported to date. This paper uniquely examines the changes over time in the effects of climatic conditions on cereal crop yields in Sub- Saharan Africa from 1989 to 2004. Using a 16-year country-wise panel dataset, the yield equations for five major crops (wheat, rice, maize, sorghum, and millet) are estimated by a combination of two-way fixed effect and sample selection models. It is found that the temperature effect was mitigated for maize and aggravated for millet, whereas the rainfall dependency declined for rice and was augmented for wheat and maize. The results suggest that changes in technologies and other supplementary factors contributed to the changes in agro-climate effects, though the directions of changes are different for different crops, depending on the type of adopted technologies. In addition, on average during the period under study, the temperature effects on cereal yields are generally negative while the rainfall effects are positive except for sorghum and millet