Abstract
Considerable attention has been given to climate change and its impacts. Agriculture is of special concern as it is the primary source of food and is dependent on weather. There is a wide range of estimated climate change impacts for the 21st century over a large number of regions. The impact of climate change on agriculture is estimated to be large, even in the face of large uncertainties. In this prospect, several studies highlight the importance of adaptation mechanisms to limit the negative effects. This study builds on the literature by conducting a comprehensive assessment of climate change impacts on the most commonly grown crops in Sub-Saharan Africa (SSA).
To provide a climate change impact assessment specific to SSA, this study focuses on the four most extensively grown crops (cassava, maize, millet and sorghum). Additionally, to estimate the effect of climate change on food production, this study estimates both crop productivity and supply responses to weather changes.
A first set of econometric analyses estimate the effect of weather on crop yields using basic weather variables. Alternative specifications using more refined weather parameters establish similar effects, and also quantify the effect of droughts and floods. The analyses reveal a significant impact of temperature, precipitation, evapotranspiration, floods and droughts on crop yields. The analyses also reveal that, in general, precipitation and temperature changes have a larger impact on crop yields in countries with less favourable agricultural conditions (LFAC). The estimation of CO2 fertilization effects on crop yields reveals significant effect of CO2 concentrations on millet yields but not yields for other crops.
A second set of econometric analyses estimate the effect of weather and climate on farmers’ cropping decisions. The analysis reveals that, in general, crop prices do not influence farmers’ decisions regarding the quantity of land to allocate to crops. Alternatively, the regression analyses suggest that farmers respond to export crop prices. The regressions results also indicate that farmers from LFAC countries appear more responsive to export crop prices than non-LFAC farmers. Farmers’ supply decisions are also influenced by weather and climate. Additionally, the regressions show a negative effect of precipitation variability and temperature variability on area allocated to some crops, indicating that, as climate risk increases, farmers participate in other activities or diversify toward other crops.
Crop productivity and supply estimates producing the most accurate predictions are used to construct predictions of crop yields, area cultivated and ultimately production under 20 climate change scenarios. Impacts are predicted for each crop for SSA in aggregate and for the preferred crop for each region. When considering both climate change and technological changes, the analyses estimated a general increase in crop areas and yields in the 21st century compared to the late-1900s. However, compared to a scenario of no climate change, the impact of climate change on agriculture in SSA is negative, as crop yields and production are predicted to decrease compared to a reference scenario.