Potential impact of climate change on cereal crop yield in West Africa

Resilience of crops to climate change is extremely critical for global food security in coming decades. Decrease in productivity of certain crops as a consequence of changing climate has already been observed. In West Africa, a region extremely vulnerable to climate change, various studies predicted significant reduction in productivity of the major crops because of future warming and shift in precipitation patterns. However, most studies either follow statistical approaches or involve only specific sites. Here, using a process-based crop model at a regional scale, we project the future changes in cereal crop yields as a result of climate change for West African countries in the absence of agricultural intensification for climate adaptation. Without adaptation, the long-term mean of crop yield is projected to decrease in most of the countries (despite some projected increase of precipitation) by the middle of the century, while the inter-annual variability of yield increases significantly. This increase of yield variability is attributed to an increase of inter-annual variability of growing season temperature and/or precipitation in future climate scenarios. The lower mean yield and larger year-to-year variation together make the regional food security extremely volatile. For a comprehensive understanding of climate change impact on crop yield, the distribution of temperature and precipitation over specific growth stages, in addition to growing season averages, should be accounted for. Although uncertainties are rife in calibrating and running a process-based crop model at regional scale, the present study offers insight into potential vulnerabilities of the agricultural system in specific countries or West Africa as a whole because of regional climate change.