Cropping Systems under Climate Change and Adaption in the Nile basin

Most assessments of the vulnerability of agriculture to climate change do not differentiate between the impacts of climate change on the different cropping systems. However, with the Nile basin dominated by different cropping systems, assessments without examining the influence of climate change on the different cropping systems may bias the understanding of climate change impacts on agriculture. In this study, we use bias corrected climate change data from the sixth phase of the Coupled Model Intercomparison Project (CMIP6) and a regionally calibrated SWAT+ model to implement the different cropping systems and assess the impact of climate change on the crop yields from the different cropping systems with in the Nile basin. We assess both a ‘no adaptation scenario’ and an ‘adaptation scenario to a longer cultivar’.

Our analyses show that 36.3 % of the crop area in the Nile basin is under multiple (double) cropping. Results show that the combined mean crop yields in the basin decrease by 10.3 ± 1.3 % with future warming under a ‘no adaptation scenario’ but increase by 13.0 ± 4.3 % under an ‘adaptation scenario to a longer cultivar’. The decrease in mean crop yields under a ‘no adaption scenario’ was mainly attributed to the shortening of the maturity period due to increased projected temperature. The decrease signal is stronger in all the single cropping systems (1.3 – 24.6 %) as opposed to the double cropping system (0.3 – 13.3 %) under the no adaption scenario depending on the GCM (General Circulation Model). Likewise, the increase signal is stronger in double cropping systems (9.0 – 19.7 %) compared to the single cropping systems (3.5 – 8.4 %) under the ‘adaptation scenario to a longer cultivar’. Thus, farmers in the Nile basin can possibly benefit from double cropping (higher cropping intensities) systems while reducing the negative impacts of climate change on crop yields. Additionally, adapting to different crop cultivars can potentially abate the impacts of future warming on yields of selected crops.