Increased Water Use for Crop Production in Africa: Policy Implications

Vanham, Davy; Gunathilake, Dahami; Thowfeek, Asma; Cofie, Olufunke O.

Increased Water Use for Crop Production in Africa: Policy Implications

Autores

Editor

International Water Management Institute

Descripción

Africa needs to increase food production to feed a growing population with a healthy nutritious diet. Food production depends on limited available water resources. Many African regions already face water scarcity today, as not only agriculture needs water but also other sectors. For informed decision making it is imperative to know how much water is used for African food production. A new IWMI led study finds that African crop production amounts to a blue and green water consumption (WC) of 119 and 1,087 km³ respectively for the year 2020, showing a high dependency on rainfed agriculture. Blue water refers to water in rivers, lakes, wetlands and aquifers. Green water is the soil water originating from precipitation. The study provides crop WC amounts for 46 different crops in a spatial resolution of 10 kilometers, that can be aggregated to (sub)national or river basin level. All results and the model to compute them are freely available to any stakeholder. The researchers found that blue and green WC have increased in Africa from 2010 to 2020, while producing more food, driven by an increase in harvested areas, leading to additional pressure on limited water resources in African river basins. Overall, crop water productivity has increased during this period. Crop yields generally remain low though and should be increased on existing agricultural lands to avoid agricultural land expansion at the expense of natural ecosystems. Expansion of irrigation is an important strategy to increase yields and make African crops more resilient to climate change, accounting for local water availability and the growing demand of other sectors. African average irrigation efficiency of blue water is with 53% rather low and should be increased. Strategies should account for the different water footprints of crops and critically evaluate the costs and benefits of cash crop exports outside Africa. Policies related to crop production need to embed nexus thinking and should be data and science based.