Impacts of climate change on rice production in Africa and causes of simulated yield changes

• Published in: Global change biology Vol. 24; no. 3; pp. 1029 - 1045
• Main Authors: van Oort, Pepijn A. J., Zwart, Sander J.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.03.2018; John Wiley and Sons Inc
• Subjects: Acclimatization; Adaptation; Africa; Biological fertilization; Carbon dioxide; Climate Change; Climate effects; cold induced sterility; Crop and Weed Ecology; Crop production; Crop yield; Dry season; Eastern Africa; Environmental impact; Fertilization; Food Supply; grain yield; heat; heat induced sterility; heat sums; High temperature; highlands; irrigated; irrigation; Irrigation systems; Mineral nutrients; nutrient management; Oryza; Oryza - growth & development; Photosynthesis; Primary; Primary s; rainfed; Rainfed farming; Rainy season; Rice; Seasons; Simulation; sowing date; Sterility; Temperature; Water; Water availability; Western Africa; Wet season; West Africa; East Africa; Africa; Western Africa; Eastern Africa; photosynthesis; heat induced sterility; rainfed; Africa; cold induced sterility; rice; irrigated; climate change
• ISSN: 1354-1013; 1365-2486; 1365-2486
• DOI: 10.1111/gcb.13967

This study is the first of its kind to quantify possible effects of climate change on rice production in Africa. We simulated impacts on rice in irrigated systems (dry season and wet season) and rainfed systems (upland and lowland). We simulated the use of rice varieties with a higher temperature sum as adaptation option. We simulated rice yields for 4 RCP climate change scenarios and identified causes of yield declines. Without adaptation, shortening of the growing period due to higher temperatures had a negative impact on yields (−24% in RCP 8.5 in 2070 compared with the baseline year 2000). With varieties that have a high temperature sum, the length of the growing period would remain the same as under the baseline conditions. With this adaptation option rainfed rice yields would increase slightly (+8%) but they remain subject to water availability constraints. Irrigated rice yields in East Africa would increase (+25%) due to more favourable temperatures and due to CO2 fertilization. Wet season irrigated rice yields in West Africa were projected to change by −21% or +7% (without/with adaptation). Without adaptation irrigated rice yields in West Africa in the dry season would decrease by −45% with adaptation they would decrease significantly less (−15%). The main cause of this decline was reduced photosynthesis at extremely high temperatures. Simulated heat sterility hardly increased and was not found a major cause for yield decline. The implications for these findings are as follows. For East Africa to benefit from climate change, improved water and nutrient management will be needed to benefit fully from the more favourable temperatures and increased CO2 concentrations. For West Africa, more research is needed on photosynthesis processes at extreme temperatures and on adaptation options such as shifting sowing dates. In the Sahel zone in West Africa, temperature rise will lead to large rice yield declines. However, more investigation to understand the response of rice plants to extreme temperatures and adaptation options is needed. In East Africa temperature rise leads to new opportunities for rice the colder highlands