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

Abstract

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.

Role of Modelling in International Crop Research: Overview and Some Case Studies

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Analysis of rice yield response to various cropping seasons to develop optimal cropping calendars in Mwea, Kenya

“…Africa is far from self-sufficient in rice, and this situation is projected to worsen in the future (van Oort & Zwart, 2018). There are five options to close the gap between demand and production: (1) expansion of land under cultivation, (2) intensification in existing farmlands by growing two or three crops a year, (3) narrowing the yield gap in farmers' fields by introducing new technologies, (4) raising yield ceiling by introducing highyielding cultivars, and (5) reducing postharvest losses (van Oort et al, 2015).…”

Global Spatial Distributions of and Trends in Rice Exposure to High Temperature

“…Moreover, the Representative Concentration Pathway (RCP), which is commonly used in future crop yield simulation research, is a greenhouse gas concentration trajectory adopted by the IPCC for its fifth Assessment Report (AR5) in 2014. Dias identified the yield and growth changes in rice under the global climate change scenario RCP 8.5 [26]; Dar focused on simulating the effect of climate change on crop yield with the Decision Support System for Agrotechnology Transfer (DSSAT) v 4.6.1 under RCP4.5 scenario [27]; Chun applied a multi-scale crop modeling approach to assess the impacts of climate change on future rice yields in southeast Asia under the RCP 4.5 and RCP 8.5 scenarios [28]; Van Oort calculated the impacts of climate change on rice production in Africa under four kinds of RCP scenarios [29]; Kim predicted potential epidemics of rice leaf blast and sheath blight in South Korea under the RCP 4.5 and RCP 8.5 scenarios [30]; Zhang investigated the spatio-temporal change in extreme temperature stress across China under the RCP (2.6, 4.5, 6.0, and 8.5) scenarios [31]. Therefore, for future rice research, RCP provides a reliable and easy way for calculations, which is the reason why this paper chooses RCP as the future scenarios.…”