Modelling climate change impact on rice growth and yield in northwest Bangladesh

Assessing the impact of climate change is crucial for addressing the challenges of sustaining and increasing rice production. This study employed the APSIM model driven by climate data from 27 global climate models under SSP245 and SSP585 emission scenarios to evaluate climate change effects on irrigated and rainfed rice in three key rice-growing regions (Rangpur, Bogura, and Rajshahi) in northwest Bangladesh. Relative changes in climate variables, rice yield, and yield components were analysed for the near future (NF: 2031–2065) and far future (FF: 2066–2100), compared to a baseline period (1988–2022). Results indicate a substantial increase in temperature during FF under the SSP585 scenario, with maximum temperature rising by up to 3.3°C (3.1°C) and minimum temperature up to 3.7°C (3.3°C) during irrigated (rainfed) rice seasons. This increase could shorten the growth period of irrigated and rainfed rice by up to 18 days and 10 days, respectively, under SSP585. Rice yields were projected to increase in the NF by up to 14.7% (irrigated) and 6.5% (rainfed) under SSP245. However, yields were expected to decline in the FF by 21% (irrigated) and 11% (rainfed) under SSP585 scenario. These projected yield changes are primarily explained by variations in spikelet number (NSP) and spikelet fertility (SPFERT) across locations. While projected climate conditions enhance NSP by 22% (irrigated) and 11% (rainfed) due to increased CO₂ concentration and solar radiation, SPFERT was projected to decline sharply, by up to 47% and 35% in irrigated and rainfed rice seasons, respectively, in the FF under SSP585. The change in SPFERT was largely attributed to the change in elevated maximum temperatures during the anthesis period across the locations. While yields may increase in NF, an adaptation strategy is needed to sustain rice production during far future in Bangladesh.