The effects of projected climate change and extreme climate on maize and rice in the Yangtze River Basin, China

Abstract

crop yield is highly sensitive to climate change and extreme climate. Here, the impact of climate change and extreme climate was assessed based on the climate variable outputs from 17 General Circumstance Models (GCMs) in the Coupled Model Inter-comparison Project phase five (CMIP5) dataset, a statistically downscaling method, a series of 12 extreme climate indices selected from the Expert Team on Climate Change Detection and Indices (ETCCDI) calculated using the downscaled climate variable outputs and a process–base Crop Simulation Model (CSM). The climate variable outputs consist history data series (1961–2005) of GCMs simulation used as baseline, future period (2006–2050) including two Representative Concentration Pathways (RCPs), 4.5 and 8.5 in the Yangtze River Basin. The results showed that: (1) the mean temperature and precipitation in growing season would increase for 81 stations for the future period under RCP4.5 and RCP8.5 relative to baseline in the Yangtze River Basin. In contrast, the mean downward shortwave solar radiation in growing season at most sites presented an upward trend for the future period under RCP4.5 and RCP8.5 relative to baseline in the Yangtze River Basin; (2) the maize and rice yield was projected to decrease by approximately 5.36% and 2.55% under RCP4.5 and 6.04% and 2.48% under RCP8.5, respectively, relative to baseline with consideration of the CO2 effect; (3) The maize and rice yield would be lowered by 2.995% and 2.268% with a 1 °C increase in the mean growing season temperature, respectively. Conversely, the maize and rice yield would increase by approximately 6.947% and 2.885% with a 1 MJ m−2 increase in the mean growing season downward shortwave solar radiation, respectively. Extreme climate indices were strongly correlated with the maize and rice yield, especially in the number of days above temperature threshold, maximum number of consecutive days with precipitation <1 mm, maximum daily highest temperature, number of heavy precipitation when precipitation ≥10 mm and precipitation ≥20 mm in the Yangtze River Basin. Although uncertainties might arise from not considering the adaptation strategies, this study highlights how climate change including temperature, solar radiation, water use and extreme climate will affect the maize and rice yield in the Yangtze River Basin.