Simulation of future global warming scenarios in rice paddies with an open-field warming facility

Rice (Oryza sativa L.) is a staple food for more than 3 billion humans, mainly in Asia. Its demand will increase because the world's population is expected to reach 9.1 billion by year 2050, including 5.5 billion in Asian countries [1]. Despite a high degree of yield increase, mainly due to Green Revolution technologies, average rice yields show a high magnitude of instability depending on weather and monsoon anomalies [2]. Climate change in addition to high population growth is pressuring the thin margin between supply and demand of rice [3]. Most of our insights regarding impacts of climate change consider observed and predicted changes in temperature over the next century [4]. By the end of this century, global surface air temperature is expected to have increased by 1.1-6.4°C relative to the average temperature during 1980-1999. The best estimate for the expected air temperature increase for Intergovernmental Panel on Climate Change (IPCC) low population growth scenario (B1) is 1.8°C with likely range of 1.1°C to 2.9°C, while the best estimate for a high growth scenario (A2) is 3.4°C with likely range of 2.0 to 5.4°C [5].There is substantial spatiotemporal, seasonal, and inter-annual variability in the warming trend. A faster increase in nighttime temperature than daytime temperature is reported for Jiangsu province [6]. Most of the studies conducted to investigate the effect of temperature on different aspects of plants are based on diel mean air temperature, assuming there is no differential influence of nighttime and daytime temperatures [7]. However, the negative impact of high nighttime temperature on rice production is greater than that of daytime or daily mean temperatures [8]. Peng et al., found a 10% decrease in rice grain yield for each 1°C rise in nighttime minimum temperature, while yield was not significantly affected by a rise in daytime maximum temperature [7]. Recently, a trend of increasing differential between daytime and nighttime temperatures