Global warming is causing a decline in rice yields due to increased nighttime temperatures. A study conducted at the International Rice Research Institute (IRRI) Farm from 1979 to 2003 found that annual mean minimum temperatures increased by 1.13°C, while maximum temperatures increased by 0.35°C. The study showed a close relationship between rice grain yield and mean minimum temperature during the dry season (January to April). Grain yield declined by 10% for each 1°C increase in minimum temperature during the dry season, while maximum temperature had no significant effect. This study provides direct evidence that increased nighttime temperatures, associated with global warming, are reducing rice yields. The study analyzed weather data and crop yield data from irrigated field experiments conducted at the IRRI Farm. It found that mean minimum temperatures increased by 1.33°C in the dry season and 0.80°C in the wet season from 1979 to 2003. Mean radiation also increased during this period. The study found a strong negative linear relationship between above-ground total biomass and minimum temperature in the dry season. Biomass production decreased by approximately 10% for each 1°C increase in minimum temperature. Similarly, spikelets per square meter were negatively related to minimum temperature in the dry season. The study also found that grain yield and yield attributes were not related to minimum temperature, maximum temperature, or radiation in the wet season. This could be due to less year-to-year variability in temperature and radiation in the wet season. The study highlights the need for greater fundamental understanding of the effects of night temperature on physiological processes governing crop growth and yield development. Current crop-growth models will need further refinement to account for the differential effects of minimum and maximum temperatures on respiration, morphological traits, and phenological development.Global warming is causing a decline in rice yields due to increased nighttime temperatures. A study conducted at the International Rice Research Institute (IRRI) Farm from 1979 to 2003 found that annual mean minimum temperatures increased by 1.13°C, while maximum temperatures increased by 0.35°C. The study showed a close relationship between rice grain yield and mean minimum temperature during the dry season (January to April). Grain yield declined by 10% for each 1°C increase in minimum temperature during the dry season, while maximum temperature had no significant effect. This study provides direct evidence that increased nighttime temperatures, associated with global warming, are reducing rice yields. The study analyzed weather data and crop yield data from irrigated field experiments conducted at the IRRI Farm. It found that mean minimum temperatures increased by 1.33°C in the dry season and 0.80°C in the wet season from 1979 to 2003. Mean radiation also increased during this period. The study found a strong negative linear relationship between above-ground total biomass and minimum temperature in the dry season. Biomass production decreased by approximately 10% for each 1°C increase in minimum temperature. Similarly, spikelets per square meter were negatively related to minimum temperature in the dry season. The study also found that grain yield and yield attributes were not related to minimum temperature, maximum temperature, or radiation in the wet season. This could be due to less year-to-year variability in temperature and radiation in the wet season. The study highlights the need for greater fundamental understanding of the effects of night temperature on physiological processes governing crop growth and yield development. Current crop-growth models will need further refinement to account for the differential effects of minimum and maximum temperatures on respiration, morphological traits, and phenological development.