Potential yields of two staple cereal crops worldwide under global warming

Most studies on model-estimated yield potential of crop under climate change are based on the principle of production function, for specific variety, from static biological dimension and at local or regional level, while few theoretically are based on time-series approach for world crop from dynamic evolutionary angle and on global scale. Therefore we conducted following research in 2019 to 2023 at Guiyang City of China: potential yields of rice and wheat worldwide by 2030 are projected creatively using Auto-regressive Integrated Moving Average and Trend-regressed model based on their history since 1961, in which the projections are tested by actual yields in recent two years and further validated by Gray System model; the impacts of global warming on past production of rice and wheat worldwide since 1961 are analyzed using binary regression model in which global mean temperature is treated as the independent variable while the crop yield as the dependent variable. Our results show that: in the future between 2022 and 2030, average yield of world rice is projected to be from 4876 kg/ha to 5195 kg/ha whereas that of world wheat from 3548 kg/ha to 3817 kg/ha; top (national) yield of world rice is projected to be from 10148 kg/ha to 10269 kg/ha whereas that of world wheat from 9914 kg/ha to 10042 kg/ha; or the ratio between average and top yields of world rice will be from 48.05% to 50.59% whereas that of world wheat from 35.79% to 38.01%; since 1961, global warming exerts a negative impact on average yield of world rice less than on its top, and a positive effect on average yield of world wheat while a negative one on its top, which partially drives the gap between average and top yields of world rice slightly narrowed and that of world wheat gradually closed. These findings indicate that: given that top yield is considered potential limit of average yield, to improve global production of these two staple cereal crops by 2030, the priorities should be given to rice as well as wheat worldwide in their both high and low yield countries.