FACE-ing climate change: Propagation of risks and opportunities for cropping systems in mid-high-latitude regions: A case study between U.S. and China corn belts

Anthropogenic activities are leading to increased concentrations of greenhouse gases, especially CO₂, in the atmosphere. This is threatening the resilience of cropping systems, although many crops show strong adaptation abilities. How interactions between climate change and increases in the atmospheric CO₂ concentration ([CO₂]) will ultimately affect regional crop production, including growth processes and water utilization, is not well understood. Climate variability has different effects on agriculture depending on the type of water resources (i.e., rain-fed vs. irrigated crops). To date, however, there have been no reports on disparities in the responses of crop productivity and water consumption to climate change between irrigated and rain-fed agricultural production at identical latitudes. We aimed to compare the responses of maize crops, in terms of productivity and water consumption, between two mid-high latitude regions under various climate change scenarios, with and without considering the effects of elevated [CO₂]. The Southwestern Plain of the Great Lakes (SPG) located in the U.S. Corn Belt and the Northeast Plain (NEPC) located in the China Corn Belt were selected as irrigated and rain-fed case study areas, respectively. Using the Agricultural Production Systems sIMulator with three global climate models under two representative concentration path emission scenarios in combination with six CO₂ trajectories, the risks and opportunities of global warming for maize crops, in terms of growth and water consumption, were characterized at a regional scale from the viewpoint of the water footprint concept. The influence of climate warming on maize crops will be stronger in the SPG than in the NEPC in terms of the future average length of the whole growing season duration (GSD-w), yield, and water consumption. The sowing date and maize variety were kept constant in these simulations. The model predicted that the protective effect of elevated [CO₂] on maize GSD-w will not be as significant as that on yield. Our results indicate that elevated [CO₂] could reduce the water intensity per unit yield of maize by 159.2 m³/t, on average, in the two study regions. The results of this study provide insights into the risks and opportunities of climate change for irrigated and rain-fed maize cropping systems in mid-high-latitude regions.