Decreasing wheat yield stability on the North China Plain: Relative contributions from climate change in mean and variability

There has been increasing interest in understanding climate change impacts on crop yield stability, including interannual yield variability and lower yield extremes, in addition to mean yield. In this study, we evaluated these impacts on wheat yield and investigated the contribution of changes in climate mean and variability, and their interaction, on the North China Plain (NCP). Wheat yield simulation experiments with control groups were conducted using the Crop Environment Resource Synthesis (CERES) model, with multiple general circulation model ensembles under two representative concentration pathways (RCPs), namely 4.5 and 8.5. Climate change was projected to reduce mean yield by 15 and 17%, increase yield interannual variability by 5 and 11%, and reduce 10-year return period lower yield extremes by 31 and 34% under RCPs 4.5 and 8.5, respectively. When analysed, changes in climate mean proved the main cause for changes in mean yield (62-71%), followed by the interactive changes in climate mean and variability (26-33%). As for the impact on yield variability, the interaction of the changes in climate mean and variability proved the main cause (48-54%), followed by changes in climate mean (33-41%). Surprisingly, climate change in variability contributed the least in both cases. Our results pertaining to the decrease in both availability and stability of wheat yield on the NCP presents a greater challenge for building a resilient food system for local areas than before. They also highlighted the importance of separating the impacts of changes in climate mean and variability on crop yield stability in a holistic framework, with particular attention paid to the tangible and interactive effects.

Automated summary

The study assessed the impacts of climate change on wheat yield stability, with findings indicating that changes in climate mean were the main driver for yield changes, followed by the interactive changes in climate mean and variability impacting yield variability.