Effects of changes in climatic means, variability, and agro-technologies on future wheat and maize yields at 10 sites across the globe

To address the rising global food demand in a changing climate, yield gaps (Y_G), the difference between potential yields under irrigated (Y_P) or rainfed conditions (Y_WL) and actual farmers’ yields (Y_a), must be significantly narrowed whilst raising potential yields. Here, we examined the likely impacts of climate change (including changes in climatic variability) and improvements in agricultural technologies on crop yields and yield gaps. Eight rigorously tested crop simulation models were calibrated for wheat and maize and run at 10 different sites around the world. Simulations were performed to estimate Y_P, Y_WL and yields achievable under three locally defined technology packages: TP₀ represents average farmer's practice, while TP₁ and TP₂ are increasingly advanced technologies. Simulations were run for the baseline (1981–2010) and twelve future climate scenarios for 2050, representing changes in the means of climate variables and in the variability of daily temperature and dry/wet spell durations. Our basic hypotheses were that (H1) mean climate changes combined with increased weather variability lead to more negative yield impacts than mean climate changes alone, and (H2) advanced technologies would serve as effective adaptations under future climatic conditions. We found that crop responses were dependent on site characteristics, climate scenarios and adopted technologies. Our findings did not support H1. As for H2, the improved technology packages increased wheat and maize yields at all sites, but yield gap reduction varied substantially among sites. Future studies should consider a broader range of climate scenarios and methods for analysing potential shifts in climate variability. Moreover, it is recommended to co-create and evaluate climate zone-specific climate-smart crop production technologies in interaction with a wide range of local stakeholders.