Effects of Changes in Climatic Means and Variability on Future Wheat and Maize Yields and the Role of Adaptive Agro-Technologies in Reducing Negative Impacts

Abstract

To address the rising global food demand in a changing climate, yield gaps (YG), the difference between attainable yields under irrigated (YP) or rainfed conditions (YWL) and actual farmers’ yields (Ya), must be significantly narrowed whilst raising potential yields. Here, we examined the likely impacts of climate change (including changes in climatic variability) and shifts in agricultural technologies on crop yields and yield gaps. Eight rigorously tested crop simulation models were calibrated for wheat and maize and run at ten different sites worldwide. Simulations were performed to estimate YP and YWL, as well as yields achievable under three locally defined technology packages: TP0 represents current average farmer’s practice, while TP1 and TP2 are increasingly advanced technologies, i.e. improved cultivars and optimised water and fertilisation management. Simulations were run for the baseline (1980-2010) and twelve future climate scenarios for 2050, representing changes in the means of climate variables and in the variability of daily temperature and duration of dry spells. Our fundamental hypotheses were that (H1) mean climate changes combined with increased weather variability lead to markedly more negative yield impacts than mean changes alone, and (H2) advanced technologies would serve as effective adaptations that also reduce yield gaps under future climatic conditions. 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, reductions of yield gaps varied substantially among sites. Future studies should consider a broader range of climate change scenarios and tackle the challenge of analysing various aspects of 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 wider range of local stakeholders.

Keywords: adaptation, Climate change impacts, crop modelling, food security, technology change, yield gap