Estimating resilience of annual crop production systems: theory and limitations

Agricultural production is affected by climate extremes, which are increasing because of global warming. This motivates the need of a proper evaluation of the agricultural production systems resilience to enhance food security, market stability, and the general ability of society to cope with the effects of climate change. Resilience is generally assessed through holistic approaches involving a large number of indicators for the environmental, social and economic factors that influence food availability, access and utilization. Here, we investigate the problem of measuring resilience in a simplified framework, focusing on the crop production component of the agricultural system. For an idealized production system composed of a single crop, using the original definition of resilience, we identify the best combination of the mean and the variance of annual crop production data to estimate crop resilience i.e. the crop resilience indicator. Through numerical experiments conducted with a conceptual crop model, we show the general properties of this indicator applied to production systems for different levels of adaptation to climate variability and in case of increasing frequencies of extreme events. Finally, we discuss the applicability of the proposed approach to real agricultural production systems and the expected effects of crop diversity on the resilience of crop production systems, following directly from the mathematical definition of the crop resilience indicator.