Why do crop models diverge substantially in climate impact projections?

Robust projections of climate impact on crop growth and productivity by crop models are key to designing effective adaptations to cope with future climate risk. However, current crop models diverge strongly in climate impact projections (Asseng et al., 2013, 2015). Previous studies tried to compare or improve crop models regarding the impact of one single climate variable (Asseng et al., 2013, 2015; Wang et al., 2017; Durand et al., 2018). However, this approach is insufficient, considering that crop growth and yield are affected by the interactive impacts of multiple climate change factors and multiple interrelated biophysical processes. Here, a new comprehensive analysis was conducted to look holistically at the reasons why crop models diverge substantially in climate impact projections and to investigate which biophysical processes and knowledge gaps are key factors affecting this uncertainty and should be given the highest priorities for improvement.