Climate fingerprints of Multi-Crop Multi-Breadbasket failures

The worlds food system is highly dependent on just a few crops, with 60% of caloric intake coming from maize, soya beans, wheat, and rice. Most of these crops are produced in just a few regions, the so-called breadbaskets of the world, making the global food system vulnerable to multi-crop multi-breadbasket failures. Moreover, climate change is increasing the chance of crop failures, due to an increase in compounding hot and dry extremes. Starting from the impact, we use an innovative data-driven method called Archetype Analysis to identify crop yield losses. We show that global multiple-crop multi-breadbasket (MCMB) yield failure is associated with specific climatic fingerprints, including hot-dry conditions, wave-like anomalies in the atmospheric circulation, and distinct sea surface temperature (SST) imprints across the globe. We identify so-called adverse archetypes, recurring representing global crop yield losses, for each individual crop type and all of them combined. These adverse archetypes are accompanied by simultaneous hot-dry-surface imprints across the world, highlighting these high-risk crop failure scenarios are driven by climate extremes. Worryingly, we find that the accompanying SST fingerprints of MCMB failure are increasing in frequency in observations, consisting of La Niña like and negative PDO conditions. However, the response of these climate modes of variability due to anthropogenic activities is not yet fully understood and climate models often inaccurately reproduce the observed SST and atmospheric circulation trends. Thus, the fact that our results indicate that simultaneous crop failures are linked to distinct SSTs and atmospheric circulation anomalies, highlights the deep uncertainty we currently face regarding food security in the future.