Title: Climate storylines for assessing compound events and extreme crop impacts

Abstract: The United States (US), Brazil, and Argentina collectively produce about 75% of the world’s soybean supply. In 2012, soybean crops failed in these three major producing regions due to spatially compound hot and dry weather across North and South America. This led to unprecedented shortages in the global supply, resulting in record-high market prices. Despite the severity of this event, the role of historical and future anthropogenic warming in influencing such occurrences remains unknown. Here, we present different impact storylines of the 2012 event by imposing the same seasonally evolving atmospheric circulation in pre-industrial, present-day (+1°C above pre-industrial), and future (+2°C above pre-industrial) climates. Our results demonstrate that anthropogenic warming strongly amplifies the impacts of such a large-scale circulation pattern on global soybean production. Although the drought intensity is similar under different warming levels, larger crop losses are driven not only by warmer temperatures but also by stronger heat-moisture interactions. We estimate that 51% (47-55%) of the global soybean production deficit in 2012 is attributable to climate change. Future warming (+2°C above pre-industrial) would further exacerbate production deficits by 58% (46-67%) compared to present-day 2012 conditions. This highlights the increasing intensity of global soybean production shocks with warming requiring urgent adaptation strategies.