The future of hot and dry events in the breadbasket regions of maize

Abstract

Heatwaves and dry spells can severely impact crop yields, making it crucial to understand the nature of these events to ensure food security in a changing climate. We use the Max Planck Institute Grand Ensemble to examine the occurrence of hot-dry extremes in key crop-producing regions known as 'breadbasket regions', either in single or multiple breadbasket regions simultaneously, focusing on the differences between 1.5 degrees C and 2 degrees C global warming scenarios. Our findings reveal strong increases in hot-dry events across all individual breadbasket regions between 1.5 degrees C and 2 degrees C of global warming, with ensemble mean probabilities indicating that occurrences more than double in South Asia and triple in East Asia. Moreover, the likelihood of multiple breadbasket regions experiencing extreme events simultaneously increases significantly between 1.5 degrees C and 2 degrees C of warming. Scenarios that were historically considered virtually impossible and very unlikely under 1.5 degrees C, such as at least four regions being affected by hot-dry events in the same growing season, could occur with a 1-in-14 year likelihood under 2 degrees C of warming. We find that, among the breadbasket regions, Central Europe, East Asia, and Central North America most often experience these events simultaneously within the same growing season. Between 1.5 degrees C and 2 degrees C warmer worlds, the probability of simultaneous occurrence increases the most for the connection between these regions. In contrast, South Asia is least likely to be affected simultaneously with other regions, possibly providing insights for risk management.