Balancing risks: How global trade dependence exacerbates and supply diversity mitigates yield failures under compound drought and heat events

Global climate change poses critical challenges to food security and market stability as extreme weather events become increasingly frequent and severe. The combined effects of compound extreme events and global trade dynamics on food security, however, remain insufficiently explored. Here, we employed a copula-based statistical approach, integrating international trade data to estimate maize yield failures under compound drought and heat events (CDHEs) and to assess how global trade dependence and supply diversity impact food security under such stressors. Our findings reveal a 70.1% probability of global maize yield failure as CDHE intensity increases, with key breadbasket regions, including Northeast China, Europe, North America, Latin America, and South Africa, particularly vulnerable. Both drought and heat events contribute similarly to global maize yield risk; however, regional desynchronies, such as distinct effects in China and Brazil, highlight differing vulnerabilities. Furthermore, countries heavily dependent on imports from regions with high yield failure risk, such as Vietnam and Colombia, face an increased probability of maize yield failure exceeding 40%. Conversely, supply diversity offers a modest buffering effect, mitigating some adverse impacts of CDHEs, albeit with notable uncertainties. Our findings underscore the compounded vulnerability of maize yields to CDHEs, intensified by trade dependencies, while highlighting the potential for supply diversification to enhance resilience. Urgent adaptations, transformative strategies, and policy interventions are critical to mitigate cascading risks within the global food system, bolster resilience to climate change, and ensure food security.