Heading toward a famine: modeling seasonality of malnutrition in Yemen, 2018-2023.

Yemen continues to experience one of the most severe child malnutrition and food insecurity crises on the planet. Seasonal synchronization of malnutrition often serves as an early marker of emerging famine. In this study we compiled data collected by the humanitarian agencies on several potential drivers of malnutrition such as food insecurity, conflict events, and environmental indicators (rainfall, temperature, and normalized difference vegetation index) in Yemen from 2018 to 2023. We characterized the seasonality of malnutrition outcomes and explore spatiotemporal synchronization using non-linear time series analyses. Our findings demonstrate significant seasonal profiles in child malnutrition, which could be synchronized with the peak in food insecurity and peaks in environmental indicators. The quantification of seasonal characteristics in term of seasonal peaks and their amplitude pave the way to build strong foundation for deeper understanding of famine evolution from a complex system perspective by defining processes and triggers that amplify malnutrition and escalate faming formation.