# **1 Introduction**

“Zero Hunger” is the second of the 17 United Nations (UN) Sustainable Development Goals adopted by all Member States in 2015. Achieving this target by 2030 is a central challenge, as the UN Food and Agricultural Organization (FAO) reports more than 2 billion people are currently estimated to suffer from hunger or food insecurity (FAO, 2019). Globally, more than 820 million people are undernourished. About 20% of those undernourished are located in Africa, in particular the Sub-Saharan Africa region, which has also experienced the fastest rise of malnutrition (FAO, 2019). The topic has gained renewed attention due to famines in Somalia in 2011-12 and the “four famines” (Maxwell et al., 2020) that took place in the Republic of Yemen in 2016 and South Sudan, Somalia, and northeast Nigeria since 2017. In their recent report, the World Food Programme (WFP) stresses the additional burden the COVID-19 pandemic imposes on already acutely food-insecure populations (WFP, 2020). As of the time of writing, the FAO raised a food crisis warning as locusts swarms are ravaging crops and pasture in East Africa (FAO, 2020).

In the fight to eradicate hunger, some major recent developments were made in the measurement and classification of food insecurity. For instance, the Food Insecurity Experience Scale (FIES) used in the SDGs distinguishes between three levels of severity: food security or mild food insecurity, moderate food insecurity, and severe food insecurity. In the latter stage, people have typically run out of food and have not eaten for one or more days. Different from this survey-based approach, the Integrated Food Security Phase Classification (IPC) system was developed to support decisionmaking with a clear analytical focus. The Food Security and Nutrition Analysis Unit (FSNAU) of the FAO pioneered this system in Somalia in 2004. Since then, the IPC framework has been adopted by various international organization and humanitarian response agencies. In our study, we rely on IPC data published by the Famine Early Warning Systems Network (FEWS NET).

The IPC framework is constructed to track and alert international and civil organizations to food insecurity situations, ultimately aiming to prevent the most extreme case (famine) at all costs. The IPC scale has five phases of acute food insecurity, where Phase 1 represents none/minimal and 5 represents catastrophe/famine (Table 1). A population enters this phase if, among other criteria, the crude death rate is at least 2 per 10,000 per day and the under-five death rate is at least 4 per 10,000 per day (IPC Global Partners, 2019). Urgent action is required to avoid populations reaching Phase 3 or higher. The latest version of the IPC framework 3.0 introduces a forwardlooking “Famine Likely” phase to call for urgent action. Nonetheless, this may already be too late as mortality has already set in and claimed many lives. The 2011 famine that took place in parts of Somalia remains a lamentable reminder for the consequences of inaction (Salama et al., 2012). The rationale behind our work is fully aligned with that of famine prediction and prevention. What distinguishes it from existing approaches is its statistical framework, forward-looking perspective and stochastic treatment of food insecurity. The quantitative, empirical framework also allows us to identify the most relevant agronomic, environmental, conflict or economic drivers behind famine dynamics among a vast set of possible candidates, in a systematic way (Pape et al., 2018). As Lentz et al. (2019) demonstrate, systematically incorporating such information leads to significant improvements over existing methods.

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