Drought intensity and successiveness together displace populations in Somalia

In recent years, a great number of Somalis are involuntarily displaced within the country. However, we do not fully understand what and how climatic, environmental, and socio-political drivers push internally displaced persons (IDPs). Among several climatic drivers, what is statistically significant to internal displacement? Is the drought intensity alone a key driver of displacement? Are social network structures important in displacement decisions? To provide quantitative evidence, we developed a bootstrapping temporal exponential random graph model (bTERGM) for internal displacement decisions in Somalia. We used the Protection and Return Monitoring Network dataset with drought indices based on precipitation, temperature, and vegetation from the Somali Water and Land Information Management. We found that IDPs tend to consider both the intensity and successiveness of droughts based on precipitation, temperature, or vegetation. The Intensity of each component alone was not a significant driver for Somali IDPs. Local network structures were not very significant in the temporal model at the monthly scale, while previous displacement experience played a critical role in IDP movements. Our results help us better understand the displacement decision-making process so that policymakers can predict IDP movements and establish adequate policies.