When the well runs dry, where do we go now? Exploring internal migration due to climate stress in Asia and Central and South America

Guy J. Abel, Asian Demographic Research Institute
Raya Muttarak, Wittgenstein Centre (IIASA, VID/ÖAW, WU)

Whether the changing climate will lead to mass migration remains an unsettled puzzle for demographers. However, estimates of the number of “environmental refugees” are often based on a simple assumption that climate change-induced extreme weather events and sea-level rise will lead to mass migration. In fact, migration is a complex interplay of multiple factors whereby non-climate drivers such as economic opportunities, political conflicts and social networks are equally important in influencing migration decisions. While estimates of climate migrants generally refer to cross-border migration, recent studies have shown that climate-related migration, if at all, is more common within a national boundary. Moreover, extant empirical studies on climate-related migration are often case studies. To this end, this paper aims to model internal migration flows taking into account socioeconomic, demographic and environmental drivers. Migration flows and relevant socioeconomic information are obtained from microcensus data supplied by the Integrated Public Use Microdata Series for 26 countries in Central and South America and Asia over the period 1970-2011. Additionally, precipitation data are employed to identify drought events and rainfall variability, potential environmental drivers of migration. Fitting a series of gravity-type spatial interaction models for each country and census year, we find higher outmigration flows from the areas frequently affected by drought to the destination that is more urban and has higher proportion of males. Migration is higher the lesser the distance between origin and destination, especially between contiguous geographical units.