Dealing with Disaster: How Consecutive Natural Hazards Affect Internal Migration in the Philippines

Abstract:

Anthropogenic climate change is causing more frequent and intense weather phenomena that lead to the increased impact and frequency of both individual and consecutive disasters. However, there is limited understanding of how to quantitatively model consecutive disasters in contemporary disaster risk research, and how both individual and consecutive disasters influence longer-term migration patterns. A longitudinal spatial analysis was conducted for the Philippines, one of the world’s most disaster-prone nations, by comparing natural hazard impact data with internal migration flows between 1990 and 2010 deduced from national census data. The correlation between internal out-migration and both individual and consecutive disaster impact is investigated at the provincial and municipal scale. A Disaster Impact Index is developed to classify the severity of the human impact of earthquakes, floods, tropical cyclones and volcanic activity. This provides the basis for estimating the recovery periods associated with each natural hazard and thus more clearly defines how successive events can be recognised as either individual or consecutive disasters. This study highlights that migration decisions are nuanced and their dependence on environmental change is complex. Higher resolution models of human mobility and disaster risk are needed to better understand multi-hazard risk and the disaster-migration nexus – the quality of available disaster impact and migration is improving, but this must also coincide with more consistent, comparable and complete data sources.