Understanding Drivers and Trends of Habitability in Kiribati from a Systems Perspective

Pacific atolls face heightened climate risk due to low elevations and limited resources. The question of (unin)habitability in these locations is often simplified to characteristics of hazard exposure, reinforcing assumptions of inevitable mass migration. Here we use a multidimensional conceptualization of habitability, built from local knowledge, to simulate habitability trends in the Pacific Island nation of Kiribati over the coming century. Our use of system dynamics modeling offers a new approach to operationalizing habitability, allowing for the incorporation of a range of interdependent factors such as natural resource availability, livelihood opportunity, and population dynamics, among others. We find that water insecurity will be a driving factor in habitability loss, intensifying under extreme climate scenarios, while population pressures will further constrain resources. We show that regional disparities will lead to high internal migration rates, with movement to national urban centers preferred over movement abroad. Our work answers calls for a holistic and locally grounded understanding of habitability through a systems lens. By identifying how drivers of habitability change over time, we offer insights into targeted and timely climate adaptation.