Climate Change Increases Trapped Populations: When Migration Cannot Be Used as an Adaptation Solution

Abstract:

Migration is considered an effective adaptation strategy to climate change impacts. Yet resource constraints caused by such impacts may restrain the ability to migrate, thereby leading to "trapped populations". There is no available estimate of the number of people who, globally, might be affected by this trapping effect. In this paper, we provide the first quantitative, global analysis of trapped populations due to resource depletion caused by climate change. To this end, we incorporate both migration dynamics and within-region income distributions in an Integrated Assessment Model. We quantify income profiles of migrants, within-region inequality, income shocks on poorest populations generated by damages, and populations trapped by climate change. We show that climate change can lead to decreases in emigration of lowest income levels -- i.e. increases in trapped populations -- by over 10% in 2100 for medium development and climate scenarios (SSP2-RCP4.5), and by up to 50% for more pessimistic scenarios (SSP3-RCP7.0) including catastrophic damages. These results suggest that the trapping effect of climate change is likely to represent a widespread part of the climate-migration nexus, leaving populations in states of extreme vulnerability. Such prospects should be of immediate and significant concern to policymakers.