Migration is a widely used adaptation strategy to climate change impacts. Yet resource constraints caused by such impacts may limit the ability to migrate, thereby leading to immobility. Here we provide a quantitative, global analysis of reduced international mobility due to resource deprivation caused by climate change. We incorporate both migration dynamics and within-region income distributions in an integrated assessment model. We show that climate change induces decreases in emigration of lowest-income levels by over 10% in 2100 for medium development and climate scenarios compared with no climate change and by up to 35% for more pessimistic scenarios including catastrophic damages. This effect would leave resource-constrained populations extremely vulnerable to both subsequent climate change impacts and increased poverty.