Globally, rural livelihoods are increasingly challenged by the dual threats of landdegradation and climate change. These issues are of particular concern in sub-Saharan Africa, where land degradation is believed to be severe and where climatechange will bring higher temperatures and shifts in rainfall. To date, however, we knowlittle about the relative effects of these various potential environmental stressors onmigration. To examine these processes, we link longitudinal data from 850 Ugandanhouseholds with environmental data on soils, forests, and climate, and then analyzethese data using approaches that account for potential spatial and temporal confounders.Our findings reveal that climate anomalies, rather than land degradation, are theprimary contributor to environmental migration in Uganda, with heat stress of partic-ular importance. Short hot spells increase temporary migration, an element of adiversified household livelihood strategy, while long-term heat stress induces perma-nent migration through an agricultural livelihoods pathway.