This study links a multisectoral, regionalized, dynamic, computable general equilibrium (CGE) model of Ethiopia with a system country-specific hydrology, crop, road, and hydropower engineering models to simulate the economic impacts of climate change scenarios from global circulation models (GCMs) to 2050. In the absence of externally funded, policy-driven adaptation investments, Ethiopia’s GDP in 2050 will be up to 10% below the counterfactual no climate change (historical climate) baseline.