The objectives are to (a) evaluate future socioeconomic and greenhouse gas emissions uncertainty, in particular, uncertainty regarding socioeconomic structure (region, sector, demand, energy and technology); and (b) contribute to a multi-model evaluation and comparison of climate model behavior and climate change response uncertainty. To that end, the project will develop probabilistic global socioeconomic and greenhouse gas emissions projections using MIT probabilistic global economic and emissions modeling capabilities, and perform a multi-model comparison exercise evaluating climate modeling performance using climate/Earth-system model evaluation experiments recommended by a National Academy of Science study on the social cost of carbon.