Climate-carbon cycle model intercomparison projects such as the C4MIP have contributed significantly towards improving our understanding of how the carbon cycle interacts with climate and how the interaction affects future climate change. Fully coupled carbon-climate simulations use prognostic, three-dimensional CO2 tracers—which are exchanged with land and ocean through surface fluxes and which induce warming through their coupling with atmospheric radiation processes. In contrast, climate simulations that are only partially coupled to the carbon cycle use prescribed time series of global monthly mean atmospheric CO2 concentrations and study the associated climate response. These prescribed CO2 simulations can neither account for the impacts of spatial heterogeneity on atmospheric CO2 concentrations nor interactively include the carbon-climate feedbacks. Here we use a land-atmosphere interactive configuration of the Energy Exascale Earth System Model (E3SM) v1.1 model with prescribed ocean CO2 fluxes to evaluate the impacts of geographic variability in CO2 for land-atmosphere coupling. Computational costs are reduced by using prescribed oceanic CO2 fluxes and dynamics, enabling the configuration to serve as a testbed for interactions of land BGC and atmospheric processes. Two simulations with and without three-dimensional atmospheric CO2 concentrations will be conducted for the evaluation. We will also compare the historical simulation with the surface, aircraft, and satellite CO2 observations. We anticipate that this model configuration will serve to inform the development of a fully coupled prognostic CO2 capability in E3SM v2 and will be adaptable as an E3SM testbed for future studies examining the interactions of non-CO2 atmospheric tracers with land biogeochemistry processes.