The strength of the land carbon sink is a critical and uncertain aspect of the global earth system, exerting a strong influence on the airborne fraction of CO₂ emissions and therefore having strong implications on permissible emissions to reach 1.5C or 2C temperature targets.  The Community Land Model (CLM) Perturbed Parameter Ensembles (PPE) have revealed large parametric uncertainty in the strength of the future land carbon sink, though this uncertainty can be somewhat reduced when the ensemble is constrained with multiple observations (e.g., LAI and LAI trends, biomass trends, land-use and land-cover change fluxes).  As the CLM PPE project works towards defining a collection of reasonable parameter sets, in parallel, we are testing and evaluating CESM2 (in preparation for CESM3) in emissions-driven mode.  A unique feature of our recent simulations is that not only CO2 emissions are active, but we are also including interactive fire aerosol and carbon emissions, replacing the standard CMIP-provided fire aerosol emissions with those prognostically simulated by the CLM fire model.  And, Biogenic Volatile Organic Compound emissions are also interactive.  This unprecedented model configuration opens new avenues to investigate complex Earth System interactions.  The intention is to then run a small ensemble of this model configuration with alternative parameter sets that represent a range of possible land carbon trajectories to more fully explore future climate change uncertainty due to land carbon sink uncertainty.