The Impact of Land Use Change and Carbon Fertilization on Land-Atmosphere Coupling

Abstract:

Previous studies have demonstrated the importance of elevated atmospheric carbon for vegetation growth, with implications for the associated fluxes of water and heat from the land surface. Additionally, land use and land cover conditions have been shown to impact regional climate through changes in surface flux partitioning. This study aims to build on such prior work by assessing the impact of both carbon fertilization of vegetation growth and historical land use change (LUC) on the coupling between the land surface and the atmosphere. Multiple metrics of land-atmosphere coupling strength are analyzed from simulations with the Geophysical Fluid Dynamics Laboratory (GFDL) Earth System Model ESM2G. We compare an ensemble of historical simulations, which include both a LUC reconstruction and enhanced vegetation growth in response to elevated CO₂, to ensembles with (1) the LUC reconstruction removed, with vegetation replaced with potential vegetation, and (2) the CO₂ fertilization effect removed, with the vegetation seeing preindustrial CO₂ levels throughout the simulation. These simulations help to elucidate the potential impact of vegetation on the decadal and lower frequency evolution of climate, and how that impact might change in the future.