Abstract

Forest biomass changes influence the forest area required to meet the demand for timber and carbon storage, and thus land use and land cover change (LULCC). The worldwide impacts of global change (e.g., climate change, CO2 fertilization, nitrogen deposition) on forest biomass have been widely recognized and examined, yet are usually ignored by existing LULCC projections. This study explores the role of forest biomass change driven by global change in future global LULCC projections and investigates the underlying drivers. We incorporated the global change impacts on forest biomass from a land surface model driven by the projections from two Earth system models (ESMs) under three Shared Socioeconomic Pathways (SSP) scenarios (SSP126, SSP370, and SSP585) into an integrated assessment model, the Global Change Analysis Model. Considering forest biomass change decreases the projected expansion of managed forests and managed pastures, reduces the loss of unmanaged pastures and unmanaged forests, and provides more areas for cropland. The relative decrease in managed forest is-4.0%,-21.7% and-31.9%, respectively under SSP126, SSP370, and SSP585 in 2100 if forest biomass change is considered. CO2 fertilization is the dominant driver of increasing forest biomass and thus LULCC, compared to the change in climate and nitrogen deposition under SSP585. Using climate forcing data from two ESMs leads to similar impacts of forest biomass change on LULCC in terms of sign and trend but different magnitudes. This study highlights the large impact of forest biomass change on shaping future LULCC dynamics and the critical role of CO2 fertilization.