This study analyzes the optimal allocation of the world's land resources over the course of the next century in the dynamic forward-looking framework, which brings together distinct strands of economic, agronomic, and biophysical literature and incorporates key drivers affecting global land use. We show that, while some deforestation is optimal in the near term, the desirability of further deforestation is limited by mid-century under the baseline scenario. While the adverse productivity shocks from climate change have a modest effect on global land use, when combined with high growth in energy prices they lead to significant deforestation and higher GHG emissions than in the baseline. Imposition of GHG emissions constraint further heightens the competition for land, as fertilizer use declines and land-based mitigation strategies expand. However, the effectiveness of such a pre-announced constraint is completely diluted by inter temporal substitution of deforestation which accelerates prior to imposition of the target.