Maintaining and improving future food and energy security poses key challenges globally, especially in the face of climate change and climate mitigation. a computable general equilibrium (CGE) model -- the Applied Dynamic Analysis of the Global Economy model focusing on agriculture and land use (ADAGE-ALU), is used to examine how the global economy, especially energy, agriculture and land use, responds when facing these challenges. Despite continued increases in land productivity and energy efficiency in future decades, the effects of population and economic growth would dominate, leading to global increases in agricultural production, but also rising food and energy prices as well as continually growing GHG emissions in the BAU scenario. Comparing the climate change scenario with the BAU scenario, there are substantial reductions in global crop production and significant further increases in food prices, but little change in fossil fuel and biofuel production and energy prices, and only mild increases in CO2 emissions due to land-use changes. Relative to the BAU case, the implementation of a carbon tax on emissions other than those from land use change leads to the expansion of global biofuel production and a shift in the mix of crops produced towards those used as biofuels feedstocks, raises food prices, and reduces oil consumption and price slightly. Meanwhile, GHG emissions are slightly reduced as a result of lower oil consumption. In the REDD scenario, some cropland is afforested to store carbon, leading to a moderate rise in food and energy prices and significant GHG emission reductions. When climate change, REDD scenarios are implemented together, we see even higher reductions in global crop production and larger food price increases, along with greater reduction in GHG emissions compared with the CC scenario.