Human biomass utilization reduces global carbon stocks in vegetation by 50%, implying that massive emissions of CO2 to the atmosphere have occurred over the past centuries and millennia. The contribution of forest management and livestock grazing on natural grasslands to global carbon losses is of similar magnitude as that of deforestation. Currently, these effects are underappreciated in existing global carbon models and assessments of the greenhouse gas emissions (GHG) from land-based production. Without full consideration of land management effects, global climate forecasts and calculations of the GHG effects of future bioenergy policies are error prone, seriously jeopardizing the robust evaluation of measures that would help achieving the 1,5°C target of the Paris Agreement.