Additional CO2 emissions from land use change — Forest conservation as a precondition for sustainable production of second generation bioenergy

In the past, deforestation, mainly driven by the conversion of natural forests to agricultural land, contributed up to one-fifth of global human induced carbon dioxide (CO2) emissions. Substitution of bioenergy for fossil energy is an intensely discussed option for mitigating CO2 emissions. This paper, by applying a global land-use model and a global energy–economy–climate model, explores how demand for cellulosic bioenergy crops will add an additional pressure on the land system in the future. In accordance with other studies, we find that CO2 emissions from land use change due to energy crop production will be an important factor in the GHG balance of bioenergy if natural forests will not be protected. But restricting land availability for biomass plantations by conserving natural forests requires additional efforts in the agricultural sector: First, our simulation results indicate that significant additional crop yield increases will be needed due to the combination of forest conservation and the cultivation of dedicated bioenergy crops. Secondly, our simulation results show that forest conservation in combination with increasing demand for dedicated bioenergy crops will lead to higher agricultural production costs of approximately 20%.