Review of the Impacts on Greenhouse Gas Emissions of Land-Use Changes Induced by Non-food Biomass Production

Abstract

The recent development of biomass production for energy purposes has spurred interest in the effects of the land-use changes (LUC) it triggers worldwide, and a surge in the number of scientific articles dealing with this topic. The processes leading from increased biomass demand to environmental impacts in relation to LUC may be analyzed as a three-step causal chain starting with the identification of reorganization of agricultural and forestry systems, the assessment of LUC occurring in response to these drivers, and the associated environmental impacts. Here we set out to review the impacts of land-use changes induced by non-food biomass production on greenhouse gases emissions. The selected body of 162 articles displays the following salient features: most articles deal with LUC triggered by biofuel production, the predominant direct LUCs are forest or grassland conversions into annual or perennial crops, and annual crops conversion into perennial crops; and while Europe and North America come first in terms of direct LUC location, a large number of articles also deal with direct LUCs occurring in South America and Asia. We show that peer-reviewed literature does not sign a blank check to non-food biomass. The number of articles evidencing a net reduction in GHG emissions following a diversion of food/feed crops towards non-food products is only 50% higher than the number of articles drawing opposite conclusions. As the LUC-related carbon intensity of biofuels strongly depends on where the feedstock is grown and which land-use it replaces, we investigated whether specific land-use change patterns can be tied to certain types of feedstocks. Contrary to our expectations, direct forest and grassland conversion is significantly less often considered for second generation feedstocks or wood.