The Biofuel Debate – Status Quo and Research Needs to Meet Multiple Goals of Food, Fuel and Ecosystem Services in the Tropics and Subtropics

The current biofuel debate is characterized by concerns about the environmental effects of large-scale biofuel plantations, controversies about GMO-based feedstocks and the recent global food crisis. Predictions for the development of the biofuel sector are either departing from the supply-side or the demand-side, but are mostly based on modelling efforts with an unclear experimental basis and only broadly defined economic settings. Results vary widely and tend to undervalue technical progress in processing efficiency or management-related increases in biomass yields. Moreover, calculations often neglect the impact of climate change, the need for irrigation and processing water, for soil fertility maintenance and the importance of socio-economic issues. Against these shortcomings and in view of several decades to centuries of Ecosystem Carbon Payback Times of most biofuel plantations, their future as a large-scale replacement for hydrocarbons will strongly depend on improved matter conversion efficiencies and successful prevention mechanisms for conflicts over land use.