Do we need a unified appraisal framework to synthesize biofuel impacts?

In the past decade a significant evidence base has been built about biofuels' environmental and socioeconomic impacts. What is still missing is a discussion about whether it is desirable, or even feasible, to synthesize this evidence in a clear, coherent and policy-relevant manner, and if so, how exactly such a synthesis should be conducted. This Short Communication presents arguments for and against the adoption of a unified framework for synthesizing biofuel impacts, and seeks common ground between the two perspectives. ► We lack coherent, comprehensive and policy-relevant syntheses of biofuels’ environmental and socioeconomic impacts. ► Assessing whether (and how) it is desirable to synthesize biofuel impacts with a unified framework is a major research gap. ► Sustainability science and the ecosystem services approach are two frameworks that can provide such unified syntheses. ► Unified syntheses are appropriate in “structured” policy situations, when facts are certain and policy priorities consensual. ► Unified syntheses might be counterproductive when high scientific uncertainty and disagreement on values/policy goals prevail.