Principles, drivers and opportunities of a circular bioeconomy.

A circular, bio-based economy could provide the pathway to a sustainable future. Here we present five ecological principles to guide biomass use towards a circular bioeconomy: safeguarding and regenerating the health of our (agro)ecosystems; avoiding non-essential products and the waste of essential ones; prioritizing biomass streams for basic human needs; utilizing and recycling by-products of (agro)ecosystems; and using renewable energy while minimizing overall energy use. Implementing these principles calls for a transformation of our current economic system, including fundamental changes to policies, technologies, organizations, social behaviour and markets.