Cellulsosic bioenergy offers significant potential for greenhouse gas mitigation and is central to almost all IPCC mitigation scenarios that keep the global temperature rise to 1.5 °C. Whether grown for liquid transportation fuel or electricity production, whether used to offset fossil fuel use or, with carbon capture and storage, used as a negative emissions technology, bioenergy remains one of the most available near-term technologies to address climate change. Yet the ecological risks are considerable: certain feedstocks grown in certain ways on certain lands could promote harm rather than attenuate it. The delivery of climate, biodiversity, pollution abatement, and water use benefits depend on understanding tradeoffs and making wise policy choices.
Results/Conclusions
Only recently has sufficient empirical evidence accumulated to show how systems and landscapes could be optimized to deliver more of what we want and minimize potential future regret. Prior land use, crop choice, and management decisions largely determine ecological outcomes. For the US, answers to crucial questions related to land availability, conservation benefits, water quality effects, and, ultimately, climate mitigation, have begun to emerge from long-term experiments. Other questions remain, and represent persistent knowledge gaps. It seems useful to illustrate a few recent gains vis a vis the priorities still needed to address in order to continue discussion of this vital topic.