Quantifying the climate effects of forest-based bioenergy

Abstract Bioenergy is a key strategy for climate change mitigation in many national and international climate change and renewable energy policies. However, over recent years, claims have been made that forest-based bioenergy can lead to losses in forest carbon (sometimes referred to as “carbon debt”) and, thus, their effectiveness at mitigating climate change has been questioned. Climate impacts of forest bioenergy are dependent on a range of case-specific factors, including biophysical features of the biomass-production system and GHG intensity of the energy source it displaces, which are largely determined by the location of the bioenergy project. Estimates of climate impacts are also strongly affected by methodological choices and assumptions, related to reference land use, spatial and temporal system boundary, allocation procedures, time horizon of assessment, metrics applied, and climate forces considered. In this chapter, these key issues are discussed and recommendations are provided for carrying out appropriate and comprehensive assessments of climate impacts of forest bioenergy systems.