Effects of Climate Change on GHG Emission Benefits of Forest Bioenergy

English Abstract:

Forest biomass-derived energy can be a renewable alternative to traditional fossil fuel-based energy sources, and as such has been proposed as one of the forest sector options to mitigate climate change. However, if climate change mitigation is indeed a driver for using forest bioenergy, then this energy source must be assessed for its effects on net greenhouse gas (GHG) emissions. Such assessments can be done using time to carbon sequestration parity, i.e., the time between biomass harvest and when the overall carbon balance offsets the loss of carbon that would have been stored if the biomass were not harvested. Numerous studies have shown that the time to carbon sequestration parity can vary from a few years to decades, depending on factors such as biomass source, geography and substituted fossil fuel. However, few of these studies account for the potential effect of climate change on time to carbon sequestration parity. We addressed this question in a case study for northwestern Ontario, Canada, that considered production of bioenergy from harvesting standing live trees to substitute coal-fired energy. The effects of climate change were simulated by altering the regeneration rate of harvested stands and the rate of natural disturbance. Our modelling experiments showed that incorporating climate change can have a substantial effect on time to sequestration parity when forest biomass comes from harvesting standing live trees. We discuss the implications of these results for forest management aimed at mitigating climate change.