Carbon Neutrality of Hardwood and Softwood Biomass: Issues of Temporal Preference

The carbon flux from burning biomass for energy is often legislated, or simply assumed, to be carbon neutral as subsequent forest growth sequesters carbon lost during energy production. In this sense, there may be no net contributions to atmospheric carbon flux associated with biomass energy. However, trees may take decades to recover the CO2 released by burning, so assumed neutrality hinges on the fact that we count CO2 removals equally independent of when they occur. If dealing with climate change is an urgent matter, we may give higher weight to current CO2 emissions over those that occur in the decades to come. If there is no urgency in dealing with climate change, then all types of biomass will eventually return to carbon neutrality. Yet, if climate change is deemed an urgent matter, biomass never returns to carbon neutrality as we give future CO2 removals less weight. If urgency is high enough, biomass may be more emissions intensive than coal, as the discounted future removals are not enough to offset the relatively higher emissions intensity experience by burning biomass for energy. The race to adopt aggressive renewable energy targets implies climate change mitigation is an urgent matter. Yet, the increasing reliance on biomass for energy production suggests there is no time preference. In the end, the potential benefits of substituting biomass for coal to produce energy might be greatly exaggerated.