Assessing the potential for unaccounted emissions from bioenergy and the implications for forests: The United States and global

Development of the bioenergy sector is being actively pursued in many countries as a means to reduce climate change and fulfill international climate agreements such as the Paris Agreement. Although biomass for energy production (especially wood pellets) can replace carbon-intensive fossil fuels, its net greenhouse gas impact varies, and the production of wood pellets can also lead to intensification in forest harvests and reduction of forest carbon stocks. Additionally, under specific conditions, emissions associated with imported biomass feedstocks may be omitted from national accounts, due to incompatibilities in accounting approaches. We assessed the risks and potential scale of emissions omitted from accounts (EOA) among key trading regions, focusing on the demand for wood pellets under different levels of climate mitigation targets. Our results suggest that the global production of wood pellets would grow from 38.9 to 120 Mton/year between 2019 and 2050 in a scenario that limits global mean temperature increase to 1.5 degrees C above pre-industrial levels. A large portion of this occurs in North America (36.8 Mton/year by 2050), Europe (47.6 Mton/year by 2050), and Asia (23.3 Mton/year by 2050). We estimate that in a 1.5 degrees C scenario, global EOA associated with international trade of wood pellets has the potential to reach 23.81 MtCO(2)eq/year by 2030 and 69.52 MtCO(2)eq/year in 2050. Emissions resulting from European biomass energy production, based on wood pellet imports from the United States, may reach 11.68 MtCO(2)eq/year by 2030 and 33.57 MtCO(2)eq/year in 2050. The production of wood pellet feedstocks may also present a substantial carbon price arbitrage opportunity for bioenergy producers through a conjunction of two distinct GHG accounting rules. If this opportunity is realized, it could accelerate the growth of the bioenergy industry to levels that harm forests' function as a carbon sink and omit actual emissions in national and global accounting frameworks.