Science-based approach for credible accounting of mitigation in managed forests

• Published in: Carbon balance and management 2018-05, Vol.13 (1), p.8-16, Article 8
• Main Authors: Grassi, Giacomo, Pilli, Roberto, House, Jo, Federici, Sandro, Kurz, Werner A.
• Format: Article
• Language: English
• Subjects: Accounting; Age; Agreements; Bioenergy; Carbon budget; Carbon Budget Model; Carbon dioxide; Climate; Climate effects; Credibility; Dynamics; Earth and Environmental Science; Ecosystems; Emissions; Environment; Environmental Management; Environmental protection; European countries; Forest; Forest management; Forestry; Forests; Future; Greenhouse effect; Greenhouse gases; Historical account; Kyoto Protocol; Legislation; Management; Paris Agreement; Policies; Reference level; Renewable energy; Science-based options for Paris agreement implementation; Sink
• ISSN: 1750-0680; 1750-0680
• DOI: 10.1186/s13021-018-0096-2

Background The credibility and effectiveness of country climate targets under the Paris Agreement requires that, in all greenhouse gas (GHG) sectors, the accounted mitigation outcomes reflect genuine deviations from the type and magnitude of activities generating emissions in the base year or baseline. This is challenging for the forestry sector, as the future net emissions can change irrespective of actual management activities, because of age-related stand dynamics resulting from past management and natural disturbances. The solution implemented under the Kyoto Protocol (2013–2020) was accounting mitigation as deviation from a projected (forward-looking) “forest reference level”, which considered the age-related dynamics but also allowed including the assumed future implementation of approved policies. This caused controversies, as unverifiable counterfactual scenarios with inflated future harvest could lead to credits where no change in management has actually occurred, or conversely, failing to reflect in the accounts a policy-driven increase in net emissions. Instead, here we describe an approach to set reference levels based on the projected continuation of documented historical forest management practice, i.e. reflecting age-related dynamics but not the future impact of policies. We illustrate a possible method to implement this approach at the level of the European Union (EU) using the Carbon Budget Model. Results Using EU country data, we show that forest sinks between 2013 and 2016 were greater than that assumed in the 2013–2020 EU reference level under the Kyoto Protocol, which would lead to credits of 110–120 Mt CO 2 /year (capped at 70–80 Mt CO 2 /year, equivalent to 1.3% of 1990 EU total emissions). By modelling the continuation of management practice documented historically (2000–2009), we show that these credits are mostly due to the inclusion in the reference levels of policy-assumed harvest increases that never materialized. With our proposed approach, harvest is expected to increase (12% in 2030 at EU-level, relative to 2000–2009), but more slowly than in current forest reference levels, and only because of age-related dynamics, i.e. increased growing stocks in maturing forests. Conclusions Our science-based approach, compatible with the EU post-2020 climate legislation, helps to ensure that only genuine deviations from the continuation of historically documented forest management practices are accounted toward climate targets, therefore