Net-zero targets are widely adopted by companies and countries worldwide. To achieve these goals, more companies are investing in diverse carbon removal portfolios. This study develops a new risk management framework that combines forestry, biochar, and geological storage offsets into portfolios that could stabilize global temperatures over multi-century time periods. We find that if a carbon storage portfolio reaches an equilibrium state of CO2 stored, it can be leveraged to stabilize global temperatures by increasing the size of the portfolio relative to the amount of removal claimed. For moderate-risk primarily forestry portfolios retaining 0.75–0.55 tCO2 of the 1 tCO2 stored, an additional 0.30–0.80 tCO2 removal is needed to offset re-releases over 1,000 years. High-risk portfolios retaining only 0.10 tCO2 require over 9 tCO2 additional removal. Portfolios that are predicted to re-release almost all CO2 cannot be leveraged and are ineffective at meeting temperature stabilization goals. These findings have implications for policy and corporate climate action.
Authors: Conor Hickey, Stuart Jenkins, Myles Allen.
