Carbon accounting for carbon dioxide removal
Sarah Nordahl, Rebecca J. Hanes, Kimberley K. Mayfield, Corey Myers, Sarah E. Baker, Corinne D. Scown
Abstract
Carbon dioxide removal (CDR) technologies are essential to address climate change and serve to compensate for legacy and hard-to-abate greenhouse gas emissions. Although near-term emissions reductions should be the priority, development and deployment of CDR must proceed now to ensure that relevant technologies are ready at scale in the future. Despite a rapid growth in CDR purchases, no single standardized methodology for evaluating project-level net CO 2 removal exists. Life cycle assessment (LCA) frequently produces net-negative emissions footprints, but only a small subset of those systems achieves a net flux of CO 2 out of the atmosphere. In contrast to LCA, CDR accounting uses expansive system boundaries and excludes avoidance credits to distinguish between systems that achieve net removal from those that only contribute to emissions mitigation. This primer discusses a framework and set of metrics for CDR accounting.