Alternative carbon price trajectories can avoid excessive carbon removal

• Published in: Nature communications Vol. 12; no. 1; pp. 2264 - 8
• Main Authors: Strefler, Jessica, Kriegler, Elmar, Bauer, Nico, Luderer, Gunnar, Pietzcker, Robert C., Giannousakis, Anastasis, Edenhofer, Ottmar
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.04.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 704/106; 704/106/694/682; 704/172; Carbon dioxide; Carbon dioxide removal; Carbon neutrality; Climate change; Climate change mitigation; Demand analysis; Global temperatures; Humanities and Social Sciences; multidisciplinary; Optimization; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-22211-2

The large majority of climate change mitigation scenarios that hold warming below 2 °C show high deployment of carbon dioxide removal (CDR), resulting in a peak-and-decline behavior in global temperature. This is driven by the assumption of an exponentially increasing carbon price trajectory which is perceived to be economically optimal for meeting a carbon budget. However, this optimality relies on the assumption that a finite carbon budget associated with a temperature target is filled up steadily over time. The availability of net carbon removals invalidates this assumption and therefore a different carbon price trajectory should be chosen. We show how the optimal carbon price path for remaining well below 2 °C limits CDR demand and analyze requirements for constructing alternatives, which may be easier to implement in reality. We show that warming can be held at well below 2 °C at much lower long-term economic effort and lower CDR deployment and therefore lower risks if carbon prices are high enough in the beginning to ensure target compliance, but increase at a lower rate after carbon neutrality has been reached. Many trajectories for reaching climate change mitigation targets exaggerate the long-term need for CO 2 removal (CDR) because they assume an exponentially increasing carbon price. Here the authors analyse alternative carbon price pathways that halt warming while limiting CDR, and may be easier to implement.