Confronting mitigation deterrence in low-carbon scenarios

Abstract Carbon dioxide removal (CDR) features heavily in low-carbon scenarios, where it often substitutes for emission reductions both the near-term and long-term, enabling temperature targets to be met at lower cost. There are major concerns around scale of CDR deployment many risk that anticipated future could dilute incentives reduce emissions now, a phenomenon known as mitigation deterrence. Here we conduct an in-depth analysis into relationship between reduction global integrated assessment model. We explore impact on illustrating how pathway 2020s is highly sensitive assumptions availability. Using stochastic optimisation, demonstrate accounting uncertainty provides strong rationale increase rates 2020s. A 20% chance failure requires additional 2030 3–17 GtCO 2 . Finally, introduce new scenarios which risks deterrence benefits formally separating climate strategies. Continual across time-horizon leads goals being breached by 0.2–0.3 °C. If treated reduction, up 700–800 can removed from atmosphere 2100, reducing end-of-century warming 0.5 This put sub-1.5 °C within reach but to, rather than replaces, reductions.