New scenarios shed further light on the role of carbon dioxide removal in 1.5°C scenarios with and without overshoot to support ambitious policy making
Carbon dioxide removal (CDR) has an important role to play in keeping 1.5°C within reach. It is therefore important to deepen the understanding of CDR: the total deployment, the timing and scale-up speed of the deployment, and the CDR portfolio and its feasibility, to limit warming to certain levels with and without a temporary exceedance (“overshoot”), and the associated climate impacts and risks, to support effective policy making.
Based on newly developed scenarios from the European project RESCUE, we find that:
- While CDR deployment is necessary, stringent emissions reductions from fossil fuels and deforestation account for the largest share in emissions reductions to limit warming to 1.5°C.
- Limiting warming to 1.5°C with no or low overshoot requires an early CDR ramp up, while a high overshoot would require significantly more CDR, especially towards the end of the century, to draw temperatures back down.
- Limiting overshoot can limit overall reliance on CDR, while a high overshoot would entail significantly higher CDR deployment. Scaling up CDR comes with sustainability and feasibility constraints.
- High overshoot pathways come with much higher climate risks and impacts compared to pathways with lower overshoot.
- CDR would need to be ramped up in countries’ NDCs, as part of more ambitious 2030 and new and ambitious 2035 targets, which separate out CDR.