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The majority of future scenarios that do not exceed 2°C warming by 2100 include large-scale implementations of so-called Carbon Dioxide Removal (CDR) measures.

Carbon dioxide removal describes anthropogenic activities that aim at removing CO₂ from the atmosphere and store it in terrestrial, marine or geological carbon reservoirs. The most prominent options currently considered in ambitious climate change scenarios are: Bioenergy combined with geological carbon capture and storage, direct air carbon capture combined with geological storage, reforestation and afforestation. In pilot studies further CDR options considered include ocean alkalinity enhancement, soil carbon enhancement through e.g. biochar or agricultural practices, or the enhancement of coastal vegetated ecosystems. 

Carbon dioxide removal (CDR) plays a critical role in comprehensive climate strategies, serving three key systemic functions. First, while being scaled up, CDR would support emission reduction efforts. Second, CDR is essential for compensating for residual emissions to allow for the achievement of net-zero emissions targets. Demand for CDR in the context of net-zero targets is expected to be driven by so-called ‘hard-to-abate’ sectors in which the cessation of emissions is considered biologically, technically economically and/ or politically challenging (Schenuit et al. 2023). Lastly, CDR would enable the transition to net-negative emissions, where more CO₂ is removed from the atmosphere than is emitted. This would provide a mechanism for reversing carbon budget overshoot, if global emissions exceed the carbon budget associated with limiting warming to 1.5°C or 2°C.

Experimental Design

The Carbon Dioxide Removal Model Intercomparison Project (or CDRMIP) was initiated for and endorsed by CMIP6. A new phase of CDRMIP is now starting in preparation for CMIP7, with a novel experimental design including:

1. Simulations to explore activity-driven CDR in Scenario-MIP scenarios, focusing on the removal efficiency, the impact of the background scenario (climate change) on the efficiency, and the potential mismatch between carbon removal estimates of ESMs and IAMs;
2. Idealized experiments to investigate the role of CDR and its efficiency under a net-zero setting, specifically the amount of residual emissions that CDR could compensate, and the role of non-carbon cycle related side-effects;
3. Idealized experiments to elucidate the asymmetry in Earth system responses with respect to emissions versus removal.

Status September 2025