Carbon dioxide removal: technologies, MRV and carbon markets, a reliability-first review
Year: 2026
Type: article
Abstract: Carbon dioxide removal (CDR) is increasingly treated as a necessary complement to rapid emissions reduction, yet the term is often applied to activities that capture concentrated carbon dioxide, avoid emissions, or store carbon only temporarily. This review examines CDR as an end-to-end system comprising atmospheric capture, transport and storage, life-cycle emissions, measurement, reporting and verification (MRV), and the carbon-market claim. It compares land-based biological removal, bioenergy with carbon capture and storage, direct air capture with storage, biochar, enhanced rock weathering, ocean alkalinity enhancement, and mineralization pathways. The central synthesis is that nominal capture capacity is not equivalent to a verified carbon dioxide removal credit: a credible claim must demonstrate a counterfactual baseline, additionality, net atmospheric removal, storage durability, monitoring adequacy, safeguards and controlled issuance. A mass-balance formulation is presented for net removal, and a closed-loop MRV architecture is proposed in which uncertainty, leakage, reversal risk and ecological monitoring continuously feed back into issuance decisions. The review also compares voluntary markets, compliance-oriented frameworks and emerging certification approaches, including the EU Carbon Removals and Carbon Farming Regulation. The analysis finds that CDR pathways differ more in measurement burden, permanence and externality profile than in headline removal potential. Durable engineered and mineral pathways offer stronger permanence claims but face energy, material, permitting and cost barriers; biological pathways can scale more rapidly but carry substantial reversal, land-use and monitoring risks. Carbon markets can help finance deployment, but should be treated as a mechanism for rewarding verified climate outcomes rather than as proof that a project is climate-positive. The paper concludes with a decision framework for project developers, buyers, verifiers and regulators.
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7171929447