As governments and companies commit to ambitious climate targets, attention is turning not only to cutting emissions but also to removing carbon dioxide from the atmosphere. Carbon dioxide removal (CDR) describes a set of approaches that take CO2 out of the air and lock it away for varying lengths of time. This article examines the main tools available, the trade-offs they present, how they fit into credible net-zero pathways, and the institutional and technical safeguards needed to scale removal responsibly.
What we mean by carbon removal
Carbon removal is distinct from reducing emissions at source. While emissions mitigation prevents greenhouse gases from entering the atmosphere, removal actively extracts CO2 and stores it in durable reservoirs such as soils, forests, rocks, or deep geologic formations. Policymakers and scientists typically treat removal as a complement to radical emissions reductions not a substitute for them because relying excessively on removal risks delaying the systemic changes that stop emissions in the first place.
Main categories of carbon removal technologies and approaches
There are two broad families of removal: nature-based solutions and engineered or technological approaches. Each has different maturity levels, permanence characteristics, co-benefits and risks.
- Nature-based solutions: These include afforestation and reforestation, improved forest management, wetland restoration, and practices that increase soil organic carbon such as regenerative agriculture. They are often lower-cost and provide ecosystem services like biodiversity and water regulation, but their long-term carbon storage can be vulnerable to disturbances like fire, pests and land-use change.
- Bioenergy with carbon capture and storage (BECCS): BECCS combines biomass combustion or processing with CO2 capture and permanent storage, delivering net negative emissions when sustainably sourced biomass is used. BECCS presents land-use and supply-chain challenges and needs careful sustainability safeguards to avoid unintended environmental impacts.
- Direct air capture and storage (DACCS): These engineered systems use chemical processes to pull CO2 directly from ambient air, compress it and inject it into secure geological formations or mineralize it into stable carbonates. DACCS offers high permanence and small land footprint but currently requires significant energy input and is relatively costly compared with many other options.
- Enhanced weathering and mineralization: This approach accelerates natural geochemical processes by spreading crushed silicate rocks on land or using industrial mineralization routes, which chemically bind CO2 into stable minerals. Enhanced weathering has substantial theoretical potential but faces logistical and energy considerations at scale.
- Soil carbon sequestration and biochar: Practices that increase organic matter in soils or convert biomass into biochar and bury it can lock carbon for decades to centuries while improving soil health. Measurement, permanence, and the variability of soils across regions create complexity for reliable accounting.
- Ocean-based approaches: Proposals range from restoring kelp forests to alkalinity enhancement and ocean fertilization. While some ocean methods show promise, they also raise ecological and governance concerns and require careful research before deployment at scale.
Key considerations: permanence, scalability and co-benefits
Three dimensions determine whether a removal solution is suitable for long-term climate strategies. Permanence refers to how long the captured carbon remains out of the atmosphere. Geological storage and mineralization deliver high permanence; forests and soils can be reversed by disturbances. Scalability concerns how much CO2 a method can realistically remove without large negative side effects, such as converting cropland to energy crops or degrading ecosystems. Co-benefits and trade-offs include biodiversity gains, water impacts, food security implications and local socio-economic effects. Decision-makers must weigh these alongside climate goals.
Measurement, reporting and verification (MRV)
Reliable MRV is essential for building trust in removal claims. For nature-based approaches, MRV combines remote sensing, field measurements and models to estimate carbon change over time. Engineered options often lend themselves to direct measurement of CO2 volumes captured and stored, which can simplify verification. Regardless of technology, transparent methodologies, independent third-party auditing and long-term monitoring commitments are critical to ensure removals represent real and permanent climate benefits.
Costs, energy use and infrastructure needs
Costs and energy requirements vary widely. Engineered solutions like direct air capture can demand considerable heat and electricity inputs, which is why clean energy supply and integration with waste heat sources are often included in deployment plans. Nature-based removals typically require less industrial energy but may require large land areas and active management to retain stored carbon. For approaches that rely on geological storage, secure transport pipelines and long-term liability frameworks are necessary. Policymakers should plan for the full life-cycle impacts of removal projects, including the emissions involved in building and operating them.
Policy and market frameworks that enable credible deployment
To scale removal responsibly, governments and institutions must create clear rules that align incentives with climate integrity. That involves defining permanence thresholds, establishing robust MRV standards, creating long-term storage liability rules, and preventing perverse incentives that allow emitters to delay cuts. Market mechanisms such as carbon procurement by governments or corporations, public funding for early-stage demonstration projects, and appropriate carbon pricing can accelerate learning and cost reductions. Standards and certification schemes help buyers and regulators distinguish high-quality removals from weaker claims.
How removal fits into corporate net-zero strategies
For companies, credible net-zero approaches prioritise deep, immediate emission reductions across operations and value chains. Carbon removal is reserved for residual emissions that are technically or economically difficult to eliminate and for restoring historical overshoots. When organizations invest in removals, they should demand high-quality projects with transparent accounting, prefer long-term removal contracts and disclose how purchases relate to their reduction trajectory. Relying primarily on removals without demonstrable emissions cuts undermines credibility and climate outcomes.
Risks and ethical questions
Relying heavily on future removal capacity poses risks. Overoptimistic assumptions about large-scale removal availability can enable continued high emissions today, which locks in climate impacts and increases reliance on unproven technologies. Land-intensive removals can compete with food production and harm vulnerable communities if governance is weak. There are also ethical questions about intergenerational responsibility and who bears the cost of removing past emissions. Transparent governance, local stakeholder engagement, and safeguards against displacement and inequitable outcomes are essential.
Where research and investment should focus
Continued research should improve MRV, lower costs for engineered removals, and refine nature-based approaches to maximize permanence and co-benefits. Pilot projects that test integration with renewable energy, industrial clusters and long-term storage can accelerate commercial readiness. Investments must also fund social science research to design fair governance and benefit-sharing mechanisms that protect communities and ecosystems. Public funding has a central role in de-risking early-stage projects until markets and standards mature.
Carbon removal is an important piece of the climate puzzle, but not a silver bullet. When chosen carefully and used alongside aggressive emissions cuts, robust removals can help humanity stabilize the climate and address residual emissions. Scaling them responsibly requires sound science, rigorous accounting, clear policy frameworks and attention to social and ecological impacts.