What Carbon Capture Can and Cannot Do
TLDR
The carbon capture climate role is narrow but potentially important. Capturing carbon dioxide can reduce emissions from selected industrial facilities, especially where process emissions are difficult to eliminate. Direct air capture and some biomass-based systems can also remove CO2 already in the atmosphere if they deliver durable storage. But carbon capture is not a substitute for rapidly reducing fossil-fuel use: its value depends on complete emissions accounting, low-carbon energy, secure storage and evidence of actual performance rather than announced capacity.
The most useful question is not whether carbon capture is simply good or bad. It is what CO2 a project captures, which emissions it prevents, how much energy it consumes, where the carbon goes and whether the result is measured across the entire system. Those details separate a credible climate contribution from an inflated claim.
Carbon capture can mean several different things
A carbon capture and storage system separates CO2 from a gas stream, compresses it, transports it and injects it into a geological formation intended to retain it. Every stage matters. A facility can capture CO2 successfully while producing a much smaller climate benefit if capture covers only part of the facility, the energy supply is highly emitting or upstream fuel production adds substantial emissions.
The terminology can obscure important differences. CCS usually means carbon capture and storage. CCUS adds “utilization,” meaning the CO2 is used in a product or process. Carbon dioxide removal, or CDR, has a more specific meaning: human activity that takes CO2 from the atmosphere and stores it durably. The IPCC therefore distinguishes atmospheric removal from capture at fossil-fuel or industrial point sources. The IPCC mitigation assessment explains that direct air capture with storage and some biomass systems can qualify as CDR, whereas point-source capture generally prevents a portion of new emissions rather than removing historical emissions from the air.
| Approach | CO2 source | Potential climate role | Evidence a credible claim needs |
|---|---|---|---|
| Point-source CCS | A power station or industrial facility | Avoids part of the facility’s emissions | Facility-wide capture coverage, energy use, upstream emissions, measured injection and durable storage |
| Direct air capture with storage, or DACCS | Ambient air | Can remove atmospheric CO2 | Net removal after energy and material emissions, measured capture and durable geological storage |
| Bioenergy with carbon capture and storage, or BECCS | CO2 released from biomass conversion | Can produce net removal under suitable conditions | Sustainable biomass sourcing, land-use effects, supply-chain emissions, capture performance and durable storage |
| CO2 utilization | A point source or the atmosphere | Varies from short-lived use to possible durable storage | Product lifetime, displacement assumptions, process emissions and the carbon’s ultimate destination |
Utilization is not automatically storage. CO2 used in a fuel may return to the atmosphere when that fuel is burned. Carbon incorporated into some materials may remain out of the atmosphere longer, but the duration and full production emissions must be evaluated. Using captured CO2 for enhanced oil recovery is likewise not automatically equivalent to climate mitigation: the accounting must include the injected CO2, operational emissions, associated fuel production and what would have happened without the project.
Preventing an emission is not the same as removing atmospheric CO2
Suppose an industrial plant would release 1 million tonnes of CO2 in a year without capture. If a project prevents 700,000 tonnes from entering the atmosphere after accounting for additional energy and related emissions, it has reduced emissions relative to that baseline. It has not removed 700,000 tonnes that were already in the atmosphere.
A removal project starts from a different carbon flow. It takes CO2 from ambient air, directly or through biomass growth, and transfers that carbon into storage. To claim net removal, the amount stored must exceed emissions from energy, construction, transport, land use and other parts of the project. The storage must also last long enough to support the claimed climate outcome.
This distinction matters in net-zero plans. Gross emissions are the emissions released before subtracting removals. Residual emissions are those remaining after feasible mitigation. Net emissions are gross emissions minus qualifying removals. The IPCC identifies roles for CDR in reducing net emissions, balancing residual emissions at net zero and producing net-negative emissions, but stresses that removals complement rather than replace rapid, deep and sustained emissions reductions.
Where carbon capture has its strongest climate case
The clearest case is often an industrial process with concentrated CO2 and limited alternatives for eliminating all emissions. Cement is a central example because making clinker releases CO2 not only from fuel combustion but also from the chemical conversion of limestone. Switching to clean electricity does not by itself eliminate those process emissions. Changes in materials, design efficiency and clinker content can reduce the problem, while capture may address part of what remains.
The IPCC identifies CCS as a mitigation option for large industrial and fossil-based sources where geological storage is available, with particular relevance to sectors including cement and chemicals. It also notes that technological maturity differs among applications and that present deployment remains below the levels represented in many modeled low-warming pathways.
Carbon removal has a different strong case: compensating for genuinely residual emissions after substantial mitigation. Some agricultural emissions, industrial processes or specialized transport activities may remain difficult to eliminate completely. Durable removal can help balance those residuals, but calling an emission “residual” should follow serious efforts to reduce it—not merely a preference to continue emitting.
Why carbon capture cannot replace emissions cuts
A stated capture rate is not a complete measure of climate performance. It may refer only to the CO2 passing through a particular capture unit, excluding startup periods, other stacks, onsite fuel use or emissions from producing and transporting fuel. A high unit-level percentage can therefore coexist with a lower facility-wide reduction.
Capture, compression, transport and injection all require energy. If that energy comes from emitting sources, some of the apparent benefit is consumed by additional emissions. For fossil-gas projects, methane released during production and transport also belongs within the climate boundary. A responsible assessment compares full-system emissions with a clearly stated alternative, using the same time period and units.
There is also an opportunity-cost question. Capital, clean electricity, pipeline capacity and public attention are limited. In applications where efficiency, electrification or zero-carbon energy can eliminate emissions more directly, adding capture to continued fossil-fuel use may not be the strongest option. That does not make every capture project ineffective; it means the technology should be compared with realistic alternatives rather than evaluated in isolation.
Durable geological storage requires more than injection
Geological storage aims to place compressed CO2 deep underground in formations with suitable capacity and confining layers. Credible storage begins with site characterization: geology, faults, existing wells, groundwater resources and expected pressure behavior all affect whether a site is suitable. Operators must also manage well construction and integrity, track the CO2 plume and pressure front, detect unexpected movement and plan for closure and post-injection care.
In the United States, EPA’s Class VI well program provides one regulatory example. Its requirements address site characterization, well construction, mechanical integrity, groundwater protection, monitoring and post-injection site care. These rules are specific to the United States, not a universal global standard.
Monitoring, reporting and verification should reconcile the carbon at each stage. Under EPA’s Subpart RR framework, facilities operating under approved plans report quantities such as CO2 received, injected, produced, emitted and sequestered. This illustrates why “captured” and “stored” are not interchangeable: captured CO2 may be lost during processing or transport, diverted to a short-lived use or never injected.
Scale check: removals, capture capacity and announcements are different numbers
The June 2026 third edition of the State of Carbon Dioxide Removal estimates total current CDR at about 2.2 billion tonnes of CO2 per year, mostly from conventional land-based methods. It estimates novel CDR at about 2 million tonnes in the 2025 activity year. The much larger total therefore should not be read as evidence that engineered removal technologies already operate at billion-tonne scale.
These are removal estimates, not totals for all point-source carbon capture. A cement plant that captures and stores some of its new process emissions may contribute to CCS deployment without producing atmospheric removal. Conversely, land-based removal can count as CDR without using capture equipment or geological injection.
Status labels matter too. Operating removal, measured annual capture, injection capacity, projects under construction and proposed pipelines are different categories. An announcement shows intention. Nameplate capacity describes a possible operating rate under stated conditions. Neither establishes how much CO2 has been removed or stored. The State of Carbon Dioxide Removal assessment explicitly separates current deployment from construction and uncertain future project pipelines.
Checklist for assessing a carbon-capture claim
- What is being claimed: avoided emissions, atmospheric removal, utilization or geological storage?
- Where does the CO2 come from, and what portion of the facility’s total emissions is covered?
- Is the capture rate measured during normal annual operation or quoted for one process stream under selected conditions?
- What baseline is used, and is the comparison with a realistic alternative?
- How much energy does capture, compression, transport and injection require, and where does that energy come from?
- Does the accounting include construction, upstream fuel production, methane leakage, biomass supply and land-use effects where relevant?
- How many tonnes were captured, transported, injected and verified as stored? Do not treat these as the same quantity.
- Where is the CO2 stored, for how long, and what monitoring detects leakage or unexpected movement?
- Are the numbers verified operating results, nameplate capacity, projects under construction or merely announced plans?
- Who bears responsibility for monitoring, remediation and long-term liability?
- What local effects accompany pipelines, injection wells, water use, industrial expansion or biomass production, and how were affected communities involved?
Claims such as “low-carbon,” “carbon-neutral” or “carbon-negative” need boundaries and a time period. Ask whether the label applies to one production step, one product, a whole facility or an entire supply chain. Then look for tonnes of CO2-equivalent per unit of output, the methods used to calculate them and independent or regulatory verification where available.
The practical conclusion
Carbon capture is most credible when its job is described narrowly. It can reduce selected industrial emissions, particularly where process chemistry leaves limited alternatives. Direct air capture with storage and carefully accounted biomass systems can remove atmospheric CO2. Durable removals may eventually help balance emissions that remain after deep mitigation.
What carbon capture cannot do is make the rest of the emissions system irrelevant. It cannot turn a partial capture rate into zero emissions, make short-lived utilization equivalent to permanent storage or convert a proposed project into verified climate performance. The next time a capture claim appears, trace the carbon from its source to its final destination and demand a whole-system emissions total. That is the shortest route to understanding what the project can—and cannot—contribute.