Summary
Carbon sequestration is the process of capturing CO2 and storing it durably in biological, oceanic, or geological reservoirs, and it plays a complementary role in net zero by neutralizing hard-to-abate residual emissions after deep cuts. It is distinct from carbon offsetting and cannot substitute for direct emissions reductions. Current sequestration capacity falls far short of what mid-century net zero pathways require, creating a defining scale gap for energy-sector planning.
What This Article Covers
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What Is Carbon Sequestration?: Defines carbon sequestration and explains why it differs from carbon offsetting.
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How Carbon Sequestration Works: The Core Science: Breaks down the science of uptake, conversion, and storage across the carbon cycle.
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Main Types of Carbon Sequestration: Compares biological, geological, technological, and hybrid sequestration methods by durability and readiness.
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The Scale Gap: Where Carbon Sequestration Stands Today: Contrasts current removal capacity with the tonnage net zero pathways demand.
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Carbon Sequestration's Role in Energy-Sector Net Zero: Examines how CCS and direct air capture fit into energy company net zero strategies.
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Limitations and Risks Energy Leaders Must Understand: Highlights the limitations and risks energy leaders must weigh when relying on sequestration.
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Frequently Asked Questions About Carbon Sequestration: Answers common questions about sequestration, offsetting, durability, and project evaluation.
What Is Carbon Sequestration?
Before you can evaluate carbon sequestration as a net zero lever, you need a precise definition. The term gets stretched to mean almost anything climate-related, and that imprecision creates real problems in disclosures, procurement decisions, and audit conversations.
The scientific definition
The IPCC defines carbon sequestration as the process of storing carbon in a long-lived carbon pool. This can happen naturally, through forests, soils, and oceans, or through engineered systems such as carbon capture and storage (CCS). The underlying mechanism stays consistent: CO2 is taken up, converted into another form, and held in a reservoir that resists rapid return to the atmosphere.
Those reservoirs, or carbon pools, matter because they carry very different durability profiles:
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Biomass (trees, crops, plankton)
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Soils and sediments
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Oceans (dissolved inorganic carbon)
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Geological formations (saline aquifers, depleted oil and gas fields)
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Carbonate minerals and concrete
A critical distinction runs through this landscape. Point-source CCS captures CO2 at a smokestack and stores it, which avoids new emissions. Carbon dioxide removal (CDR), by contrast, pulls legacy CO2 already in the atmosphere back down through methods like BECCS and direct air capture with storage. Both rely on similar engineering, yet only one delivers net-negative outcomes.
Carbon sequestration vs. carbon offsetting: a critical distinction
These are not the same thing, and conflating them is one of the most common and costly mistakes in corporate decarbonization plans. Sequestration is a physical outcome: CO2 removed and durably stored, judged on removal volume, durability, and leakage risk. Offsetting is a market mechanism: buying credits to compensate for emissions elsewhere, judged on additionality, baselines, and permanence. You can have sequestration without offsetting, and offsetting without genuine sequestration.
For net zero, sequestration earns its place by neutralizing hard-to-abate residual emissions after deep cuts, and in some cases by delivering net-negative results. It is a complement to reduction, never a substitute.
How Carbon Sequestration Works: The Core Science
Before you can evaluate any net zero strategy that leans on carbon sequestration, you need to understand what is actually happening at a molecular level. Sequestration is not a single technology. It is any process that moves carbon dioxide through three steps: uptake from the atmosphere, conversion into another chemical or physical form, and storage in a reservoir that resists rapid release back into the air.
The carbon cycle and where sequestration fits
CO2 moves continuously among the atmosphere, the biosphere, the oceans, and the lithosphere. Plants absorb it through photosynthesis and release it through respiration and decomposition; oceans dissolve it at the surface; rocks consume it slowly through weathering. Sequestration is a deliberate intervention in this exchange. It occurs only when captured carbon is converted into a stable form (biomass, dissolved bicarbonate, carbonate minerals, or compressed fluid) and then locked into a reservoir that keeps it out of circulation for decades to millennia.
Biological fixation through photosynthesis
Plants convert CO2 and water into carbohydrates using sunlight, storing carbon in leaves, wood, roots, and soil organic matter. The catch is durability. When biomass decays or burns without capture, the CO2 returns. Managed forests, long-lived wood products such as construction timber, and stable soil carbon extend storage from years into decades or centuries, but these sinks stay reversible through fire, pests, or land-use change.
Physical and chemical ocean uptake
The ocean absorbs atmospheric CO2 at its surface, where it dissolves to form carbonic acid, then bicarbonate and carbonate ions. This is the planet's largest active carbon sink, yet it is climate-sensitive: warmer temperatures and shifting circulation patterns can reduce uptake and even reverse it.
Geological trapping underground
In engineered systems, captured CO2 is compressed into a supercritical fluid and injected into porous rock, typically below 800 meters. Three mechanisms hold it there: structural trapping beneath impermeable caprock, solubility trapping as CO2 dissolves into formation water, and mineral trapping as it slowly reacts with host rock to form solid carbonates. This is the highest-durability option, which is why it dominates energy-sector planning. For the reporting implications, see our decarbonization guide.
Main Types of Carbon Sequestration
There is no single "carbon sequestration" method, and treating them as interchangeable is where most decarbonization plans go wrong. Options differ sharply in durability, technology readiness, and how defensible they will be under audit. The taxonomy below runs roughly from lower-durability, higher-readiness biological approaches up to the high-durability engineered and hybrid pathways that most net-zero plans lean on for hard-to-abate emissions.
Biological sequestration: forests, soils, and oceans
Biological sequestration stores CO2 in living systems through natural processes: afforestation and reforestation build carbon in biomass, improved soil management enhances stable soil organic carbon, and the ocean's biological pump moves fixed carbon to depth. These approaches are the most mature and account for nearly all of the roughly 2.2 GtCO2 per year of carbon dioxide removal happening today. The catch for energy-sector reporters is durability. Biological sinks are reversible; fire, pests, drought, or land-use change can release stored carbon within decades. Measurement, reporting, and verification (MRV) for soil and biomass carbon is also complex and uncertain, which matters when disclosures face auditor and investor scrutiny.
Geological sequestration and CCS
Geological storage is one of the few high-durability options, with storage horizons measured in thousands of years. In conventional carbon capture and storage (CCS), CO2 is captured, compressed to a supercritical state, transported, and injected into deep saline aquifers or depleted oil and gas reservoirs, where structural, residual, solubility, and mineral trapping keep it in place. Deployment remains modest against the scale required: global operational capture capacity is around 50 MtCO2 per year. That is well under 1% of annual energy-related emissions, but it is the workhorse for point-source decarbonization in power, cement, steel, refining, and low-emissions hydrogen.
Technological capture: post-combustion, pre-combustion, oxy-fuel, and direct air capture
The capture front end comes in several flavors. Post-combustion capture uses amine solvents on flue gas, achieves high capture rates, and suits retrofits, though it carries a meaningful energy penalty. Pre-combustion converts fuel to syngas and separates CO2 at high pressure, while oxy-fuel combustion burns fuel in near-pure oxygen for simpler separation; both tend to fit new-build industrial facilities better than retrofits. Direct air capture (DAC) pulls CO2 from ambient air using solid sorbent or liquid solvent systems. The IEA estimated large-scale DAC costs at roughly USD 125 to 335 per tonne in 2022, with the potential to fall as systems scale. Paired with geological storage, DACCS qualifies as high-durability carbon dioxide removal.
Hybrid approaches: BECCS and enhanced rock weathering
Two hybrid pathways combine biology with engineering. BECCS pairs bioenergy with geological storage: because biomass absorbs CO2 as it grows and the resulting emissions are captured and stored, it can deliver net-negative emissions, subject to intense scrutiny over biomass sustainability, land use, and lifecycle accounting. Enhanced rock weathering spreads pulverized basalt on agricultural soils to accelerate natural CO2 uptake, a novel removal method with active MRV research and potential soil co-benefits. Matching any of these to your context means treating sequestration as a portfolio decision, not a single bet; our decarbonization guide covers how these fit alongside direct emissions cuts.
The Scale Gap: Where Carbon Sequestration Stands Today
To understand carbon sequestration's real position in the net zero landscape, you have to look past the headlines and at the actual tonnage. The numbers tell an uncomfortable story: what we remove today and what mid-century pathways demand are separated by orders of magnitude.
Natural sinks versus engineered solutions
Total current carbon dioxide removal (CDR) sits at roughly 2.2 GtCO2 per year globally, and almost all of it comes from conventional methods such as afforestation, reforestation, forest management, and soil carbon practices. The 2026 State of Carbon Dioxide Removal report estimates that newer, or "novel," methods delivered only about 2 MtCO2 in 2025. That is not a rounding error away from the target; it is a different universe of scale.
The broader capture picture is not much larger. Operational CCUS capture capacity remains around 50 MtCO2 per year, less than 1% of annual energy-related CO2 emissions. Capacity now under construction could nearly double that operational base by 2030, but the IEA warns that most announced projects still lack a final investment decision. Announcements therefore should not be counted as delivered sequestration.
How far current capacity falls short of net zero requirements
The 2026 State of Carbon Dioxide Removal assessment puts the gap between current progress and more sustainable Paris-aligned pathways at about 0.3 GtCO2 per year in 2030, 1.2 GtCO2 in 2035, and 5.2 GtCO2 in 2050. The precise need varies by scenario, but the direction is unambiguous: direct emissions cuts must accelerate while durable removals grow by orders of magnitude.
This scale gap is the defining challenge, and it carries direct consequences for corporate net zero plans. Companies that benchmark their sequestration claims against these global baselines, and that distinguish durable engineered removals from reversible nature-based ones, are the ones whose disclosures will survive auditor and investor scrutiny. Our decarbonization guide covers how to keep those distinctions defensible.
Carbon Sequestration's Role in Energy-Sector Net Zero
Nowhere is carbon sequestration being operationalized faster than in the energy sector, where it is moving from pilot decks into commissioned plants, financed storage hubs, and audited procurement contracts. The reason is structural: even aggressive electrification and efficiency plans leave residual emissions from hydrogen, refining, gas processing, and industrial clusters. CCS can reduce those emissions at the source, while direct air capture (DAC) is reserved for the harder residual tail. This sequencing matters: reduce what can be reduced first, then use high-durability removals for the emissions that remain.
How CCS fits into energy company net zero strategies
For utilities and majors, the emerging playbook favors shared infrastructure over one-off retrofits. Companies bolt capture onto power and industrial facilities, then connect to common CO2 transport and storage networks such as Northern Lights, HyNet, and CarbonNet. This hub model is the most commercially viable structure because it lets multiple emitters use the same pipeline and offshore reservoir. DAC enters the strategy differently, as a removal instrument. ENGIE, for instance, is procuring 15,000 carbon removal credits from Deep Sky's DAC facilities as part of its net-zero-by-2045 commitment. For firms building these portfolios, the harder work is often structuring defensible decarbonization data across capture, transport, and removal.
Real-world energy sector projects and milestones
The reference cases are now live or near-term. Net Zero Teesside Power is developing a gas-fired power plant with carbon capture linked to the Northern Endurance Partnership's offshore transport and storage network. In Norway, Heidelberg Materials' Brevik CCS facility began operating in 2025 and is designed to capture about 400,000 tonnes of CO2 per year from cement production for transport and permanent storage through Northern Lights. Together, these projects show why shared transport and storage hubs are emerging as the practical model: they connect several emitters to common infrastructure and spread costs across the cluster.
Limitations and Risks Energy Leaders Must Understand
Sequestration is necessary in many net-zero pathways, but each method carries constraints that must appear in project evaluation and public claims.
Energy, land, water, and infrastructure requirements
Capture equipment consumes energy and can reduce the output of the host facility. DAC requires substantial low-carbon heat and electricity, while afforestation and BECCS can compete for land, water, food production, and biodiversity. Geological storage also depends on pipelines, shipping terminals, injection wells, and suitable reservoirs that may take years to permit and build. Lifecycle assessment should include those inputs rather than reporting only the tonnes entering a capture unit.
Durability, reversal, and long-term liability
Forests and soils can lose stored carbon through fire, drought, disease, or land-use change. Geological storage is far more durable, but only when site characterization, well integrity, monitoring, corrective action, and closure responsibilities are clearly governed. A credible project states who carries liability if stored CO2 migrates or monitoring reveals a reversal.
Measurement quality and the risk of overclaiming
Removal accounting must distinguish gross capture from net removal after energy use, transport, leakage, and upstream emissions. It must also avoid double counting between a project developer, a credit buyer, and a host country's inventory. The central strategic risk is substitution: future sequestration should never be used to postpone reductions that are technically and economically available today.
Frequently Asked Questions About Carbon Sequestration
Is carbon sequestration the same as carbon offsetting?
No, and conflating the two is one of the most common mistakes in corporate climate planning. Carbon sequestration is a physical climate outcome: CO2 is removed and durably stored in geological, terrestrial, or ocean reservoirs. Carbon offsetting is a market and accounting mechanism in which one entity buys credits to compensate for its emissions using activity that occurs elsewhere. The two do not always overlap. You can pursue genuine carbon dioxide removal without offsetting, for example by building and counting your own BECCS or DACCS capacity. You can also purchase offsets that involve no real removal at all, such as questionable avoided-deforestation credits. Many offset schemes face integrity concerns around additionality, accurate baselines, and permanence, which is why offsetting and sequestration deserve separate treatment in any transition plan.
Can carbon sequestration replace cutting emissions?
It cannot. The IPCC is explicit that carbon dioxide removal complements deep emissions reductions but cannot serve as a substitute for them. Every pathway that limits warming to 1.5 or 2 degrees still relies on aggressive direct cuts across every sector first. Sequestration's legitimate role is narrow: counterbalancing hard-to-abate residual emissions that are physically or economically impossible to eliminate, and potentially delivering net-negative emissions later. A net-zero plan built primarily on purchased removals is not aligned with the science, and investors and auditors increasingly scrutinize the ratio of real reductions to removals.
How long does sequestered carbon actually stay stored?
It depends entirely on the storage type, and the difference matters enormously for offsetting fossil emissions. Geological storage in saline aquifers is considered highly durable over thousands of years when well-managed and monitored. Biological storage in forests and soils is vulnerable to fire, disease, and land-use change, and often has timescales of only decades to a century. High-quality offset standards commonly use a minimum threshold of 100 years, and climate scientists argue that removals used to counteract long-lived fossil CO2 should be effectively permanent. This is why geological options are preferred when the goal is neutralizing fossil emissions.
What is the difference between CCS and direct air capture?
CCS captures CO2 at the point of emission, such as a power plant or cement kiln, and prevents new emissions from reaching the atmosphere. Direct air capture (DAC) pulls CO2 directly from ambient air. When DAC is paired with permanent geological storage, forming DACCS, it constitutes genuine carbon removal because it lowers the existing atmospheric stock rather than just avoiding additions. Both are needed in net-zero pathways, but they serve different functions.
How much CO2 is currently being sequestered globally, and is it enough?
Not remotely. Around 2.2 GtCO2 per year of carbon dioxide removal occurs today, almost entirely from conventional methods such as forestry and soil management. Novel CDR delivered only about 2 MtCO2 in 2025. The assessed removal gap grows to several gigatonnes per year by mid-century, which should temper any transition plan that leans heavily on future removals.
Which industries benefit most from carbon sequestration in a net zero strategy?
CCS is most relevant for power, cement, steel, chemicals, and oil and gas processing, where electrification is limited and process emissions are unavoidable. BECCS and DAC are better suited to generating the net-negative emissions needed to counterbalance aviation, agriculture, and other sectors that cannot fully decarbonize. Our energy sector work and decarbonization guide cover how these fit into a broader plan.
What should energy companies look for when evaluating a carbon sequestration project?
Assess five things: storage durability, with geological favored over biological for fossil emission offsets; MRV quality and independent third-party verification; full lifecycle emissions including the energy penalty of capture; a clear liability framework for long-term storage; and whether the project genuinely complements direct reductions rather than delaying them. Rigorous accounting here protects your sustainability reporting from later restatement.