Carbon credits and carbon offsets are two of the most frequently confused terms in corporate sustainability. They are related concepts, but they operate through different mechanisms and carry different implications for how a company claims emissions reductions. Getting this distinction right matters because regulators, auditors, and investors are paying close attention to which instruments companies use and how they use them.
Defining the Terms
Carbon Credit
A carbon credit is a tradeable certificate representing the right to emit one tonne of carbon dioxide equivalent (tCO2e). Carbon credits are primarily associated with compliance markets, specifically emissions trading systems (ETS) such as the EU Emissions Trading System (EU ETS). Under these cap-and-trade systems, a regulatory authority sets a cap on total permitted emissions within a sector or jurisdiction. Participants receive or purchase allowances equal to that cap. At the end of each compliance period, they must surrender enough allowances to cover their actual emissions. Entities that emit less than their allowance can sell surplus credits to those who need more.
The key characteristic of a carbon credit in an ETS context is that it operates within a binding regulatory framework with a declining cap. The cap is what drives actual emissions reduction at the system level.
Carbon Offset
A carbon offset is also a certificate representing one tonne of CO2e, but it represents an emission reduction or removal that has been achieved outside the buyer's own operations. When a company purchases a carbon offset, it is paying for a project elsewhere to reduce or sequester emissions on its behalf. Offset projects include renewable energy development, reforestation and afforestation, avoided deforestation (REDD+), methane capture from landfills, and direct air capture.
Carbon offsets are used predominantly in voluntary carbon markets. Companies purchase them voluntarily to compensate for emissions they have not yet been able to eliminate through operational changes.
Compliance Markets vs Voluntary Markets
| Dimension | Compliance Market (ETS) | Voluntary Market (VCM) |
|---|---|---|
| Participation | Mandatory for covered sectors | Voluntary |
| Instrument | Carbon allowance / credit | Carbon offset (Verified Carbon Unit, Gold Standard, etc.) |
| Standard setter | Government / regulator | Independent standard bodies (Verra, Gold Standard, ACR) |
| Price driver | Cap level, policy certainty, macro | Corporate demand, project quality, co-benefits |
| Use in reporting | Regulatory compliance; some frameworks accept for Scope 2 | Voluntary claims ("carbon neutral", net zero residual offsets) |
| Example | EU ETS allowance, UK ETS, RGGI (US) | Verra VCS credit, Gold Standard credit, ACR offset |
How Offsets Are Verified
The credibility of a carbon offset depends entirely on the rigour of the standard under which it was issued. A project cannot simply claim that it reduced emissions; an independent third party must verify the reduction using a methodology approved by the relevant standard body. The major voluntary carbon market standards are:
- Verra Verified Carbon Standard (VCS): The largest voluntary carbon standard by volume. Projects are verified against approved methodologies. Credits are issued as Verified Carbon Units (VCUs) and registered on the Verra registry.
- Gold Standard: Requires projects to demonstrate not only emission reductions but co-benefits across the UN Sustainable Development Goals. Often considered a higher-quality standard due to its broader requirements.
- American Carbon Registry (ACR): One of the first voluntary carbon standards, widely used in the US, now expanding globally.
- Architecture for REDD+ Transactions (ART TREES): Specifically for jurisdictional REDD+ programmes covering avoided deforestation.
Additionality is the core test: For an offset to be credible, the emission reduction must be "additional" — it would not have occurred in the absence of the carbon project and the revenue it generates. Projects that would have happened anyway (e.g., a hydropower plant that was economically viable without carbon revenue) fail the additionality test and should not generate offsets.
The Role of Offsets in Net-Zero Strategy
The Science Based Targets initiative (SBTi), the most widely recognised framework for corporate net-zero target setting, is explicit about the role of offsets: they cannot count toward a company's near-term emissions reduction targets. Companies with SBTi-validated targets must reduce absolute Scope 1, 2, and 3 emissions by at least 90 percent before using any form of compensation to address residual emissions. The residual 10 percent (or less) can then be addressed through high-quality, permanent carbon removal, not just avoidance or reduction offsets.
This means that a company claiming "net zero" while using offsets to compensate for unchanged operational emissions is not aligned with SBTi standards. This distinction is increasingly enforced by the EU Green Claims Directive and scrutinised by financial auditors under CSRD assurance requirements.
Legitimate Uses of Offsets Today
Despite the above, offsets have a legitimate role in the transition period before deep decarbonisation is achieved. Accepted uses include:
- Carbon neutrality claims for current year residual emissions: Purchasing high-quality offsets to claim carbon neutrality for emissions not yet eliminated, provided the company is on a credible reduction trajectory and discloses the use of offsets.
- Beyond-value-chain mitigation: Contributing to climate outcomes beyond the company's own value chain as a form of philanthropic climate action, disclosed separately from operational emission figures.
- Internal carbon pricing: Using voluntary carbon market prices as a shadow carbon price in investment decisions to align capital allocation with decarbonisation goals.
Quality Criteria When Purchasing Offsets
Not all offsets are equal. When evaluating offset purchases, apply these quality criteria:
- Additionality: Would the emission reduction have occurred without the carbon project revenue?
- Permanence: Is the removal or avoidance permanent? Forest projects face reversal risk from fire or disease. Higher-permanence projects (direct air capture, enhanced rock weathering) carry a premium.
- Measurability: Are emissions reductions quantified using a rigorous, approved methodology rather than rough estimates?
- No double counting: Is the credit registered on a recognised registry and retired (cancelled) on purchase to prevent resale?
- Co-benefits: Does the project deliver verified social or biodiversity benefits alongside the climate outcome?
Tracking Credits and Offsets in Your Carbon Inventory
Carbon tracking platforms need to handle both compliance allowances and voluntary offsets in the emissions accounting workflow. Key requirements include:
- Separate accounting of market-based versus location-based Scope 2 figures (required by GHG Protocol)
- Registry ID recording for each offset purchased and retired
- Flagging offsets as compensation versus reduction to maintain inventory integrity
- Automated reconciliation of allowance holdings against compliance obligations for ETS participants
Mixing offsets into the core GHG inventory without proper disclosure of their compensatory nature is one of the primary greenwashing risks that regulators are now actively investigating. Your carbon tracking system should enforce clear boundaries between actual operational reductions and offset-based compensation.
Summary
Carbon credits are regulatory instruments used in mandatory emissions trading systems. Carbon offsets are voluntary instruments used to compensate for emissions elsewhere. Neither substitutes for actual operational emission reductions, but both play a role in a well-structured climate strategy when used correctly and disclosed transparently. As regulatory frameworks tighten, companies that rely on offsets without a credible reduction trajectory will face increasing scrutiny from auditors, investors, and regulators alike.
