By Jamey Mulligan, Head of Carbon Neutralization, Amazon

There is a general perception in the voluntary carbon market that newer credits are better. This occurs even though the most commonly retired credits have a “vintage” – the year in which the carbon reduction or removal occurred – that is several years old

But do carbon credits get stale?

No. What matters is the quality of the credit, not the year in which the mitigation occurred. Part of the conventional thinking around vintage is that, because the carbon standards’ methodologies are updated over time as shortcomings come to light, there may be some loose correlation between vintage and quality. But quality is a function of methodology, not vintage. And an older vintage does not necessarily mean credits were issued under an outdated methodology. Newly issued credits may have an older vintage due to lags between mitigation results and verification but are issued under still-active methodologies. If a credit was issued several years ago and has been sitting unsold since, one might wonder why no one else has snapped it up. But at the end of the day, if a credit is properly quantified and comes from a project that would not have occurred without carbon finance, it is valid no matter its history.

Why do some high-quality credits carry an older vintage?

Principally, because of the time it takes to quantify, verify, issue, and bring credits to the voluntary carbon market after the mitigation has occurred. For example, in nature-based carbon dioxide removal such as forest restoration, carbon accumulation in very young trees is relatively slow and hard to measure. Due to the costs of sending technicians to the field to measure forest biomass, it often makes sense to measure forest carbon on a three- or five-year cycle in the early years of a project. This means that carbon sequestered and stored in year two, for example, may not get accounted for, assigned a vintage, and made available for purchase as a credit until year six.

Lags between vintage and issuance can be even greater in jurisdictional programs that reduce deforestation across entire national or sub-national regions. National forest monitoring systems used for verification can have a one- to two-year delay in producing official data sets. In jurisdictions establishing crediting programs for the first time, important consultations with Indigenous peoples and local communities can take years to do properly, and some jurisdictions need to have buyers secured to justify committing additional resources to undertake the efforts needed for stakeholder consultation and verification. The verification process itself, once the program is ready for crediting, can take an additional 18–24 months especially the first time through. As a result, jurisdictional credits freshly issued in 2025 and 2026 will carry a vintage as early as 2018.

What really matters in the end?

When considering any credit purchase, no matter the vintage, buyers should directly evaluate the quality of the credit, based on key quality parameters such as leakage, durability, and additionality (of which vintage is not one), as set out in the carbon standard methodology. Buyers should also evaluate the big-picture impact of their purchase. How will proceeds be used? Will this transaction encourage more of the kinds of activities we want to see take root in the voluntary carbon market? In many jurisdictional programs, credit proceeds are reinvested in further forest protection and sustainable development. For example, when a company purchases a credit with a 2018 vintage, those proceeds could provide resources to forest communities for local priorities like clean drinking water and health clinics today, even though the underlying mitigation occurred years ago. Transacting these credits also affirms for jurisdictions and communities the value in continuing their efforts to protect and restore the forest.

The carbon market’s overreliance on newer vintages as indicators of quality reflects a misunderstanding of what really makes a carbon credit valuable. The effectiveness of a carbon credit lies not in its age but in the robustness of its underlying methodology and the integrity of its impact.

Jamey Mulligan is Head of Carbon Neutralization at Amazon. Visit the Amazon Sustainability Exchange to learn more about accessing high-integrity carbon credits sourced with Amazon’s industry-leading approach to carbon neutralization.

Any opinions expressed in this commentary reflect the views of the authors and not of Carbon Pulse.

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