A Carbon Project Glossary
If you've ever heard "vintage" or "additionality" in a carbon program pitch and wondered what they actually mean, you're in good company. Carbon markets have their own vocabulary, and terms like "vintage" and "additionality" tend to get tossed around without much explanation. This glossary covers the terms you're most likely to encounter in the California Soil Restoration Project (CSRP), in plain language and alphabetical order.
Additionality
Some carbon market registries will only enroll acreage that is newly planted with perennial cover for carbon storage eligibility. Programs check additionality by looking at field history and how land was managed before enrollment. Oakville Bluegrass Cooperative and Recover Ag strongly believe that growers who have proved the benefits of continuous living cover and no-till should not be cut off from a new income stream because they started early. That’s why we created the Soil Health Trailblazer path in the California Soil Restoration Project.
Baseline
In soil carbon sampling, Soil Organic Carbon (SOC) is a number from a lab report, typically represented as a percentage (%), for the concentration of carbon by weight in the soil sample. The first soil sample determines the baseline value. In CSRP, Recover Ag combines baseline soil sample numbers with satellite data to estimate how much carbon a field holds at enrollment. Later measurements are compared against that baseline to calculate change.
Buffer pool
A share of credits set aside and not sold, held in reserve to cover losses if stored carbon is later released, from activities like land use changes. Many programs and registries require one.
Carbon credit
A tradable certificate representing one metric ton of carbon dioxide equivalent that was removed from the atmosphere or kept out of it.
Carbon dioxide equivalent (CO2e)
The standard unit for carbon credits. Soil carbon is converted to CO2e because a carbon atom stored in soil came from carbon dioxide in the air. One ton of carbon stored in soil corresponds to about 3.67 tons of CO2, since the oxygen in CO2 adds weight.
Carbon removal credit
A credit for carbon pulled out of the atmosphere and stored, such as carbon that roots and residues add to soil. Avoidance or reduction credits, by contrast, are for emissions that were prevented, such as burning less fuel. CSRP issues removal credits. Many buyers place a higher value on removals, though prices vary widely.
Crediting period
The span of years a project can generate credits under its methodology. The crediting period for CSRP is 25 years.
Insetting and offsetting
Offsetting means a company buys credits from outside its own supply chain to balance out its emissions. Insetting means a company invests in emissions cuts or carbon removal within its own supply chain, such as a winery or food company supporting the growers it buys from. Both create demand for agricultural credits.
Issuance
The point when credits are officially created and recorded in a registry, after the data has been verified. Recover Ag expects to issue CSRP's first credits in February 2027.
Methodology
The rulebook a program follows. A methodology spells out which management changes qualify, how carbon is measured and calculated, and how uncertainty is handled. Sometimes called a protocol.
MRV (measurement, reporting, and verification)
The full process of measuring carbon change, documenting it, and having it independently checked. In CSRP, Recover Ag handles MRV on growers' behalf.
Permanence
How long stored carbon stays in the ground. Soil carbon can be lost through tillage, orchard or vineyard removal, or land use changes, such as converting a field to annual crops or selling it for development. Programs guard against these losses with monitoring periods and a buffer pool, which covers carbon that is later released (see Buffer pool and Reversal).
Registry
An independent database that tracks every credit with a serial number, from issuance to final use, so the same ton can't be sold twice. Verra, Climate Action Reserve, and Isometric are examples.
Remote sensing
Measuring conditions on the ground using satellite imagery. Recover Ag uses remote sensing alongside soil samples to estimate soil carbon across whole fields, which can reduce the number of samples needed.
Retirement
When a buyer uses a credit to make a climate claim, the credit is retired in the registry and can never be resold. Retirement is the end of a credit's life.
Reversal
When stored carbon is released back into the atmosphere, for example after deep tillage or removing an orchard. Buffer pools and monitoring exist to account for reversals.
Sequestration
The process of capturing carbon dioxide from the air and storing it, in this case in soil. Living roots and plant residues tend to be the main way carbon enters orchard and vineyard soils.
Soil organic carbon
The carbon held in soil organic matter, which comes from roots, plant residues, and soil microbes. Soil organic carbon can also improve water holding capacity and nutrient availability, which is part of why the soil report from baseline sampling can be useful on its own.
Uncertainty
The margin of error in a carbon measurement. Soil carbon can vary a lot from one spot to the next, even within a single field, so every estimate comes with a range rather than an exact number. Methodologies typically handle this by crediting toward the low end of that range, which means the credits issued tend to be conservative. Combining soil samples with satellite data can help narrow the range.
Verification
An independent third party reviews a project's data and methods before credits are issued. Verification is what gives buyers confidence that a credit represents real carbon.
Vintage
The year a credit is associated with, usually the year the carbon removal took place. Buyers often look at vintage when deciding what to purchase.
CSRP is accepting applications for the 2027 vintage right now, but field data is due by October 16. Want to learn more about CSRP? Visit our program page.