Additionality

What is additionality?

A carbon credit is supposed to represent one metric ton of carbon dioxide equivalent kept out of, or removed from, the atmosphere. Additionality asks whether that benefit was actually caused by the credit. If a farmer, landowner or company would have made the same change without the carbon revenue, selling a credit for it does not change the climate outcome, and any buyer using the credit to offset its own emissions would be claiming a benefit that did not occur.

Additionality is one of the core integrity criteria for carbon credits, alongside permanence, accurate measurement and avoiding double counting.

How additionality is assessed

Carbon registries use tests such as:

• Regulatory surplus. The practice is not already required by law.
• Common practice. The practice is not already widespread in the region.
• Financial or barrier analysis. The project would not be viable, or would face barriers, without carbon revenue.
• Baselines. Measuring against what would have happened in a business-as-usual scenario.

Additionality in agriculture

Agricultural carbon programs pay for practices such as cover crops, reduced tillage and improved nitrogen management that build soil carbon sequestration or cut emissions. Additionality is a recurring question for these programs, because some growers already use the practices and others might have adopted them anyway. Many programs therefore limit eligibility to practices newly adopted after a set date.

Frequently asked questions