Carbon Market Watch response to Verra’s proposed “tonne-year accounting” method

Carbon Market Watch opposes Verra's proposed "tonne-year accounting" method, which would allow projects storing carbon temporarily to issue credits based on the duration of storage (e.g., 100 tonnes for 1 year equals 1 credit). The organization argues this approach is logically flawed regarding radiative forcing, incompatible with finite global carbon budgets, and creates a risk where short-term benefits are prioritized over long-term climate costs. Additionally, it warns that the method could encourage selection bias, allowing high-risk projects to avoid long-term monitoring requirements.

• The proposed tonne-year accounting method is logically flawed because it assumes that balancing cumulative radiative forcing over a specific time horizon produces equivalent outcomes, regardless of how that forcing is distributed. Under this rule, storing 100 tCO2 for one year is treated as equivalent to storing 1 tCO2 for 100 years.
• Tonne-year accounting is incompatible with the concept of a limited global carbon budget. Short-term storage provides little benefit because once the carbon is released, the budget remains short by that amount, meaning such storage does not help the world stay within its finite carbon budget.
• The method is described as myopic because it allows a large decrease in radiative forcing in a single year to compensate for a small increase in radiative forcing over 100 years. This structure ensures financial and climate benefits accrue in the short term, while the costs and increased climate impacts are shifted to future society.
• Allowing AFOLU projects to use tonne-year accounting instead of buffer pools creates risks regarding additionality and selection bias. Projects with high reversal risks in the mid- to long-term—such as those in areas prone to forest fires or landowners planning near-term timber harvests—may use this method to avoid long-term monitoring and compensation requirements.

APA

Carbon Market Watch (n.d.). Carbon Market Watch response to Verra’s proposed “tonne-year accounting” method. https://carbonmarketwatch.org/wp-content/uploads/2022/04/CMW-response-tonne-year-accounting.pdf

Chicago

Carbon Market Watch. Carbon Market Watch response to Verra’s proposed “tonne-year accounting” method. n.d. https://carbonmarketwatch.org/wp-content/uploads/2022/04/CMW-response-tonne-year-accounting.pdf.

Wikipedia

{{cite press release |author=Carbon Market Watch |title=Carbon Market Watch response to Verra’s proposed “tonne-year accounting” method |url=https://carbonmarketwatch.org/wp-content/uploads/2022/04/CMW-response-tonne-year-accounting.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@misc{carbonmarketwatchndcarbon, author = {{Carbon Market Watch}}, title = {{Carbon Market Watch response to Verra’s proposed “tonne-year accounting” method}}, publisher = {Carbon Market Watch}, url = {https://carbonmarketwatch.org/wp-content/uploads/2022/04/CMW-response-tonne-year-accounting.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }