Evaluating and Improving Carbon Offsetting Programs

This policy brief by the Stockholm Environment Institute (SEI) evaluates the role of carbon offsetting programs in climate policy. It discusses the potential for offsets to reduce mitigation costs and provide sustainability benefits, while warning of risks such as non-additionality, leakage, and permanence. The document highlights significant variability in how different protocols quantify offsets and argues for the standardization of these protocols to ensure market integrity.

• Carbon offsets can lower the overall cost of meeting emission targets, allowing for more ambitious climate goals, and may provide social, environmental, and technology transfer benefits to host regions.
• Offset programs face four primary policy risks: additionality (projects that would have happened regardless), permanence (e.g., forestry projects lost to fire or logging), leakage (increased emissions elsewhere), and quantification and verification errors.
• There is a risk that offsets may delay the adoption of lower-emitting technologies by providing near-term cost advantages, potentially locking in higher-emission infrastructures over the long term.
• The American Climate and Energy Security Act (ACESA), approved by the US House of Representatives in June 2009, proposed emission targets of 17% below 2005 levels by 2020 and 83% below 2005 levels by 2050, allowing up to 2 billion tons of offsets annually.
• SEI research indicates that the amount of offsets credited to a project can vary by a factor of 2 or more depending on the protocol used, emphasizing the need for standardized quantification procedures.
• Aviation offset calculators show significant variance in results primarily due to differing policy choices regarding the treatment of non-CO2 climate emissions, rather than scientific gaps.
• Certain project types are less suitable for offsetting due to difficulties in measurement or baseline definition; in such cases, or where regulation is more efficient (such as for HFC emissions), offsets should only be used as transitional tools.

APA

Kollmuss, A. (n.d.). Evaluating and Improving Carbon Offsetting Programs. Stockholm Environment Institute. https://www.sei.org/mediamanager/documents/Publications/Climate-mitigation-adaptation/Economics_of_climate_policy/Evaluating-Improving-Carbon-Offsetting-Programs.pdf

Chicago

Kollmuss, Anja. Evaluating and Improving Carbon Offsetting Programs. Stockholm Environment Institute, n.d. https://www.sei.org/mediamanager/documents/Publications/Climate-mitigation-adaptation/Economics_of_climate_policy/Evaluating-Improving-Carbon-Offsetting-Programs.pdf.

Wikipedia

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BibTeX

@techreport{kollmussndevaluating, author = {Kollmuss, Anja}, title = {{Evaluating and Improving Carbon Offsetting Programs}}, institution = {Stockholm Environment Institute}, url = {https://www.sei.org/mediamanager/documents/Publications/Climate-mitigation-adaptation/Economics_of_climate_policy/Evaluating-Improving-Carbon-Offsetting-Programs.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }