Making Sense of the Voluntary Carbon Market

The report analyzes the voluntary carbon market, contrasting it with compliance markets and evaluating ten specific offset standards. It identifies structural flaws in project-based offsetting, such as the difficulty of proving additionality and inherent conflicts of interest where auditors are paid by project developers. The authors argue that while the voluntary market fosters innovation and participation, it requires more rigorous, transparent standards to ensure environmental integrity and the delivery of sustainable development co-benefits.

• The voluntary carbon market is significantly smaller than the compliance market, with a trading value of €62.6 million in 2006 compared to €23 billion for the compliance market.
• Additionality—the requirement that emission reductions would not have occurred without the offset project—is the most contentious issue in the market because it relies on a subjective counterfactual reality that cannot be proven.
• A structural design flaw exists in offset markets where both buyers and sellers are incentivized to maximize the number of offsets generated, removing the natural checks and balances found in typical markets.
• Conflicts of interest arise because third-party auditors are typically hired and paid by the project developers, creating pressure on auditors to approve projects to maintain business relationships.
• The Clean Development Mechanism (CDM) has been successful in generating large volumes of offsets but has failed to consistently deliver the promised sustainable development co-benefits for host countries.
• The Gold Standard is identified as the most stringent of the reviewed standards, requiring explicit social and environmental benefits and a rigorous stakeholder process.
• The Voluntary Carbon Standard (VCS) 2007 aims to be a base-quality standard with lower administrative costs, but it is criticized for lacking a separate approval body to review auditor-approved projects.
• Biological sequestration (LULUCF) projects face unique challenges regarding permanence—the risk that sequestered carbon is released by fire or disease—and leakage, where project activities cause emissions increases outside the project boundary.
• Industrial gas destruction projects are controversial because they are often the cheapest to implement but provide few social benefits and may create perverse incentives to build new polluting facilities to generate offsets.
• The Chicago Climate Exchange (CCX) is a pioneer in the US market, but its offsets—particularly those for no-till agriculture—have been criticized for lacking additionality by rewarding practices already in place.
• The Plan Vivo system focuses on small-scale community projects and exclusively sells ex-ante credits, which are projected future reductions and therefore carry higher risk for the buyer.
• The Climate, Community & Biodiversity Standards (CCBS) serves as a project design standard rather than a full-fledged offset standard, meaning it guides design but does not verify quantified emissions reductions.
• Double counting occurs when the same emission reduction is claimed by both a voluntary buyer and a host country's national inventory, a particular risk for projects in Annex B countries.

APA

Kollmuss, A., Zink, H., & Polycarp, C. (2008). Making Sense of the Voluntary Carbon Market. Stockholm Environment Institute. https://www.sei.org/mediamanager/documents/Publications/SEI-Report-WWF-ComparisonCarbonOffset-08.pdf

Chicago

Kollmuss, Anja, Helge Zink, and Clifford Polycarp. Making Sense of the Voluntary Carbon Market. Stockholm Environment Institute, 2008. https://www.sei.org/mediamanager/documents/Publications/SEI-Report-WWF-ComparisonCarbonOffset-08.pdf.

Wikipedia

{{cite report |last1=Kollmuss |first1=Anja |last2=Zink |first2=Helge |last3=Polycarp |first3=Clifford |title=Making Sense of the Voluntary Carbon Market |publisher=Stockholm Environment Institute |date=March 2008 |url=https://www.sei.org/mediamanager/documents/Publications/SEI-Report-WWF-ComparisonCarbonOffset-08.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{kollmuss2008making, author = {Kollmuss, Anja and Zink, Helge and Polycarp, Clifford}, title = {{Making Sense of the Voluntary Carbon Market}}, institution = {Stockholm Environment Institute}, year = {2008}, month = mar, url = {https://www.sei.org/mediamanager/documents/Publications/SEI-Report-WWF-ComparisonCarbonOffset-08.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }