Less than 16 percent of CO2 reductions from certificates fulfilled
Carbon Crediting is substantially overestimated
Thousands of projects worldwide promise to offset greenhouse gas emissions. Companies, private individuals and states can buy credits that certify the compensation of a certain amount of emissions. Most projects aim to avoid the release of additional greenhouse gases, for example by protecting forests or building wind turbines instead of a coal-fired power plant.
However, climate offsetting is increasingly being criticized. It is being questioned whether the credits are realistic and whether their purchase has an effect that would not have existed without the offset payments.
An international research team has now analyzed the state of research on these issues in a large meta-study. Their evaluation comprises 14 individual, high-quality studies on more than 2,300 carbon crediting projects. The meta-study covers one fifth of the total credit volume issued to date, which corresponds to almost one billion tons of CO2 emissions. In order to compare the climate protection effect, the researchers also examined 51 studies on comparable projects for which no carbon credits were issued.
Crediting can result in more emissions
The meta-study shows that less than 16 % of the carbon credits examined were actually based on emission reductions. The research team also broke down individual areas:
For projects to reduce sulphur hexafluoride (SF6), which has a particularly strong greenhouse gas effect, the actual emission reductions amounted to 16 % of the carbon credits. Projects to avoid deforestation had 25 % of the claimed effect. Only 11 % of the supposed greenhouse gas reductions were achieved by projects in which conventional cooking stoves were replaced by more climate-friendly ones in poorer countries. The reduction in the greenhouse gas trifluoromethane (HFC-23) was comparatively well achieved, with a value of 68 %.
With regard to wind energy, the data shows that the projects would probably have been implemented without the sale of carbon credits and that the issuing of credits has therefore not led to any additional climate protection. Improved forest management was also implemented in reference regions without access to carbon credits to the same extent as in areas that benefited from carbon credits.
In addition to this multiple ineffectiveness, the meta-study even shows negative effects for the climate: in industrial companies that emit the greenhouse gases trifluoromethane (HFC-23) and sulphur hexafluoride (SF6), the amount of emissions not only continued, but increased as soon as the companies purchased credits.
The research team has prepared the results in a generally understandable way with charts that can be filtered according to project objectives and regions. The data will be continuously updated.
“Systematic quality issues”
“There is an urgent need to establish better rules for issuing carbon credits. All project types face systematic quality issues, and the quantification of emission reductions needs substantial improvement,” says study head Dr. Benedict Probst, head of the Net Zero Lab at the Max Planck Institute for Innovation and Competition.
Study author Dr. Malte Toetzke, who conducts research at the Professorship of Public Policy for the Green Transition at TUM, emphasizes: “Carbon credits can certainly be an important investment in those climate protection projects that are difficult to finance in any other way. If certificates were only allowed for such projects, carbon credits could be less easily misused for greenwashing. This would drive up the price of the credits, which would be a sensible incentive for companies to increasingly reduce their own emissions instead of buying credits.”
Probst, B.S., Toetzke, M., Kontoleon, A. et al. Systematic assessment of the achieved emission reductions of carbon crediting projects. Nat Commun 15, 9562 (2024). DOI: 10.1038/s41467-024-53645-z
- All data in filterable charts
- Researchers from the Max Planck Institute for Innovation and Competition, the Technical University of Munich, ETH Zurich, the University of Cambridge, Harvard University, the Mercator Research Institute on Global Commons and Climate Change, the University of Leeds, the University of California, Berkeley, the Öko-Institut, the University of Wuppertal, the University of Oxford and the Vrije Universiteit Amsterdam were involved in the study.
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Malte Toetzke is also involved in the new Transformation Finance Lab of the TUM Think Tank. The TUM Think Tank brings together actors from the realms of science, civil society, politics and business to jointly develop proposals and instruments to address urgent problems.
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Malte Toetzke's research is funded by a TUM Friedrich Schiedel Fellowship for Social Sciences and Technology and a TUM Global Postdoc Fellowship.
Contacts to this article:
Dr. Malte Toetzke
Technical University of Munich (TUM)
Professorship of Public Policy for the Green Transition
malte.toetzke@tum.de
