Over 80% of carbon credits issued by more than 2,000 projects have a much lower climate impact than they claim, a new meta study finds. This has serious implications for the role of carbon markets in combating the climate crisis.
The peer-reviewed paper, whose lead author was Benedict Probst of the Max Planck Institute appeared in Nature Communications, shed renewed light on the serious quality issues plaguing the voluntary carbon market (VCM).
The comprehensive paper reviewed 65 studies to assess credit quality by analysing the impact of 2,346 carbon crediting projects.
The findings are staggering. The authors estimate that out of 972 million carbon credits – a fifth of total credits issued globally to date – an astonishing 812 million are unlikely to represent a full tonne of CO2 reduced, as they claim. In other words, only 16% are likely to accurately report their climate impact.
Hot air
The low quality of credits was particularly marked for certain project types. Wind power projects in China and improved forest management projects in the United States, fare particularly badly, as they appear to have not reduced emissions at all. Also appearing on the low end of the spectrum are cookstove projects, which only achieved a tenth of the emission reductions for which credits were issued.
This is followed by credits issued for the destruction of sulphur hexafluoride (SF6), one of the most potent greenhouse gases, and avoided deforestation credits where actual emission reductions are estimated at a low 16.4% and 24.7% of issued credits respectively. Only fluoroform (HFC-23) destruction projects fared better, with 68.3% of credits likely to represent real reductions, which is still only a two-thirds success rate.
These grim findings confirm longstanding problems in carbon crediting projects which academics, NGOs, rating agencies and the media have long flagged. For instance, a study commissioned by Carbon Market Watch last year found that only one in 13 carbon credits issued by REDD+ forestry projects represented real emissions reductions.
These findings underline once more that carbon credits must not be used for offsetting nor be permitted to count towards emissions targets, a truly reckless idea prominently floated in 2024 by the SBTi’s board and the VCMI, which calls it a bridging solution.
View an interactive presentation of the study’s findings.
