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Restoring credibility in carbon offsets through systematic ex post evaluation

Nature Sustainability volume 8, pages 733–740 (2025)Cite this article

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Abstract

A key factor undermining the credibility of carbon offsets is the evaluation of project baselines and their impact. The ex ante scenarios constructed by project developers in accordance with rules set by certification schemes have been challenged by ex post evaluations from scientists, who frequently document cases of credit allocations that overestimate the actual emission reductions. Increasing credibility requires methodologies that reliably measure project outcomes and prevent overcrediting—an objective that ex post evaluations may be well suited to achieve. We explore how systematic ex post evaluations could restore credibility to certification schemes in the voluntary carbon market.

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References

  1. Balmford, A. et al. Credit credibility threatens forests. Science 380, 466–467 (2023).

    CAS  Google Scholar 

  2. Jones, J. P. G. Scandal in the voluntary carbon market must not impede tropical forest conservation. Nat. Ecol. Evol. 8, 1203–1204 (2024).

    Google Scholar 

  3. Blake H. The great cash-for-carbon hustle. New Yorker https://www.newyorker.com/magazine/2023/10/23/the-great-cash-for-carbon-hustle (23 October 2023).

  4. Greenfield, P. Revealed: more than 90% of rainforest carbon offsets by biggest certifier are worthless, analysis shows. Guardian (18 January 2023).

  5. Delacote, P. et al. Strong transparency required for carbon credit mechanisms. Nat. Sustain. https://doi.org/10.1038/s41893-024-01310-0 (2024).

  6. Evidence Synthesis Report Part 1: Carbon Credits (Science Based Targets Initiative, 2024); https://sciencebasedtargets.org/news/sbti-releases-technical-publications-in-an-early-step-in-the-corporate-net-zero-standard-review

  7. Probst, B. S. et al. Systematic assessment of the achieved emission reductions of carbon crediting projects. Nat. Commun. 15, 9562 (2024).

    CAS  Google Scholar 

  8. Delacote, P., Le Velly, G. & Simonet, G. Revisiting the location bias and additionality of REDD+ projects: the role of project proponents status and certification. Resour. Energy Econ. 67, 101277 (2022).

    Google Scholar 

  9. Guizar-Coutiño, A., Jones, J. P. G., Balmford, A., Carmenta, R. & Coomes, D. A. A global evaluation of the effectiveness of voluntary REDD+ projects at reducing deforestation and degradation in the moist tropics. Conserv. Biol. 36, e13970 (2022).

  10. West, T. A. P., Börner, J., Sills, E. O. & Kontoleon, A. Overstated carbon emission reductions from voluntary REDD+ projects in the Brazilian Amazon. Proc. Natl Acad. Sci. USA 117, 24188–24194 (2020).

    CAS  Google Scholar 

  11. West, T. A. P. et al. Action needed to make carbon offsets from forest conservation work for climate change mitigation. Science 381, 873–877 (2023).

    CAS  Google Scholar 

  12. Badgley, G. et al. California’s forest carbon offsets buffer pool is severely undercapitalized. Front. For. Glob. Change 5, 154 (2022).

    Google Scholar 

  13. Macintosh, A. et al. Australian human-induced native forest regeneration carbon offset projects have limited impact on changes in woody vegetation cover and carbon removals. Commun. Earth Environ. 5, 149 (2024).

    Google Scholar 

  14. Stapp, J. et al. Little evidence of management change in California’s forest offset program. Commun. Earth Environ. 4, 331 (2023).

    Google Scholar 

  15. Gill-Wiehl, A., Kammen, D. M. & Haya, B. K. Pervasive over-crediting from cookstove offset methodologies. Nat. Sustain. https://doi.org/10.1038/s41893-023-01259-6 (2024).

  16. West, T. A., Bomfim, B. & Haya, B. K. Methodological issues with deforestation baselines compromise the integrity of carbon offsets from REDD. Glob. Environ. Change 87, 102863 (2024).

    Google Scholar 

  17. West, T. A. P. & Fearnside, P. M. Brazil’s conservation reform and the reduction of deforestation in Amazonia. Land Use Policy https://doi.org/10.1016/j.landusepol.2020.105072 (2021).

  18. Seyller, C. et al. The ‘virtual economy’ of REDD+ projects: does private certification of REDD+ projects ensure their environmental integrity? Int. For. Rev. 18, 231–246 (2016).

    Google Scholar 

  19. Akerlof, G. The market for ‘lemons’: quality uncertainty and the market mechanism. Q. J. Econ. 84, 488–500 (1970).

    Google Scholar 

  20. Requirements for the Development and Assessment of Mechanisms Methodologies (A6.4-STAN-METH-001) (United Nations Framework Convention on Climate Change, 2023); https://unfccc.int/sites/default/files/resource/A6.4-STAN-METH-001.pdf

  21. King, D. Voluntary Carbon Markets: Potential, Pitfalls, and the Path Forward (Climate Crisis Advisory Group, 2024); https://cdn.prod.website-files.com/660df44c73d9da2a5912020a/668c12ad7c26d9a68b174756_CCAG%20VCMs%20Report.pdf

  22. Carbon Market Watch et al. Open Letter on the Use of Carbon Credits to Meet Scope 3 GHG Targets (Carbon Market Watch, 2024); https://carbonmarketwatch.org/publications/open-letter-on-the-use-of-carbon-credits-to-meet-scope-3-ghg-targets/

  23. Statement from the SBTi Board of Trustees on Use of Environmental Attribute Certificates, Including but Not Limited to Voluntary Carbon Markets, for Abatement Purposes Limited to Scope 3 (Science Based Targets Initiative, 2024); https://sciencebasedtargets.org/news/statement-from-the-sbti-board-of-trustees-on-use-of-environmental-attribute-certificates-including-but-not-limited-to-voluntary-carbon-markets-for-abatement-purposes-limited-to-scope-3

  24. Greenfield, P. & Harvey, F. Climate target organisation faces staff revolt over carbon-offsetting plan. Guardian (11 April 2024).

  25. Aligning Corporate Value Chain to Global Climate Goals (Science Based Targets Initiative, 2024).

  26. SBTi Corporate Net-Zero Standard Version 2.0 (Science Based Targets Initiative, 2025); https://sciencebasedtargets.org/resources/files/Net-Zero-Standard-v2-Consultation-Draft.pdf

  27. Pande, R. Fixing forest carbon credits. Science 383, eadn4923 (2024).

    Google Scholar 

  28. Duflo, E., Glennerster, R. & Kremer, M. in Handbook of Development Economics (eds Schultz, T. P. & Strauss, J. A.) 3895–3962 (Elsevier, 2007).

  29. Malan, M. et al. Evaluating the impacts of a large-scale voluntary REDD+ project in Sierra Leone. Nat. Sustain. 7, 120–129 (2024).

    Google Scholar 

  30. Haya, B. K., Abayo, A., Rong, X., So, I. S. & Elias, M. Voluntary Registry Offsets Database v2024-10 (Berkeley Carbon Trading Project, University of California, Berkeley, 2024).

  31. Alix-García, J. & Millimet, D. L. Remotely incorrect? Accounting for nonclassical measurement error in satellite data on deforestation. J. Assoc. Environ. Resour. Econ. 10, 1335–1367 (2023).

    Google Scholar 

  32. Dechezleprêtre, A., Nachtigall, D. & Venmans, F. The joint impact of the European Union emissions trading system on carbon emissions and economic performance. J. Environ. Econ. Manage. 118, 102758 (2023).

    Google Scholar 

  33. Filewod, B. & McCarney, G. Avoiding carbon leakage from nature-based offsets by design. One Earth https://doi.org/10.1016/j.oneear.2023.05.024 (2023).

  34. Cinelli, C. & Hazlett, C. Making sense of sensitivity: extending omitted variable bias. J. R. Stat. Soc. B 82, 39–67 (2020).

    Google Scholar 

  35. Simonet, G., Delacote, P. & Robert P. On managing co-benefits in REDD+ projects. Int. J. Agric. Resour. Gov. Ecol. 12, 170–188 (2016).

  36. Trencher, G. et al. Demand for low-quality offsets by major companies undermines climate integrity of the voluntary carbon market. Nat. Commun. 15, 6863 (2024).

    CAS  Google Scholar 

  37. Evans, A., Gayle, D. & van der Zee, B. Carbon credit trade rules approved, breaking lengthy deadlock—COP29 day one, as it happened. Guardian (11 November 2024).

  38. UK Department for Energy Security and Net Zero Integrating Greenhouse Gas Removals in the UK ETS: Consultation Analytical Annex (UK Government, 2024); https://assets.publishing.service.gov.uk/media/6699254bce1fd0da7b592858/integrating-ggrs-in-the-ukets-consultation-analytical-annex.pdf

  39. Blanchard, L., Haya, B., Lezak, S. & Anderegg, W. The history of ‘contribution’ approaches for climate mitigation: a narrative review. SSRN https://doi.org/10.2139/ssrn.4971756 (2024).

  40. Angelsen, A. REDD+ as result-based aid: general lessons and bilateral agreements of Norway. Rev. Dev. Econ. 21, 237–264 (2016).

    Google Scholar 

  41. Poyser, A. in Sustainable Investments in Green Finance (eds Taneja, S. et al.) 139–162 (Business Science Reference, 2024).

  42. Haya, B. K. et al. Comprehensive review of carbon quantification by improved forest management offset protocols. Front. For. Glob. Change 6, 958879 (2023).

    Google Scholar 

  43. VM0007 REDD+ Methodology Framework (REDD+MF), v1.8 (Verra, 2024); https://verra.org/documents/vm0007-redd-methodology-framework-reddmf-v1-7/

  44. de Chaisemartin, C. & d’Haultfoeuille, X. Credible answers to hard questions: differences-in-differences for natural experiments. SSRN https://doi.org/10.2139/ssrn.4487202 (2023).

  45. LaLonde, R. J. Evaluating the econometric evaluations of training programs with experimental data. Am. Econ. Rev. 76, 604–620 (1986).

    Google Scholar 

  46. Bernard, D. et al. How Much Should We Trust Observational Estimates? Accumulating Evidence Using RCTs with Imperfect Compliance Discussion Paper No. 18794 (CEPR, 2024); https://cepr.org/publications/dp18794

  47. Battocletti, V., Enriques, L. & Romano, A. The voluntary carbon market: market failures and policy implications. Univ. Colo. Law Rev. 95, 519 (2024).

    Google Scholar 

  48. Mitchard, E. et al. Serious errors impair an assessment of forest carbon projects: a rebuttal of West et al. (2023). SSRN https://doi.org/10.2139/ssrn.4661873 (2023).

Download references

Acknowledgements

The BETA contributes to the Labex ARBRE ANR-11-LABX-0002-01. This research is part of the Agriculture and Forestry research programme by the Climate Economics Chair. B.G. is funded by Dragon Capital and acknowledges funding from the UKRI/NERC projects BIOADD (ref. no. NE/X002292/1), BIOESG (ref. no. NE/X016560/1) and RENEW (ref. no. NE/W004941/1). S.C.-F. acknowledges funding from the ANR project PENSEE (no. 16-CE32-0011-01).

Author information

Authors and Affiliations

  1. Université de Lorraine, AgroParisTech-INRAE, BETA, Nancy, France

    Philippe Delacote & Tara L’Horty

  2. Climate Economics Chair, Paris, France

    Philippe Delacote, Anna Creti & Tara L’Horty

  3. Toulouse School of Economics, INRAE, University of Toulouse Capitole, Toulouse, France

    Sylvain Chabé-Ferret & Anouch Missirian

  4. Institute for Advanced Studies in Toulouse, Toulouse, France

    Sylvain Chabé-Ferret

  5. Université Paris Dauphine PSL Research University, UMR LEDA, Paris, France

    Anna Creti

  6. Vibrant Planet, School of Informatics, Computing and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA

    Katharyn Duffy

  7. University of California, Berkeley, Berkeley, CA, USA

    Micah Elias

  8. Blue Forest, Sacramento, CA, USA

    Micah Elias

  9. Department of Biology, University of Oxford, Oxford, UK

    Alejandro Guizar-Coutiño

  10. Canadian Forest Service, Sault Ste Marie, Ontario, Canada

    Ben Filewod

  11. Land, Environment, Economics, and Policy Institute, Department of Economics, University of Exeter Business School, Exeter, UK

    Ben Groom

  12. Department of Land Economy, University of Cambridge, Cambridge, UK

    Andreas Kontoleon

  13. CEE-M, Université de Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France

    Gwenole LeVelly

  14. Institute for Environmental Studies (IVM), Vrije University Amsterdam, Amsterdam, the Netherlands

    Thales A. P. West

Authors
  1. Philippe Delacote
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  2. Sylvain Chabé-Ferret
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  13. Thales A. P. West
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Contributions

P.D. proposed the initial concept and led the paper writing. S.C.-F., A.C., K.D., M.E., A.G.-C., B.F., B.G., A.K., G.L., T.L., A.M. and T.A.P.W. contributed to paper development and revisions in their specific areas of expertise.

Corresponding author

Correspondence to Philippe Delacote.

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The authors declare no competing interests.

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Peer review information

Nature Sustainability thanks Keith Jin Deng Chan and Gregory Trencher for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Tables 1 and 2, Discussion and references.

Supplementary Table 3

Overview of baseline parameters for forestry carbon offset protocols according to certification documents for each methodology16,42.

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Delacote, P., Chabé-Ferret, S., Creti, A. et al. Restoring credibility in carbon offsets through systematic ex post evaluation. Nat Sustain 8, 733–740 (2025). https://doi.org/10.1038/s41893-025-01589-7

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