21. Berkeley. (2024). Voluntary Registry Offsets Database. (v2024-08-31) [Data set]. https://gspp.berkeley.edu/research-and- impact/centers/cepp/projects/berkeley-carbon-trading-project/offsets-database. 22. Food and Agriculture Organization of the United Nations (FAO). (2021). Africa Open D.E.A.L: Open Data for Environment, Agriculture and Land & Africa’s Great Green Wall. https://www.fao.org/policy-support/tools-and-publications/resources- details/en/c/1445219/. 23. Potential net carbon gain means the difference between the existing carbon stocks of a given ecosystem and the potential stocks that the ecosystem could support. This is a function of environmental and physical conditions that limit a location’s capacity to support living biomass. 24. Soil organic carbon stocks refer to a carbon pool where carbon is stored in soils in a relatively stable state, following the decomposition of organic matter. 25. Ashpole, M. and Carpena, P . (2024). Methodological Note – Potential Unrealised Carbon Across the Great Green Wall. Tree Aid. https://treeaid.org/media/3vijf11v/tree-aid-carbon-finance-methodological-note.pdf. 26. Beck, H. et al. (2023). High-resolution (1 km) Köppen-Geiger maps for 1901-2099 based on constrained CMIP6 projections. Scientific Data 10, Article number: 724. https://www.nature.com/articles/s41597-023-02549-6. 27. BloombergNEF. (2024). Carbon Credits Face Biggest Test Yet, Could Reach $238/Ton in 2050, According to BloombergNEF Report. https://about.bnef.com/blog/carbon-credits-face-biggest-test-yet-could-reach-238-ton-in-2050- according-to-bloombergnef-report/. 28. Ashpole, M. and Carpena, P . (2024). Methodological Note – Potential Unrealised Carbon Across the Great Green Wall. Tree Aid. https://treeaid.org/media/3vijf11v/tree-aid-carbon-finance-methodological-note.pdf. The analysis in Figure 2 is based on the published methodology from Walker et al., 2022 and 2020-2024 datasets. The dataset predicts potential biomass using bioclimatic variables in future climate scenarios and applying a forest machine learning algorithm. The model accounts for known pixel-level uncertainty at a 500m grid resolution. The resulting data was used by Tree Aid to assess the carbon stock potential of the 11 GGW countries, classified by Köppen-Geiger climate zones. 29. A challenge for early carbon projects in GGW countries was the limited availability of methodologies that accounted for carbon beneath the ground, which accounts for almost half of the carbon potential in the region (27.8% belowground biomass and 32.4% soil organic carbon). However, in recent years, voluntary carbon market standards, such as Plan and Verra (the Verified Carbon Standard) have introduced methodologies to account for soil carbon. 30. Project developers using this paper as an introductory analysis should research which project type has the highest potential within pools, and which interventions would best benefit communities. Additional examples of land uses and interventions can be found in the supporting case studies in the following document: Food and Agriculture Organization of the United Nations (FAO). (2022). Africa Open Data for Environment, Agriculture and Land (DEAL) and Africa’s Great Green Wall: Technical land use report. https://openknowledge.fao.org/server/api/core/bitstreams/257e955a-e522-4f0b- 96bc-2c55775b52ba/content. 31. Abatable. (2024). VCM Investment Attractiveness Index. https://app.abatable.com/intelligence/tools/vcm-investment-index. 32. Sources: –The Integrity Council for the Voluntary Carbon Market (ICVCM). (2024). The Core Carbon Principles. 9. Sustainable development benefits and safeguards. https://icvcm.org/core-carbon-principles/. –United Nations Department of Economic and Social Affairs. (2016). Free Prior and Informed Consent – An Indigenous Peoples’ right and a good practice for local communities – FAO. https://www.un.org/development/desa/ indigenouspeoples/publications/2016/10/free-prior-and-informed-consent-an-indigenous-peoples-right-and-a-good- practice-for-local-communities-fao/. 33. Sources include: –Carbon Market Watch. (2023). Zeroing in on greenwashing: How corporations misuse net zero pledges. https:// carbonmarketwatch.org/2023/03/09/zeroing-in-on-greenwashing-how-corporations-misuse-net-zero-pledges/. –Sky News. (2022). Congolese farmers barred from own land for tree planting project by French oil giant Total Energies. https://news.sky.com/story/congolese-farmers-barred-from-own-land-for-tree-planting-project-by-french-oil-giant- total-energies-12766904. –The Guardian. (2023). Carbon credit speculators could lose billions as offsets deemed worthless. https://www.theguardian.com/environment/2023/aug/24/carbon-credit-speculators-could-lose-billions-as-offsets- deemed-worthless-aoe. 34. Avoided deforestation “occurs when land that would have been demonstrably deforested is not, because of a change in policy, funding, actions, goals, etc.” Source: United Nations initiative on Reducing Emissions from Deforestation and forest Degradation (UN-REDD). (2024). https://www.un-redd.org/glossary/avoided- deforestation#:~:text=Definition,%2C%20actions%2C%20goals%2C%20etc. 35. Cannon, J. (2023). REDD+ projects falling far short of claimed carbon cuts, study finds. Mongabay. https://news.mongabay.com/2023/08/redd-projects-falling-far-short-of-claimed-carbon-cuts-study-finds/. 36. African Development Bank Group (AfDB). (2024). Great Green Wall Initiative. https://www.afdb.org/en/topics-and-sectors/ initiatives-and-partnerships/great-green-wall-initiative. 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The Untapped Potential of Great Green Wall Voluntary Carbon Market Projects 2024