Supplementary Data for "Mechanism-based framework enables consistent assessment of carbon offsetting projects"

Supplementary Data 1 contains data on the reallocation of projects and credits. Table 1.1 and Table 1.2 illustrate the reallocation of projects and credits from the sub-/sectors to the groups. Table 1.3 provides information on the sectors defined in the Voluntary Registry Offsets Database, the groups to which they are reallocated, as well as the number of projects and credits for each sector/group (based on database version v2025-12). Supplementary Data 2 includes the exports from the project registries on October 16, 2024. Table 2.1 and Table 2.2 contain data on the projects listed in the registries of Verra Verified Carbon Standard (VCS) and Gold Standard (GS). Supplementary Data 3 provides the information that was the basis for selecting relevant methodologies for determining project mechanisms by which offsetting projects influence greenhouse gas sources and storage. Table 3.4 lists the 31 selected methodologies that were analyzed to develop the categorization scheme CatCOP. These methodologies consist of the two most applied methodologies per sector (Table 3.1), with at least 50 projects (Table 3.2), and the methodologies applied by at least 50 projects (Table 3.3). Supplementary Data 4 contains the methodologies' information on the project’s mitigation type, aim, scope, and quantification formulas, as well as the summarized characteristics to determine the project mechanisms and the connected categories.