Fig. 1

Comparison between two hypothetical REDD+ projects, using a strictly historical reference scenario, in light of the forest transition theory, after Angelsen [54]. The forest transition pathway is displayed in red, with high initial forest cover decreasing ever more rapidly, before stabilizing when forested areas become scarce. Under the Medium Forest/High Deforestation (MFHD) or Low Forest/High Deforestation (LFHD) scenario, where the country would reach the end of the forest transition, the historical baseline (blue dashed line) largely overestimates deforestation, artificially provoking a large amount of credited carbon. On the contrary, under the High Forest/Low Deforestation (HFLD) scenario, the historical baseline (green dashed line) largely underestimates deforestation, inducing a debt in carbon credits. *Timeline is hypothetical and only reflects the duration of the forest transition within each country