Bastin et al. (Reports, 5 July 2019, p. 76) claim that 205 gigatonnes of carbon can be globally sequestered by restoring 0.9 billion hectares of forest and woodland canopy cover. Reinterpreting the data from Bastin et al., we show that the global land area actually required to sequester human-emitted CO2 is at least a factor of 3 higher, representing an unrealistically large area.