The restoration of trees remains among the most effective strategies for climate change
mitigation.We mapped the global potential tree coverage to show that 4.4 billion hectares
of canopy cover could exist under the current climate. Excluding existing trees and
agricultural and urban areas, we found that there is room for an extra 0.9 billion hectares
of canopy cover, which could store 205 gigatonnes of carbon in areas that would naturally
support woodlands and forests. This highlights global tree restoration as our most effective
climate change solution to date. However, climate change will alter this potential tree
coverage.We estimate that if we cannot deviate from the current trajectory, the global
potential canopy cover may shrink by ~223 million hectares by 2050, with the vast majority
of losses occurring in the tropics. Our results highlight the opportunity of climate change
mitigation through global tree restoration but also the urgent need for action.