Large-scale reforestation is a prominent proposed climate mitigation strategy, but its full temperature impact remains poorly understood. Here, we present a systematic comparison of temperature responses to three distinct reforestation potentials using a fully-coupled Earth System Model. We find that reforestation consistently provides net global cooling, ranging from −0.13∘C to −0.25∘C, due to carbon uptake partially offset by biogeophysical warming. Crucially, a comparable net global cooling can be achieved with substantially smaller (450 Mha less area) but strategically located reforestation. Reforestation locally cools the tropics but causes albedo-driven warming in higher latitudes, which is often amplified by non-local effects. The different reforestation patterns alone can induce a wide range of non-local effects, showing that planting locations shape the biogeophysical response through atmospheric and oceanic feedbacks. Our findings underscore the importance of climate-smart policies that focus on the geographical placement of reforestation, considering both biogeochemical and biogeophysical effects to maximize cooling benefits. Strategic reforestation can achieve similar global cooling with half the forest area, by avoiding reforestation in high latitudes, as revealed by implementing three distinct reforestation scenarios in a fully coupled Earth System Model.
Fahrenbach et al. (Wed,) studied this question.