Reforestation scenarios shape global and regional temperature outcomes

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.