Restoring tree cover changes albedo, the fraction of sunlight reflected from the Earth's surface. While tree cover typically removes carbon dioxide from the atmosphere, albedo changes can offset or negate these benefits, leading to global warming. Previous studies have underestimated the climate impact of tree cover restoration due to a lack of spatially explicit data on albedo. This study provides maps showing that carbon-only estimates may be up to 81% too high. Dryland and boreal regions have severe albedo offsets, but some areas across all biomes provide net-positive climate benefits. However, most tree cover restoration projects still face at least a 20% albedo offset. Strategic deployment of tree cover restoration requires accounting for albedo changes, and the study provides tools to do so. Tree cover restoration can impact climate through changes in albedo, which alters the Earth's radiation balance. Albedo changes can counteract the cooling benefits of carbon storage, especially in areas with high solar radiation, snow cover, or slow carbon accumulation. The study converts albedo changes to CO₂ equivalents (CO₂e) by calculating radiative forcing and comparing it to CO₂ emissions. This allows for a direct comparison of albedo and carbon impacts. The results show that albedo offsets range from -469 to +28 Mg CO₂e ha⁻¹, with a median of -120 Mg CO₂e ha⁻¹, indicating that restoring tree cover generally causes some albedo-driven warming, especially in arid and northern regions. The study maps potential albedo changes and combines them with maximum potential carbon storage to identify net climate-positive areas. It finds that drylands have a greater proportion of net climate-negative areas than boreal regions. However, all biomes have some net climate-positive locations. The study refines three previously published maps of tree cover restoration opportunities, showing that 18-48% of these areas experience substantial albedo offsets. The results highlight the need to account for albedo changes when planning tree cover restoration projects. The study also examines on-the-ground projects and finds that 84% of project pixels occur in net climate-positive locations, with 29% experiencing a substantial albedo offset. The majority of projects have at least a 20% albedo offset, emphasizing the need to consider albedo changes in climate impact assessments. The study acknowledges uncertainties in radiative kernels and carbon datasets but finds that overall climate impacts are relatively small, with small variations in albedo offset across different models. The study concludes that tree cover restoration is a promising natural climate solution if located in climate-positive areas. However, it is not a panacea for climate change and must be combined with efforts to reduce fossil fuel emissions and protect intact ecosystems. The study provides tools to account for albedo changes in tree cover restoration, emphasizing the importance of spatially explicit data for effective climate mitigation.Restoring tree cover changes albedo, the fraction of sunlight reflected from the Earth's surface. While tree cover typically removes carbon dioxide from the atmosphere, albedo changes can offset or negate these benefits, leading to global warming. Previous studies have underestimated the climate impact of tree cover restoration due to a lack of spatially explicit data on albedo. This study provides maps showing that carbon-only estimates may be up to 81% too high. Dryland and boreal regions have severe albedo offsets, but some areas across all biomes provide net-positive climate benefits. However, most tree cover restoration projects still face at least a 20% albedo offset. Strategic deployment of tree cover restoration requires accounting for albedo changes, and the study provides tools to do so. Tree cover restoration can impact climate through changes in albedo, which alters the Earth's radiation balance. Albedo changes can counteract the cooling benefits of carbon storage, especially in areas with high solar radiation, snow cover, or slow carbon accumulation. The study converts albedo changes to CO₂ equivalents (CO₂e) by calculating radiative forcing and comparing it to CO₂ emissions. This allows for a direct comparison of albedo and carbon impacts. The results show that albedo offsets range from -469 to +28 Mg CO₂e ha⁻¹, with a median of -120 Mg CO₂e ha⁻¹, indicating that restoring tree cover generally causes some albedo-driven warming, especially in arid and northern regions. The study maps potential albedo changes and combines them with maximum potential carbon storage to identify net climate-positive areas. It finds that drylands have a greater proportion of net climate-negative areas than boreal regions. However, all biomes have some net climate-positive locations. The study refines three previously published maps of tree cover restoration opportunities, showing that 18-48% of these areas experience substantial albedo offsets. The results highlight the need to account for albedo changes when planning tree cover restoration projects. The study also examines on-the-ground projects and finds that 84% of project pixels occur in net climate-positive locations, with 29% experiencing a substantial albedo offset. The majority of projects have at least a 20% albedo offset, emphasizing the need to consider albedo changes in climate impact assessments. The study acknowledges uncertainties in radiative kernels and carbon datasets but finds that overall climate impacts are relatively small, with small variations in albedo offset across different models. The study concludes that tree cover restoration is a promising natural climate solution if located in climate-positive areas. However, it is not a panacea for climate change and must be combined with efforts to reduce fossil fuel emissions and protect intact ecosystems. The study provides tools to account for albedo changes in tree cover restoration, emphasizing the importance of spatially explicit data for effective climate mitigation.