This article discusses the role of forests in mitigating climate change by sequestering carbon dioxide. Forests currently absorb billions of tons of CO₂ annually, providing significant economic benefits. However, concerns about the permanence of carbon stocks and the environmental and socioeconomic impacts of large-scale reforestation programs have limited their use in climate policies. Forests can contribute to climate change protection through carbon sequestration and offer economic, environmental, and sociocultural benefits. A key opportunity is reducing carbon emissions from deforestation and degradation. Forests are important components of the global carbon cycle, removing nearly 3 billion tons of anthropogenic carbon annually and storing large reservoirs of carbon. The potential for managing forest carbon sinks and reservoirs to mitigate atmospheric CO₂ buildup is complex. Four major strategies are available: reforestation, increasing forest carbon density, expanding the use of sustainable forest products, and reducing emissions from deforestation and degradation. Estimates suggest that reforestation could sequester 0.16 to 1.1 Pg C year⁻¹ by 2100. The Fourth Assessment of the Intergovernmental Panel on Climate Change estimated that an economic potential of 0.12 Pg C year⁻¹ could be reached by 2030 at U.S. $20 per ton of CO₂. Land transformation requirements are large, with examples like China's efforts to offset fossil fuel emissions. Increased forest carbon density through management and landscape-scale strategies can also contribute to carbon sequestration. The joint use of carbon sequestration and forest-derived products can optimize climate mitigation. Reducing deforestation has high potential for cost-effective contributions to climate protection. Current deforestation rates are 13 Mha year⁻¹, with net emissions of 1.5 Pg C year⁻¹. Reducing deforestation by 50% by 2050 could avoid emissions equivalent to 50 Pg C. Combining all forestry activities, there is economic potential to achieve 0.4 Pg C year⁻¹ by 2030 using carbon sequestration and avoidance at U.S. $20 per ton of CO₂. These levels of carbon sequestration could offset 2 to 4% of projected emissions by 2030. Tropical regions would account for 65% of the total offset. Forestry, and reforestation in particular, can lead to unintended environmental and socioeconomic impacts. However, well-directed carbon sequestration projects, along with the provision of sustainably produced timber, fiber, and energy, will yield numerous benefits. The potential of carbon sequestration depends on the alignment of climate protection and ancillary benefits. Sustainable involvement of tropical regions is essential to take up the full global potential for climate change mitigation through forestry.This article discusses the role of forests in mitigating climate change by sequestering carbon dioxide. Forests currently absorb billions of tons of CO₂ annually, providing significant economic benefits. However, concerns about the permanence of carbon stocks and the environmental and socioeconomic impacts of large-scale reforestation programs have limited their use in climate policies. Forests can contribute to climate change protection through carbon sequestration and offer economic, environmental, and sociocultural benefits. A key opportunity is reducing carbon emissions from deforestation and degradation. Forests are important components of the global carbon cycle, removing nearly 3 billion tons of anthropogenic carbon annually and storing large reservoirs of carbon. The potential for managing forest carbon sinks and reservoirs to mitigate atmospheric CO₂ buildup is complex. Four major strategies are available: reforestation, increasing forest carbon density, expanding the use of sustainable forest products, and reducing emissions from deforestation and degradation. Estimates suggest that reforestation could sequester 0.16 to 1.1 Pg C year⁻¹ by 2100. The Fourth Assessment of the Intergovernmental Panel on Climate Change estimated that an economic potential of 0.12 Pg C year⁻¹ could be reached by 2030 at U.S. $20 per ton of CO₂. Land transformation requirements are large, with examples like China's efforts to offset fossil fuel emissions. Increased forest carbon density through management and landscape-scale strategies can also contribute to carbon sequestration. The joint use of carbon sequestration and forest-derived products can optimize climate mitigation. Reducing deforestation has high potential for cost-effective contributions to climate protection. Current deforestation rates are 13 Mha year⁻¹, with net emissions of 1.5 Pg C year⁻¹. Reducing deforestation by 50% by 2050 could avoid emissions equivalent to 50 Pg C. Combining all forestry activities, there is economic potential to achieve 0.4 Pg C year⁻¹ by 2030 using carbon sequestration and avoidance at U.S. $20 per ton of CO₂. These levels of carbon sequestration could offset 2 to 4% of projected emissions by 2030. Tropical regions would account for 65% of the total offset. Forestry, and reforestation in particular, can lead to unintended environmental and socioeconomic impacts. However, well-directed carbon sequestration projects, along with the provision of sustainably produced timber, fiber, and energy, will yield numerous benefits. The potential of carbon sequestration depends on the alignment of climate protection and ancillary benefits. Sustainable involvement of tropical regions is essential to take up the full global potential for climate change mitigation through forestry.