<p>Forests currently store more carbon in their vegetation and soil than all of the carbon in earth’s atmosphere. But how much additional CO₂ can be removed and sequestered by forests in the future, and at what cost? This study examines the potential and costs of forest-based mitigation in 215 countries, utilizing a dynamic economic model, FAO data, and new estimates of feasible area and pace of forest restoration. It finds that at a carbon price of $100/tCO₂ in 2050, 8 GtCO₂ could be sequestered through forest mitigation activities. Of that total, 38% would come from afforestation and reforestation, 26% from avoided deforestation, and 37% from changes in forest management. The majority of mitigation is expected to come from tropical regions, although this share decreases with higher levels of incentives. In a scenario in which afforestation and reforestation activities are limited to observed historical rates, mitigation potential is up to 42% lower in 2050 under high carbon payments, particularly impacting mitigation in temperate forests. These findings inform the cost and scale of meeting national forest-based mitigation targets, and provide a robust foundation for guiding policymakers in the development of evidence-informed forest-based mitigation actions.</p>