Potential for low-cost carbon dioxide removal through tropical reforestation

Achieving the 1.5–2.0 °C temperature targets of the Paris climate agreement requires not only reducing emissions of greenhouse gases (GHGs) but also increasing removals of GHGs from the atmosphere^1,2. Reforestation is a potentially large-scale method for removing CO₂ and storing it in the biomass and soils of ecosystems^3–8, yet its cost per tonne remains uncertain^6,9. Here, we produce spatially disaggregated marginal abatement cost curves for tropical reforestation by simulating the effects of payments for increased CO₂ removals on land-cover change in 90 countries. We estimate that removals from tropical reforestation between 2020–2050 could be increased by 5.7 GtCO₂ (5.6%) at a carbon price of US $20 CO₂^–1, or by 15.1 GtCO₂ (14.8%) at US$50 tCO₂^–1. Ten countries comprise 55% of potential low-cost abatement from tropical reforestation. Avoided deforestation offers 7.2–9.6 times as much potential low-cost abatement as reforestation overall (55.1 GtCO₂ at US$20 tCO₂^–1 or 108.3 GtCO₂ at US$50 tCO₂^–1), but reforestation offers more potential low-cost abatement than avoided deforestation at US$20 tCO₂^–1 in 21 countries, 17 of which are in Africa.