Potential for low-cost carbon dioxide removal through tropical reforestation

Achieving the 1.5-2.0 degrees 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 bio-mass 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 GtCO(2) (5.6%) at a carbon price of US$20 CO2-1, or by 15.1 GtCO(2) (14.8%) at US$50 tCO(2)(-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 GtCO(2) at US$20 tCO(2)(-1) or 108.3 GtCO(2) at US$50 tCO(2)(-1)), but reforestation offers more potential low-cost abatement than avoided deforestation at US$20 tCO(2)(-1) in 21 countries, 17 of which are in Africa.