Summary/Abstract
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. Reforestation is a potentially large-scale method for removing CO2 and storing it in the biomass and soils of ecosystems, yet its cost per tonne remains uncertain. This paper produces 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. According to the analysis, a hypothetical tropics-wide carbon price of $20 per ton of carbon dioxide—around the current price in European and Californian carbon markets—would incentivize land users to increase reforestation by enough to remove an additional 5.7 billion tons of carbon dioxide (5.6%) from 2020-2050, equivalent to thirty years of current greenhouse gas emissions from Kuwait. A higher price of $50-100 per ton of carbon dioxide—consistent with what’s needed to achieve the Paris Climate Agreement—would increase removals by between 15.1 and 33.3 billion tons of carbon dioxide (14.8-32.5%) between 2020-2050—equivalent to thirty years of current emissions from the United Kingdom or Japan. Based on these findings, tropical countries should accelerate reforestation, and developed countries should step up international finance for reforestation, especially through provisions of the Paris Climate Agreement related to reducing emissions from deforestation and forest degradation, “plus” re-growing forests (REDD+).