Mitigating climate change through afforestation: new cost estimates for the United States

We provide new cost estimates for carbon sequestration through afforestation in the U.S. We extend existing studies of carbon sequestration costs in several important ways, while ensuring the transparency of our approach. Our costs estimates have five distinguishing features: (1) we estimate costs for each county in the contiguous U.S., (2) we include afforestation of rangeland, in addition to cropland and pasture, (3) our opportunity cost estimates account for capitalized returns to future development (including associated option values) in addition to returns to agricultural production, (4) we develop a new set of forest establishment costs for each county, and (5) we incorporate data on Holdridge life zones to limit afforestation in locations where temperature and moisture availability prohibit forest growth. We find that at a carbon price of $50/ton, approximately 200 million tons of carbon would be sequestered annually through afforestation. At a price of $100/ton, an additional 100 million tons of carbon would be sequestered each year. Our estimates closely match those in earlier econometric studies for relatively low carbon prices, but diverge at higher carbon prices. Our results indicate a smaller, but still important, role for forest-based carbon sequestration in offsetting U.S. greenhouse gas emissions.