Brown, Sandra (Winrock International, 621 N Kent St., Suite 1200, Arlington, VA, 22209; Phone: 703-525-9430 x 678; Email: sbrown@winrock.org)

Estimating the Potential Carbon Supply from Changes in Land Use: Afforestation of Grazing Lands in the USA as a Case Study

S.Brown *, A.Dushku, J.Kadyszewski

Most estimates of carbon sequestration potential on the land tend to be of the theoretical potential, without consideration of current land values and alternate uses. To fill this gap in knowledge, the goal of this work is to answer the basic question: “How many carbon credits would landowners offer for sale for a particular class of activity at various price points and where are these located?” Information about current land use, potential changes in land use and the incremental carbon resulting from the change, opportunity costs, conversion costs, annual maintenance costs, and measurement and monitoring costs were obtained and used in the analyses for two regions in the USA (west coast and south central states). The analyses are performed in a geographic information system (GIS) to include the diversity of land uses, rates of carbon sequestration, and costs over three time periods of 20 years, 40 years and 80 years. We will present the general approach that was used to identify and locate classes of land where there is potential to change the use to a higher carbon content, estimate rates of carbon accumulation for each major potential land-use change activity for each land class, and assign values to each contributing cost factor. Results indicate that at a price of less than $10/t C, about 230 million tons of carbon could be sequestered over 40 years by afforestation of 1.1 million hectares of existing grazing lands in Arkansas, Louisiana, and Mississippi. If the price of carbon was up to $20/ton, twice as much carbon could be sequestered on about 4 million ha in these southern states. In the western states (e.g. CA and OR), similar amounts of carbon could be sequestered by afforestation after 40 years for the same price points, but more land would be needed.