Susan Asam1, Tom Wirth2, and Kimberly Klunich2. (1) ICF International, 1725 Eye St. NW, Suite 1000, Washington, DC 20006, (2) U.S. EPA, 1200 Pennsylvania Avenue, N. W, Mail Code: 6207J, Washington, DC 20460
The 2006 Intergovernmental Panel on Climate Change (IPCC) Inventory Guidelines (2006 GL) were finalized earlier this month. They usher in a new era of Inventory methodologies, making it an ideal time to pause and reflect on the evolution of carbon accounting methodologies that have been employed to estimates emissions and sinks from the Agriculture and Land Use, Land-use Change, and Forestry (LULUCF) sectors of the Inventory of U.S. Greenhouse Gas Emissions and Sinks. Since the first inventory submission in 1994, the U.S. Inventory has strived to improve the estimation methodologies used to calculate GHG emissions and sinks. This effort involves continual revisions and refinements to models and Inventory methodologies, including efforts to comply with the evolving IPCC guidance to ensure consistency with other national inventories. This presentation will provide a retrospective look at trends in the Agriculture and LULUCF sections of the U.S. Inventory. It will explore how estimates for a selected time range (e.g., 1990-2000) have varied across subsequent base years (e.g., BY 2001, 2002, 2003, and 2004 Inventories) and will discuss the data and methodological improvements that these variations have been attributed to. Secondarily, it will assess whether or not the trends in variance correspond with recent uncertainty estimates to determine if the reported uncertainty ranges cover the observed year-to-year variance. The presentation will conclude with a look forward to the changes that will be incorporated to comply with the newly released 2006 GL. It will discuss the newly combined Agriculture, Forestry, and Other Land Uses (AFOLU) section and the implications of that and other changes recommended in the new guidelines.