Ex-ante greenhouse gas balance of agriculture and forestry development programs

ex-act (ex-ante carbon-balance tool) is a tool developed by the food and agriculture organization of the united nations (fao). it provides ex-ante measurements of the mitigation impact of agriculture and forestry development projects, estimating net c balance from ghg emissions and carbon (c) sequestration. ex-act is a land-based accounting system, measuring c stocks, stock changes per unit of land, and ch4 and n2o emissions expressed in t co2-eq per hectare and year. the main output of the tool is an estimation of the c-balance associated with the adoption of improved land management options, as compared with a "business as usual" scenario. ex-act has been developed using primarily the ipcc 2006 guidelines for national greenhouse gas inventories, complemented by other existing methodologies and reviews of default coefficients. default values for mitigation options in the agriculture sector are mostly from the 4th assessment report of ipcc (2007). thus, ex-act allows for the carbonbalance appraisal of new investment programmes by ensuring an appropriate method available for donors and planning officers, project designers, and decision makers within agriculture and forestry sectors in developing countries. the tool can also help to identify the mitigation impacts of various investment project options, and thus provide an additional criterion for consideration in project selection.