APPENDIX A: Methodology Differences between the 2006 and 2008 National Footprint Accounts A formal process is in place to assure continuous improvement of the National Footprint Accounts (NFA) methodology. Coordinated by Global Footprint Network, this process is supported by its partners and by the National Footprint Accounts Committee, as well as other stakeholders.
FAO ResourceSTAT The most extensive change from the 2006 edition of the National Footprint Accounts to the 2008 edition was in response to a revision in the structure of the United Nations Food and Agriculture Organization’s Corporate Statistical Database (FAO ResourceSTAT Statistical Databases 2007). This database, which serves as the basis for the national Footprint calculations, formerly aggregated all products into 10 groups, the Food Balance Sheets. FAO no longer provides these aggregated product groups, so in the 2008 edition of the NFA raw, non-aggregated data was used instead. This substantially altered the lists of commodities for which production and trade data are available, leading to more detailed accounts but also requiring the use of additional conversation factors to determine the primary product equivalents of processed products. These new conversion factors were compiled from a variety of FAO and other United Nations sources.
Cropland Due to these updates in FAO ResourceSTAT, the cropland section of the National Footprint Accounts now tracks 195 different agricultural commodities. This is an increase from approximately 80 in the 2006 edition of the NFA. The changes to the list of agricultural products reported in FAO ResourceSTAT included the addition of several new categories of crops for animal fodder. The production of these crops carries with it a cropland Footprint, even though the crops themselves are consumed by livestock and thus play a more direct role in the grazing land Footprint calculation. The overall effect of this has been a slight increase in the cropland Footprint, accompanied by a slight decrease in the grazing land Footprint, since the Accounts now show more of a nation’s livestock feed requirement being met by cropped fodder.
Grazing Land The methodology for calculating the grazing land Footprint has changed substantially in the 2008 edition of the NFA. The overall calculation now follows a methodology set forth by Helmut Haberl and colleagues (Haberl et al. 2007). Starting with the total feed requirement for all domestic livestock, the quantity of feed provided by crop residues, cropped grass and
other crop-derived market feed is subtracted. The remaining feed requirements are then assumed to be met by pasture grass. The area of grazing land required to produce this quantity of grass, multiplied by an equivalence factor, yields the grazing land Footprint. Since the new FAO ResourceSTAT database does not report the fractions of produced crops used for feed except in those categories of crops used exclusively for feed, it was assumed that these fractions have remained constant since 2003, the last year in which they were reported. In addition, the 2008 edition of the NFA tracks the embodied cropland and grazing land Footprint of 59 traded products derived from livestock, up from approximately 10 in the 2006 edition. This change again was necessary because of changes in the FAO ResourceSTAT datasets.
Fishing Grounds In the 2006 edition of the NFA, fish catches were calculated in only 10 different categories. The list has since been expanded; in the 2008 edition, catch tonnages for more than 1500 different marine species allowed calculation of a fishing grounds Footprint for each. This very significant increase in resolution means that for many countries, their fishing grounds Footprint in the 2008 edition of the NFA differed substantially from that reported in the 2006 edition. The estimate of the quantity of sustainable catch, measured in terms of primary production per hectare of continental shelf, has also been recalculated, based on an estimate of sustainable fisheries yields from the FAO (Gulland 1971). The fish section of the NFA is still in need of further improvement. A grant from the Oak Foundation will allow Global Footprint Network to revisit this section of the Accounts in the coming year.
Forest Land The forest Footprint calculation has undergone two major revisions. The first was an increase in the number of forest products tracked in the NFA from 6 to 33, following a change in the FAO ResourceSTAT data. The second change involved national average forest growth rates, which are now calculated from a smaller number of data sources. Harvest rates are also no longer used as substitutes for forest growth rates anywhere in the Accounts. In addition, some marginal forest areas which were previously excluded from the NFA calculations are now included as bioproductive areas.
Carbon Uptake Land Several new sources of carbon dioxide emissions, in addition to those from combustion of fossil fuels, are now accounted for. These other emissions include those from industrial processes 29