Calculation Methodology for the National Footprint Accounts

Abstract

Human demand on ecosystem services continues to increase, and there are indications that this demand may be outpacing the regenerative and absorptive capacity of the biosphere. The productivity of natural capital may increasingly become a limiting factor for the human endeavour. Therefore, metrics tracking human demand on, and availability of, regenerative and waste absorptive capacity within the biosphere are needed. The Ecological Footprint is one such metric; it measures human appropriation of ecosystem products and services in terms of the amount of bioproductive land and sea area needed to supply these services. The area of land or sea available to serve a particular use is called biocapacity, and represents the biospheres ability to meet human demand for material consumption and waste disposal. The Ecological Footprint and biocapacity accounts cover six land use types: cropland, grazing land, fishing ground, forest land, built-up land and carbon uptake land (to accommodate the Carbon Footprint). For each component, the demand for ecological services is divided by the yield for those ecological services to arrive at the Footprint of each land use type. Ecological Footprint and biocapacity are scaled with yield factors and equivalence factors to convert this physical land demanded to world average biologically productive land called global hectares. This allows for comparisons between various land use types with differing productivities. The National Footprint Accounts calculate the Ecological Footprint and biocapacity of individual countries and of the world. According to the 2008 edition of the National Footprint Accounts, humanity demanded the resources and services of 1.31 planets in 2005. This situation, in which total demand for ecological goods and services exceeds the available supply, is known as overshoot. On the global scale, overshoot indicates that stocks of ecological capital are depleting or that waste is accumulating.