Compare methods

	Ecological Footprint Analysis	Water Footprint Analysis
Field	Environmental Sociology	Environmental Sociology
Family	Process / pipeline	Process / pipeline
Year of origin	1996	2011
Originator	Mathis Wackernagel & William E. Rees	Arjen Y. Hoekstra (with Chapagain, Aldaya & Mekonnen)
Type	Bioproductive-area accounting pipeline for human demand versus biocapacity	Volumetric freshwater-appropriation accounting pipeline
Seminal source	Wackernagel, M., & Rees, W. E. (1996). Our Ecological Footprint: Reducing Human Impact on the Earth. New Society Publishers. ISBN: 9780865713123	Hoekstra, A. Y., Chapagain, A. K., Aldaya, M. M., & Mekonnen, M. M. (2011). The Water Footprint Assessment Manual: Setting the Global Standard. Earthscan. ISBN: 9781849712798
Aliases	Ecological Footprint Accounting, Footprint-Biocapacity Accounting, Wackernagel-Rees Footprint, EF Analysis	Water Footprint Assessment, Blue-Green-Grey Water Accounting, Virtual Water Analysis, Hoekstra Water Footprint
Related	4	3
Summary	Ecological footprint analysis measures human demand on nature by translating the resources a population consumes and the wastes it generates into the area of biologically productive land and sea required to supply them. Introduced by Mathis Wackernagel and William Rees in their 1996 book Our Ecological Footprint, the method expresses both demand (the footprint) and supply (biocapacity) in a common unit, the global hectare, so that the two can be compared directly. When a population's footprint exceeds the biocapacity available to it, the difference is an ecological deficit, and at the planetary scale a persistent deficit signals overshoot of the biosphere's regenerative capacity. The 2002 analysis by Wackernagel and colleagues operationalized this accounting at the global level, estimating that humanity moved from using about 70 percent of the biosphere's capacity in 1961 to roughly 120 percent by the late 1990s. The carbon component, the area of forest needed to sequester fossil-fuel emissions, is typically the largest and fastest-growing share. Footprint analysis is thus a sustainability accounting tool that renders an abstract idea, living within ecological limits, into a single comparable balance sheet.	Water footprint analysis is a volumetric accounting method that measures the appropriation of freshwater used to produce the goods and services consumed by an individual, community, business, or nation. Formalized in Arjen Hoekstra's Water Footprint Assessment Manual of 2011, it decomposes water use into three components: the green water footprint (rainwater consumed, mainly through crop evapotranspiration), the blue water footprint (surface and groundwater consumed), and the grey water footprint (the volume of freshwater needed to dilute pollution to meet ambient quality standards). By tracing water through supply chains and aggregating these components, the method reveals how much and what kind of water lies behind products and consumption — including virtual water embedded in trade — and then assesses whether that appropriation is sustainable relative to local water availability and pollution-assimilation capacity.