Standards and methodology are starting to emerge that measure the demand for natural capital that may be contrasted with the planet's ecological capacity to regenerate.[5] It represents the amount of biologically productive land and sea area necessary to supply the resources a human population consumes, and to assimilate associated waste. Using this assessment, it is possible to estimate how much of the Earth (or how many planet Earths) it would take to support humanity if everybody followed a given lifestyle. For 2007, humanity's total ecological footprint was estimated at 1.5 planet Earths; that is, humanity uses ecological services 1.5 times as quickly as Earth can renew them.[6] Every year, this number is recalculated to incorporate the three-year lag due to the time it takes for the UN to collect and publish statistics and relevant research.
Although the term ecological footprint is widely used and well known,[7] it goes beyond the metaphor. It represents an accounting system for biocapacity that tracks how much biocapacity there is, and how much biocapacity people use. Calculation methods have converged thanks to standards released in 2006 and updated in 2009.[8]