The ecological footprint is a measure of the biologically productive area that a human population requires to produce the resources it consumes, and absorb its wastes, using prevailing technology. A fundamental requirement for sustainability is that renewable resources must be used at a rate slower than the rate at which nature can replenish them and wastes be emitted at a rate slower than that at which the biosphere can absorb them. Societies that do not meet this minimum condition run ecological deficits.

To know whether humanity meets this requirement, and to properly manage ecological assets, measurement of the use of nature is required. Resource accounts are needed to track how much nature exists and how much is used by people. Ecological accounting operates like financial accounting: ...