Ecological footprint analysis measures human demand on nature. It compares human consumption of natural resources with planet Earth's ecological capacity to regenerate them. It is an estimate of the amount of biologically productive land and sea area needed to regenerate the resources a human population consumes and to absorb the corresponding waste, given prevailing technology. Using this assessment, it is possible to estimate how many planet Earth's it would take to support humanity if everybody lived a given lifestyle. While the measure is widely used, some also criticize the approach.
In 2003, the average biologically productive area per person worldwide was approximately 1.8 global hectares (gha) per capita. The US footprint per capita was 9.6 gha, and that of Switzerland was 5.1 gha per person, whilst China's was 1.6 gha per person. The WWF claims that the human footprint has exceeded the biocapacity (the available supply of natural resources) of the planet by 25%.