The amount of the environment that a person, business, country, or other entity requires to produce the goods and services it consumes and to deal with its waste products. The concept underlies the Ecological Footprint open source accounting tool, which attempts to quantify the amount of productive land and water needed to supply food, fibres, fish, livestock, timber, and land space for a given population and to absorb its waste, such as carbon emissions and solid waste. The footprint is measured in global hectares (gha)—the globally averaged amount of productive land and water available on the planet, which currently equates to about 1.7 gha per person. Hence an individual whose footprint exceeds this is running an ecological deficit. For example, in 2013 it was estimated that individuals in the UK had a footprint of 5.1 gha, while for people in the USA it was 8.6 gha, both far greater than those countries’ biocapacity, i.e. the available cropland, grazing land, forest land, fishing grounds, and built-up land needed to service the lifestyle of the population. This indicates that such lifestyles are far from sustainable given current technologies.