One U.S. acre is equal to 0.405 hectares. For U.S. audiences, Footprint results are often presented in global acres (ga), rather than global hectares (gha). See global hectare, local hectare.

See land type.

The amount of biocapacity set aside to maintain representative ecosystem types and viable populations of species. How much needs to be set aside depends on biodiversity management practices and the desired outcome. E.O. Wilson suggested to dedicate half Earth, or half of our planet’s biocapacity, for wild species. According to this estimates, this would enable 85% of the 20th century biodiversity to survive.

There were ~ 11.9 billion hectares of biologically productive land and water on Earth in 2023. Dividing by the number of people alive in that year (8 billion) gives 1.5 global hectares per person, i.e., the biocapacity that exists per person on our planet. This area also needs to accommodate the wild species that compete for the same biological material and spaces as humans.

The capacity of ecosystems to regenerate what people demand from those surfaces. Life, including human life, competes for space. The biocapacity of a particular surface represents its ability to regenerate what people demand, powered by solar-driven photosynthesis. Biocapacity is therefore the ecosystems’ capacity to produce biological materials used by people and to absorb waste material generated by humans, under current management schemes and extraction technologies. Biocapacity can change from year to year due to climate, management, and also what portions are considered useful inputs to the human economy. In the National Footprint and Biocapacity Accounts, the biocapacity of an area is calculated by multiplying the actual physical area by the yield factor and the appropriate equivalence factor. Biocapacity is usually expressed in global hectares.

The land and water (both marine and inland waters) area that supports significant photosynthetic activity and the accumulation of biomass that can be used by humans. Non-productive areas as well as marginal areas with patchy vegetation, too dispersed to harvest, are not included. The total biologically productive area on land and water in 2023 was approximately 11.9 billion hectares.

A generic term for factors which are used to translate a material flow expressed within one measurement system into another one. For example, a combination of two calculation factors—“yield factors” and “equivalence factors”—translates hectares into global hectares. The extraction rate calculation factor translates a secondary product into primary product equivalents.

Download calculation factors here.

The carbon Footprint measures CO₂ emissions associated with fossil fuel use. In Ecological Footprint accounts, these amounts are converted into biologically productive areas necessary for absorbing this CO₂. The carbon Footprint is added to the Ecological Footprint because it is a competing use of bioproductive space, since increasing CO₂ concentrations in the atmosphere is  represents a build-up of ecological debt. Many carbon Footprint assessments express results in tonnes of CO₂ emissions released per year, without translating this amount into area needed to sequester it.

Use of goods or of services. The term consumption has two different meanings, depending on context. As commonly used in regard to the Footprint, it refers to the use of goods or services. A consumed good or service embodies all the resources, including energy, necessary to provide it to the consumer. In full life-cycle accounting, everything used along the production chain is taken into account, including any losses along the way. For example, consumed food includes not only the plant or animal matter people eat or waste in the household, but also that lost during processing or harvest, as well as all the energy used to grow, harvest, process and transport the food.

As used in Input-Output analysis, consumption has a strict technical meaning. Two types of consumption are distinguished: intermediate and final. According to (economic) System of National Accounts terminology, intermediate consumption refers to the use of goods and services by a business in providing goods and services to other businesses. Final consumption refers to non-productive use of goods and services by households, the government, the capital sector, and foreign entities.

Ecological Footprint analyses can allocate total Footprint among consumption components, typically Food, Shelter, Mobility, Goods, and Services—often with further resolution into sub-components. Consistent categorization across studies allows for comparison of the Footprint of individual consumption components across regions, and the relative contribution of each category to the region’s overall Footprint. To avoid double counting, it is important to make sure that consumables are allocated to only one component or sub-component. For example, a refrigerator might be included in either the food, goods, or shelter component, but only in one.