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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.

area type

See land type.

biodiversity buffer

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.

biological capacity available per person (or per capita)

There were ~ 12 billion hectares of biologically productive land and water on Earth in 2011. Dividing by the number of people alive in that year (7 billion) gives 1.72 global hectares per person. This area also needs to accommodate the wild species that compete for the same biological material and spaces as humans.

biological capacity or biocapacity

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 renew what people demand. 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 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.

biologically productive land and water

The land and water (both marine and inland waters) area that supports significant photosynthetic activity and the accumulation of biomass used by humans. Non-productive areas as well as marginal areas with patchy vegetation are not included. Biomass that is not of use to humans is also not included. The total biologically productive area on land and water in 2011 was approximately 12 billion hectares.

carbon Footprint

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 considered to represent a build-up of ecological debt. Some carbon Footprint assessments express results in tonnes 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.

consumption components (or consumption categories)

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.

Consumption Footprint

See the Ecological Footprint of consumption.

Consumption Land Use Matrix

Starting with data from the National Footprint Accounts, a Consumption Land Use Matrix allocates the six major Footprint land uses (shown in column headings) allocated to the five basic consumption components (row headings). For additional resolution, each consumption component can be disaggregated further. These matrices are often used as a starting point for sub-national (e.g. state, county, city) Footprint assessments. In this case, national data for each cell is scaled up or down depending on the unique consumption patterns in that sub-national region compared to the national average.

Consumption Land Use Matrix

Built-up Land

Carbon Footprint


Grazing Land

Forest Land

Fishing Ground


conversion factor

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 conversion factors—“yield factors” and “equivalence factors”—translates hectares into global hectares. The extraction rate conversion factor translates a secondary product into primary product equivalents.

Conversion Factor Library

See Footprint Intensity Table.

derived product

The product resulting from the processing of a primary product. For example wood pulp, a secondary product, is a derived product of roundwood. Similarly, paper is a derived product of wood pulp.

double counting

In order not to exaggerate human demand on nature, Footprint Accounting avoids double counting, or counting the same Footprint area more than once. Double counting errors may arise in several ways. For example, when adding the Ecological Footprints in a production chain (e.g., wheat farm, flour mill, and bakery), the study must count the cropland for growing wheat only once to avoid double counting. Similar, but smaller, errors can arise in analyzing a production chain because the end product is used in produce the raw materials used to make the end product (e.g. steel is used in trucks and earthmoving equipment used to mine the iron or that is made into the steel). Finally, when land serves two purposes (e.g. a farmer harvests a crop of winter wheat and then plants corn to harvest in the fall), it is important not to count the land area twice. Instead, the yield factor is adjusted to reflect the higher bioproductivity of the double-cropped land.

ecological debt

The sum of annual ecological deficits. Humanity’s Footprint first exceeded global biocapacity in the mid-1980s, and has done so every year since. By 2011 this annual overshoot had accrued into an ecological debt that exceeded 11 years of the Earth’s total productivity.

ecological deficit / reserve

The difference between the biocapacity and Ecological Footprint of a region or country. An ecological deficit occurs when the Footprint of a population exceeds the biocapacity of the area available to that population. Conversely, an ecological reserve exists when the biocapacity of a region exceeds its population’s Footprint. If there is a regional or national ecological deficit, it means that the region is importing biocapacity through trade or liquidating regional ecological assets, or emitting wastes into a global commons such as the atmosphere. In contrast to the national scale, the global ecological deficit cannot be compensated for through trade, and is therefore equal to overshoot by definition.

Ecological Footprint

A measure of how much area of biologically productive land and water an individual, population or activity requires to produce all the resources it consumes and to absorb the waste it generates, using prevailing technology and resource management practices. The Ecological Footprint is usually measured in global hectares. Because trade is global, an individual or country’s Footprint includes land or sea from all over the world. Without further specification, Ecological Footprint generally refers to the Ecological Footprint of consumption. Ecological Footprint is often referred to in short form as Footprint. “Ecological Footprint” and “Footprint” are proper nouns and thus should always be capitalized.

Ecological Footprint of consumption (EFC)

The most commonly reported type of Ecological Footprint, it is defined as the area used to support a defined population’s consumption. The consumption Footprint (in gha) includes the area needed to produce the materials consumed and the area needed to absorb the carbon dioxide emissions. The consumption Footprint of a nation is calculated in the National Footprint Accounts as a nation’s primary production Footprint plus the Footprint of imports minus the Footprint of exports, and is thus, strictly speaking, a Footprint of apparent consumption. The national average of per capita Consumption Footprint is equal to a country’s Consumption Footprint divided by its population.

Ecological Footprint of exports (EFE)

The Footprint embodied in domestically produced products which are exported and consumed in another country.

Ecological Footprint of imports (EFI)

The Footprint embodied in domestically consumed products which are imported from other countries.

Ecological Footprint of production (EFP)

In contrast to the consumption Footprint, a nation’s productive Footprint is the sum of the Footprints for all of the resources harvested and all of the waste generated within the defined geographical region. This includes all the area within a country necessary for supporting the actual harvest of primary products (cropland, pasture land, forestland and fishing grounds), the country’s built-up area (roads, factories, cities), and the area needed to absorb all fossil fuel carbon emissions generated within the country. In other words, the forest Footprint represents the area necessary to regenerate all the timber harvested (hence, depending on harvest rates, this area can be bigger or smaller than the forest area that exists within the country). Or, for example, if a country grows cotton for export, the ecological resources required are not included in that country’s consumption Footprint; rather, they are included in the consumption Footprint of the country that imports the t-shirts. However, these ecological resources are included in the exporting country’s primary production Footprint.

Ecological Footprint Standards

Specified criteria governing methods, data sources and reporting to be used in Footprint studies. Standards are established by the Global Footprint Network Standards Committee, composed of scientists and Footprint practitioners from around the world. Standards serve to produce transparent, reliable and mutually comparable results in studies done throughout the Footprint Community. Where Standards are not appropriate, Footprint Guidelines should be consulted. For more information, consult www.footprintstandards.org.

ecological reserve

See ecological deficit / reserve.

embodied energy

Embodied energy is the energy used during a product’s entire life cycle in order to manufacture, transport, use and dispose of the product. Footprint studies often use embodied energy when tracking trade of goods.

equivalence factor

A productivity-based scaling factor that converts a specific land type (such as cropland or forest) into a universal unit of biologically productive area, a global hectare. For land types (e.g., cropland) with productivity higher than the average productivity of all biologically productive land and water area on Earth, the equivalence factor is greater than 1. Thus, to convert an average hectare of cropland to global hectares, it is multiplied by the cropland equivalence factor of 2.51. Grazing lands, which have lower productivity than cropland, have an equivalence factor of 0.46 (see also yield factor). In a given year, equivalence factors are the same for all countries.

Footprint Intensity

The number of global hectares required to produce a given quantity of resource or absorb a given quantity of waste, usually expressed as global hectares per tonne. The National Footprint Accounts calculate a primary Footprint Intensity Table for each country, which includes the global hectares of primary land use type needed to produce or absorb a tonne of product (i.e., global hectares of cropland per tonne of wheat, global hectares of forest per tonne carbon dioxide).

Footprint Intensity Table

A collection of the primary and secondary product Footprint intensities from the National Footprint Accounts. Footprint intensity is usually measured in gha per tonne of product or waste (CO2). The Footprint Intensity Table is maintained by Global Footprint Network, supported by the Network’s National Accounts Committee.

Footprint neutral or negative

Human activities or services that result in no increase or a net reduction in humanity’s Ecological Footprint . For example, the activity of insulating an existing house has a Footprint for production and installation of the insulation materials. This insulation in turn reduces the energy needed for cooling and heating this existing house. If the Footprint reduction from this energy cutback is equal to or greater than the original Footprint of insulating the house, the latter becomes a Footprint neutral or negative activity. On the other hand, making a new house highly energy efficient does not by itself make the house Footprint neutral, unless at the same time it causes reduction in other existing Footprints. This Footprint reduction has to be larger than the Footprint of building and occupying the new house.

global hectare (gha)

Global hectares are the accounting unit for the Ecological Footprint and biocapacity accounts. These productivity weighted biologically productive hectares allow researchers to report both the biocapacity of the earth or a region and the demand on biocapacity (the Ecological Footprint). A global hectare is a biologically productive hectare with world average biological productivity for a given year. Global hecares are needed because different land types have different productivities. A global hectare of, for example, cropland, would occupy a smaller physical area than the much less biologically productive pasture land, as more pasture would be needed to provide the same biocapacity as one hectare of cropland. Because world productivity varies slightly from year to year, the value of a global hectare may change slightly from year to year.

Guidelines (for Footprint studies)

Suggested criteria governing methods, data sources and reporting for use when Footprint Standards are not appropriate or not yet developed.


1/100th of a square kilometre, 10,000 square meters, or 2.471 acres. A hectare is approximately the size of a soccer field. See also global hectare and local hectare.

Intertemporal yield factor

A scaling factor that accounts for changes in the world-average yield of the same land use type over time.

IO (Input-Output) analysis

Input-Output (IO, also I-O) analysis is a mathematical tool widely used in economics to analyze the flows of goods and services between sectors in an economy, using data from IO tables. IO analysis assumes that everything produced by one industry is consumed either by other industries or by final consumers, and that these consumption flows can be tracked. If the relevant data are available, IO analyses can be used to track both physical and financial flows. Combined economic-environment models use IO analysis to trace the direct and indirect environmental impacts of industrial activities along production chains, or to assign these impacts to final demand categories. In Footprint studies, IO analysis can be used to apportion Footprints among production activities, or among categories of final demand, as well as in developing Consumption Land Use Matrices.

IO (Input-Output) tables

IO tables contain the data that are used in IO analysis. They provide a comprehensive picture of the flows of goods and services in an economy for a given year. In its general form an economic IO table shows uses—the purchases made by each sector of the economy in order to produce their own output, including purchases of imported commodities; and supplies—goods and services produced for intermediate and final domestic consumption, and exports. IO tables often serve as the basis for the economic National Accounts produced by national statistical offices. They are also used to generate annual accounts of the Gross Domestic Product (GDP).

land or area type

The Earth’s approximately 12 billion hectares of biologically productive land and water areas are categorized into five types: cropland, grazing land, forest land, fishing ground, and built-up land. Forest land serves two distinct and competing uses: Forest products and CO2 sequestration.

Life cycle analysis (LCA)

A quantitative approach that assesses a product’s impact on the environment throughout its life. LCA attempts to quantify what comes in and what goes out of a product from “cradle to grave,” including the energy and material associated with materials extraction, product manufacture and assembly, distribution, use and disposal and the environmental emissions that result. LCA applications are governed by the ISO 14040 series of standards (http://www.iso.org).

local hectare

A productivity weighted area used to report both the biocapacity of a local region, and the demand on biocapacity (the Ecological Footprint). The local hectare is normalized to the area-weighted average productivity of the specified region’s biologically productive land and water. Hence, similar to currency conversions, Ecological Footprint calculations expressed in global hectares can be converted into local hectares in any given year (e.g., Danish hectares, Indonesian hectares) and vice versa. The amount of Danish hectares equals the amount of bioproductive hectares in Denmark—each Danish hectare would represent an equal share of Denmark’s total biocapacity.

National Footprint Accounts

The central data set that calculates the Footprint and biocapacity of the world and more than 200 nations from 1961 to the present (generally with a three year lag due to data availability). The ongoing development, maintenance and upgrades of the National Footprint Accounts are coordinated by Global Footprint Network and its 80 plus partners.

natural capital

Natural capital can be defined as all of the raw materials and natural cycles on Earth. Footprint analysis considers one key component, life supporting natural capital, or ecological capital for short. This capital is defined as the stock of living ecological assets that yield goods and services on a continuous basis. Main functions include resource production (such as fish, timber or cereals), waste assimilation (such as CO2 absorption or sewage decomposition) and life support services (such as UV protection, biodiversity, water cleansing or climate stability).


Global overshoot occurs when humanity’s demand on nature exceeds the biosphere’s supply, or regenerative capacity. Such overshoot leads to a depletion of Earth’s life supporting natural capital and a buildup of waste. At the global level, ecological deficit and overshoot are the same, since there is no net-import of resources to the planet. Local overshoot occurs when a local ecosystem is exploited more rapidly than it can renew itself.

Planet equivalent(s)

Every individual and country’s Ecological Footprint has a corresponding Planet Equivalent, or the number of Earths it would take to support humanity’s Footprint if everyone lived like that individual or average citizen of a given country. It is the ratio of an individual’s (or country’s per capita) Footprint to the per capita biological capacity available on Earth (1.72 gha in 2011). In 2011, the world average Ecological Footprint of 2.7 gha equals 1.54 Planet Equivalents.

primary product

In Footprint studies, a primary product is the least-processed form of a biological material that humans harvest for use. There is a difference between the raw product, which is all the biomass produced in a given area, and the primary product, which is the biological material humans will harvest and use. For example, a fallen tree is a raw product that, when stripped of its leaves and bark, results in the primary product of roundwood. Primary products are then processed to produce secondary products like wood pulp and paper. Other examples of primary products are potatoes, cereals, cotton, and types of forage. Examples of secondary products are kWh of electricity, bread, clothes, beef, and appliances. Note that primary products and primary production Footprint are Footprint specific terms. They are not related to, and should not be confused with the ecological concepts of primary production, gross primary productivity (GPP) and net primary productivity (NPP).

production Footprint (also primary demand)

see Ecological Footprint of production (EFP).


The amount of biological material useful to humans that is generated in a given area. In agriculture, productivity is called yield.

secondary product

All products derived from primary products or other secondary products through a processing sequence applied to a primary product.

tons, metric (also tonne)

One metric ton equals 1000 kg, or 2205 lbs. All figures in the National Footprint Accounts are reported in metric tons.


The amount of regenerated primary product, usually reported in tons per year, that humans are able to extract per area unit of biologically productive land or water.

yield factor

A factor that accounts for differences between countries in productivity of a given land type. Each country and each year has yield factors for cropland, grazing land, forest, and fisheries. For example, in 2008, German cropland was 2.21 times more productive than world average cropland. (The German cropland yield factor of 2.21, multiplied by the cropland equivalence factor of 2.51 converts German cropland hectares into global hectares: one hectare of cropland is equal to 5.6 gha.

Note that primary product and primary production Footprint are Footprint specific terms. They are not related to, and should not be confused with the ecological concepts of primary production, gross primary productivity (GPP) and net primary productivity (NPP).