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FAQs

General

What is the Ecological Footprint?

The Ecological Footprint is a resource accounting tool used by governments, businesses, educational institutions and NGOs to answer to a specific resource question: How much of the biological capacity of the planet is required by a given human activity or population?

What does the Ecological Footprint measure?

The Ecological Footprint measures the amount of biologically productive land and sea area an individual, a region, all of humanity, or a human activity that compete for biologically productive space. This includes producing renewable resources, accommodating urban infrastructure and roads, and breaking down or absorbing waste products, particularly carbon dioxide emissions from fossil fuel. The Footprint then can be compared to how much land and sea area is available.

Biologically productive land and sea includes cropland, forest and fishing grounds, and do not include deserts, glaciers and the open ocean.

Current Ecological Footprint Accounts use global hectares as a measurement unit, which makes data and results globally comparable. Calculation methods are standardized so results of various assessments can be compared.

Which Footprint calculator should I use?

There are a number of online Ecological Footprint calculators in use today. When evaluating other Ecological Footprint calculators, the most important consideration is whether the calculator is actually measuring the Ecological Footprint and not just using the term footprint as a proxy for general environmental impact. These calculators may offer interesting insights but they are not aligned with the international Ecological Footprint Standards, which were adopted in 2006 in order to ensure that Footprint studies were both credible and consistent.

The Ecological Footprint as defined by the Ecological Footprint standards calculates how much biologically productive area is required to produce the resources required by the human population and to absorb humanity’s carbon dioxide emissions. Approximately 90 percent of all leading Ecological Footprint practitioners worldwide have joined Global Footprint Network and have agreed to adhere to these standards and to use a common set of data.

For globally comparable and credible Ecological Footprint calculator results, look for transparent information on the methodology used, and check to see if the calculator was created by a Global Footprint Network partner, as partnership requires compliance with Ecological Footprint standards.

What is biocapacity?

Biocapacity is shorthand for biological capacity, which is the ability of an ecosystem to produce useful biological materials and to absorb carbon dioxide emissions.

What is overshoot?

Overshoot, which in this context is shorthand for ecological overshoot, occurs when a population’s demand on an ecosystem exceeds the capacity of that ecosystem to regenerate the resources it consumes and to absorb its carbon dioxide emissions.

The Ecological Footprint is often used to calculate global ecological overshoot, which occurs when humanity’s demand on the biosphere exceeds the available biological capacity of the planet. By definition, overshoot leads to a depletion of the planet’s life supporting biological capital and/or to an accumulation of carbon dioxide emissions.

How is an Ecological Footprint calculated?

Ecological Footprints can be calculated for individual people, groups of people (such as a nation), and activities (such as manufacturing a product).

The Ecological Footprint of a person is calculated by adding up all of people’s demands that compete for biologically productive space, such as cropland to grow potatoes or cotton, or forest to produce timber or to sequester carbon dioxide emissions. All of these materials and wastes are then individually translated into an equivalent number of global hectares.

To accomplish this, an amount of material consumed by that person (tonnes per year) is divided by the yield of the specific land or sea area (annual tonnes per hectare) from which it was harvested, or where its waste material was absorbed. The number of hectares that result from this calculation are then converted to global hectares using yield and equivalence factors. The sum of the global hectares needed to support a person is that person’s total Ecological Footprint.

The Ecological Footprint of a group of people, such as a city or nation, is simply the sum of the Ecological Footprint of all the residents of that city or nation.

Typically, the Footprint is reported as “the Footprint of consumption.” It is the productive area needed to provide for that person’s or population’s consumption. Ecological Footprint accounts can also calculate the Footprint of production which is the direct demand on nature by that population’s economy. What the economy produces plus all that is imported minus what the economy exports is the amount that population consumes.

When calculating the Footprint of a business or organization, the organization’s activities to be included within the assessment must be clearly defined.

What is the proper way to use the term Ecological Footprint?

The term Ecological Footprint, capitalized, is a proper name referring to a specific research question: how much of the biological capacity of the planet is required by a given human activity or population? Often, the word ‘footprint’ is used generically to refer to human impact on the planet, or to a different research question. For example, the term ‘carbon footprint’ often refers to the number of tonnes of carbon emitted by a given person or business during a year, or to the tonnes of carbon emitted in the manufacture and transport of a product. There is a carbon component to the Ecological Footprint. It measures the amount of biological capacity, in global hectares, demanded by human emissions of fossil carbon dioxide.

The term Ecological Footprint has been deliberately excluded from trademark to encourage its widespread use. Global Footprint Network strives to maintain the value of this term by encouraging our partners and others using the word footprint or Ecological Footprint to apply the term consistently, using the definition found in the Ecological Footprint Standards. Global Footprint Network encourages research answering different questions to be referred to as something other than Ecological Footprint.

How does the Ecological Footprint relate to carrying capacity?

Carrying capacity is a technical term that refers to the maximum population of a species that a given land or marine area can support. Many species have easily defined and consistent consumption needs, making carrying capacity relatively easy to define and calculate. For humans, however, carrying capacity estimates require assumptions about future per-person resource consumption, standards of living and “wants” (as distinct from “needs”), productivity of the biosphere, and advances in technology. An area’s carrying capacity for humans is thus inherently speculative and difficult to define.

Ecological Footprint accounts approach the carrying capacity question from a different angle. Ecological Footprints are not speculative estimates about a potential state, but rather are an accounting of the past. Instead of asking how many people could be supported on the planet, the Ecological Footprint asks the question in reverse and considers only present and past years. The Footprint asks how many planets were necessary to support all of the people that lived on the planet in a given year, under that year’s standard of living, biological production and technology. This is a scientific research and accounting question that can be answered through the analysis of documented, historical data sets.

Is the Ecological Footprint anti-trade, anti-technology, or anti-GDP?

The Footprint tracks current human demand on nature in terms of the area required to supply the resources used and absorb the CO2 emitted in providing goods and services. Trade is accounted for by allocating this demand to the country that ultimately consumes these goods and services. This accounting reflects import and export flows, but makes no judgment regarding the benefits, disadvantages or fairness of trade. The Ecological Footprint is therefore neither pro- nor anti-trade.

As new technologies come on line that affect biocapacity and resource-efficiency, their impact on resource supply and demand are reflected in biocapacity and Footprint assessments. In other words, the Footprint and biocapacity results reported in any given year are in part a function of the technology used in that year. This accounting does not judge whether the use of a technology is positive or negative, but only shows how the technology impacts resource flows. Footprint assessments are historical rather than predictive, and make no judgment about the value of technologies that may become available in the future.

The Footprint approach is neither pro- nor anti-GDP. Gross Domestic Product (GDP) is an economic indicator used to track the annual value added to an economy. For a more comprehensive understanding of national trends, additional indicators are required—unemployment statistics, longevity figures, or ecological asset measures, for example. Global Footprint Network is working to have nations adopt the Ecological Footprint as a complement to, rather than as a substitute for, the GDP as a national indicator, in parallel with their use of the GDP.

Though they are often compared and contrasted, Ecological Footprints and Water Footprints are, as indicators, fundamentally incapable of being substituted. The Ecological Footprint does not, and is not intended to measure freshwater flows. Because this is nevertheless a vital renewable resource, in 2002, A.Y. Hoekstra proposed that the Water Footprint be created as a sustainable water use indicator measuring the total volume of freshwater directly or indirectly used by a population.

In essence, the Ecological Footprint measures the biological capacity a population uses and the Water Footprint measures the freshwater a population uses. They each provide a different piece of information in the sustainability puzzle. Instead of being seen as competing metrics, they should be seen as two complementary indicators of natural capital use in relation to human consumption.

For more information on the similarities and differences between the Ecological and Water Footprints, please consult A.Y. Hoeksta’s article Human appropriation of natural capital: A comparison of ecological footprint and water footprint analysis and A. Galli’s article Integrating Ecological, Carbon and Water footprint into a “Footprint Family” of indicators: Definition and role in tracking human pressure on the planet.

Methodology

What is an equivalence factor?

The equivalence factor is the key factor that allows land of different types to be converted into the common unit of global hectares. The equivalence factor itself is a productivity-based scaling factor that converts one hectare of world-average land of a specific land type, such as cropland or forest, into an equivalent number of global hectares. These equivalence factors are based on assessments of the relative productivity of land under different land types in any given year. In the most current Ecological Footprint accounts, an index of suitability for agricultural production is used as a proxy measure of the productive capacity of different land types. Other updated and refined methods for this calculation are continually being explored.

Equivalence Factors are available through a license. If you would like to obtain a license for use of the equivalence factors, please send your request to licensing@footprintnetwork.org.

What is a yield factor?

Within a given land type, such as cropland, the ability of an area to produce useful goods and services can vary dramatically based on factors such as climate, topography, or prevailing management. Yield factors allow different areas of the same land type to be compared based on the common denominator of yield. National yield factors for pasture, for example, compares the productivity of average pastures in a specific nation to world-average pastures. These yield factors convert one hectare of a specific land type, such as pasture, within a given nation into an equivalent number of world-average hectares of that same land type. The equivalence factors can then be used to convert world-average hectares of a specific land type into global hectares.

The national yield factor for a given land type is calculated as the ratio of national average yields of that land type, for example German forest, and world-average yields of that land type. Yield factors are calculated for each land type in each nation in each year.

Yield Factors are available through a license. If you would like to obtain a license for use of the Yield factors, please send your request to licensing@footprintnetwork.org.

When should I use the units global hectares, global hectare years, and global hectares per year?

A global hectare is a productivity normalized area that provides a defined continuous flow of goods and services for human use. Technically, a person with a 5 global hectare Ecological Footprint demands 5 global hectares of area over any time period. In one year, that person demands the amount of goods and services produced by 5 global hectares in that year. In two years, that person demands the amount of goods and services produced by 5 global hectares in two years. In one day, that person demands the amount of goods and services produced by 5 global hectares in one day, and so on. As the Ecological Footprint refers to a continuous demand, and biocapacity refers to a continuous supply, both are correctly reported in global hectares.

In the case of an activity with a discrete start and end, such as the creation of an individual product, a different unit is required. In calculating the Ecological Footprint of a product, the product does not require a continuous flow of goods and services but rather demanded the amount of goods and services produced by a given number of global hectares for a given, specific amount of time. Producing one book, one apple, or one table, which requires the use of a specific area for a finite amount of time, has a Footprint correctly reported in ‘global hectare-years.’

In the case of a product whose consumption is amortized over time, such as the structural materials in a building, the product begins with a total Ecological Footprint measured in global hectare-years. This total Ecological Footprint is then divided over the lifetime of the building, and the Ecological Footprint of that durable product in any single year is expressed in global hectare-years per year, or global hectares.

There is no instance in Ecological Footprint accounting where ‘global hectares per year’ is the correct unit to use.

How does the Ecological Footprint address waste flows?

From and Ecological Footprint perspective, the term ‘waste’ includes three different categories of materials, and each category is treated differently within Footprint accounts.

First, biological wastes such as residues of crop products, trimmings from harvested trees, and carbon dioxide emitted from fuel wood or fossil fuel combustion are all included within Ecological Footprint accounts. A cow grazing on one hectare of pasture has a Footprint of one hectare for both creating its biological food products and absorbing its biological waste products. This single hectare provides both services, thus counting the Footprint of the cow twice (once for material production and once for waste absorption). This results in double counting the actual area necessary to support the cow. The Footprint associated with the absorption of all biological materials that are harvested is thus already counted in the Footprint of those materials.

Second, waste also refers to the material specifically sent to landfills. If these landfills occupy formerly biologically productive area, then the Footprint of this landfill waste can be calculated as the area used for its long term storage.

Finally, waste can also refer to toxics and pollutants released from the human economy that cannot in any way be absorbed or broken down by biological processes, such as many types of plastics. As the Ecological Footprint measures the area required to produce a material or absorb a waste, materials such as plastics that are not created by biological processes nor absorbed by biological systems do not have a defined Ecological Footprint. These materials can cause damage to ecosystems when they are released into the environment, and this loss of biocapacity can be measured using an Ecological Footprint approach when it actually occurs. Such assessments are difficult, however, and not often completed. Assessments of the Footprint of toxics and pollutants, when completed, generally refer to the Footprint of extracting, processing, and handling these materials, but not to the Footprint of creating or absorbing these materials themselves.

How does the Ecological Footprint account for recycling?

As the Ecological Footprint reflects the demand for productive area to make resources and absorb carbon dioxide emissions recycling can lower the Ecological Footprint by offsetting the extraction of virgin products, and reducing the area necessary for absorbing carbon dioxide emissions. Recycling paper, for example, can decrease the total amount of virgin timber that must be harvested to meet global demand for paper, thus reducing humanity’s total Ecological Footprint.

The savings that result from the recycling process can be allocated to the person who recycles a material and/or the person who buys recycled material in a number of different ways:

  • 100% to the person who buys the recycled paper (the wood fibre in a 100% recycled ream of paper could have no forest Footprint, since the footprint of that wood fibre was already allocated to the person who bought the virgin paper),
  • 100% the person who recycles the paper (a person purchasing 100% virgin paper who recycled all of it would have no Footprint for the wood fibre in that paper, since all of it is reused later, assuming that no fiber is lost in the recycling process), or
  • Split between the person who buys recycled paper and the person who recycles paper (the savings can be split 50%/50%, or in any other allocation).

Different researchers use different allocation principles for the savings from recycling, and standards compliant Footprint studies (www.footprintstandards.org) will state their chosen allocation method explicitly. Regardless of allocation method, however, the largest reductions in Ecological Footprint can most commonly be achieved by reducing the total amount of materials consumed, rather than attempting to recycle them afterwards.

How is an Ecological Footprint calculated?

Ecological Footprints can be calculated for individual people, groups of people (such as a nation), and activities (such as manufacturing a product).

The Ecological Footprint of a person is calculated by adding up all of people’s demands that compete for biologically productive space, such as cropland to grow potatoes or cotton, or forest to produce timber or to sequester carbon dioxide emissions. All of these materials and wastes are then individually translated into an equivalent number of global hectares.

To accomplish this, an amount of material consumed by that person (tonnes per year) is divided by the yield of the specific land or sea area (annual tonnes per hectare) from which it was harvested, or where its waste material was absorbed. The number of hectares that result from this calculation are then converted to global hectares using yield and equivalence factors. The sum of the global hectares needed to support a person is that person’s total Ecological Footprint.

The Ecological Footprint of a group of people, such as a city or nation, is simply the sum of the Ecological Footprint of all the residents of that city or nation.

Typically, the Footprint is reported as “the Footprint of consumption.” It is the productive area needed to provide for that person’s or population’s consumption. Ecological Footprint accounts can also calculate the Footprint of production which is the direct demand on nature by that population’s economy. What the economy produces plus all that is imported minus what the economy exports is the amount that population consumes.

When calculating the Footprint of a business or organization, the organization’s activities to be included within the assessment must be clearly defined.

What is a global hectare?

A global hectare is a common unit that encompasses the average productivity of all the biologically productive land and sea area in the world in a given year. Biologically productive areas include cropland, forest and fishing grounds, and do not include deserts, glaciers and the open ocean.

Using a common unit, i.e., global hectares, allows for different types of land to be compared using a common denominator. Equivalence factors are used to convert physical hectares of different types of land, such as cropland and pasture, into the common unit of global hectares.

Global hectares can also be converted into global acres.

Data Accuracy and Improvement

How accurate are Ecological Footprint measurements?

Current Ecological Footprint accounts provide a robust, aggregate estimate of human demand on the biosphere as compared to the biosphere’s productive capacity. As with any calculation system, Footprint accounts are subject to uncertainty in source data, calculation parameters, and methodological decisions. Exact error bars or standard errors for calculations have not been rigorously compiled, and no full, comprehensive, and quantitative estimate of uncertainty has yet been carried out. Several organizations, including Global Footprint Network, are seeking to allocate resources towards obtaining more accurate estimates of this nature.

How does Global Footprint Network address data quality?

Global Footprint Network’s Ecological Footprint accounts for nations rely on well-established international data sets, mostly provided by the United Nations and the United Nations Food and Agriculture Organization. These data sets are official, widely obtainable, and are available in a consistent format across nations, allowing comparisons to be made between countries. The data are taken at face value, except where a substantial error is apparent and recognized widely by the research community (for example, historical fisheries catch distortions or jumps of two orders of magnitude in trade flows for a single year). Global Footprint Network encourages national governments, statistical offices, and research organizations to participate in collaborative reviews of data quality and methodology.

Are the Ecological Footprint calculations based on subjective judgment about the state of the world or the supposed need for environmental activism?

Like other accounting systems, such as the Systems of National Accounts and GDP, Ecological Footprint accounts build on a single, clearly defined research question, and attempt to provide the best possible objective, transparent, and scientific answer to this question. The process of initially defining a research question inherently involves normative judgments about which questions are important to pursue. Once a research question is identified, however, answering it is a scientific process.

Ecological Footprint accounts do not say anything about what should be, or what any person or group of people should do. Rather, they provide an objective and reproducible answer to the question of how much of the planet’s regenerative capacity is occupied by human activities. No normative or opinion-based judgments or weighting factors enter into Ecological Footprint accounting methodology. For example, the equivalence factors that allow different land types to be aggregated in the common unit of global hectares are based on empirical measurements of productivity.

As an organization, Global Footprint Network does not engage in environmental advocacy other than to suggest that the maintenance of accurate ecological accounts has an important role to play in decision making.

Are there any standards set for Ecological Footprint assessments?

Global Footprint Network’s Standards Committee has released an official standards document that addresses Footprint methodology and communication, including use of source data, derivation of conversion factors, establishment of study boundaries, and accurate communication of findings (www.footprintstandards.org). These standards are widely used by Global Footprint Network’s partners and by other analysts who conduct Ecological Footprint research and assessments.

At the national level, Global Footprint Network maintains the National Footprint Accounts, which provide benchmark Ecological Footprint results for 150 nations from 1961-2005. The data and methods used in these accounts are overseen by Global Footprint Network’s National Accounts Committee.

Carbon and Energy

Is the Ecological Footprint the same as the carbon footprint?

Recently, a number of organizations and governments have begun using the term ‘carbon footprint’ to refer to the quantities of carbon dioxide emissions associated with an activity, process, or product. This carbon footprint, typically measured in tonnes of carbon dioxide, is an initial step towards calculating a full carbon Footprint, which in turn is one piece of the total Ecological Footprint. A carbon Footprint translates tonnes of carbon dioxide released into the demand this places on biological capacity, measured in terms of the total area, in global hectares, required to sequester these carbon emissions.

The carbon Footprint adds value to simple carbon emissions data in two ways:

  • The carbon Footprint puts the magnitude of emissions into a meaningful context. Many people do not know how to interpret 1,000 tonnes of carbon emissions, but they can easily understand that if 1,000 global hectares would be required to absorb this carbon, but only 500 global hectares are available, this is a problem if we want to prevent this waste product from building up around us.
  • The Ecological Footprint provides an overarching systems perspective that can reveal spill-over effects, when reducing demand in one area leads to an increase in demand elsewhere. For example, will shifting from fossil fuels to biomass fuels decrease or increase humanity’s overall demand on the planet’s biological capacity? Would increasing the use of biomass fuels be more or less effective than returning cropland to forest cover?

Water

How does the Ecological Footprint treat water usage?

The Ecological Footprint of a biological resource represents the amount of biologically productive land and water area required to produce that material. Although freshwater is a natural resource cycled through the biosphere, and related to many of the biosphere’s critical goods and services, it is not itself a material made by biologically productive area, or a waste (such as carbon dioxide) absorbed by it. Ecosystems simply do not create water in the same manner as timber, fish, or fiber products.

As a result, the Footprint of a given quantity of water cannot be calculated with yield values in the same manner as a quantity of crop or wood product. When values for a ‘water footprint’ are reported, these are most commonly refer to either a measurement of total liters of water consumed, or to the Ecological Footprint required for a utility to provide a given supply of water. A water footprint can also be calculated based on the area of catchments or recharge zone needed to supply a given quantity of water. The area obtained from this calculation, however, cannot be added to other Ecological Footprint land areas, as this would create double counting (a forest, for example, can be used for both timber production and as a water catchment, but adding these two values together would count the amount of forest available twice).

Ecological Footprint accounts do directly reflect the influence of water availability on the biocapacity of ecosystems. Estimates of the amount of biocapacity that is dependent on freshwater supply, or of the lost capacity associated with water use for non-bioproductive purposes, could be calculated. As the relationship between freshwater and biological capacity is highly site specific, this analysis would need to be completed at a regional or local scale on a case-by-case basis.

Though they are often compared and contrasted, Ecological Footprints and Water Footprints are, as indicators, fundamentally incapable of being substituted. The Ecological Footprint does not, and is not intended to measure freshwater flows. Because this is nevertheless a vital renewable resource, in 2002, A.Y. Hoekstra proposed that the Water Footprint be created as a sustainable water use indicator measuring the total volume of freshwater directly or indirectly used by a population.

In essence, the Ecological Footprint measures the biological capacity a population uses and the Water Footprint measures the freshwater a population uses. They each provide a different piece of information in the sustainability puzzle. Instead of being seen as competing metrics, they should be seen as two complementary indicators of natural capital use in relation to human consumption.

For more information on the similarities and differences between the Ecological and Water Footprints, please consult A.Y. Hoeksta’s recent article Human appropriation of natural capital: A comparison of ecological footprint and water footprint analysis.

Pollutants and Non-Renewables

How does the Ecological Footprint account for pollution and toxic waste?

Toxics and pollutants released from the human economy that cannot in any way be absorbed or broken down by biological processes, such as many types of plastics, cannot be directly assigned an Ecological Footprint. As the Ecological Footprint measures the area required to produce a material or absorb carbon dioxide emissions, materials such as mercury that are not created by biological processes nor absorbed by biological systems do not have a defined Ecological Footprint (although their extraction, processing, and transport may have an associated carbon Footprint, for example). Many of the most important concerns surrounding toxic materials, such as future storage risks and human health impacts, are best captured by indicators other than the Ecological Footprint.

Many of these materials can cause damage to ecosystems when they are released into the environment, however, and this resultant loss of biocapacity can be measured using Ecological Footprint accounting and allocated to the activity that caused the release of the pollutant. The relationships between pollution and ecosystem damage are very site specific, data intensive, and difficult to calculate in practice. Even if no specific calculation is undertaken, however, any loss of biocapacity associated with the release of pollutants will be reflected in future assessments of the affected area.

We are using up many of our non-renewable resources such as copper, tin, coal and oil. How does the Ecological Footprint measure this resource depletion?

As the Ecological Footprint measures demand on the biosphere’s productive capacity, materials that are extracted from outside the biosphere (such as copper and other minerals that are mined beneath the ground) do not have a yield value that can be used to translate their creation into a productive area. One tonne of copper thus does not have an Ecological Footprint in the same way as one tonne of timber, which requires bioproductive area for its creation. There is, however, an Ecological Footprint associated with the energy and other materials used in extracting, refining, processing, and shipping these mineral resources, and together these are often reported as the Footprint of the mineral. Additionally, when mined materials such as mercury or arsenic enter the environment, they may cause damage and a loss of productivity.

Non-renewable fossil fuel resources are treated differently from other minerals, however, since they actually represent an ancient material of biological origin, and their combustion releases a material, carbon dioxide, which is part of the biosphere’s material cycles. The Footprint of carbon released from the combustion of fossil fuels is thus defined as the amount of productive area required to sequester the carbon dioxide emissions and prevent its accumulation. An alternative method would be to calculate the consumption of fossil fuels according to the productive area required to regenerate them, which would result in a carbon Footprint many hundreds of times higher than the current calculation.

Biodiversity

How does the Ecological Footprint relate to biodiversity?

The Ecological Footprint is not an indicator of the state of biodiversity, and the impact of a particular activity or process on biodiversity does not directly affect the Ecological Footprint calculation for that activity. Given the same yields, for example, the Ecological Footprint of Forest Stewardship Council (FSC) timber and uncertified timber is identical. These two practices will have very different consequences for the available future capacity of the forest to produce timber, which would be reflected in future biocapacity assessments but not in current Ecological Footprint accounts.

Although not a direct measure of biodiversity, the Ecological Footprint supports biodiversity assessment and conservation in two important ways. First, the Ecological Footprint can be used as a large scale indicator of the underlying drivers or pressures that cause biodiversity loss. For this reason, the Convention on Biodiversity (CBD) and the Streamlining European Biodiversity Indicators (SEBI) processes have both adopted the Ecological Footprint as an indicator of pressure on biodiversity.

In addition, the Ecological Footprint can also be used to translate the consumption of a given quantity of material (such as one kilogram of paper) into the specific local land area from which it was harvested (such as one square meter of forest in Finland). After this initial translation, complementary indicators and assessment tools can be used to measure the impact on biodiversity associated with harvesting from that ecosystem. This approach has been used in Global Footprint Network’s work in contribution to the Sustainable Consumption and Production program of the United Kingdom’s Department for Environment, Food, and Rural Affairs (DEFRA).

Nuclear Power

Why is nuclear electricity no longer a separate Ecological Footprint component?

Nuclear power has been included as a separate footprint component in national Footprint calculations since 1997. Because it is difficult to calculate the extent of the nuclear demand on the biosphere, it was assumed that one unit of nuclear electricity had an equivalent Footprint to one unit of electricity produced with a world average mix of fossil fuels.

After extensive discussions and consultations, Global Footprint Network’s National Accounts Committee recommended eliminating the nuclear land component from the National Footprint Accounts in order to increase their scientific consistency. This change has been implemented in the 2008 edition of the National Footprint Accounts.

The National Accounts Committee concluded that the emissions proxy approach for calculating the Footprint of nuclear electricity was not scientifically sound because:

  1. There is no scientific basis for assuming parity between the carbon footprint of fossil-fuel electricity and demands associated with nuclear electricity.
  2. The primary concerns related to nuclear electricity are often cited as costs and undue subsidies, future waste storage, the risk of plant accidents, weapons proliferation and other security risks. Ecological Footprint accounts are designed to be historical rather than predictive, and thus consideration of potential future impacts on biocapacity should not be included.

Actual carbon emissions associated with nuclear electricity are included in the National Footprint Accounts. However these emissions are only one among many environmental considerations relevant to nuclear power.

In the National Footprint Accounts for the year 2003, the nuclear Footprint represented approximately 4 per cent of humanity’s total Footprint. Therefore, for most nations, the effect of this methodological change on their 2005 results reported here will negligible. However, for countries with significant nuclear power supply such as Belgium, Finland, France, Japan, Sweden and Switzerland, the method change influenced their national Footprint values to a greater extent.

This exclusion of the nuclear Footprint component does not reflect a stance on nuclear energy. It simply acknowledges that only some aspects of nuclear energy are easily measured in terms of demand on regenerative capacity, the research question addressed by the Ecological Footprint.

However, the Living Planet Report—Japan for 2012 included an estimate for the biocapacity implications of the Fukushima accident. Click to read Japan’s 2012 Ecological Footprint. The calculation concluded that if the exclusion zone would need to be upheld for 100 years, the biocapacity occupied due to this one accident corresponds to 3 fold Japans’ yearly biocapacity. If the area included the contaminated zone above levels that were considered safe previous to Fukushima, the total demand, stretched over 100 years would be 10 fold Japans’ yearly biocapacity.