published on 13 May 2018 in earth

Small steps, great footprints

Which one takes up more space, an apple or a steak?
Have you ever wondered how much space is taken up by an apple or a steak? Quite easy: an apple occupies about 0.6 sq. m while a steak occupies 21 sq. m, the area of a room. Does it seem incredible? Instead, that’s just the way it is! Besides our apple, we must consider the ground to cultivate the apple tree on, the wood for the crates that are used to transport the apples, the fuel for transportation, an infrastructure for collection and sale, etc. These are all activities that we do not see, but which have a great influence. If we compare the space that is occupied physically by an apple or by a steak, and what is necessary to bring these two foods to our tables, we notice that the two values are quite different. Why? In the calculation we have not only considered the space they occupy physically, but also the amount of soil consumption to produce the apple, i.e. its ecological footprint.

The ecological footprint is an indicator that provides a measure of the amount of the Earth’s surface required to provide each human being with the resources he needs to live, and to absorb the waste that is produced by his activities. This indicator expresses the land and sea areas that are biologically productive, used by a determined population (i.e. an individual, a family, a city, etc.) to produce the energy and resources that it consumes and to eliminate the waste it produces each day. An ecological footprint of an individual or of a family includes:

  • consumption of food, clothing and luxury goods;
  • means of transport and types of vehicles used ;
  • use of the house.

Instead, if we wish to calculate the ecological footprint of a city or a nation, we must consider the following:

  • the surface area of land that is cultivated, to produce food (agricultural surface);
  • the area required as pastures, for the animal products (pastures surface);
  • the forest surface used to produce wood and paper (forest surface) and to absorb the production of carbon dioxide from energy consumption (surfaces for the production of energy);
  • the surface area of land that is necessary for building infrastructures (degraded surfaces, built on surfaces or however non ecologically productive surfaces);
  • the surface area of the sea that is necessary to produce fish and shellfish (marine surface).

In a globalized world like ours, people consume resources and ecological services coming from areas that can be very distant from where they are consumed, therefore their footsteps are the sum of the areas that have been used, independently from where they may be found on the Planet. However, all these types of surfaces are not always used: for example if we want to assess meat consumption, we would mainly consider the surface of the pastures and the agricultural surface used to produce the animal feed and fodder. If instead, we consider the buildings we would mainly quantify the degraded surfaces, and give less importance to the surfaces with forests, from which wood is taken and used for building.
Mathis Wackernagel and William Rees of the University of British Columbia were the first to create, define and study the ecological footprint concept, starting from 1990. At present this instrument is used by scientists, companies, governments, agencies, individuals and institutions to monitor the use of ecological resources and to promote sustainable  development.
In conclusion, we may say that the information obtained from the ecological footprint refers to the pressure that human beings make on the planet Earth, just like our footprints when we walk on the sand. Unfortunately however, unlike the latter, our ecological footprints cannot be cancelled easily.

Sustainability indicator
In ecology, the term sustainability indicates the capacity of an ecosystem to remain in a well-balanced situation, where the resources that are consumed are not more than those produced in the ecosystem. As mentioned above, the ecological footprint is an indicator, and more precisely it is defined a sustainability indicator, i.e. an instrument that provides information in a concise and clear manner, with regard to a very complex phenomenon with a broad meaning. In our case the ecological footprint, therefore, allows us to have a measure of the sustainability of our lifestyle. Since the concept of sustainability has many aspects, besides the ecological footprint there are other indicators that explain if a system is sustainable or not, like the ecological backpack, the carbon footprint and the water footprint. With the help of these indicators we can understand if our lifestyle is sustainable, and if it is not, we can quantify how much we are exaggerating.

The Global Footprint Network is a non-governmental organization dedicated to research and development and to the promotion of this indicator, and definition of the investigation principles and methods.
In particular it is engaged in the calculation of the ecological footprint, i.e. the demand for natural resources, and the planet’s capacity to satisfy this demand – the biocapacity of over 230 countries, territories and regions spread all over the world. This helps to define if there is a deficit or a surplus with regard to the use of natural capital. The results are updated on an annual basis, and also the calculations, and these are published in the National Footprint Accounts. There are over 6,000 data collected annually for each of the analysed nations, and these come from different sources that are recognized on an international scale. In order to determine the ecological footprint, the yields of the primary products of the area are used (land that can be cultivated, forests, fish stocks and pastures), that are necessary to support a particular activity.
For example if I wish to calculate the ecological footprint of your weekly diet, and you eat 1 kg of meat, 1.5 kg of pasta, you need to multiply your consumption of meat and pasta by a conversion factor that ties the meat or the pasta to the area that is necessary for their production. Biocapacity, instead, is measured by calculating the quantity of biologically productive marine and terrestrial area that is available to provide the resources that the population consumes and to absorb its waste, with a particular technology and management systems. In the calculation, the different productivity of the ecosystems in the various countries is taken into consideration.
The consumption of a nation is calculated by adding the imports and subtracting the exports of the national production. The results of this analysis provide a picture of the ecological impact of the nation. If the ecological footprint is less than the biocapacity, the examined country will have an ecological surplus, an ecological reserve that will guarantee that its requirements are satisfied and will therefore be sustainable from the point of view of the ecological footprint. In case of the contrary, i.e. if the ecological footprint is less than the biocapacity, there will be an ecological deficit, and the country will not be sustainable from the point of view of the ecological footprint. In the first case the Country is considered an ecological creditor, in the latter case it is an ecological debtor. The “Calculation Methodology for the National Footprint Accounts, 2011 Edition” provides the indications and the principles used in 2011 for the National Footprint Accounts and the principles and methods used for the calculations, for a better understanding of the method.

Debtors or creditors?
Today, over 80% of the world population lives in countries that exploit more resources than those available within their country’s boundaries. These countries, in fact, use the surplus resources of those countries that use less biocapacity to satisfy their needs, i.e. they use the surplus of the ecological creditors. Up to about 50 years ago, most counties of the earth had more ecological resources than the amount they used, but their number has strongly decreased in time, while pressure on the biocapacity reserves is constantly increasing.
Since the 80s, humanity has been living above its ecological possibilities, and therefore there is an ecological overshoot in which the demand for resources is greater than what the Earth can provide annually. In fact it has been calculated that our planet needs about one year and four months to regenerate what we use in a year. According to the Living Planet Report 2012, which is a report that is made by the WWF,  Global Footprint Network, the Zoological Society of London and Water Footprint Network, the total biocapacity available on our planet is 12.2 billion Gha (global hectare*), i.e. 1.8 Gha per capita, while humanity’s ecological footprint exceeds 18 billion Gha (2.7 per capita); and consequently our footprint currently exceeds the biocapacity by 30%, and we are using the equivalent of 1.5 planets a year to satisfy our needs.
If all the inhabitants of the Planet were to consume like those in the United States or in the Arab Emirates, we would need 4.05 and 5 planets respectively in order to satisfy our requirements. If everyone consumed the same amount as us Italians, we would need 2.55 planets instead. On the other hand the citizens of Congo and Bangladesh consume the equivalent of only 0.61 and 0.37 planets respectively. Some estimates of the United Nations state that with the present rhythm of growth of the population and of consumption, by 2050 the equivalent of two planets will be required to support the living requirements of human beings, while according to Global Footprint Network, we will really need 3 planets! These data make us reflect on our lifestyle and on the negative consequences that this can lead to for our planet, jeopardizing, in the long term, not only its wellbeing and its health, but that of the human population in general. To be aware of this situation is the first step towards organizing ourselves and facing it. A scientifically rigorous evaluation, such as the ecological footprint enables us to make ecologically more sustainable choices that respect nature better, on an individual scale, but also on a Municipal and National scale.
Do you want to discover your ecological footprint? Try to calculate it here.

*Global hectare (Gha): A productivity weighted area used to report both the biocapacity of the earth, and the demand on biocapacity (the Ecological Footprint). The global hectare is normalized to the area-weighted average productivity of biologically productive land and water in a given year. Source: Footprint Network, Glossary

A handbook to reduce our ecological footprint
Have you calculated your ecological footprint, and found it is larger than what you thought? How to start acting practically? It is easier than you might think, even in our everyday choices, we can make a difference!
Here are some simple suggestions to decrease our ecological footprint.


  • Prefer food at 0 km and from the shorter supply chain
  • Limit the consumption of meat and cheese, eat more fruit and vegetables
  • Decrease all waste to the minimum


  • Use public transport and bicycles instead of cars whenever possible
  • Prefer electric and LP Gas cars
  • Use car-pooling and car sharing
  • Prefer to travel by train rather than by plane whenever it is possible


  • Reduce water and electricity consumption (for example fill up the washing machine well, and close the tap when brushing your teeth)
  • Improve the insulation of your house to avoid dispersion of heat
  • Recycle waste
  • Purchase goods that require a minor use of resources and energy to be produced
  • Try teleworking, and try to make purchases and carry out day-to-day operations remotely

For further information and advices, visit Ecological Footprint website.

Edited by Nadia Mirabella

Research material
Wackernagel M., Rees W. E., Our Ecological Footprint: Reducing Human Impact on the Earth. New Society Publishers, 1996
Global Footprint Network, Reading and references
Global Footprint Network, Academic references
Global Footprint Network, Ecological overshoot (video)
Global Footprint, Interactive map

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