Calculating the ecological footprint: How it is measured

Calculating your own ecological footprint is quite complicated.

The good thing: There are calculators that can determine your ecological footprint based on simple questions.

When you eat, drive or turn on your heating: All day long you use up resources that have to be grown on earth. You can find out how much land is required to grow the resources you use by calculating your ecological footprint. You can then compare your ecological footprint with the footprint that the earth allows for each person on average. Because the earth has only limited resources (experts speak of a limited biocapacity). This is how you can find out if you are using too many resources.

The permitted ecological footprint is currently 1.7 global hectares (gha) per person. This compares to an actual average global footprint of 2.8 gha. So we consume more resources than the earth can provide us. The so-called “Earth Overshoot Day” is also calculated from these two values. This is the day when the Earth’s annual capacity is used up. In 2018, “Earth Overshoot Day” was reached on August 1st.

Germany makes a significant contribution to the fact that the global ecological footprint is too large: in Germany, the average footprint is five gha per person.

Calculating your ecological footprint: the basics

The Global Footprint Network has been calculating the ecological footprint of more than 200 countries and regions since 2003. The footprints are calculated by the “National Footprint Accounts” on the basis of data from UN institutions, the Intergovernmental Panel on Climate Change IPCC and the International Energy Agency, among others.

The method for calculating the ecological footprint is constantly being renewed. It is based on the fact that the productive land area of ​​the earth is divided into different landforms:

Cultivated area (e.g. grain cultivation),
Forest,
pastureland,
Water,
cultivated land and
the carbon footprint of a person/country that needs to be offset.

All these areas are not easily compared with each other: For example, one hectare of a grain field is “more productive” than one hectare of seawater. Therefore, all areas are converted into so-called “global hectares”: A global hectare (gha) stands for a certain productivity. For example, one hectare of arable land in 2010 was 2.51 gha. On this basis, one can calculate the ecological footprint for all types of land individually and add them up to get the total footprint.

You can read exactly how the ecological footprint is calculated in the publication “Working Guidebook to the National Foodprint Account” (version from 2019).

Calculate ecological footprint: These calculators exist

You can find some calculators on the Internet that estimate your ecological footprint based on simple questions. They ask you about these four areas:

nutrition
Reside
mobility
consumption
For example, your ecological footprint is particularly large if you fly a lot, eat meat often and do not use green electricity.

Recommended calculators:

Bread for the World calculates your ecological footprint based on 13 questions. For each of the four areas you can compare your footprint with that of an average German – and of course you can also compare your entire footprint. Unfortunately, it is not explained how and on the basis of which data the individual values ​​are calculated.

The Austrian Federal Ministry for Sustainability and Tourism has a slightly more comprehensive calculator for your ecological footprint. According to the ministry, the computer uses the methods of the “Global Footprint Network”, but in the 2010 version.

The “Global Footprint Network” not only calculates the ecological footprint of nations, but it also provides you with a calculator for your own footprint. Again, you only have to provide general information about your lifestyle, but you can specify some of it if you want. The calculator determines your ecological footprint, your CO2 footprint and your personal “Earth Overshoot Day”.