What is meant by the term ecological footprint?

© Bought from HollyHarry, adobe

Introduction

What we eat and how we produce something has an enormous impact on our planet Earth. The image the footprint creates, helps to make the consequences of these environmental impacts tangible. It shows what a reckless, thoughtless food production demands of the world, and can pave the way to more sustainable solutions.

In our Nutrient Descriptions or nutrient texts, we dedicate a chapter to the "ecological footprint." There, we specify several sustainability indicators, such as the carbon footprint or the water footprint. In this article we explain what is behind it.

The steadily rising warming that we feel worldwide is the consequence of the gradual accumulation of greenhouse gases in our atmosphere.^34,35,36 The newest IPCC report underlines the urgent need to restructure the agri-food systems to mitigate and adapt to climate change. Over 20% of the global greenhouse gas emissions come from agriculture, forestry, and land use. According to the WWF, about 37% of greenhouse gases are due to our food system.³³ The non-profit organization, Global Footprint Network, speaks to the fact that about 30% of the total ecological footprint in Europe is attributable to food production.³⁰

Since the beginning of ecological footprint accounting in the 1990s, the concept has developed significantly.⁵⁴ On the one hand, the ecological footprint includes key figures, which show how heavily an ecosystem is stressed. This enables countries, companies, and institutions, as well as private individuals, to balance their resource consumption. So, questions like: How much bio-productive land do we need? Is the biological capacity of the Earth sufficient?⁴ can be answered. Currently, we are taking more from the earth than it can regenerate - we would need at least one more Earth to maintain the current average (!) lifestyle for a longer time.

On the other hand, in addition to this global perspective, individual sustainability indicators have also become more important, which has led to a diversity of methodological approaches and different footprinting methods.⁵⁴ Even if experts still argue over details and definitions, they are basically in agreement: the production of food consumes a lot of land, raw materials, chemicals, and causes greenhouse gas emissions. Ecosystems are interfered with, changing entire landscapes (e.g. from rainforest to soy monoculture), causing plants and animals to lose their homes. In the process, biodiversity is decreasing and the associated ecosystem resources that are necessary for us humans are being lost.¹²

It is generally known that the consumption of animal products leads to an increased ecological footprint. A 2023 study conducted in Poland shows the following result: a vegetarian diet had a 47% lower carbon footprint and a vegan diet even reduced it by 64.4%; the land footprint was 32.2% and 60.9% lower, respectively, and the water footprint was reduced by 37.1% and 62.9%, respectively. All this in comparison to a diet that includes meat.⁴⁹

Background: Problems with the Greenhouse Effect

During the second half of the 20th century, food production doubled. However, this gain did not come without losses, as it left behind an enormous footprint on the ecosystem.⁴²

The earth, as we know and need it, is based on different cycles that keep the system in balance. We humans probably now have our hand in all cycles. Scientists have noticed the negative effects of this. Now, we must name, quantify, and reduce these effects and their triggers. As a tool for this task, researchers have developed various concepts and indicators. Among other things, the ecological footprint, the carbon footprint, and the water footprint.

The earth's cycles (carbon cycle, nitrogen cycle, water cycle, etc.) are very complex; human interference and its effects can hardly be described in one article. Thus, we only go into the greenhouse effect here - as we also often give the carbon footprint or CO₂ equivalent in our ingredient articles.

99.9% of the earth's atmosphere consists of three gases: nitrogen (78.09%), oxygen (20.95%), and argon (0.93%). Despite this, it is trace gases (CO₂, CH₄, CO, NO_x, CFC, O₃) that have the biggest influence on the climate.¹³

Around the year 1820, researchers recognized that the Earth has some kind of insulation.²¹ Certain molecules, the so-called trace gases, are essential for the Earth's heat budget; its balance is indispensable for us humans. Carbon dioxide (CO₂), one of these trace gases, helps the earth not to radiate all the heat from the sun out again, but instead to store some of it: the sun's radiation passes through the atmosphere unhindered; the earth's surface warms. The now warmed earth emits the converted sunlight in the form of infrared radiation. CO₂ and the other greenhouse gases, such as water vapor, absorb part of this infrared radiation. These gases keep the earth warm like a blanket. Without this blanket, the average surface temperature of the earth would be about -21 °C instead of the pleasant 14 °C today.^14,16 Think of the earth as a grapefruit, the thickness of its finely calibrated insulating layer can be compared to the skin of the grapefruit.¹³ This effect was later called the greenhouse effect. As in a glass house/greenhouse, the sunlight can shine in, but the heat cannot fully escape back out.

The climate that suits us humans so well, had developed gradually over millions of years. A good 200 years ago, we changed the chemical composition of the earth's atmosphere because industrialization based on coal began. In addition, advances in medicine and technology led to exponential population growth. The use of fossil fuels soon also included oil and gas. In contrast to wood, fossil fuels (by definition) have formed over millions of years. By burning them, vast quantities of CO₂ (and equivalents) were abruptly, in the earth's sense of time, released, increasing the atmospheric concentration by 33%.¹³

Greenhouse gases are therefore also part of the cycle. Using energy from fossil fuels, we intervene massively in this cycle. By burning carbon stores (C), such as crude oil or forests, we are suddenly releasing countless greenhouse gases (CO₂, CH₄, NO_x, water vapor). This amplifies the greenhouse effect. More greenhouse gases in the atmosphere absorb and reflect more solar heat. The radiation balance changes, the earth warms up.¹⁴

Researchers have long been aware of the consequences this entails. Eunice Foote, a pioneer of climate sciences, recognized in 1850, through experiments, that water vapor and carbon dioxide (CO₂) have a warming effect on the climate.²²

Although climate researchers cannot predict all the effects of climate change, climate change or global warming itself is undisputed and well documented. The global warming caused by humans goes hand in hand with many effects that not only jeopardize our comfort, but even our survival. Climate change is just one of many complications we are facing: rising sea level, acidification of the oceans, melting of permafrost and huge ice masses (glaciers), changed distribution of fresh- and saltwater, changes and loss of natural habitats (domestic species vs. invasive species), spread of diseases, destabilization of ecosystems, and loss of coral reefs. Imbalances between soils and climate, hydrological patterns, plant and animal life, weather processes, and seasonality jeopardize food production. All of these dangers force (now and in the future) masses of people to emigrate, which in turn could lead to political instability.^34,11 Read more about this topic in our article, Ecology: Grassroots movements AND political action required.

We often forget how much we depend on a favorable climate; how closely our health is linked to the Earth.

To bring this situation under control, instruments are needed to identify, assess, measure, and set limits for emissions and relate effects. For this reason, researchers have developed sustainability indicators.

Indicators for Measuring the Footprint

Our ingredient articles (a sample) work with different methods and units of measurement. Below, we clarify the ones that are most frequently used:

The ecological footprint: This expression is ambiguous in German. Since the introduction of the first footprint metric by Mathis Wackernagel and William E. Rees in 1996 (called ecological footprint), many new concepts have emerged. To summarize, there are two perspectives.^54,55 From a global perspective, the systematic calculation of the ecological footprint generates concrete numbers using the unit, "global hectares" (gha) and compares these numbers with the biocapacity of the earth. This definition is based on the original interpretation made by Wackernagel and Rees.

At the same time, the ecological footprint is also a collective term for other footprints, above all, the carbon footprint (measured in kg CO₂eq/kg), followed by the water footprint (measured in m³/t = l/kg), the land footprint (+change in land use), material footprint, and chemical footprint (et al.⁵⁵). While these footprints can be viewed as subsets, they can - from a consumer-oriented perspective - also be very helpful as a stand-alone criterion, e.g. for sustainability comparisons of food or production steps in the food industry.

The English language has taken these developments into account and often makes the following distinction: while the term "ecological footprint" is usually referred to in "global hectares" and describes the global footprint of mankind or a society (nation), the term "environmental footprint" is often used to describe the sum of different, individually defined footprints. Thus, in the second case, the plural, "environmental footprints," is often used or even referred to as a footprint family ("environmental footprint family").⁵⁵ Terminologies, such as "footprint-type indicators,"⁵⁶ "environmental indicators,"⁵⁴ or "environmental impacts" can be used even more objectively (environmental pollution, effects on the environment, etc.). German-language equivalents exist, but they are rather rare: most often, the plural "ecological footprints" is found in scientific assessments;⁴⁶ occasionally the term "environmental footprint" is encountered, either in singular or plural form, or the idea of the "multidimensional footprint" with several sustainability indicators.

Life cycle analysis (LCA or life cycle assessments) is understood as a standardized procedure that shows the environmental impacts of a product from production to disposal. Depending on the question, there exist different types of life cycle assessments. Consumer-oriented footprint analyzes often work with numbers from life cycle analyzes. Since footprint calculations are less standardized than life-cycle analyzes, proponents of LCA occasionally distance themselves from certain methods of footprint analyzes.⁵⁴

Global and National Ecological Footprint

From a global perspective, the ecological footprint measures how much we - as individuals, society, or humankind - consume in terms of resources in the form of biologically productive land and sea area and how much we produce in terms of waste, in relation to the regenerative capacity of the earth.^19,30 In other words: How much productive area (in global hectares) is needed for...?

If the ecological footprint of a society exceeds the biocapacity of the region, that region falls into a biocapacity deficit. The raw material consumption for goods and services surpasses regeneration. The ecological deficit of a region is compensated by importing or liquidating its own ecological assets (e.g. overfishing, deforestation) and/or emissions into the atmosphere (CO₂eq). If the region's biocapacity exceeds its ecological footprint, it has a biocapacity reserve.³⁰

The unit for ecological footprint and biocapacity is given as global hectares (gha, not Gha), which is calculated using the usable area of the earth. In this way, is the ecological footprint of a city, a state, or a nation comparable to its own biocapacity or that of the world.³⁰ On average, mankind currently needs 2.5 gha/capita. This ecological footprint corresponds to a biocapacity of 1.6 gha/capita.^1,4 While, in Europe and North America, the average lies at 5-7 gha/capita, it is between 0 and 3 gha/capita in Africa, Asia, and Latin America.²⁹ One gha corresponds to 10,000 square meters or an area of 100 x 100 meters of average cultivation capacity.

Other Footprint Indicators

As the area-centered ecological footprint become more widely known (see last chapter), the number of proposals for consumer-oriented environmental indicators or footprints also increased. As a rule, these footprints are defined using life-cycle analyzes,^40,54,55 but often differ in their objective or approach.

Digression: Life Cycle Analysis (LCA)

Life cycle analyzes (LCA = life cycle assessment, life cycle analysis) or life cycle assessments (eco-balance sheets) are multi-stage procedures for calculating all effects on the environment during the life cycle of products or services, as well as operations or processes. The International Organisation for Standardization (ISO) has set the following guidelines for the LCA: ISO 14040 and ISO 14044. Objective and definition (life cycle inventory analysis) are of great importance - as is the impact assessment and evaluation.^6,15 The LCA is an iterative process, i.e. the individual steps should be repeated.

Depending on the defined system boundary, the life cycle analysis comprises different phases. For example, the LCA of a product, "from cradle to grave" or "cradle-to-grave," contains the following phases: raw material extraction, production, distribution, use, and disposal. Using the "from cradle to gate" or "cradle-to-gate" method, the calculation ends at the factory gate of the manufacturer.

There are very many procedures and evaluation methods for the creation of life cycle assessments. The following impacts on the environment, isolated or combined, are considered: greenhouse gas potential (CO₂eq), water use, resource consumption (minerals, metals, fossil fuels), ozone depletion, human toxicity, particulate matter (PM), ionizing radiation, human health, photochemical ozone formation, acidification and eutrophication, as well as land use. The result of a life cycle analysis can end with many different units, such as kg CO₂eq/kWh, kg CO₂eq/l, l/t-shirt, kg of chemicals per unit, etc.

Carbon Footprint

While the life cycle analysis considers all environmental impacts caused by a company, a municipality, or an organization of any kind, the carbon footprint focuses on a subset, the carbon emissions (or CO₂ equivalents, CO₂eq), that an organization directly or indirectly causes. Both the life cycle assessment and carbon footprint are not only applicable to products (see product carbon footprint = PCF), but also to services, companies, or organizations.¹⁷

There are also different methodological approaches to the carbon footprint analysis.⁵⁴ Basically the carbon footprint (or the CO₂ balance) stands for the total amount of greenhouse gas (GHG) emissions, expressed as CO₂ equivalents (CO₂eq).¹⁷ This considers that, for example, both carbon dioxide (CO₂) and methane (CH₄) contribute to climate change - however, to varying degrees. The climate change potential from methane is approximately 24 times more pronounced than that of carbon dioxide. These differences are weighted in the form of substance-specific damage factors, i.e. 1 kg CO₂ + 1 kg CH₄ = 25 kg CO₂eq/kg.¹⁵

Carrots, for example, have a small footprint with 0.1 kg CO₂eq/kg; avocados, bought in Germany, produce an average of 0.6 kg CO₂eq/kg (1.10 in Denmark according to CONCITO⁴⁵); tomatoes from a heated greenhouse come to 2.0 kg CO₂eq/kg. Frontrunners are animal products with footprints up to 21.7 kg CO₂eq/kg (organic beef). However, also a pineapple - imported to Germany by plane - can sometimes come to 15.1 kg CO₂eq/kg.⁴⁶

The results of a carbon balance sheet can vary greatly depending on the calculation guidelines⁵⁴ and food. The carbon footprint from foodstuffs makes up a ¼ of all emissions.¹ Generally speaking, fruits and vegetables are an essential and extremely healthy part of the diet. In comparison to many animal products, they cause considerably less greenhouse gas emissions per kilogram and per calorie. A diet rich in vegetables and fruits therefore not only has health benefits, but makes a lot more ecological sense.^2,8,9

Unfortunately, however, there is a trend towards a globalized diet with lots of meat and refined products, while traditional and seasonal products are becoming less important.²⁶ Since phytochemicals are not present in animal foods, we cause long-term damage to our bodies with this trend: this is because phytochemicals mostly offer benefits to our health. However, there are important criteria to consider if you wish to explore new avenues.

The carbon footprint can also be expressed in different units, such as: CO₂eq/kcal, CO₂eq/ha etc.

Water Footprint

The water footprint can be seen as an alternative to the global ecological footprint. In this case, it then represents the amount of freshwater required (in m³/year) instead of the area that is needed to maintain the population.¹⁸ From a consumer-oriented perspective, however, the following approach applies: the water footprint shows the impacts of a product on freshwater resources, by mapping out the amount of water used^10,54 (m³/t) in the manufacturing process. Around 90% of the global freshwater consumption in the last one century was attributable to agricultural production.^37,42

The water footprint analysis (WFA) includes freshwater use, scarcity, pollution, consumption, production, and trade; along the entire production and supply chain of goods. The water footprint is intended to help use water more efficiently, sustainably, and fairly.²³

The water footprint is divided into three categories: the blue water footprint shows the consumption of surface water and groundwater, whereby consumption refers to the loss of the available ground surface water in an area. Losses occur when the water evaporates, flows into another basin, into the sea, or into a product. The green water footprint represents rainwater; the gray water footprint stands for the amount of fresh water required to absorb pollution without reducing water quality.³⁷

The total average water footprint of vegetables amounts to (in m³/t): 194 green, 43 blue, and 85 gray water - in total, 322 m³/t (l/kg). In relation to the nutritional value, 1.34 l/kcal is needed. Eggs have a water footprint of 3265 m³/t (l/kg) and 2.29 l/kcal. For the production of beef, 10.19 l/kcal are even required.^24,25

In general, a diet without animal products goes hand in hand with a smaller water footprint. This rule applies to the average. In individual cases, plant products can also have a negative impact on the water balance. In areas suffering from water scarcity in particular, the impact of water consumption for food production is more dramatic.¹⁰

Land Footprint/Land Use Change

The land footprint indicator measures the total area of land required to produce products or services consumed by people in a given country or region.⁴³ There are different methods or models to calculate the land footprint.^29,54 This often leads to an inconsistent use of the term, which is sometimes used synonymously with ecological footprint. From a global perspective, it is possible to show the extent to which countries or regions (e.g. Europe) are dependent on foreign land (including imports and exports).³⁶ For example, the EU has such a large land footprint that its own area is no longer sufficient to meet its needs. Thus, the EU uses additional external lands, as big as France and Italy combined, to meet the needs of EU residents.^32,20

Another analysis method refers to the area that is required to manufacture a product as the "land footprint." For example, a large-scale calculation came to 16.51 Mha (1 Mha = 1,000,000 ha) land footprint for soybeans in 2013.³⁸ In contrast, soybean cultivation could also be represented as an individual aspect, for example within the calculation of the ecological footprint of a single person who consumes soy.

In life cycle assessments, land use change (LUC) is also known as "land conversion" or "land transformation." This describes emissions caused by a change from a previous use to a current use; for example, by changing grassland, Savannah, or forests to arable land. It is assumed that land use changes and - to a much lesser extent - land use (LU = land use, also called "land occupation") are among the main causes of global carbon emissions, especially in the tropical regions of South America, Asia, and Africa. The emissions from LUC in the 1980s and 1990s accounted for approximately 20% of the total global carbon emissions.³¹

An example of emissions from land use change in Brazil: changes in land use to pasture, soybean cultivation, and sugar cane amounted to 4.1, 2.3, and 0.3 t CO₂/ha per year, respectively.⁴⁴

Greenhouse gas emissions from agriculture worldwide amounted to 9.3 billion tons of CO₂ (Gt CO₂eq) in 2018. Of this, 5.3 Gt CO₂eq are attributable to agriculture and animal husbandry and the remaining 4 Gt CO₂eq comes from land use and land use changes.²⁷

Material Footprint

In all phases of its life cycle, a product requires use of raw materials (packaging, recycling, mining of minerals, etc.). Thus, the cumulative raw material input determines its material intensity, which can be a multiple of its own mass.³⁹

The use of materials has risen in the last decades to an unprecedented degree; driven to the abstruse by continuous growth and consumption. Material resources amount to approx. 90 billion tons per year; this is expected to double by the year 2050. This liberal use of materials comes at the cost of natural ecosystems and biodiversity. We are currently surpassing the so-called "Safe Operating Space." Exceeding this safe threshold jeopardizes the conditions that have made human development and well-being possible. According to one calculation, Germany, for example, would have to reduce its consumption of raw materials by at least 75% in the next 30 years.³⁹

The growing need to use resources more economically, makes it necessary to measure the use of natural materials through life cycle analysis, both at the country and product level.³⁹

Chemical Footprint

The chemical footprint is an indicator of the potential risk posed by a product. The analysis should provide a comprehensive quantification of the chemicals used, consumed, produced, or altered throughout the life cycle of the product and the associated risks.⁴⁰

In contrast to other measured values, such as the carbon footprint, the recording of the chemical footprint is much less developed. Although some companies include the chemicals component in their sustainability reports, no standardized method or indicator has yet emerged.⁴¹

Other footprints include: nutritional footprint,⁴⁷ energy footprint, nitrogen footprint, and biodiversity footprint.⁴⁰

Comparability and Difficulties

Organizations, companies, and institutions choose different methods for their investigations into the sustainability of products, services, operations, etc., each of which deliver different units, as well as define their own system boundaries. As a result, comparisons and associated interpretations are often difficult to determine. There are differences in agricultural products or food from one country of production to another and they depend on prevailing climatic conditions, among other things. Whether to look at or compare imported or locally produced products is also of interest. Certain parameters are often difficult to understand and also present a confusing picture to consumers. Results should always be scrutinized and put into perspective.

With complex methods, like the life cycle analysis, various aspects can lead to difficulties: for example, the packaging has direct impacts (such as the energy or material required) that are necessary for production. However, it also has indirect impacts, as the type of packaging influences both shelf life and food waste.⁷ These indirect aspects are quite difficult to ascertain in calculations.

The LCA is constantly evolving. However, some aspects are less developed, especially "eco toxicity" and "biodiversity," which are two key impacts of food production systems. Within the life cycle analysis of food, the dominant unit is "kg," which means that all environmental impacts and resource uses are related to the mass of the products. However, this functional unit does not cover all the functions of foods, which include the nutritional content as a fundamental component - along with pleasure, cultural value, satiety, etc.⁵

The fact is, however, that a third of all man-made caused greenhouse gases come from our current food system. The savings that can or would be achieved through a climate-friendly diet even exceed the emissions from transportation and energy.^3,33 This motivates us to show you how you can eat in a climate-friendly, but also people-friendly way, in the sense of a healthy and enjoyable diet. We also attach great importance to animal welfare and prefer an organic, vegan nutrition. If you lose sight of nature, you also lose health.

A change in nutritional behavior "away from meat and closer to a plant-based diet" is a key challenge when it comes to making our food system more sustainable.²⁸

There are other practical methods, developed from the EAT-Lancet-Kommission, which, with the help of the "Planetary Health Diet," show how conscious consumption can protect the Earth and human health.⁴⁸

Further information on the topics of nutrition, ecology, and health you can find in the article, Basic Knowledge.

Greenwashing

In the case of greenwashing, companies present themselves to the public with environmentally friendly initiatives and describe themselves as "climate-neutral." However, there are currently still no binding commitments. Companies have multiple opportunities to behave incorrectly. Therfore, certain environmental associations do not (yet) recognize such labels. The EU is working on a directive (2023/2024), individual countries are working on regulations, and the ISO is also working on a standard to make these disclosures more transparent and credible.⁵⁰

However, scientific studies indicate that these supposed compensations are much less certain than the climate damage caused by greenhouse gases - there is therefore no equivalency.⁵¹

The Schweizer Post, for example, bought a piece of forest in Germany to remove part of their carbon emissions from the atmosphere with the help of wood. Accusations of "greenwashing" emerged.⁵³ After all, the forest does not care to whom it belongs, it cannot store anymore CO₂ than it otherwise would.

There are countless other examples: a shoe brand that campaigns against plastic waste, but produces plastic shoes itself; clothing companies that advertise "sustainable" fashion, although 99% of them use environmentally harmful materials and manufacture under poor social conditions; or terms like "biodegradable" may be written on food packaging, despite only a small part of the packaging is degradable (but the package as a whole is not) - and the product itself is harmful for the climate.

The problem is that greenwashing is not a lie, but a half-truth that is not so easy to check or discern due to its complexity. Consumer deception through misleading, non-verifiable environmental claims is considered an unfair business practice and, according to a press release from the European Parliament (2024), will be forbidden in the future. Only official certificates should be permitted in the EU.⁵²