Environmental Impact Indicators (EII) for Dummies

“Global warming expressed in CO2e” – ever read an environmental report and wondered what these impact indicators actually mean? This article introduces you to the most common EII which you to might encounter when reading an extrafinancial disclosure or preparing your first life cycle assessment!

EII help to monitor the effects of human activities on the environment. There are several different EII, each designed to provide quantitative information about a certain area of the ecosystem.

Why should I need to know about EII?

Understanding Environmental Impact Indicators (EII) is becoming increasingly crucial for businesses, especially in the context of the growing emphasis on sustainability and environmental responsibility. Here are some key reasons why you need to be familiar with EII:

1. Compliance with Environmental Disclosure Regulations

Depending on the EU Member State you’re in, the Corporate Sustainability Reporting Directive (CSRD) might mandate that you delve into EII. This directive is a part of the EU’s broader strategy to ensure transparency in corporate sustainability, pushing companies to disclose their environmental impacts comprehensively. By understanding and utilizing EII, you can ensure your business stays compliant with these evolving regulations.


2. Understanding environmental Impact

No matter where you are on your sustainability journey, measurement is key to understanding. For instance you would want to conduct Life Cycle Assessments. These are comprehensive analyses that evaluate the environmental impacts of a product or process from cradle to grave. To conduct an LCA, several EIIs are required. These assessments are often necessary for obtaining certifications such as the PEP ecopassport or the EPD International AB. If you’re interested in learning more about LCA, be sure to check out our related blog post, LCA for Dummies.


From the industry, for the industry

eolos aims to pride our clients with science-based and future-oriented LCA to support the product design and business strategy decision-making. We also assist customers to go through the “data jungle” for accurate computation and comprehensive declarations.

Which EII are there?

🥵 Global Warming potential

CO2eq or CO2e means carbon dioxide equivalent. It is the unit in which GlobalWarmingPotentials (GWPs) are measured.

🌎 GWP in turn is a method to understand how different gases contribute to global warming compared to CO2. This is done measuring how much heat a gas traps in the atmosphere over a specific period, like 100 years, relative to CO2.

👉 CO2, by definition, has a GWP of 1.
👉 Methane (CH4) is estimated to have a GWP of 27-30 over 100 years.
CH4 emitted today lasts about a decade on average, which is much less time than CO2. But CH4 also absorbs much more energy than CO2. The net effect of the shorter lifetime and higher energy absorption is reflected in the GWP.

This helps us track emissions and prioritize efforts to reduce greenhouse gas pollution!

🌎 What is the ozone layer?
You might have heard plenty about it in the 80’s. Ozone is a gas in earth’s stratosphere which protects the earth from the harmful ultraviolet radiations.

😟 What can harm the ozone layer?
The release of chemicals like CFCs (chlorofluorocarbons) and HCFCs (hydrofluorocarbons), used in e.g. Hashtagsolvents, HashtagsprayAerosols, Hashtagrefrigerators, HashtagairConditioners causes ozone layer depletion. The thinning of this layer means more UV radiation on earth which is having negative effects on ecosystems and also on human health (skin cancers).

📊 How to measure it ?
Analogue to measuring the Global Warming Potential in CO2 equivalents, the Ozone Depletion Potential (ODP) is measured CFC-11eq. Meaning that it defines the potential of ozone depletion of different gases relative to the reference substance chlorofluorocarbon-11 (CFC-11).

which means that…
👉 CFC-11, by definition, has an OD of 1.
👉 HCFC-22 or HashtagR22, has an OD of 0.05. It is a refrigerant used in air conditioners and refrigeration equipment. 0.05 might seem low, but it is already high enough for the EU to have it banned in 2014.

💪 The world working together in 1987
In the 80s the world was forced to take action against the use of ozone depleting gases. Thanks to the Montreal Protocol in 1987 the ozone layer is projected to recover by the middle of this century. It has been estimated, that it is saving around two million people each year by 2030 from skin cancer.

🤨 Watch out!
To replace the banned ozone depleting gases, other gases have been used by the industry, e.g HFCs. Unfortunately those have a very high global warming potential (HashtagGWP) which essentially simply shifts the environmental problem from one impact area to another. The EU is targeting to reduce by 80% the use of HFCs by 2030.

When burning e.g. fossil fuels, sulfur dioxide and nitrogen oxides are released into the atmosphere. There, these substances resolve into an acidic solution and later fall back to the Earth’s surface; for example, as acid rain. 🌧️

🌱 What does this mean for the environment?
Too much acid can have several negative effects on the ecosystem. It can disrupt the pH balance of rivers, lakes, and oceans, making them inhabitable for aquatic species. It can also rob the soil of essential nutrients or damage tree leaves.

📊 How to measure it?
Similarly to measuring the Global Warming Potential in CO2 equivalents*, acidification potential is typically measured in sulfur dioxide (SO2) equivalents. Meaning that it defines the potential of acidification of different gases relative to the reference substance sulfur dioxide (SO2).

🌼 Wasn’t acid rain a problem of the 70s?
Acid rain was particularly problematic before environmental regulations all over the world led to reduced sulfur dioxide and nitrogen oxides levels in the atmosphere. Still, to track the environmental impact of companies and products, acidification potential is an important impact indicator to keep track of.

💧What is eutrophication of water?
Eutrophication comes from the greek word “eutrophos” which means “well-nourished”. Water eutrophication primarily results from excessive nutrient input, notably nitrogen (N) and phosphorus (P). These nutrients originate from wastewater and agricultural runoff .

🌱 What does this mean for the environment?
Excessive nutrients foster algal blooms and deplete oxygen levels in water, harming aquatic life like fish and seagrass while disrupting essential habitats.

📊 How to measure it?
Eutrophication potential is evaluated by measuring nutrient availability, often expressed in phosphate equivalents (PO4,3- eq) for freshwater systems and nitrogen equivalents (N eq) for marine environments.

🌎What is ozone?
Ozone is O3 – three oxygen atoms forming a molecule.

At around 15km over earths surface, in the stratosphere, ozone protects us from dangerous UV rays from space! However, close to earths surface, in the troposphere, ozone formation is a form of pollution that we want to avoid. 😶‍🌫️

☀️How is Ground-level ozone created?
Certain compounds* released by e.g. industrial facilities like gasoline vapors or chemical solvents will react with help of sunlight and create ozone. That’s why it’s called Photochemical ozone formation

😷 Is Ground-level ozone dangerous?
It can have negative effects on human health and the environment, causing for example human respiratory problems, or vegetation damage. It is also known as summer smog because pollution is higher in summer due to higher UV radiation.

💧What are abiotic resources?
The term “abiotic” describes non-living components, as opposed to biotic elements (which are living). E.g. water, stone, metal, minerals, sand. They are crucial to the human civilization and natural ecosystems.

🪨 What impact has abiotic depletion on the ecosystem?
Mining of abiotic resources for example lead to the destruction of natural habitats, soil erosion or pollution. (Next to many other social & economic impacts)

📊 How is the depletion of abiotic resources included in LCAs?
In an LCA, ADP (abiotic depletion potential) is split into two categories: one for elements, eg non-fossil-based resources (minerals and metals) and one for fossil resources.

non-fossil resource depletion is calculated in Antimony (Sb) equivalents. It was chosen as a reference substance because it is the first element in the alphabet for which a complete set of necessary data (extraction rate and ultimate reserve) is available.

fossil resource depletion is calculated in MJ: the weight of material is converted to its potential energy. (1 kg of coal hard is 27.91 MJ)

🤨 Why is this indicator controversial?
The scientific LCA community is warning that there is an uncertainty on this Impact Indicator, because there is no “perfect” way of quantifying it. However, they agree that quantifying it is still crucial and has to be part of the LCA approach.

How is primary energy different to “regular” energy use?

⚡️ Primary energy is the energy contained in natural resources like coal, oil or sunlight and that has not yet been transformed by man. It is different to the energy actually used due to conversion and transmission losses.
For example:

3.3kWh of primary energy are needed to produce 1 kWh of electricity with the average European electricity mix.

♻️What does this indicator account for?
This indicator considers the total primary energy needed for the different stages of the life cycle (manufacturing, distribution, installation, use, and end-of-life). It is all direct and indirect energy used to transform raw materials into products (for example natural gas used as raw material to produce plastics).

💧 What does the indicator “net use of fresh water” refer to?

Water use refers to all permanent or temporary human-induced removal of water from a watershed and that is not re-distributed in the same watershed. The term “net” refers to the fact that if water is used in closed loop processes (eg cooling system), only the net water consumption should be considered (such as water losses).


🌎 What are some challenges about this indicator?

The net use of fresh water has been neglected in the past because it is less relevant in northern European countries and is a cheap resource, so it is often not recorded. In addition, the EII “net use of fresh water” is not a “water footprint” in a broader sense because it does not consider potential environmental impacts of water use (on ecosystems, humans, stock/fund resources) in different geographical locations less prone to water scarcity.


eolos contributors to this article

Hanna Benarroch

Data Analyst

What you do makes a difference, and you have to decide what kind of difference you want to make

Irina Chèvre

Business Analyst

Passionate about creating a link between economy and natural sciences

Beyond compliance: How do we convert requirements into opportunities?

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