CO2e: The meaning of the CO₂ equivalent simply explained

|  December 19, 2023

🕓 Reading time 3 minutes

Table of contents

1. What is CO2?

2. What does CO2 equivalent mean and what does the e in CO2e stand for?

3. Which gases are expressed in CO2 equivalent?

4. How are companies responsible for CO2e?

1. What is CO2?

CO2 stands for carbon dioxide. It is a colorless, odorless gas and one of the most important greenhouse gases in the Earth's atmosphere. Carbon dioxide is produced primarily by natural processes such as respiration and volcanic activity, but also by human activities such as the combustion of fossil fuels (coal, oil, and gas).

CO2 plays a significant role in climate change because it helps trap heat in the atmosphere, leading to global warming.

2. What does CO2 equivalent mean and what does the e in CO2e stand for?

CO2 equivalents are units of measurement that aggregate different greenhouse gases into a single value based on their respective contribution to the greenhouse effect relative to carbon dioxide (CO2). These units allow the impact of different gases on climate change to be compared and quantified.

The "e" in CO2e stands for "equivalent." It is used to indicate that other greenhouse gases are expressed in terms of their contribution to global warming in CO2 equivalents. These calculations are based on the Global Warming Potential (GWP) of the respective gases compared to CO2 over a specific period of time, for example, 100 years. CO2e allows for the unification of the various greenhouse gases into a single unit, facilitating the comparability of their impacts on climate change.

3. Which gases are expressed in CO2 equivalent?

Various gases are expressed in CO2 equivalents based on their potential to contribute to the greenhouse effect compared to carbon dioxide (CO2). The most important greenhouse gases measured in CO2 equivalents include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and various fluorinated greenhouse gases (F-gases). These F-gases include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). Since 2015, nitrogen trifluoride (NF3) has been added to the list as another gas. Depending on the activity, several of these greenhouse gases may be released simultaneously during various processes.

4. How are companies responsible for CO2e?

Companies are responsible for their CO2e emissions due to their operations, production processes and supply chains. The responsibility of companies for CO2e is defined in three scopes divided into:

1. Direct emissions (Scope 1): This refers to direct greenhouse gas emissions from sources within a company's control. This includes, for example, emissions from the combustion of fuels in its own facilities or vehicles.

2. Indirect emissions from purchased energy (Scope 2): These are the indirect emissions that arise from the production of purchased energy such as electricity, heat or cooling that a company uses.

3. Other indirect emissions (Scope 3): These include all other indirect emissions that arise outside the company's direct control, such as supply chains, business travel, end-use of products, etc.