Greenhouse Gases, CO2e, Carbon | Sustainability Terms | EcoOnline US

Greenhouse gases, CO2e, carbon and more: common sustainability terms you should Know

Written by Dina Adlouni

Published February 5, 2024

It’s lunch time and William, the EHS manager at a manufacturing company, is speaking with his superior, Brian. He shares the latest performance metrics and highlights of the last few months when Brian mentions that investors and board members are very keen on sustainability and how the organization can showcase its initiatives in this area.  

“This is a new focus that we have to start preparing for,” Brian tells William. “Let’s slowly begin to gather as many metrics as we can about our GHGs, like our total CO2e, and carbon emissions.” 

William nods his head in agreement, but in reality, he’s never heard of the term GHG or knows how to begin to gather information on carbon emissions.  

Are you just beginning your sustainability journey and trying to figure out how to connect EHS to ESG? Read this blog to understand more about the following terms you should know to help get you started: 

  • Greenhouse gases (GHGs) 
  • Carbon dioxide (CO2) 
  • CO2e 
  • Carbon  

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 What are greenhouse gases (GHGs)?

Greenhouse gases, also known as GHGs, are those which trap heat from the sun, raising the atmosphere’s temperature. Over the past few decades, there has been a drastic increase in GHGs in the atmosphere due to human activities like burning fossil fuels, waste, and trees (among many other things). This results in climate change and global warming, affecting all corners of the world.  

The following greenhouse gases, also known as the Kyoto basket, are under the Kyoto Protocol. What is the Kyoto Protocol? This is an international treaty which was adopted in 1997 to help control and reduce the amount of GHGs emissions. Today, there are various ESG-related reporting frameworks and standards that organizations must follow to help curb the effects of climate change.  

Greenhouse Gas Global Warming Potential (GWP) 
1. Carbon dioxide (CO2) 1
2. Methane (CH4) 29.8
3. Nitrous oxide (N2O) 273
4. Hydroflurocarbons (HFCs) 5-14,600
5. Perfluorocarbons (PFCs) 78 - 12,400
6. Sulfur hexaflouride (SF6) 25,200
7. Nitrogen trifluoride (NF3)3 17,400


You may have noticed the term GWP or Global Warming Potential in the above table. This refers to how much a gas can heat up the atmosphere over approximately 100 years.  

The first gas, carbon dioxide, for instance, has a GWP of 1 because all other gases are in reference to it. Methane or CH4, for example, heats the atmosphere 29.8 times more than carbon dioxide over a 100-year period. Because of this, it’s important that you not only measure your carbon dioxide emissions, but all the above gases to get an accurate view of your organization’s GHG emissions.  

The importance of carbon dioxide

Speaking of carbon dioxide (CO2), let’s dive into this important gas. This is one of the most common greenhouse gases which is released into the atmosphere by human activity like burning fossil fuels, trees, and waste. Unfortunately, this gas is the main culprit when it comes to climate change.  

Many refer to their GHG emissions as carbon emissions which is inaccurate and confusing. As mentioned above, all other GHGs are measured in reference to carbon dioxide; however, as stated earlier, you should not limit your emissions measurement to just this gas.  A better way of referencing your greenhouse gas emissions is carbon dioxide equivalent - also known as CO2e.  

Smoke rising from the vessels of a power plant

What does carbon dioxide equivalent mean?

Because there are so many different greenhouse gases with different Global Warming Potentials, you need to convert them all to the same unit to find your total emissions value. This unit is known as CO2e or carbon dioxide equivalent (CDE).  

Let’s take the following example: 

If you find that one kg of methane is released due to your organization’s activities, you would multiply this by its GWP to get the CO2 equivalent: 

 1kg of CH4 x 29.8 = 29.8 kg CO2e.  

This helps standardize all calculations, so they are easily compared to previous calculations you’ve made or other organizations in your industry who are looking at the same greenhouse gases.  

Why the term carbon can be confusing

Carbon is one of the most common elements in the world, as it is found in all living things. It’s represented by the letter C and has an atomic weight of 12. It’s also one of the elements that, when combined with two molecules of oxygen, makes carbon dioxide.  

What can be confusing about carbon is many refer to their GHG emissions as carbon accounting, carbon emissions, carbon reporting, carbon footprint, etc. This is very misleading because people are actually referring to their total GHG or carbon dioxide emissions when using these terms. Don’t let the word carbon fool you!  

What's next?

It can be difficult to understand the many elements that go into your emissions reporting, but you’ve already taken the first step by educating yourself on the topic. Keep going! 

Get a better understanding of how to properly report on your organization’s GHG emissions with our eBook, GHG Reporting: How to Keep Your Investors and the Environment Happy. It’s time to strengthen your sustainability strategy to not only stay compliant with legislation but also make a more positive impact on the environment.  

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Author Dina Adlouni

Dina is a Content Marketing Manager at EcoOnline. She has been a content writer for eight years and has been writing about health and safety for the past three years. 

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