What is "Carbon Dioxide Equivalent (CO2e)"?

Carbon Dioxide Equivalent (CO2e) is the unit of measurement for the warming effect of greenhouse gases.

There are many different greenhouse gases of which carbon dioxide is the most widely known. Different greenhouse gases affect the climate in different ways. Some stay in the atmosphere for a long time but do not cause as much warming per kg emissions, like carbon dioxide. Others, like methane, heat the earth a lot, but do not stay very long in the atmosphere.


CO2e is the exchange rate of other greenhouse gases to carbon. The exchange rate (called Global Warming Potential, GWP) expresses how many kg of carbon dioxide emissions warm the climate equally as 1 kg of another greenhouse gas, over a certain period of time (usually 100 years). CO2e translates the potency, how much infrared radiation a ton of each gas absorbs, and longevity, how long a ton of each gas radiates the heat back to the atmosphere, in relation to the emissions of a ton of carbon dioxide. It allows us to compare and equate the effect of different greenhouse gases into a singular climate footprint! By knowing the GWP of different gases the total climate impact of a product can be condensed into one single unit: kilograms of carbon dioxide equivalents (kg CO2e).