Carbon Footprint Explained: What does CO2e mean?

CO₂e stands for “carbon dioxide equivalent,” which is a metric used to compare the impact of different greenhouse gases on climate change. It is a way to express the global warming potential of various greenhouse gases relative to carbon dioxide (CO₂), which is taken as the standard reference with a value of 1.

 

Greenhouse gases are gases that trap heat in the Earth’s atmosphere, leading to the greenhouse effect. The most common greenhouse gases include carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulphur hexafluoride (SF₆) and Nitrogen trifluoride (NF₃).

Each greenhouse gas has a different global warming potential (GWP), which measures how much heat a particular gas can trap in the atmosphere compared to the same amount of CO₂ over a specific time period (usually 20, 100, or 500 years). For example, methane has a much higher GWP than CO₂ but has a shorter atmospheric lifetime.

Here are some common greenhouse gases and their GWPs over a 100-year period:

• Carbon dioxide (CO₂): GWP = 1
• Methane (CH₄): GWP = 28
• Nitrous oxide (N₂O): GWP = 265
• Hydrofluorocarbons (HFCs): GWP = 4 – 12,400 (GWP varies depending on the specific compound)
• Perfluorocarbons (PFCs): GWP = 6,610 – 23,500 (GWP varies depending on the specific compound)
• Sulphur hexafluoride (SF₆): GWP = 23,500
• Nitrogen trifluoride (NF₃): GWP 16,100

When calculating the CO₂e of a particular emission source or activity, the emissions of different greenhouse gases are converted into an equivalent amount of CO₂ based on their presence and GWPs. For example, if you emit 1 ton of methane (CH₄) into the atmosphere, its CO₂e would be 28 times that amount.

The accumulation of greenhouse gases in the atmosphere, primarily CO₂, CH₄, and N₂O, leads to an enhanced greenhouse effect. This causes the Earth’s temperature to rise, leading to climate change. The impacts of climate change include rising global temperatures, more frequent and intense heatwaves, melting glaciers and polar ice, sea-level rise, altered weather patterns, and more severe weather events such as hurricanes and droughts. These changes can have significant consequences for ecosystems, agriculture, water resources, and human societies.

Reducing greenhouse gas emissions, is crucial to mitigating climate change and limiting its negative impacts. Governments, organizations, and individuals needs to work together to develop strategies to reduce emissions and transition to cleaner and more sustainable energy sources to tackle this global challenge. The current national policies and plans are not sufficient to avoid the worst impacts of the climate change. Hence, it is crucial that organisations adopt highest possible ambition to rapidly reduce their greenhouse gas emissions.