CO2e Units — What Is a Metric Ton of CO2e?
What's the 'e' in CO2e?
Carbon dioxide emissions make up only about 75% of total greenhouse gas emissions. Beyond carbon dioxide (CO2), the other quarter or so of emissions are made up of methane, nitrous oxide, hydrofluorocarbons, etc. Scientists have converted the global warming potential of all gases into carbon dioxide equivalents (CO2e), so that we have a single apples-to-apples unit to work with.
A note about units
CO2e is always measured in metric units. A metric ton (or tonne) is the equivalent of 1,000 kg — not to be confused with a 'ton' in the imperial system of measurement.
| Unit | In Metric Tons | In Kilograms |
|---|---|---|
| Kilogram (kg) | 0.001 t | 1 kg |
| Metric Ton (t) | 1 t | 1,000 kg |
| Kiloton (kt) | 1,000 t | 1 million kg |
| Megaton (Mt) | 1 million t | 1 billion kg |
| Gigaton (Gt) | 1 billion t | 1 trillion kg |
To give you a sense of scale, here are some common items and their corresponding approximate emissions footprint in CO2e —
| 🍔 | Producing a typical cheeseburger | 5 kg CO2e |
| 🚗 | Burning a full tank of gas in your car (~14 gallon tank) | 125 kg CO2e |
| ✈️ | Taking a roundtrip flight from NY to LA | 1 t CO2e |
| 🧍🏽♀️ | The average total footprint per year of an American | 18 t CO2e |
| 🏢 | Microsoft in 2020 (scope 1-3) | 11 Mt CO2e |
| 🌎 | World emissions 2020 | 50 Gt CO2e |