Flight CO₂ emission formula
As much as the planes are efficient, the distances traveled are large, so the emissions of CO₂ are large as well. It's estimated that from 1 kg of fuel there is more than 3 kg CO₂ emitted. To compute the emissions, we take in the account the following factors:
Amount of CO₂ emitted per one hour of flight per one passenger. We assume, based on the analysis of www.carbonindependent.org, that it is equal to 90 kg/hour per passenger.
Seat occupancy: the previous value assumes that the airplane is full. This is rarely the case. Worldwide, on the average, the seat occupancy on a regular passenger flight is around 80%. That's the value we take. You can modify it in the advanced mode.
Duration of a flight: having emissions per hour, we need the duration of the trip to compute the emission along the whole journey.
Radiative forcing factor: finally, the emission takes place high in the atmosphere, and that's precisely where we don't want the CO₂ to be because of its greenhouse effect. To account for that, we include a radiative forcing factor. We take its value to be 2, based again on the analysis from www.carbonindependent.org.
The final formula is
Emitted CO2 = Duration_of_flight * Emission_per_hour_per_passenger * Radiative_forcing / Seat_occupancy
If you fly there and back you have to double the emission. We can do it for you. Just change the Flight option from One-way to Return.
Choose your holiday destination, and you got a bunch of tonnes of the CO₂. What does it mean? To put this number in a context, let's get back to the beginning. Why do we care about the CO₂ emissions? Because of the global warming. CO₂ is a greenhouse gas meaning that once it is high in the atmosphere it works like a ceiling of the greenhouse: it lets the heat in but does not let it out. The IPCC estimated that to keep the global warming under some control, the increase of the average temperature by 2 degrees in the year 2050, emission per every person on the earth must stay below 2500 kg of the CO₂. Annually.
Our daily choices impact the environment and us: our Kaya identity calculator can help you quantify that impact. If you wonder whether to travel by a car or a bike the Car vs bike calculator might help you make your mind. More of a flying fan? With Flight radiation calculator you can check how much radiation the sky traveling gives you.
Miłosz Panfil, PhD