Flight Emissions

First, the distances are calculated between the airports selected, using the greater circle method: we compute the distance in Km from longitude and latitude using the haversine formula (cf. https://en.wikipedia.org/wiki/Haversine_formula).

Then we can use the factor emission (cf. next section) to get our first estimation per equivalent person:

• Emission = Distance * Factor
• [kgCO2e/year] = [Km/year] * [kgCO2e/km]

Finally, we add a factor depending on the class of the seat taken (economy class, business class, first class). Connections are not taken into account.

Emission Factors

We use the last version of the carbon base data (2021) from he French Agency for Ecological Transition (ADEME) which uses an emission factor expressed in kgCO2e/peq.km (peq = person equivalent):

• Short-Haul: 0.141
• Medium-Haul: 0.102
• Long-Haul: 0.083

Note: they use actual air traffic consumption data provided by the Directorate General of Civil Aviation (DGAC) - https://www.bilans-ges.ademe.fr/fr/accueil/documentation-gene/index/page/Aerien2 to compute those factors.

Note bis:The data only focus on classic airliners, able to carry both passengers and cargo and does not take into account the Radiative Forcing Factor.

Short-Haul - Medium-Haul - Long-Haul

Airliners are classified as short medium long haul, however this definition is not standardized. We use the same rule used by the emission factor source (cf. ADEME documentation link):

• Short-Haul: < 1.000 Km
• Medium-Haul: < 3.500 Km
• Long-Haul: < 20.000 Km

Seat Types

Emission factors were calculated according to the number of passengers a flight transports. A first class seat would occupy a larger area compared to an economy class equivalent per passenger and therefore attribute to a larger percentage of the overall planes emission.

For the seat type factor we compute them from the UK Government source (https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019). We average the deltas between classes (grouped by Haul):

• Economy: 1
• Business: 2.2
• First: 4

Note: The distance definition for the haul classification from UK does not stick perfectly to the one from ADEME but are more than enough close for the estimation (700Km - 3700Km).

National Average CO2 Emission

Our national co2 emission average "getEmissionAvg()" give us:

• 130 kgCO2e/year (by person)
• 126 kgCO2e/year (by passenger)

Those constants come from the:

Directorate General of Civil Aviation (DGAC) - Emissions from TARMAAC source commercial aviation, including APU, are considered here (https://eco-calculateur.dta.aviation-civile.gouv.fr/les-chiffres-cles):

• Emission: 2,44 mtCO2e
• Passengers: 179.6 millions
• Flights: 1,57 millions

As well as the The National Institute of Statistics and Economic Studies (INSEE) - which collects, analyses and disseminates information on the French economy and society (https://www.insee.fr/fr/statistiques/5225246#tableau-figure1):

• Population: 67,626,396