ICAO launches its carbon emissions calculator and provides full details on methodology used
Fri 13 June 2008 – The International Civil Aviation Organization (ICAO) has finally launched its carbon emissions calculator and provided a general description of the methodology used in the approach. It has been provided in an open-source format that will facilitate individual air carriers that may wish to customize it with their own data.
In a downloadable PDF document, a general description is provided of the methodology adopted by ICAO in order to estimate the CO2 emissions of a flight; the detailed calculation process implemented by the calculator; a description of the data coverage and sensitivity; and the steps needed to be taken by a company wishing to customize the calculator with its own data set.
The methodology has employed a distance-based approach to estimate an individual’s aviation emissions using data currently available on a range of aircraft types. ICAO used what it describes as the best publicly available data regarding fuel consumption and has committed itself “to continuously monitor and seek improvements in the data used in order to obtain better emissions estimation.”
ICAO says that as passengers’ aviation emissions are affected by continuously changing variables specific to each flight, it has been necessary to develop average factors to account for the effect of these flight parameters.
When the user inputs the airports of origin and destination for a direct flight, the calculator compares with published scheduled flights to obtain the aircraft types used to serve the two airports concerned and the number of departures per aircraft. Each aircraft is then mapped into one of the 50 equivalent aircraft types in order to calculate the fuel consumption for the trip based on the great circle distance between the two airports.
The passenger load factors and passenger to cargo ratios, obtained from traffic and operational data collected by ICAO, are then applied to obtain the proportion of total fuel used which can be attributed to the passengers carried. The system then calculates the average fuel consumption for the journey (using information obtained from the CORINAIR database), weighted by the frequency of departure of each equivalent aircraft type. This is then divided by the total number of economy class equivalent passengers, giving an average fuel burn per economy class passenger.
The result is then multiplied by 3.157 in order to obtain the amount of CO2 footprint attributable to each passenger travelling between those two airports.
ICAO has placed a link on its home page to the calculator, which in turn has links allowing for the downloading of the methodology and inviting comments on how the calculator can be improved.