Environmental Change Institute, University of Oxford

Calculating The Carbon Dioxide Emissions of Flights

flight trails

Calculation of aviation emissions is becoming more common both for personal offsetting and businesses' corporate social responsibility reporting. However, there are many different emissions calculators that have been developed, each with their own assumptions and approaches, meaning there is widespread inconsistency between different calculation methods.

The ECI has evaluated a sophisticated methodology developed by Sabre Holdings, which is comprised of companies that retail travel products and provide industry leading travel distribution and technology solutions, and sees the potential for the Sabre methodology to become the industry standard. Previous emissions calculators calculate CO2 based on the distance between airports and a series of assumptions about what would be a 'typical' plane for that flight, and how many seats there would be, on average, on board. This means a flight from london to New York would be identical irrespective of what model of plane was used, or how many seats there were on board. However, because Sabre Holdings run the booking system, they know the exact model of plane flown and the seating configuration on board, meaning this approximation can be removed. This will allow:

  • CO2 values for an individual flight, with and individual carrier to be calculated
  • CO2 values to be presented to the customer at point of sale, allowing them to purchase the most environmentally benign flight.
  • Create a market pull to encourage flight operators towards more efficient planes and denser seating configurations
  • Improve the sophistication of corporate emissions reporting. At present a company wishing to reduce emissions is faced with the choice of 'fly' versus 'don't fly'. Now if they choose to fly, they can choose low-carbon flights as a corporate policy and see this reflected in their CSR reporting.

Further Links

Jardine, C.N. (2009) Calculating The Carbon Dioxide Emissions of Flights. Final report by the Environmental Change Institute

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