Aircraft carbon emissions estimations per passenger can be provided to individual travellers and corporations before the journey starts, so they can:
– Better understand part of the environmental impact of their trips
– Adopt strategies to minimise negative effects
– Decide to eventually offset the emissions they cannot avoid
– Use the information to report and manage these types of emissions
Travellers already can easily access a large number of independently produced aviation carbon calculators, developed by either NGOs, offsetting companies, international institutions, industry associations, academia, or a combination of all these. The problem is that currently, aircraft carbon calculators provide very different results for the same flight. We can classify the reasons for these variances into three groups:
1) Availability and use of relevant data
Some information required to estimate emissions is easily accessible, like distance between airports or aircraft type. Other data like aircraft configuration, load factors, engines, freight load, fuel burn formulas, etc… may not be accessible to the public. This is already a source of discrepancy between calculators.
For example, some calculators make rough assumptions on the length of the flight, like simply dividing flights into long, short or medium haul categories. Other calculators are more precise and consider the full great circle distance of the flight plus a factor to account for deviations from the “perfect” itinerary.
2) Need to make arbitrary decisions and/or simplifications
Based on the available data, each carbon calculator estimates the fuel consumption of the aircraft. We then need to calculate the emissions corresponding to each passenger/seat.
Some calculators provide emissions estimations per available seat, and others make the calculation per passenger boarded instead. Obviously the results in the estimated emissions vary significantly in these cases since generally any airline flight carries between 20 and 40% of available seats without passengers.
3) Scientific uncertainty
Unlike other types of greenhouse gas emissions, the effects of aircraft emissions depend on the altitude at which airplanes fly, the temperature and the humidity. In addition, aircraft emissions include not only CO2 but other substances. The scientific community hasn’t yet reached a consensus on the climate change effects of these non-CO2 emissions.
Currently, some carbon calculators include a multiplying factor to account for the non-CO2 emissions. This is obviously a source of significant variations in the results of calculators.
The table below shows the estimated CO2 emissions (kg) for a passenger on a round trip Madrid – Frankfurt obtained on some of the publicly available calculators (November 2013)
The consequences of the different results shown by carbon calculators are that basically:
– Travellers won’t be able to understand the impact of their trips, and why the calculators offer such different results.
– The credibility of any carbon calculator will be jeopardised. The proliferation of carbon calculators, rather than helping the situation, deteriorates it, since any calculator can be explained in isolation, but the differences between them make the whole system of carbon calculation questionable.
– Travellers won’t be so motivated to take action to reduce and/or offset their emissions as they would be in a situation in which all calculators offered the same results for the same flight or where there was one standard industry calculator.
– Corporations will be using significantly different sources of information when reporting their carbon emissions; therefore, it will be very difficult to compare the environmental performance between companies.
We believe there is a strong need to reach a consensus on the methodology and data used, resulting in a single carbon calculator used by all industry stakeholders.
Once an acceptable level of precision has been reached in estimating emissions, the problem becomes more a matter of compromise than one of precision.
The agreement should go beyond national borders. National legislation should also consider the international use of one single calculator.
The aviation industry has already witnessed the benefits of standard solutions in many areas of their operations, from the electronic ticket to the use of standard messaging systems. These standards reduce costs, help the cooperation between industry players and improve efficiencies. A similar logic could be applied to carbon calculators.
In our view, in order to reach the status of an industry standard, a carbon calculator should meet at least the minimum requirements of integrity, neutrality and global coverage.
At Amadeus, we selected to partner with the International Civil Aviation Organisation in 2009 since we believe ICAO complies with all aforementioned requirements. ICAO is the UN body that takes care of civil aviation and is formed by 191 member states. Today, the estimations from the ICAO calculator are available in our distribution platforms.
Finally, we believe that the subject of climate change should not be a reason to compete among industry stakeholders, but instead should serve to unite towards one common goal. In this respect, the efforts made by our competitors, by airlines, by industry bodies and by NGOs are very plausible. We would like to continue building an industry-wide forum to discuss the implementation of one single accepted carbon emissions calculator.
*Tomás López Fernebrand is the Senior Vice President, General Counsel and Corporate Secretary of Amadeus IT Group.