It seems that whenever environmental concerns over aviation emissions become mainstream, some disaster overtakes the industry and survival, rather than going green becomes the primary goal; in the mid-2000’s, environmental pressure groups got an easy solution to reduced aviation emissions in the form of the Global Financial Crisis and now, Covid-19 has seen airline timetables decimated, with flight and passenger numbers down by over 90% in many cases.

Overall emissions from air transport have plummeted as a result, but for those still flying, the individual environmental cost has actually risen. Offsetting your flight in 2020 should have been more expensive than it was in 2019 if your carbon calculator was able to adapt; if it wasn’t, then congratulations, you received a discount that you probably didn’t ask for. Here’s what should’ve happened.

In general, most of the fuel that an aircraft burns in flying from A to B is used up in getting itself to B. Most of the weight it has to carry is itself, although the passenger load does contribute to the weight, and therefore the amount of fuel used. Consider a typical B737-800 on a typical sector with a typical Low-Cost Carrier (LCC) load factor (in normal times) of around 95%, or 178 passengers. This passenger load could make up over 20% of the take-off weight of the aircraft, but that still means that the vast majority of the weight required to get to B isn’t passengers, it’s the aircraft and the fuel.

In the times before the pandemic, this typical LCC passenger would need to offset around 107kg of CO2 for a typical UK-Spain leisure routeing, assuming no radiative forcing effects. Because LCCs are adept at filling their aircraft, the fuel used can be spread over lots of passengers, and so it’s the most efficient way of transporting these passengers between A and B on this type of aircraft. But then came the pandemic, and quite a few things changed.

Even though airlines only flew a fraction of their normal schedules, load factors across the board are well down on pre-pandemic levels, meaning aircraft are emptier than before. Even the best in the industry struggled to achieve average load factors much above 70% in the second half of 2020; in our example, that means a reduction down to 134 passengers, or 44 fewer than before on our B737-800. The weight of passengers onboard isn’t as high as before, and the aircraft can burn a bit less fuel as a result, but the aircraft itself still weighed the same, so still needs roughly the same amount of fuel to get to B as it did before. But this time with 44 fewer passengers over which to spread the total emissions.

The service is now not as efficient as it was, flying around a load of empty seats with only a bit less fuel needed. The typical passenger should now pay more to offset their CO2 for the journey from A to B – almost 25% more, it turns out, as the pandemic has raised the offset amount to around 134kg of CO2 per passenger.

Example emissions per pax with decreasing load factors

Although overall emissions from air transport were well down in 2020 (and continue to be in 2021), emissions expressed on a per passenger basis will in most cases have gone up, meaning any passenger who offset their CO2 should be charged more than they were in 2019. But only if the calculator he or she used was able to keep up with the effects of the pandemic.

At RDC, our solutions for calculating flight, seat and per passenger emissions are flexible enough to account for changing in the market place, such as lower load factors, while retaining the accuracy needed to justify our methodology’s accreditation for use in the UK Government’s Carbon Offsetting Quality Assurance Scheme. Get in touch to find out how we can help you deliver on your aviation environmental data needs.


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