Flight Emissions Calculations
Photo ‘Landing in London’ by Dave Sag and used with permission.
Carbon Planet has always been dedicated to openness and transparency. When dealing with a subject as complex as carbon, and the various ways and means by which emissions are calculated, we’ve always felt that the more information we can share with the world, the better for all. So I’m very excited to announce that we’ve released the underlying research that underpins our highly acclaimed flight emissions calculator under the Creative Commons ‘Attribution-Noncommercial-Share Alike‘ License.
This means you are free to to copy, distribute and transmit the work, and if you find errors, or need to adapt it to your own local circumstances you may adapt the work. However if you do this you must attribute the work using the words “Derived from the Flight Emissions Calculator by Carbon Planet – flights.carbonplanet.com” (but not in any way that suggests that Carbon Planet endorses you or your use of the work). If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.
Note also this is a noncommercial license so you may not use this work for commercial purposes.
Carbon Planet’s flight emissions calculator uses the best available science to determine the most accurate level of emissions for your flight.
What factors need to be considered?
There are, in fact, several different constituents, depending on the length of the flight:
Variance in emissions per passenger/km for short-, medium- and long-haul flights is attributable to increased emissions required for takeoff, taxiing and idling (i.e. the shorter the flight, the higher the proportion of fuel used for takeoff, taxiing and idling), as well as to the different types of passenger crafts used for different flight lengths.
Because the Earth is curved and planes don’t fly in vectors between two points, the distances are calculated using an approximation formula (i.e. the Great Circle Distance Formula) described at meridianworlddata.com: How to calculate the distance between two points on the Earth
The radiative forcing index:
Aviation’s impact on climate change is not due to CO2 emissions alone; other greenhouse gases, including NOx compounds, ozone, methane, water, contrails and particles, are emitted from aircraft exhausts with CO2 simultaneously.
With these compounds released directly into the atmosphere, their potential harm to the anthropogenic radiative force exerted in this area of the Earth’s atmosphere is much greater than terrestrial fossil fuel combustion, mainly because of the longer residence times required for the latter.
Such an effect is taken into account by the development of the radiative forcing index (RFI) which compares the effect caused by combustion of fuels at air traffic height, to that of the CO2 emissions alone.
The radiative forcing index is internationally agreed upon to be approximately 1.9. This means that the effect of an aircraft’s emissions when they are released in the atmosphere has approximately 2 times the warming potential than the same production of emissions would have — if the aircraft were on the ground.
Economy vs Business and First Class:
Passengers who fly Business Class occupy more cabin space and consume more resources than those who fly Economy, with passengers in First Class occupying and consuming the most aboard the aircraft.
Passengers flying long haul international Business Class on average are responsible for twice as much GHG emissions than from those traveling Economy Class; emissions from flying First Class are three times higher.
The paper ‘GHG Emissions Resulting from Aircraft Travel‘ is available for download at the bottom of flights.carbonplanet.com. — DS