Global climate change caused by our fossil fuel emissions is forcing us to assess many aspects of our behaviour. Flying is a particularly sensitive example because we have become accustomed to hopping on an airplane and dashing off at 700 or 800 kilometres per hour to some foreign country for the taste of another culture, for a change of scenery, for a family gathering, for an exotic adventure, or for a routine business deal. Not only are we destroying the uniqueness of the place that we came to experience by homogenizing the entire planet—the source of Yogi Berra’s oxymoronic comment that, “Nobody goes there any more. It’s too crowded.”—but flying happens to be the single most polluting activity over which any single individual has control. This is because flying is a choice. So the subject of flying and its contribution to the 37.4 billion tonnes of carbon dioxide emissions in 2023, although uncomfortable, deserves some consideration.

Here are some calculations of each passenger’s individual contribution to atmospheric carbon dioxide by taking a return flight from Vancouver B.C. to various destinations:

• London, England – 7581 km = 3.0 tonnes
• Brisbane, Australia – 11,869 km = 4.6 tonnes
• Beijing, China – 8513 km = 3.4 tonnes
• New York, USA – 3905 km = 1.52 tonnes
• Toronto, Canada – 3360 km = 1.32 tonnes
• Puerto Vallarta, Mexico – 3551 km = 1.4 tonnes

This is a complex subject, but the amount of carbon dioxide emitted by flying is dependent on the length of the flights and the altitude at which they occur. Because of the large amounts of energy required in taking off and landing, short flights are the least efficient. However, once airborne, these planes fly at lower altitudes, causing less atmospheric pollution than the “radiative forcing” and the condensation trails occurring with the stratospheric flying of international flights.

The carbon dioxide output, measured in grams per person per kilometre, is usually calculated by assuming that the aircraft is filled to 80% of its passenger load. A short flight, considered to be less than 463 km, produces 257 g/p/km. A medium flight of more than 463 km produces 177 g/p/km. And longer flights at high altitudes produce 113 g/p/km. But these figures will vary according to many factors. Another calculation, based on the efficiency of a Boeing 737-400 flying at 780 km/hr is 115 g/p/km, but this calculation does not include the effects of “radiative forcing” and condensation trails, which almost double the heating effects on climate.

A more thorough BBC calculation estimates 133 g/p/km for domestic flights, but adds 121 g/p/km for “secondary effects”, bringing the total to 254 g/p/km. For long flights, it calculates 102 g/p/km but adds 93 g/p/km for the effects of high altitude flying, bringing the total to 195 g/p/km. This 195 g/p/km is the CO₂ output that has been used to calculate the tonnes of carbon dioxide produced per person by flying to various destinations from Vancouver.

Generally, of the 37.4 billion tonnes of carbon dioxide added to the atmosphere in 2023 from burning fossil fuels, about 1.1 billion tonnes came from transporting 4.1 billion air passengers locally and internationally, a number that is expected to double to 8.2 billion by 2035. If this number seems large, consider that on the single day of August 11, 2023, Air Travel Statistics reported that the flying public occupied 18,586,233 airplane seats, compared to 13,967,001 on January 21, the lowest day of the year.

For comparisons, the average person breathes out about 1 kilogram of carbon dioxide per day, so the daily CO₂ output that we each contribute to exist, using the 195 g/p/km measure, is added to the atmosphere for every 5 kilometres or 26 seconds of flying. The average weight of an Asian is about 60 kg, a North American is about 80 kg, and a car is about 1.5 tonnes. So, drive to the airport, fly to Puerto Vallarta and back for a quick winter holiday, then drive home again, and your contribution to the amount of atmospheric carbon dioxide will be close to the weight of your car. Fly to England and back, and it will be about twice the weight of your car. Notably, this CO₂ is added to the extremely thin layers of the troposphere and stratosphere that average about 1/500 the diameter of the Earth and provide most of our atmospheric heating and weather.

According to the calculations of climatologists, the output of carbon dioxide needed for climate stability will have to be about 2 tonnes per person per year for the global population. It is presently about 5 tonnes per person, but this output is clearly not distributed equally around the planet. And given that only about 10% of the world’s population flies, then the implications become clear when considering a flight to anywhere at any time.

Ray Grigg for Sierra Quadra

Top image credit: Out my window -Photo by Kartik Chaturvedi on Unsplash