When we left our Parisian life back in 2016, we also said “goodbye” to our routine of eco-friendly city dwellers – a shame, you tell us, when we often went on flying trips . We admit it: we didn’t question ourselves about our flights impact and then, as we read somewhere “driving cars pollute more than flying”, or “we pollute less by flying once a year than our neighbor who takes his car every day”. Fake news, truths?… After two years on the road, we wanted this time to be sure: studies reports, calculators, calculation methodologies… We screened all the data found to make them speak – and tell you why we stopped flying!
This post is not meant to be moralistic, but tries to provide answers and solutions. In any case, nobody will take the rusty plane that illustrates this article, a Yak-40 from Aeroflot (in Osh, Kyrgyzstan)
Online calculators: CO2 emission balances by each transportation
To start this reflection, we have done a lot of research on the available data on greenhouse gas emissions. Warning! Lists of numbers that follow may seem very boring, perhaps not realistic at all: we are only transcribing here available data from different sources.
If you are not interested, you can skip this table below:
It’s a Swiss calculator used for the calculation of CO2 emissions (site available in French, English, German). A simulation gives us for example:
– 190 g CO2 /km for a return flight Paris – New York
– 200 g CO2 /km for 5000km with a regular car
Note: the calculation takes into account only one passenger per car (the driver). On the website, calculation method is clearly detailed: it includes for cars emissions due to their production and fuel, and for flights production of fuel and a factor of 2 – considering the condensation trails.
The foundation of Yann Arthus-Bertrand, a famous nature photographer, has also created its own online calculator (site available in French & English). It’s based on the Bilan Carbone® methodology developed, among others, by french association ADEME and distributed by Association Bilan Carbone (A.B.C) which also proposes MOOCs to understand and calculate our carbon footprint. A simulation gives us for example:
– 240 g CO2 /km for a return flight Paris – New York
– 230 g CO2 /km for 5000km with a regular car
Note: the calculation takes into account only one passenger per car (the driver).
It’s the official calculator of the French General Directorate of Civil Aviation, a department attached to the Ministry of Transport (site only in French). On this page we can read that 1 ton of CO2e represents:
– a return flight Paris – New York (12000km), ie 85g CO2e /km
– or an equivalent of emissions produced by an average car in France to cover 5000km, ie 198g CO2e / km
Note: the calculation takes into account only one passenger per car (the driver). CO2e (CO2 equivalent) corresponds to cumulative greenhouse gases (CO2 and others) and is calculated as follows: “X g CO2e” = “X g CO2” x 1,22
ADEME (Agency of Environment and Mastery of Energy) is a French association which finances studies. It also had an online calculator, as well as figures on the emissions of different transports. Here are some data from this source:
– Electric car : 22 g CO2/km
– Long-haul aircraft : 118 g CO2/km
– Diesel car of medium size: 127 g CO2/km
– Bus: 130 g de CO2/km
– Fuel car of medium size: 135 g CO2/km
– Domesctic flight: 145 g CO2/km
– SUV: 250 g CO2/km
Note: only CO2 emissions from public transport are estimated per passenger according to an average filling rate. Regarding cars, you need to divide by the number of passengers!
For the electric cars, data are to be put into perspective (calculation for France where 80% of our electricity is of nuclear origin and doesn’t include the pollution generated by batteries…) This number is perhaps a little bit outdated, but still interesting to get an idea of magnitude order of CO2 emissions by transport.
Have you noticed some discrepancies between these sources?
Isn’t it surprising to discover that cars emit more than double CO2 / km compared to planes, according to an official calculator of DGAC (an entity attached to the French Ministry of Transport)? Which calculator, which methodology can we trust?
Good question. In any case, data used by some calculators or articles claiming that cars are at least as much polluting as planes (link here) often don’t take into account several essential factors:
- Filling rate of car: in reality, we rarely go on vacation 1000km from home, all alone at the wheel! Taking the example of a family of 4 people or a car filled by carpooling, CO2 / km emission will have to be divided by the number of passengers seated in the car (to have the same reference as airplane or other public transport).
- Worsening effect of greenhouse gases due to condensation trails (contrails): it would be necessary to add a coefficient of at least 2 to the global footprint of aircraft, according to the latest data.
… as well as hidden ecological costs, such as:
- Pollution generated during production of vehicles and fuels (with the exception of the MyClimate.org calculator),
- Consumption of products on board: single use plastic, meal trays, wipes, packaging etc.
- Carbon footprint of aircraft crew and all the staff necessary for the proper functioning of an airport, to get them to their working place…
Note: We will not talk about other types of pollution, such as fine particles (that a car emits more per kilometer compared to an airplane). Why? Because these pollutions have a different action: fine particles are involved in the health problems, but here we are interested in pollution and mainly the one involving CO2, which is the current reference indicator to evaluate the global warming (gas effect Greenhouse).
Plane as a means of transport: an underestimated impact
In fact, whether by car or plane, the difference between CO2 emissions emitted by one or the other is not huge. What makes the difference is the journey distance: nobody thinks to drive 12,000 km to spend a week of vacation!
Let’s take an example of a Parisian family of four. For their summer holidays, they hesitate between going to New York by plane (around 20 hours of travel time) or getting off in the Spanish coast by car (same travel time):
| PARIS | travel mode: flight | NEW YORK |
| 20 hours | 12000 km | 2000kg CO2 /person |
| PARIS | travel mode: car | BARCELONA |
| 20 hours | 2200 km | 100kg CO2 / person |
* Order of magnitude for a round trip “door to door” and a CO2 emission expressed per person (average of the 3 calculators described above)
With an equal travel time (20 hours), the number of kilometers is not the same at all: plane can lift people thousands of kilometers in a few hours, but these kilometers traveled make you have a higher impact on the environment. And if, instead of calculating our CO2 emissions per kilometer, we calculate them per hour of travel? With the above example of our family of 4, this would give:
Flight: 100Kg of CO2/hr/passenger
Car: 5Kg of CO2/hr/passenger
We stopped flying: a personal choice
When we left France without taking a flight, we wanted to combine our passion for travel with our ecological convictions. As I said in the introduction, we didn’t realize yet how much air travel could pollute… It was only when we made our overview after years on the road that we started to look at the numbers: with an equivalent distance traveled by hitchhiking, we issued about 233 kg / person against 1.2 Ton / person if we had flown!
But let it be clear: we don’t want to make you feel guilty, nor to give you moral lessons. If you read us, it’s because we share a passion for travel! And even if we wish, ideally, not to travel by plane, it will certainly arrive one day when we will use a plane – nobody is irreproachable!
If we want to remind you of this, it’s because often by starting the discussion about flights and its ecological impact, we find ourselves in a dead end – with on one side people who are well aware of the problem and have changed (or not!) their way of traveling, and other people in denial, who try to justify themselves by putting forward arguments that are not always relevant. Here is a small anthology of what we have heard, with our detailed answers:
Even if we don’t like the habits of your neighbor Kevin, by using his car daily to make 2 kilometers whereas you decide to make a round-trip by plane in New-York once a year, your holidays will generate a lot more pollution than Kevin’s ride… Let’s do the math:
– 200 gr CO2 /km x 365 x 2 km = 146 kg CO2 /year for your neighbor Kevin
– A round trip Paris – New York = 2000 kg CO2 for you!
Note: we took the average CO2 emissions of the 3 online calculators for this calculation. It also doesn’t take into account the fact that first kilometers made by car emit much more CO2, but the final result (with a factor of 10 difference between the two!) will not change much…
First, we would like to sincerely congratulate you and support you in your efforts: eat vegetarian food and take your bike for short distances, it’s as good for the environment as for health!
But as you suspect, by flying once a year you cancel all your daily efforts (we don’t say that to discourage you and make you stop your efforts in favor of ecology, on the contrary!). The biggest polluter is not necessarily the one we believe in…
As the author of the excellent article “Demography and Climate” (which you are invited to read) says: “The vast majority of humanity’s ecological weight comes from the rich countries with low fertility, and population growth in poor countries will not change much“.
We should stop making future parents feel guilty in their fight against global warming, and review our transport habits once and for all!
That’s true, but who elects politics in our developed countries and buys the products / services of the industry? So, you and I are polluting too – and not just a little: about 15% of greenhouse gas emissions come from individuals… But if, instead, we start to review all our way of consumption (from our plane trips to products from this industry that we consume)?
Choosing to live with a reasoned consumption is far from to go back to the Stone Age; it’s even a beautiful form of Evolution when you understand the Climate crisis! On the other hand, trying stubbornly to live a society based on hyper-consumption and infinite growth (which our interlocutor seems to appreciate) with limited ressources, it’s in our opinion a very regressive behavior. As for everything, to make things working, you have to find a wining balance: in a modern world, you can totally learn to travel without plane!
Yes… and no! If you know the principle of supply and demand, you would know that if there was a drastic drop in demand, airlines would be forced to close lines to continue to be profitable!
True, digital communication and technology industry account for about 2% of global CO2 emissions (source: climatecare.org) – ie. a little less than aviation sector, which accounts for around 3-4% of global CO2 emissions. That said, you don’t have to be good at math to understand that a person who uses Internet but doesn’t take flight pollutes less than a person who uses Internet AND the plane!
Some companies now offer to offset your emissions when you purchase a flight ticket, on the same principle as MyClimate or GoodPlanet.
Of course it’s better than nothing, but it doesn’t solve much! This is the famous dead end of “infinite growth with limited resources”.
We agree, if you’re here it’s because we have a common passion for travel… Fortunately, there are alternatives to flying to travel and improve its ecological impact: you must read our great guide about traveling without a flight!
Where there is a will, there is a way! Have you thought of going less far, or using other means of transportation?
According to MyClimate.org:
– We shouldn’t exceed to emit 0.6Ton CO2 / year / person to stop global warming
– A citizen of European Union emits on average 8Tons of CO2 / year
Which solutions to fly less?
Traveling less far and/or much longer
Going on a weekend in Europe thanks to a low-cost flight: the idea is tempting, but the carbon footprint is enormous! Almost twice as much CO2 emissions / km as a long-haul!… The solution: revisit your way of traveling, by favoring closer destinations for weekends, or by traveling far away but for a longer period of time (days off accumulation for long holidays, combination with a combination of two neighboring destinations rather than 2 return trips, etc.).
Change your transportation habits
This is also the conclusion of Clement, Julien’s little brother and a backpacking engineer when he shared his thoughts on transport and ecology: in order to limit our impact while traveling, we must first begin to learn about existing different transportation means, the pollution they generate and at the end, build our own opinion on the subject. If you are interested by the subject, here is a small list of useful links:
- How to organize a trip without flying and what are the alternatives?
- Tips to have a sustainable behaviour (first part)
Stay grounded
It’s what we are doing since we left France, and we only see advantages! If the “stay grounded” movement rings a bell to you, you can visit the websites Stay Grounded and StayOnTheGround… and at the same time sign their petition “I stay on the ground”!
Useful link:
* Post written according to our personal experience *