Travel Emissions: How to Know Your Mobility Footprint

“Would you like to offset your carbon emissions from this flight?” This question may sound familiar if you recently booked a flight. For example, for a fixed amount, the travel agency offers to plant some trees for you. A great idea. Flying causes a lot of carbon emissions, contributing to climate change. The least you can do is compensate for it. But how do we know just how much CO₂ a plane emits? And what about other means of transportation? This article tries to shed some light on how to calculate your travel emissions.

Transportation emissions are a significant contributor

First of all, transportation is a significant contributor to carbon emissions. As an example, here is a breakdown of Dutch household emissions. Figures for other countries may be different, but this is a solid indicator for developed countries in general.

We can see that transportation causes one-fifth of total emissions. Please note that ‘transportation’ only refers to travel, or to the mobility of people in the household (commuting, vacation, etc). Emissions caused by the transportation of goods are included in the calculation of the other categories. For instance: home delivery of your brand new shoes is included in the ‘clothing and stuff’ category, not in ‘transportation’.

Calculating your personal transportation emissions

Of course, the above figures are on average and are not helpful in calculating the emissions for your personal travel pattern. For example, it matters greatly if you are a frequent flyer or not. Almost 40% of average household transportation emissions are caused by flying. If you never fly, your CO₂ footprint will differ a lot.

A rough estimate of your emissions

If you are happy with a general impression of your emissions, you can simply try this Scone Calculator. We will estimate your emissions based on your mobility pattern, the size of your car and the type of fuel you use, and the number of flights you take. Scone will also offer the option to compensate your CO₂ emissions.

A rough estimate of your travel emissions

If you would like to zoom in more on your yearly travel emissions, you can list your means of transportation and the number of kilometres you travel with each. When looking at the emission of one tonne of CO₂, we can easily see the enormous difference between the means of transportation.

To emit one tonne of CO₂:

• You have to drive a gasoline car for 5000 km
• You can only take one long-distance flight of 6000 km
• You have to travel 30,000 km by public transport.
• You can ride your bicycle for eternity

Put the list above next to your personal list of travelled kilometres to help you get an impression of the alternatives. Did you notice how close a car and a plane are in terms of emissions? That is, if you’re travelling solo. But when it comes to taking the family on vacation, going on a road trip is much better than flying with the whole bunch. If you’re already enjoying the idea of taking your people on a road trip, keep that thought but make it lazier; let the conductor do the driving by taking the train!

Here is a more extensive list of mobility options, with emissions per kilometre travelled:

Getting even more serious: how to specify and track your mobility

The above calculations will do in most cases. It allows you to make a rough estimate of your travel emissions. But it is still a rough estimate.

Looking to be more specific? You might want to know the emissions for your car instead of cars in general. All the emission figures above are based on averages, but there are huge individual differences between cars. Whether you drive a 2011 Jeep Grand Cherokee for short distances in the city or your 2020 Volkswagen Golf for longer trips on the highway matters: your Jeep will emit at least tenfold and maybe even thirteenfold more than the Volkswagen (306 grams versus 26 grams per kilometre on average). If you want to do the calculations for your own car(s): Cars & Travel has a detailed list of emissions for various brands and models.

Looking for serious lifestyle changes? If you want to change your mobility patterns, it is highly encouraging to keep a record of your emissions on a weekly or monthly basis. The Scone app allows you to automatically keep track of your mobility and related emissions. See it as a competition with yourself to lower your mobility footprint every month.

Your indirect travel emissions

We have been talking about travel emissions, but we didn’t mention one pretty important thing. In the data above, not all emissions are taken into account. Take flying for example: you can calculate carbon emissions by just looking at kerosene use. That is what we have done in this article. But what if we also look at the emissions caused by building the plane? Or what if we take into account the emissions related to building and maintaining entire airports? The same goes for trains and the infrastructure needed, like train stations and railways.

The problem is that calculating so-called indirect emissions is extremely complicated. What are the emissions related to constructing an airport? How do you even begin to attribute it to individual flights? It is easy to see why many people choose to leave those factors out in footprint calculations. But we have to be honest about this issue. And when it comes to electric driving, honesty may help us to stay away from overly enthusiastic conclusions. Because your electric car does not have zero emissions. But that is a topic for another day.