What is your carbon mileage?

Which decisions make the biggest real difference to your transport-related carbon footprint? Do you need to sell your car and give up holidays?

This guide provides an in-depth analysis of the greenhouse gas emissions of transport and provides some tips for reducing your transport-related greenhouse gas emissions.

Transport contributes around one fifth of global greenhouse gas emissions, making it a big part of the climate change problem (and its solution).

To get a better understanding of transport-related emissions overall, let's firstly break down the main sources:

Breakdown of global transport-related greenhouse gas emissions

While this chart provides an overview of the breakdown of the total emissions problem, it isn't the best way to compare their emissions intensity as some modes are more widely used than others.

To compare the emissions of different transportation modes more fairly we instead need to compare their relative emissions per distance travelled by each passenger as shown below.



Flying represents one of the most emission-intensive ways of travelling, particularly over short distances where the high fuel consumption required for take off increases the emissions per distance travelled. The only reason flying doesn't represent a larger share of global emissions is that flying remains a luxury for a very small number of people, with only 10-15% of people in rich countries and less than 3% of the world's population flying regularly and this small group are responsible for 70% of flights. If you fly more often than 4 times each year then you're in this small minority and flights are likely driving a large share of your personal carbon footprint.

Although many of us have been grounded this past year with the COVID-19 pandemic, global aviation traffic could soon rebound to pre-COVID levels unless we collectively use this as an opportunity to shift our travel behaviour.

Some tips for reducing your flights include:

When you do need to fly, the following tips can reduce your flying emissions by 20-40%:



If you drive frequently then it is likely responsible for a large share of your personal carbon footprint. While driving alone represents a similar emission intensity per distance travelled to plane travel, the impact of car travel can be reduced dramatically:

And when it is time to replace your car make sure to buy a fuel-efficient vehicle or even better a hybrid or battery electric vehicle. As shown below, the fuel efficiency of a vehicle is largely driven by its size and powertrain technology.

Vehicle fuel consumption

The analysis shows:

Thankfully, fuel economy ratings and minimum standards are slowly improving the fuel-efficiency of vehicles in most countries, together with incentives to help accelerate the shift toward electric vehicles. For a more detailed comparison of the fuel economy of different vehicle models see the relevant databases in your local area (e.g. in the US, UK, and Australia).


Rail and bus

Travelling by rail and bus represents the lowest emission travel choice for medium to long distances, easily outcompeting flying and driving. Also, by avoiding the time and hassle of airport transfers, security checks and boarding, rail and bus trips are often surprisingly competitive with flying in door to door travel times, especially for short to medium distance trips. For similar reasons, rail and bus travel is often more enjoyable, productive and time-efficient than driving. Instead of focussing your attention on the car ahead or searching for a place to park, you can free up your travel time to read your favourite book or get through your emails.


Active transport

Cycling, walking and running represent the lowest emission travel choice for short distance travel, easily beating rail, bus and car travel. These forms of travel also have the added benefit of helping keep you fit and healthy. Cycling may also take less time than you think. Studies have shown that most people underestimate time related to car journeys and overestimate the time it will take to cycle. The average cycling speed is 20-25km/h, which is quite competitive with the average driving speed in most major cities. What's more, if you walk or cycle you don’t need to find a car park when you arrive, saving you time and money.

The transport priority pyramid

To summarise:

Next steps

If this all seems confusing then don't worry; we have created an app to help you calculate and reduce your carbon footprint. You begin by answering a targeted set of questions about your household. We then provide a personalised benchmark and breakdown of your carbon footprint. We then help you reduce your carbon footprint by providing a tailored plan and ongoing support to help you get your carbon footprint under control. The service is free and only takes around 15-20 minutes.

Try the app now