2. Travel by land and sea

‘Minimal’ means transport by this mode amounting to no more than a few per cent of the total target.

The lifestyle carbon footprint covers personal behaviour so this target includes commuting but not travel while at work. However, we encourage participants to take action regarding their work travel too.

There are numerous permutations of surface travel options which would meet the target level of carbon emissions. Here is the rationale behind our suggestion.

Firstly, it is hard to incorporate car ownership within this option because of the high carbon footprint of manufacturing a car, on top of the carbon emissions of its use. The table below summarises some key figures for small to medium cars.
 

1. Figures from Berners-Lee (2020: 145-148)
2. The typical lifespan of a UK car when it is scrapped is approximately 14 years (SMMT, 2021)
3. Similar figures for the annualised emissions are obtained using data from Carbon Brief (2020).
4. Figures calculated using data from BEIS (2021). Obviously, with annual travel by car being on average much higher than 1000 km, these figures would be much higher for average users. For data on average UK travel distances per person per year by mode of transport, see: Dept for Transport (2021).
5. Assuming charging using a high-specification renewable electricity tariff (see target 5).

As you can see, target 2 can only accommodate owning a small petrol car with low annual mileage – and only by excluding other much more efficient transport options. Sharing a small and/or electric car with others would bring down the emissions further (e.g. one car per multi-adult household or sharing with another household), and we invite you to explore these options if you are not able to manage without owning a car. (It should also be noted that buying a car second-hand is generally a better option than a new one – see further discussion of lifecycle emissions in target 7.)

However, in general terms, if you need to use a car, then car clubs, lift-shares or taxis are much more carbon-efficient options as you are effectively sharing the vehicle with larger numbers of people. Our suggested package of surface travel options includes up to 950 km of car travel in these ways. An average petrol car emits approximately 530 gCO₂e/km once all lifecycle factors are included (Berners-Lee: 62–63). If these journeys are, on average, shared with one other person, then the total carbon emissions of this element are 0.25 tCO₂e per person per year. 950 km is equivalent to two local journeys every week. If the car has lower fuel consumption (or is a battery electric vehicle) then the travel distance for these shared-vehicle journeys can be higher.

The climate issues related to car ownership and use are discussed in more depth in Berners-Lee (2020: 62-63; 145-148) and Carbon Brief (2020).

Regarding train travel, the carbon emissions are based on a UK intercity train emitting 50 g/passenger-km. This figure is derived from official UK government conversion factors (BEIS, 2021) and also includes additional emissions to account for further lifecycle/ infrastructure factors from Berners-Lee (2020: 33–35). 5,000 km of long-distance train travel is equivalent to about four return journeys from London to Glasgow. In total, the carbon emissions of the long-distance train travel portion of the target are 0.25 tCO₂e.

Regarding bus and short-distance train travel, travelling 5,000 km would emit 0.2 tCO₂e over the year, assuming average emissions of 40 g/passenger-km (city bus: approx. 30g/passenger-km; tube/tram: 45g/passenger-km – both figures from Berners-Lee, 2020: 30-35). This 5,000 km distance is approximately equivalent to a daily commute of 10 km each way.

We have assumed zero travel by ferry in this option, but ferry travel as a foot passenger could be incorporated if desired. We invite you to explore this option using data such as that from BEIS (2021). As a car weighs around 20 times as much as a human adult, ferry travel by car will lead to roughly 20 times as much fuel consumption and is difficult to accommodate within this target. Very high carbon options such as cruise ships are best avoided.

The footprint of ‘active travel’ – walking and cycling – is effectively included under ‘food’ (target 3) and ‘possessions’ (target 7).