Train vs plane: what's the real carbon difference?

If you want to shrink the footprint of a European holiday, the single biggest lever is usually how you get there. For most trips within Europe, swapping a flight for the train is the most effective change you can make.

What the numbers say

Our World in Data compares the greenhouse-gas emissions of different ways to travel, using emission factors published by the UK government. The figures are per passenger, per kilometre:

• Domestic flight246 g
• Petrol car, 1 person170 g
• Short-haul flight151 g
• Bus97 g
• National rail35 g
• Coach27 g
• Eurostar4 g

Rail highlighted in green. Source: Our World in Data, based on UK Government (DESNZ) 2022 emission factors. UK averages, rounded.

Two comparisons stand out:

• National rail emits around 86% less than a domestic flight per kilometre: 35 g against 246 g of CO₂-equivalent.
• The Eurostar emits around 97% less than a short-haul flight: roughly 4 g against 151 g.

To put that in context: for a 500 km journey, the train would mean around 18 kg of CO₂-equivalent per person, compared with roughly 123 kg on a domestic flight.

Why trains are so efficient

• Steel wheels on steel rails. Rolling resistance is very low, so it takes little energy to keep a train moving.
• Lots of people per vehicle. A single high-speed train can carry hundreds of passengers.
• Electricity. Most of Europe’s main lines are electrified, and as power grids add more renewable energy, every journey gets cleaner without anyone having to buy a new train. The Eurostar’s very low figure reflects France’s largely low-carbon electricity.

Planes, by contrast, burn a large share of their fuel during take-off and climb, which is why short flights tend to be the least efficient per kilometre. At altitude, effects beyond CO₂, such as contrails, add further warming.

Door to door, not departure to arrival

Flight times look short on paper, but they leave out the journey to an airport outside town, check-in, security and boarding. Stations are usually in city centres. For journeys up to around four to six hours by rail, the train is often just as fast door to door, and every one of those hours is usable: read, work, eat or simply watch the landscape change.

When the train doesn’t win, yet

Rail isn’t always practical. Very long distances, islands and routes with poor connections can make flying the only realistic option. Even then, there are ways to cut the footprint:

• Go one way by train. Fly out and take the train home, or the other way round.
• Travel less often, but for longer. One three-week trip beats three one-week trips.
• Take the night train. Overnight services turn travel time into sleeping time and save the cost of a hotel.
• Stay local once you arrive. Walk, cycle and use public transport, and choose small, local operators for tours.

A note on the numbers

These are averages for journeys in the UK, rounded for clarity. Real emissions depend on how full the train or plane is, whether a line is electrified, and how a country generates its electricity. The overall picture, though, is consistent across studies: for most trips within Europe, the train has a much smaller footprint than flying.

Ready to try it? Browse our favourite train routes or read our guide to planning your first European rail trip.