Is the train really better than flying from London to Paris?
Both options cover the same journey, so the comparison is fair: one passenger, one way, city centre to city centre.
Compared on: one-way trip per passenger, London to Paris (~465 km)
Eurostar (high-speed rail)
2.4 kg CO₂eInternational rail at ~0.005 kg CO₂e per passenger-km on a largely low-carbon French/UK grid.
Source: DEFRA/DESNZ UK conversion factors — international rail
Short-haul flight (economy)
70 kg CO₂eIncludes take-off and landing, which dominate a flight this short. Excludes airport transfers.
Source: DEFRA/DESNZ UK conversion factors — short-haul international, economy
Short-haul flight with radiative forcing
133 kg CO₂eSame flight uplifted for non-CO₂ effects at altitude (contrails, NOₓ).
Source: DEFRA/DESNZ UK conversion factors — with radiative forcing uplift
What this means
- The train is roughly 25–50× lower carbon for this route.
- Short flights are disproportionately bad: the climb uses fuel regardless of distance.
- Swapping four return London–Paris flights for the train saves around half a tonne of CO₂e a year.
Your own number, not an average
Averages answer the question; your own footprint tells you what to change first. The calculator takes about two minutes and needs no account.
Figures are averages drawn from public databases and peer-reviewed LCA work; see our methodology for how each factor is applied.