Transport accounts for around 16% of global CO₂ emissions. Choosing how you travel matters — but by exactly how much? We crunched the numbers for popular routes across all major transport modes.
Our Methodology
We used average emission factors per passenger-kilometre from peer-reviewed sources:
- Flights: 255g CO₂e/km (including radiative forcing multiplier of ~2×)
- Car (solo driver): 171g CO₂/km (average petrol car)
- Car (4 passengers): 43g CO₂/km per person
- Bus/Coach: 68g CO₂/km
- Train (European average): 41g CO₂/km
Note: these are averages. A newer EV on a green grid emits far less. A packed 747 emits less per seat than a half-empty regional jet.
London → Paris (344 km)
✈️ Flight: 88 kg · 🚗 Car (solo): 59 kg · 🚌 Bus: 23 kg · 🚆 Train: 14 kg
The Eurostar wins by 6×. For this short route, flying is the worst choice by a wide margin.
New York → Los Angeles (4,490 km)
✈️ Flight: 1,145 kg · 🚗 Car (solo): 768 kg · 🚌 Bus: 305 kg · 🚆 Train: 184 kg
Amtrak wins on emissions, but takes 3 days. The bus is a surprisingly green middle ground.
Sydney → Melbourne (878 km)
✈️ Flight: 224 kg · 🚗 Car (solo): 150 kg · 🚌 Bus: 60 kg · 🚆 Train: 36 kg
The XPT train is 6× cleaner than flying. The overnight sleeper saves on accommodation emissions too.
The Big Picture
Three clear rules emerge from the data:
- Short routes (<700 km): Always take the train if available. Flying is rarely justified on environmental grounds.
- Long routes (>2,000 km): Flying beats driving solo. But the bus or train beats both if time permits.
- Carpooling changes everything: A car with 4 passengers drops to 43g/km — cleaner than the European rail average.
Every distance page on HowFarFrom shows a CO₂ breakdown for your specific route. Try the calculator →