The graphic shows that a single journey from London to Paris by plane will cost £64, take 4 hours 40 minutes, and emit 59kg equivalent of carbon dioxide. By train, the same journey will cost £49, take 2 hours 55 minutes, and emit 2kg equivalent of carbon dioxide. Assumptions: the start and end location are the main train terminal in the centre of each city; travel costs are for the cheapest advance tickets bought in advance and include all connecting journeys; carbon emissions are calculated using UK government greenhouse gas emissions factors for short-haul flights, ferry and international rail travel. To find out more, visit www.imperial.ac.uk/stories/climate-action

Reducing demand for air travel starts at work

The graphic shows that a single journey from London to Paris by plane will cost £64, take 4 hours 40 minutes, and emit 59kg equivalent of carbon dioxide. By train, the same journey will cost £49, take 2 hours 55 minutes, and emit 2kg equivalent of carbon dioxide. Assumptions: the start and end location are the main train terminal in the centre of each city; travel costs are for the cheapest advance tickets bought in advance and include all connecting journeys; carbon emissions are calculated using UK government greenhouse gas emissions factors for short-haul flights, ferry and international rail travel. To find out more, visit www.imperial.ac.uk/stories/climate-action
How do the cost, time and carbon emissions of a single journey from London to Paris by plane, compare to travelling by train?

Laura Warwick, Research Postgraduate on the Science and Solutions for a Changing Planet Doctoral Training Partnership, says flying shouldn’t be the default option when it comes to international travel.

Aviation is becoming an increasingly contentious issue in the UK. The government’s decision to step in to assist regional airline Flybe seems to be at odds with the UK Committee on Climate Change’s warning that continued expansion of aviation is incompatible with long-term climate targets. In fact, if current trends continue, emissions from aviation could make up over half of the UK carbon budget in 2050.

How equitable is flying?

This is particularly troubling given the privileged nature of flying in the UK: in 2018, just 10% of fliers were responsible for over half of all international flights. In contrast, 48% of the UK population did not take a single flight abroad. The uncomfortable truth is that those of us who fly more than three times a year are part of an exceptional group of people who are having a disproportionate impact on our planet. A quick look at a carbon calculator like this one highlights just how quickly emissions from air travel can dominate your carbon footprint.

Technological solutions that reduce aviation emissions, such as biofuels or hydrogen power are currently in development. However, these technologies are not yet ready for commercial deployment. Therefore, we must act now to reduce the demand for air travel.

Businesses can lead the shift to sustainable transport

Organisations in the service sector – from universities to management consultancies – are home to large numbers of frequent fliers. 30% of business travellers report flying for work once a month or more. A recent study at Imperial showed aviation emissions accounted for 9% of the university’s total emissions in the 2017/18 academic year. The privileged status flying has in society was mirrored across the College’s community, with 15% of travellers responsible for 50% of the emissions recorded in the data.

It’s time to change that. Organisational leaders have an opportunity to lead the way by championing sustainable travel options – and you can help by changing your approach to business travel.

What can you do about climate change? Check out our climate action playlist.

Do you need to travel at all?

The first decision to make when planning a work trip is whether you need to travel at all. Academics, like many professionals, are concerned that reducing their air-travel will have a negative effect on their success. However a recent study has indicated that this is not the case. Work travel could also be reduced by using video conferencing, employing local scientists to undertake fieldwork, or combining several work objectives into one trip.

What’s the rush?

When planning a trip, our default option is often to fly. Many workplace travel booking systems assume flying is a preference, even when a different option could be cheaper or quicker. For example, in 2016, over 1.6 million people travelled from Amsterdam Schiphol airport to London Heathrow. While some of these people will have been on connecting flights or travelling elsewhere in the United Kingdom, how many of them realised that, for the same price, they could have taken a high-speed train to Brussels then the Eurostar straight to the heart of London?

The graphic shows that a single journey from London to Amsterdam by plan will cost £54, take 4 hours 47 minutes, and emit 58kg equivalent of carbon dioxide. By train, the same journey will cost £35, take 4 hours 30 minutes, and emit 3kg equivalent of carbon dioxide.

Assumptions: the start and end location are the main train terminal in the centre of each city; travel costs are for the cheapest advance tickets bought in advance and include all connecting journeys; carbon emissions are calculated using UK government greenhouse gas emissions factors for short-haul flights, ferry and international rail travel.

To find out more, visit www.imperial.ac.uk/stories/climate-action
How does a single journey from London to Amsterdam by plane compare to travelling by train?

Assuming you begin in the centre of the city, and allowing time for check-in and travel to and from the airport, the flight takes 4 hours and 50 minutes. The train arrives just before that, with a total journey time of 4 hours and 30 minutes. The flight produces the equivalent of 57kg of the climate change-causing greenhouse gas carbon dioxide, per person, and the train produces just 3kg. It would take the average UK household one month to produce the same amount of carbon dioxide through their electricity usage.

Organisations can make it easier for their employees to travel sustainably by embracing slow travel policies; for example, by introducing policies that favour greener transport choices, or changing their default option for continental travel.

  • The graphic shows that a single journey from London to Frankfurt by plane will cost £67, take 5 hours 25 minutes, and emit 101kg equivalent of carbon dioxide. By train, the same journey will cost £71, take 7 hours 21 minutes, and emit 4kg equivalent of carbon dioxide. Assumptions: the start and end location are the main train terminal in the centre of each city; travel costs are for the cheapest advance tickets bought in advance and include all connecting journeys; carbon emissions are calculated using UK government greenhouse gas emissions factors for short-haul flights, ferry and international rail travel. To find out more, visit www.imperial.ac.uk/stories/climate-action
  • The graphic shows that a single journey from London to Dublin by plane will cost £59, take 5 hours 20 minutes, and emit 74kg equivalent of carbon dioxide. By train, the same journey will cost £47, take 8 hours 55 minutes, and emit 4kg equivalent of carbon dioxide. Assumptions: the start and end location are the main train terminal in the centre of each city; travel costs are for the cheapest advance tickets bought in advance and include all connecting journeys; carbon emissions are calculated using UK government greenhouse gas emissions factors for short-haul flights, ferry and international rail travel. To find out more, visit www.imperial.ac.uk/stories/climate-action
  • The graphic shows that a single journey from London to Barcelona by plane will cost £57, take 6 hours 5 minutes, and emit 177kg equivalent of carbon dioxide. By train, the same journey will cost £81, take 10 hours 25 minutes, and emit 9kg equivalent of carbon dioxide. Assumptions: the start and end location are the main train terminal in the centre of each city; travel costs are for the cheapest advance tickets bought in advance and include all connecting journeys; carbon emissions are calculated using UK government greenhouse gas emissions factors for short-haul flights, ferry and international rail travel. To find out more, visit www.imperial.ac.uk/stories/climate-action

Even when the train takes longer or seems more expensive it can have other benefits. Time spent on the train can be productive for work and there is no need to worry about luggage limits or liquid restrictions. The journey can also become part of the conference and networking. Big conferences in Europe often attract lots of scientists travelling by train, making the journey one of the best places to make connections.

A network of sleeper trains also criss-crosses Europe, making train travel a time-efficient way to get to destinations such as Prague and Venice. When comparing prices, it is worth remembering the money saved on overnight accommodation at your destination. And the difference in carbon emissions is huge. Getting the train instead of flying from London to Prague saves 153kg of carbon dioxide – the equivalent of powering your home for three months!


My sister lives in Berlin and my dad in Prague, which makes family meet-ups tricky. When it was my dad’s 70th last year, I got up early to take the Eurostar to Brussels and then continental trains over to Berlin, via Cologne. This took a whole day but it wasn’t part of my holiday day as I worked on my laptop with the on-board WiFi. I spent a couple of days in Berlin with my sister, then the two of us took a Czech train south to Prague. It’s excellent scenery along the Elbe and very relaxing. Great food in the dining car too.

Simon Levey

Navigating the network

Despite all the benefits, if you must make the arrangements yourself, booking train travel across multiple countries can be confusing and it’s often difficult to know if you are getting the best price. Luckily, on the internet it’s easy to find people who have already done the hard work for you. The Man in Seat 61 website has compiled incredible details on the best and cheapest way to travel to almost anywhere in Europe, and beyond, by train.

Choosing not to fly is one of the biggest decisions you as an individual can make to help avert the climate crisis. By following the steps above, we can stop thinking of aviation as a default option and try to travel in a more environmentally friendly way.

To find out more about how your individual choices can help tackle climate change, check out our digital feature on 9 things you can do about climate change.

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