Text and photos: Marie-Louise Wöhrle
Marie-Louise Wöhrle is a PhD student at the University of Edinburgh, and was visiting fellow at CSSM in 2025
When we first hold a call to coordinate my Visiting Fellowship at the CSSM in 2025, the CSSM’s project coordinator Mo mentioned that the CSSM is happy to support sustainable travel for fellows. As a researcher interested in biodiversity conservation and environmental sustainability (and of course the microbes within those worlds), I perk up – as a PhD student, flights are often the only option affordable to me, and the chance to attempt to travel more sustainably rightfully excites me.
The journey from Edinburgh to Helsinki can be a 2.5 hours long direct flight over the North Sea, then the Gulf of Bothnia, and finally the Gulf of Finland. It can also be, as I discover over a few hours of making spreadsheets, a 3.5 day long journey, taking me by train and ferry through England, the Netherlands, Germany, and (again) the Baltic Sea.
I set off at lunchtime in Edinburgh to take a train to London, where I’d been staying with a friend for the night. It is absolutely possible to get by train from Edinburgh to Brussels or Amsterdam within a single day. Stopping here for the night, we got to catch up in-person without adding the two train trips back and forth between Edinburgh and London we would otherwise have taken. Travel policy at universities often make it difficult to include stops travelling even when staff are happy to pay for additional costs themselves, so it is lovely to be given the autonomy to include this stop on my trip. We use the time wisely for dinner and mudlarking along the Thames.
Early the next morning, I set off to St. Pancras to take the Eurostar via Brussels to Amsterdam. I am always surprised at how smooth and quickly the Eurostar check-in usually works, though I am very aware that as an EU citizen I must have an easier time here. This train ride does always remind me what a luxury it is to not have to worry about borders. In airports to me they almost feel abstracted, (partially automated) passport controls between security and ticket checks. The ends of either side of the Eurotunnel, however, are surrounded by tall fencing and barbed wire, materially emphasising not just the border but also years of anti-refugee and hostile environment policies across Europe.
Arriving in Amsterdam in the late afternoon, I took a walk around the city before preparing myself for the next day. Because I am still a PhD student, I do spend some travel time working. Amsterdam is home to Micropia, the self-declared world’s only microbe museum, and I had three hours’ time the next day to take a closer look at its exhibition design before I had to rush away to catch my next train. I just about made it to Amsterdam Centraal on time for my first of three trains that day.
On this next day, I was travelling across Germany, and I was a little concerned because trains in this country have quite a reputation for running late. I got to my first stop vaguely on time, but my second train to Hamburg runs into some bigger delays. Despite this, I made it onto an incredibly crowded third train to Travemünde just the minute before its planned departure.
The final leg of my trip is a ferry between Travemünde and Helsinki, that ships mainly container trucks but also a reasonable number of people going on holiday between the two ports. The ship takes 30 hours to cross the Baltic Sea, and I am very lucky to catch a very sunny day while I am on board. Arriving in Helsinki two nights and one day after I boarded the ship, I even make it to the CSSM that day.
Instead of 184kg, my European rail adventure produced an estimated 98.92-108.92kg Co2e.
My 1.700km travelling on the Finnlines ferry generated roughly 69-79kg of Co2e per passenger, around a tenth of the Co2 emissions per passenger that a plane would over the same distance. I also travelled approximately 1.387km on various trains. Using calculators from British national rail, Eurostar, and the German DB, these added up to 28.64kg of Co2e. I also took the tube in London (23.2km total, for 0.78kg Co2e), a ferry across the Ij in Amsterdam (600m total, for 0.01kh Co2e), and a bus in Travemünde (approximately 5km, for 0.49kg Co2e) – although these values are estimates based on distances and average Co2e for the mode of transport. Instead of 184kg, my European rail adventure produced an estimated 98.92-108.92kg Co2e.
The way customers can currently compare the sustainability of travel methods is using Co2e, which standardises the impacts of CO2, methane, nitrous oxide and other emissions into a more digestible and comparable singular number. A flight between Edinburgh and Helsinki produces about 184kg of Co2e per passenger. Despite the far longer route in kilometers, was my European rail adventure more sustainable by Co2e?
On the other hand, I stopped for ice creams and dinners of unknown impact, and I bought myself a plush tardigrade at Micropia that I would not have bought at an airport, likely adding around another 1kg Co2e in material (compare Robertson and Klimas 2019) and unknown emissions from production and shipping.
Uptake of carbon calculators and their effects on everyday practices have been relatively slow (Salo et al. 2019), and through this exercise I feel why. Although overall my efforts hopefully reduced my carbon footprint for this trip by half, my trip cost 4-5 times as much money as a flight would have, and several more hours in preparation and booking. I may have a vague idea that trains are among the most carbon-friendly ways to travel. However, calculating just the trip emissions took me around 40 minutes, three different calculators, a government report, and some time on a maps website to calculate trip lengths for my tube, ferry, and bus trips. Travelling mindfully of carbon footprints is still a luxury, though institutional financial support for sustainable business travel is a good first step in better directions.
References
Robertson, M.R. and Klimas, C. (2019) “A Playful Life Cycle Assessment of the Environmental Impact of Children’s Toys,” DePaul Discoveries: Volume 8, Article 7. Available at: https://via.library.depaul.edu/depaul-disc/vol8/iss1/7
Salo, M., Mattinen-Yuryev, M.K., and Nissinen, A. (2019) “Opportunities and limitations of carbon footprint calculators to steer sustainable household consumption – Analysis of Nordic calculator features,” Journal of Cleaner Production: Volume 207. Available at: https://doi.org/10.1016/j.jclepro.2018.10.035
UK Government, Department for Energy Security and Net Zero (2022) “Greenhouse gas reporting: conversion factors 2022” Available at: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2022