July 14th, 2017

No-fly zone: is low carbon travel worth the effort?

7 minute read

by Sarah Ettlinger


I last set foot on an aeroplane in 2015, for a Copenhagen-London round trip. The time before that was the same journey in 2008. Yet during this time I have split my time between Denmark and the UK for reasons of work, study and family, and thus still chosen to travel a lot. These days, my ‘commute’ is to the UK from my base in Copenhagen once each quarter.

Making ‘not flying’ part of my identity, both personally and professionally, means letting myself in for many long, disrupted and frustrating lower-carbon journeys. All too often, I arrive bleary-eyed, toothbrush in hand, after 20-24 hours’ travel. I have spent nights on coaches, on day trains running through the night (thanks, DB, for cancelling the night trains from Copenhagen) and, once, unexpectedly in a hostel in Aachen. At some point during each journey I find myself asking, “Are the carbon savings worth the hassle?” And once I arrive, friends and colleagues ask the same thing. This blog is my attempt to answer that question.


Travel preferences

In part, my approach to travel is a response to the travel hierarchy that Eunomia follows. Modelled on the waste hierarchy, it is a rule of thumb that we try to apply when designing projects and planning journeys. At the top of the hierarchy is travel prevention – we aim only to travel when necessary (more on this later). Then, in preference order, come travel by:

  • walking;
  • cycling;
  • public transport: rail/tram, tube, bus;
  • hire cars and car clubs;
  • personal cars; and (lastly)
  • flying.


However, the waste hierarchy (as written into the Waste (England and Wales) Regulations) requires only reasonable measures to be taken, and allows that deviations from the hierarchy may sometimes be justified. Relevant considerations include:

  • technical feasibility and economic viability; and
  • the overall environmental, human health, economic and social impacts.


Fly in the ointment

In some of these respects, my commute doesn’t fare so well. It is easily triple the price of a flight and takes 3-4 times as long; and while it is easier to work productively on a train than on a plane, overall the direct and indirect costs are considerably higher. It is questionable whether the land-based trip should even be thought of as “technically feasible”: all too often it proves not to be, or at least to be subject to frequent disruption (I write this sitting on the floor of a train, as the one on which I had a seat reservation has gone missing).

So why do I continue to travel this way, for both work and leisure? It’s mainly because, from an environmental perspective, it performs pretty well. The choice I face is, then, between a costlier, slower, less convenient journey and one that results in 5-10 times more carbon (equivalent) emissions. The chart below shows that, depending on who you ask and whether an uplift for radiative forcing is applied, estimates of carbon emissions for the journey from Copenhagen to London, done either entirely by rail or by flight, vary a good deal. I’ve used Eunomia’s methodology which utilises BEIS greenhouse gas reporting emissions factors, as well as online calculators at Loco2 and Ecopassenger; Ecopassenger’s estimate of the carbon emissions of the flight is almost 150% greater than Loco2’s, in part due to the application of an uplift for radiative forcing.


Estimated CO2e Emissions for single journey Copenhagen to London: Eunomia - Fly: 174Kg, Train: 16kg; Loco2 - Fly: 90Kg, Train: 17kg; Ecopassenger: Fly: 270kg, Train: 90kg

Train lines and air lines – estimates of travel-related carbon emissions can vary considerably, but all sources show air travel emissions dwarfing those from rail journeys.


However, while the absolute figures vary, the message from each source is the same – avoiding air travel saves a lot of CO2. Even the lowest estimate of the saving – from the Loco2 website – shows a saving of 73kg of CO2e. If you then multiply this up by my 8 journeys a year, that’s 0.6 tonnes of CO2e, that’s a large proportion of my estimated total footprint (with trains) of 7.3 tonnes – which is already low compared to the UK average of 13 tonnes. For me, it wouldn’t be easy to find an alternative way of cutting 0.6 tonnes of emissions.

I recognise that it is my privilege that affords me the ability to give a higher weighting to the environmental factors than the other aspects. I have no immediate dependents and the flexibility to manage my own time; I have no disabilities that would exacerbate the difficulty of the journey; and either Eunomia or I will accept the additional cost.


Guilt investment?

Perhaps you’re asking, “why don’t you just pay to offset the extra carbon emissions?” Well, Eunomia already does operate a carbon fund that monetises the emissions produced in the course of our work and finds creative ways to more than offset them. But I’m personally rather sceptical of the offsetting approach: paying to “get away with” something we know causes harm doesn’t sit well with me (“be the change you wish to see in the world…”, etc.). I also met Christian Hunt and Alex Randall, the activist duo behind Cheat Neutral, when I was at a young impressionable age and the sentiment has stuck ever since!


Plane flies over rail tracks

Plane truth: flying is a far more emissions-intensive way of travelling than rail. Photo: Eric Fredericks (CC BY-SA 2.0), via Flickr.


When considering business travel, I also believe I have a responsibility to be an ethical environmental consultant. A recent Isonomia article asked whether an environmental consultant is ethically obligated to seek to influence a client to give relatively high value to achieving environmentally beneficial outcomes. I would add that how we carry out our work (how we “walk the walk”, as we like to say) is also important. What signals does a (would-be ethical) environmental consultant send if they hop on a plane for an hour-long meeting at a location only a few hours away by train?


Going the extra mile

The problem for the travel-conscious consultant, however, is that they risk making themselves less competitive:

  • As mentioned above, at the top of the ‘travel hierarchy’ is travel prevention: we should be advocating no travel at all where it’s appropriate. Of course, there are social benefits to meeting face-to-face, but with a bit of forward planning, video conferencing works wonders and is an effective replacement for many of the meetings we currently travel to. Clients sometimes stipulate several face to face meetings in the specification of the work they want carried out, leaving the consultant with an invidious choice between committing to excess travel, or failing to meet the specification. One solution to this is to offer to attend meetings, but propose a discount if videoconferencing is used instead. That leaves the choice with the client, but steers them towards making the environmentally preferable choice.
  • With air travel being so cheap, a consultant who favours environmentally preferable land-based transport incurs extra costs. If an early meeting is scheduled, it may even mean overnight accommodation is needed, with the further costs that entails; the consultant should ideally make clear in their proposal if certain start times are to be avoided.
  • We also need to think creatively about how to obtain good value from time spent travelling. On a recent trip to Oslo, the 17 hour ferry journey was an opportunity to get to know a new colleague and a co-worker from a partner organisation that I will be collaborating with; and it allowed us to finalise the next day’s presentation face-to-face, and rehearse how we would deliver it.


However, the key challenge is to try to help the client to place the same value on carbon savings as the consultant does. One way to do this might be to present as part of a proposal the “carbon cost” of delivering the work. This would factor in emissions from the offices where work will be carried out, but would primarily consist of travel emissions. Showing the client what the carbon impact of the consultant’s proposed travel (or travel prevention) methods would be, how this compares with more carbon-intensive alternatives, and how the impacts will be mitigated may be a means of showing why an approach that appears slightly more expensive or less convenient is actually better value. However, such an approach would ideally not focus only on total carbon emissions, or it risks simply disadvantaging consultants based far from the client

I know realistically that I will fly again – both for work and leisure – but when I can choose to avoid it I will. Perhaps eventually the efficiency of air travel will improve, and I will be able to fly with a lighter heart and less environmental impact. But I don’t plan to change my unusual carbon-saving commute – even with the disruptions and lack of sleep, above all, I do enjoy the journeys.


Sarah Ettlinger



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Tom, thanks for your comment.
If you have to fly, then doing as you suggest is a good idea. I wouldn’t agree that your personally attributable emissions are then zero. There will be a few hundred people whose decisions to fly have made the flight viable. No one on that flight is more or less responsible for that.


Sarah, is there any merit to researching and booking your tickets only for flights at times of moderate demand?
When you’re not the notional passenger at the tipping point who causes that flight to be viable, or an additional flight to be laid on, aren’t your personally attributable carbon emissions zero?