What’s the lowest-carbon way to get between the UK and Iceland?

As most people know by now, air-travel is really bad for the environment. So land-travel is, environmentally, almost invariably the best way to get between Britain and continental Europe. With the help of the invaluable advice of the man in Seat 61, I take the bus or train, accept that it takes a bit more time and money than a plane, and both enjoy the journey and get on with work as I travel.

But what do you do if, like me, you live in the UK and your work takes you to the Atlantic island of Iceland—or, worse, if you live in Iceland and want to go elsewhere in Europe?

That’s what this blogpost tries to work out.

Why aviation is a climate disaster

But first, in case you missed the memo: aviation may only account for 2-3% of global greenhouse gas emissions, but that’s largely because few people in the world fly (so far). For those of us who do fly, air travel makes up a large proportion of our carbon footprints. The average UK person’s greenhouse-gas emissions are around 15 tonnes CO₂-equivalent per year; one economy-class transatlantic return flight emits about 1 tonne per passenger. A few years ago, it was common to say that emissions of 2-3 tonnes per person per year might be sustainable. So even by that reckoning, a tonne of aviation emissions should be a once-in-a-lifetime kind of luxury. These days, though, we’re talking about the urgency of sucking more greenhouse gas out of the atmosphere than we put in, which makes a tonne of emissions look even worse.

Moreover, the effect of aviation on climate is greater than burning the same amount of fuel at ground level. How readily those problems can be avoided by better aircraft design is not yet clear, but the 2016 UK government guideline (here, §8.39) is that aviation emissions correspond to heating the climate nearly twice as much as the same emissions at ground level. So that transatlantic trip with its one tonne of greenhouse gas emissions actually has the same effect as emitting two tonnes at ground level.

Although increased efficiency, electrification, airships, and biofuels or synthetic fuels are all noisily touted possibilities for cleaner aviation, there’s no likelihood that per-passenger aviation emissions will fall sharply in the foreseeable future. And don’t imagine that spending extra money on ‘carbon offsetting’ will do anything to make things better (for a little bit on why, in the real world, offsetting will probably do nothing to ameliorate the impact of flying, see here on Delta Airlines’ greenwash and here on Amtrak’s greenwash).

So travelling by land is virtually always better than by air: check out these average figures for greenhouse gas grams per passenger-kilometre expressed as a CO₂-equivalent from the fabulously useful Finnish emissions data-centre Lipasto.

• Petrol car, 2016, 1 occupant: 140
• Diesel train, 2016: 76.4
• Coach, 2016, average occupancy 14 people: 41
• Electric intercity train, 2007: 15

• Scheduled flight (Europe, ≤ 463 km), 2008: 260 direct emissions (494 counting high-altitude effects)
• Scheduled flight (long-haul), 2008: 135 direct emissions (257 counting high-altitude effects)
• Charter flight (long-haul), 2008: 68 direct emissions (129 counting high-altitude effects)

(In case you’re wondering, I assume that charter flights have much better per-passenger-km emissions because they’re always full, and don’t waste space on large first-class seats.)

So should I go to Iceland by boat instead of plane?

Leaving the Faroes on the Norrøna, 2001. Back when boats were the budget travel option, and you had to stick your panorama shots together with sellotape.

Unfortunately (from the point of view of low-carbon travelling), you can’t go to Iceland on an intercity train. Is it better to go by boat than plane?

Clearly, taking a proper, wind-powered sailing boat would be ideal: virtually zero-emissions. Such trips do exist commercially: €4,000 and twenty-three days of (no doubt wonderful) touristic island-hopping will get you from Cumbria to Iceland. Maybe I’d do that if I was on my way to a year’s research leave in Iceland, had the time to spare, and could somehow get a funding body to pay for it… But it’s not viable for most work trips.

Ferry travel between the UK and Iceland used to be easy: you could sail from Aberdeen to Shetland, from Shetland to the Faroes, and from the Faroes to Iceland. At 4-7 days each way, that journey was a long time for work travel, but within the range of what I think we should start to view as normal.

Unfortunately, the rise of cheap airlines in the 1990s (promoted by perverse incentives from governments) has encouraged the collapse of UK passenger shipping. The only scheduled sailings to Iceland these days are from Denmark. Getting the train from Britain to Denmark in order to sail to Iceland may sound wildly inefficient, but the carbon cost of overland travel is so small compared with air and sea travel that, from an environmental point of view, it’s an almost trivial detour. On the other hand, although shipping can be very efficient, passenger ferries usually carry a lot of weight per passenger (think duty-free shops and swimming pools) and run on dirty fossil fuel. So it’s not self-evident that sailing to Iceland is a good option climate-wise.

As far as I can see, Smyril Line, the one relevant ferry operator, doesn’t publish per-passenger-km emissions data, but the master’s student Viðar Jökull Björnsson has published figures that look plausible (though they seem not to account for a proportion of Smyril Line’s business being freight rather than passengers). Viðar reckons that Smyril Line emissions are 180 grams CO₂-equivalent per passenger-kilometre.

This allows some back-of-envelope calculations for three different itineraries from Leeds to Reykjavík. I’ve put the actual data-sources and figures in the .xls spreadsheet here. Counting the effects of high-altitude emissions, the ultimate findings—which are rough, but surely in the right ball-park—are:

• Maximum boat travel. Train from Leeds (UK) to Hirtshals (Denmark); ferry from Hirtshals to Seyðisfjörður (Iceland); coach from Seyðisfjörður to Reykjavík: 408 kg CO₂-equivalent.
• Maximum air travel. Train from Leeds to Edinburgh (UK); flight from Edinburgh to Reykjavík (Iceland): 422 kg CO₂-equivalent.
• Plane/Boat mix. Train from Leeds to Edinburgh (UK); flight from Edinburgh to Tórshavn (Faroe Islands); ferry from Tórshavn to Seyðisfjörður (Iceland); coach from Seyðisfjörður to Reykjavík: 384 kg CO₂-equivalent.

This is not good news. However you look at it, a trip from Leeds to Reykjavík and back is getting on for a tonne of CO₂-eq greenhouse gas emissions. Ouch.

Given the uncertainties in my calculations, there’s no clear winner here. It might be that with more precise data (e.g. real data for the actual airlines and routes, information on the percentage of the Smyril Line business that is freight, better data about coach-emissions in Iceland, more nuanced reckoning of high-altitude effects, etc.) one itinerary would pull clearly ahead. If anyone can contribute on this I’d love to hear it!

Really, this analysis brings into focus that we should minimise travel from the UK to Iceland: in my world that would involve e-conferencing, looking at digital facsimiles of manuscripts, and aiming for a really substantial, worthwhile visit once a decade or so, rather than hopping over for conferences once or twice a year.

The least worst travel option

But if we are going to travel between Britain and Iceland, it’s probably right to promote sea-travel. Fossil-fuelled sea-travel is bad, but seems to have far more scope for efficiencies than air-travel. Admittedly technologies like electric or wind-powered ships might be little nearer at hand than similarly exciting aviation technology, while there seems to be no sign of nuclear propulsion making the jump from military shipping (where it is routine) to civil shipping. But if consumer demand shifted from planes back to boats, there would surely be potential for a virtuous circle whereby the Smyril Line ferry, the Norrøna, would take lots more passengers per trip (there’s certainly the space for them), for lower ticket prices per passenger. Embarking passengers who would otherwise have flown on board the Norrøna would only marginally increase its fuel consumption, but would dramatically reduce aviation emissions. And increased demand would increase the likelihood of old routes, like the Shetland-Faroes one, reopening.

So, on the present calculations, the next time I do really have to go to Iceland, the best combination of a manageably quick journey, minimal carbon cost, and positive exertion of consumer pressure is probably to fly from Edinburgh to Tórshavn and get the boat onwards from there.

But if anyone actually can tell me how to sail to Iceland on an actual sail-boat, do!

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