The (Hidden) Cost of Travel

I recently travelled in the Caribbean for Seas Your Future and here is my attempt to figure out my additional carbon footprint of this trip.

The obvious: travel by air and road

Transferring between east Cornwall and London Heathrow airport took two round trips by car, as the  flight hours were somewhat antisocial. That’s 880 miles, half of which was in a small Volvo diesel, the other in a medium-sized BMW saloon. Using the calculator of carbonfootprint.com, this part of my travels caused 270 kg of CO₂ emissions.

I used myclimate.org for estimating the carbon equivalent emissions (CO2-e) for my flights.  I was routed from LHR to EWR (Newark, NJ, USA) and on to SJO (San José, Costa Rica) on the way out, totalling 5700 miles and 1.5 t of CO2-e (t stands for metric tonnes). I returned from PTY (Panama Tocumen) via EWR to LHR (5850 miles 1.5 t CO2-e).

Here are some additional considerations regarding the calculation methodologies of different carbon calculators that illustrate that we are still dealing with estimations: for example, myclimate.org takes a whole range of factors into account that makes their calculations more realistic than some other carbon footprint calculators for flights. Its method is based on the detailed information used also by the aviation industry ICAO, which takes care of aircraft type, average loading and other factors. However, myclimate.org also accounts for non-CO2 impacts in the atmosphere, which are collectively termed radiative forcing (RF). The intensity of RF is still a matter of discussion and the RF factor 2 used by myclimate.org is now considered quite conservative. A recent publication by Stanford University recommends a factor of 2.7 to 3.0, which leaves me to correct my result by multiplying the original 3 t CO2-e by 1.5 to get a ‘worst case’ impact of 4.5 t CO2-e. Knowing whether or not that’s the right answer may have to wait. When, a year ago, I calculated the footprint of the Antarctic Quest 21 expedition, I still confidently used an RFI of 1.9, something I would not do now.

My travels in and between Costa Rica and Panama racked up around 270 miles by coach or minibus, 50 miles by local bus services, 40 miles by taxi and 15 miles by metro. Using carbonfootprint.com I arrived at a total of 30 kg CO2-e for this ground transport.

Have you ever considered the carbon footprint of a night in a hotel?

I spent 2 nights in the hostel of Academia Tica in San José, one night in an Air B&B in Puerto Video and 2 nights in a Panama City hotel. For the remaining 4 nights I occupied a bunk on Pelican of London, which is accounted for differently. As a rough estimate, I spent around £600 on hotel accommodation, food and drinks, and this was used by carbonfootprint.com to estimate 160 kg CO2-e for secondary emissions.

The International Council on Clean Transportation (ICCT) estimate the carbon footprint of a hotel night as 15 kg CO2-e. In this case, it makes little difference to my secondary emissions, it just illustrates a different approach that assumes a certain standard of hotel across the board.

How to account for tall ship sailing as transport and accommodation?

As a sailor, this is something of interest – even if the research outcomes are going to be uncomfortable…but there is no time left to shy away from an uncomfortable truth.

To figure out the footprint of my time on the tall ship Pelican of London is not straight forward. I could not find a carbon calculator that includes tall ships in its portfolio, so I have to resort to an approximation: while Pelican is not a cruise liner, ferry, or private yacht, I can learn from each of those categories something about the carbon footprint of traveling by sea.

1. A cruise liner, I imagine (not that I’ve been on one), has lots of staff and passengers, air conditioning and hot showers, swimming pools and gyms, champagne at the bar and black tie dinner with the captain. The ICCT states that the most efficient large cruise ships emit about 250 g CO₂ per passenger per kilometre. Similar to aeroplanes, cruise ships emit more than just CO₂, but also black carbon (essentially soot), oxides of sulfur and nitrogen and volatile organic compounds. This means that the CO2-e is higher by an estimated factor of 1.4, amounting to around 350 g CO2-e pax/km. For the 300 km I travelled on board, my emissions would be 105 kg CO2-e, and I stayed 5 nights on the ship as if it were a hotel, which adds 75 kg CO2-e (see above), making it around 180 kg CO2-e for my stay on the Pelican.
2. According to Direct Ferries, the United Kingdom’s Department of Energy, Food and Rural Affairs (DEFRA) states that a foot-passenger on a ferry produces 19 g CO2-e per kilometre travelled (a total of 5.7 kg CO2-e). Add 75 kg for the hotel aspect and I’d arrive at ca. 81 kg CO2-e for may stay on Pelican.
3. We motor-sailed the 300 km between Bocas and Shelter Bay, using the engine on relatively low revs and fore-and-aft sails to pull us along. Guidance provided by 8 Billion Trees for a large motor sailing yacht provides another way to estimate emissions. This includes around 2.5 kg CO2 emitted for each litre marine diesel burned. Given our mode of travel, our fuel consumption may have been an estimated 300 L of marine diesel for the engine and 100 L for running the generator for 24 hours, amounting to around 1000 kg CO₂ emitted. Divided by the 9 sailors on board, this figure makes me responsible for some 110 kg CO₂. I have no way of finding out how the wide range of possible emissions of particulate matter, nitrogen oxide, volatile organic carbon and carbon monoxide that are provided by the ICCT guidance could be translated into carbon equivalents. Therefore, I’ll apply the factor of 1.4 provided by the ICCT for cruise liners to get to 155 kg CO2-e for that voyage. This approach looks somewhat arbitrary because it is – but it will have to do for now and I hope that in future I’ll find a better way. When the Pelican carries her full complement of 47 sailors, the per head CO2-e calculated here is reduced considerably. Again, add 75 kg CO2-e for accommodation and I arrive at 230 kg CO2-e.

The Pelican is a different ship from any of those three options, and the range of 81 to 230 kg CO2-e is quite large. Given that there are no cocktail bars or jacuzzies on board, we wash our own coffee mugs and clean our cabins, preserve water and the cook works with a tight budget and makes sure that little is wasted, it would be tempting to settle for the lower end. However, the motor sailor estimate may be more realistic, so I’ll go with 230 kg CO2-e.

Summary table of carbon equivalent footprint

Carbon dioxide equivalent in metric tonnes	CO2-e (t)
Ground transport by private car in the UK	0.27
Flights	4.50
Ground transport with public transport and taxi at destination	0.03
Hotel accommodation and subsistence for my time not on board Pelican of London	0.16
Transport, accommodation and subsistence for my time on board Pelican of London	0.23
Total	5.19

What to do with this information?

Trying to estimate the carbon footprint of my travels was, once more, an exercise in satisfying curiosity and learning. Some of the information available leaves a large uncertainty about the results of my calculations, especially when it comes to traveling by boat. Not surprisingly, the results show that aviation is a major component of long-haul travel and that transport by private car is a lot more greenhouse gas intensive than using public transport. More intriguing is the realisation that hotel accommodation and eating out are quite carbon intense, too and that there is a lot more to learn about the carbon footprint of using non-standard ships and yachts.

Of course, my travels are done, and I can only mitigate the impact by offsetting the estimated carbon footprint I generated. I travelled for the sail training charity Seas Your Future and my work is related to youth development at sea. For this reason, I chose innovative, forward-looking carbon offsets in the rapidly developing world of blue carbon, which are part of the portfolio of the carbon offset organisation Earthly, which I used before for specific projects:

1. Seaweed Farming Innovation Cornwall: an early stage, nature-based project that works on scaling up seaweed farming in the UK. Seaweed is fast growing and creates habitat, could become an alternative to fossil fuel, plastic and fertiliser, and in that way, play a role in creating a circular economy.
2. Peatland Protection, Rimba Raya: this project protects a highly endangered ecosystem from being converted to palm oil plantations. This peatland forest that is biodiversity and carbon-rich and sustains local communities, addressing the whole range of UN socio-economic and environmental sustainable development goals.