Everyone knows that flying is carbon-intensive. But the footprint of any trip depends on a host of factors in addition to the simple question of how far you are travelling: the aeroplane model, how many seats are empty, how much luggage passengers carry, the time of day and potentially even whether passengers have emptied their bladders before boarding.
Perhaps more important than any of these, however, is the class of travel. That may partly explain why the Foreign Office has just joined the 10:10 climate campaign to cut its emissions by 10% this year and plans to stop its staff travelling business class. As commentators often point out, economy is clearly lower carbon because it maximises the number of passengers that each flight can carry. But how exactly much difference does this make?
In the absence of reliable data to help answer this question, I did some sums of my own. Starting with a long-haul scenario, I took a BA 747 floorplan and worked out the area of different blocks of seats, based on the standard length of a 747 being a little over 70 metres. The results of my rough-and-ready study are as follows.
• Economy ("World Traveller" on British Airways): 0.66 sq metres per seat
• Premium economy ("World Traveller Plus"): 1.1 sq metres per seat
• Business ("Club World"): 2.3 sq metres per seat
• First: 3.6 sq metres per seat
Purely in terms of physical space, then, the answer appears to be that flying first class on BA gives you a footprint around 5.5 times larger than that of an economy passenger, with a business seat clocking in at 3.5 times the economy option.
For short-haul trips, the differences aren't so great. As this floorplan shows, first class doesn't exist on BA's European flights and the business seats are much smaller than the giant recliners found in the business area of the 747. Roughly speaking, short-haul business class appears to be equivalent to long-haul premium economy, each with a carbon footprint per ticket around 50% larger than standard economy class.
There are a few extra factors to consider, however. For one thing, a typical square metre of the densely packed economy section of the plane carries more weight than a square metre of the more sparsely populated first-class and business-class areas. Since extra weight means extra fuel consumption, this should reduce the carbon benefits of economy a little.
On the other hand – and probably much more significant – there is the financial implication of the different types of tickets. I plugged in a week-long return journey from London to New York in March to BA's flight finder and compared the price for each type of ticket to the floor-space the seat occupies. The results look like this:
• Economy: £362, or £548 per sq metre
• Premium economy: £844, or £750 per sq metre
• Business: £2048, or £886 per sq metre
• First: £8432, or £2342 per sq metre
For this trip, flying business class means spending around 60% more per unit of floor space than you'd pay in economy, while going first class means paying more than 300% extra.
It seems fairly obvious that the more you pay for a square metre of cabin, the more profit you give to the airline and the more you subsidise the cheaper classes of tickets. Put another way, if no one flew business or first class, the price of economy travel would have to rise, leading ultimately to lower occupancy rates, fewer flights and less global warming.
And there are even more sources of emissions caused by the more expensive tickets: the running of business-class airport lounges and first-class spas; the manufacturing of larger, fancier seats (complete with "crisp white 400–thread Egyptian cotton duvets" in the case of BA first class); and indeed the extra air travel encouraged by the large number of air miles thrown in with many business and first-class tickets.
For all these reasons, the difference in carbon footprint between economy travel and the more expensive options is impossible to pin down with any precision. But it's likely that the climate cost of flying in style will be even greater than the size of your luxury reclining seat might suggest.