Here’s a back-of-the-envelope comparison of plane and train journeys in light of some new (to me) information from EAA:
According to a highly authoritative source (ie top Google hit), train journeys are around 19 times as efficient* per distance travelled as taking a plane would be. Extrapolating from those figures (which are somewhat suspicious given the discrepancies between them when you’d think plane journeys would be pretty direct), an hour in the air is equivalent to something in the region of 175 KGs of CO2 emitted. Overland times will obviously vary more depending on the route you have to take, but seem to average at about 10 kilos of CO2 emitted in one plane-hour’s worth of train journey. Quite a difference.
But a very quick look at Ryan Air’s/EasyJet’s sites suggests you can get to, say Germany and back for about £55. The same journey by train would apparently cost about £86 – about 1.5 times as much, allowing for a few inevitable excess fees from Ryan Air. It seems like there’s good reason to be sceptical of typical offsetting options, not least because they allow for a certain amount of greenwashing by the airlines. But according to Effective Animal Activism’s latest estimates, giving approximately £4.60 ($7.40) to their top rated charities averts a tonne of CO2. This is, ostensibly, a *side-benefit* – their main purpose for those who support EAA’s charities is reducing very large amounts of animal suffering - which I hope the inevitable critics of the uncertainty of offsetting will consider. Nonetheless, taking it at face value as the only gain, this means that if you pay, say, £65 for the plane ticket and give the £20 saved towards these charities, you’ll have the net effect of reducing effective CO2 emissions by roughly 4 tonnes compared to the comparative neutrality of taking the train.
But that doesn’t account for the time saved – imagine that you might have done paid work, or perhaps money-saving labour with the extra time you gain from flying. Broadly speaking, the further you travel, the greater the proportion of time you seem to save, so it’s hard to generalise. A four hour flight, according to that page, could be anything between 8 to 15ish hours. So let’s say the plane saves you approximately 6 hours. What this is worth depends largely on your income, and how productively you use your free time. If you earn £10 an hour and use free time at about half your employment efficiency (ie you do about half the good with your free time as you would by just donating the salary of your equivalent working time), the difference between plane and train is just over another 6 tonnes of CO2 averted for a gain of about 10 tonnes averted CO2 compared to taking the train.
*accounting for the effect of emissions higher into the atmosphere.