Trains aren't as green as all that you know

An interesting number from the trains regulator:

Due to the effects of the pandemic, passenger kilometres fell by 81% and trains planned fell by 22% compared with 2019-20. As a result, estimated normalised CO2e emissions increased by 316% from 35.2g to 146.5g CO2e per passenger kilometre.

Which we can compare to:

The average carbon dioxide (CO2) emissions from new passenger cars registered in the European Union (EU) in 2018 increased for the second consecutive year, reaching 120.4 grams of CO2 per kilometre.

Yes, clearly, lockdown was exceptional. The point being - and it’s an obvious one but all too rarely baldly stated to our mind - that emissions from any particular mode of transport depend upon the capacity utilisation of that mode.

Empty trains have greater emissions, per passenger km, that single occupancy cars. Further, a little manipulation tells us that a four occupant car has about the same emissions as the average pre-lockdown and special circumstances train journey.

Trains just aren’t as green as many seem to think, nor cars as un-green as the general insistence.

There is also a point that can be derived from this. For a train system to be properly green, as is generally assumed it always will be, it has to be packed. It’s not possible to have a system that goes everywhere, at all hours, with lots of spare capacity, and still have it be green. We can have green transport by the usual measures. But it does require that the trains which are a part of it be a heaving mass of folk fighting for a seat. Or, obviously, just as green, four people in a car.