According to the study “Ganzheitliche Ökologsche Bilanzierung von Verkehssystemen” (Complete Ecological Balancing of Transport Systems) comissioned by the liberal Friedrich-Naumann-Stiftung to Dr. Klaus Rademacher, the notion that “trains are better for the environment and particularly for the climate” would be a contemporary “Spinat-Irrtum” (spinach-hoax) false data like the iron value of spinach, that was repeated over years. Sounds interesting – what’s in it?
At the core of this unconventional statement is Rademachers observation, that climate effects from the manufacturing of vehicles and the infrastructure needs of each mode of transport are typically not taken into account in climate effect comparisons and his assumption that if taken into account the plane might be the most climate-friendly means of transport (unless you can use a fully seated car).
His observation is partly correct, most comparisons don’t dig further than comparing well-to-wheel emissions, only when comparing Battery Electric Vehicles (BEV) with Internal Combustion Engine (IEC) Vehicles, vehicle production efforts have recently been normally taken into account. This makes comparisons of BEVs with planes or trains tricky, by the way.
It’s just partly correct, as the study suggests that there is no data available. Rademacher himself did not dig very deep. Though he studied some of the publications of the Umweltbundesamt (UBA), the German environmental agency, he obviously did not find the right ones. Detailed comparison of different modes of transport including all effects including manufacturing effort and the environmental effects of the infrastructure is available here.
Though some of the UBA data is disputable (like the allocation of infrastructure cost to different type of road transport by needed surface space instaed of by passenger numbers) helped me at leats to solve the problem of comparing BEVs with planes or trains. Though it did not specify BEVs in particular you could see that the climate effects of the vehicle manufacturing are just insignificant enough for planes and trains that you may simply ignore them in a comparison of climate effects without falsifying the result. I mean, you compare means of transport which are used around the clock 365 days for approximately 20 years (planes) or 40 years (trains) with cars that are parked 96% of their approximate 12 year lifespan and have an average 1,5 passengers per car which results in a disastrous effective occupancy rate of 1,25%. Rademacher calculates 33g CO2 per passenger-km to cover the production effort of a car, presumably correctly, as in line with other calculations.
Planes and cars have a similar per seat production effort. If you take the 64 times higher occupancy rate and the 1.7 time longer lifespan into account you may end up with less than 0.3g CO2 per passenger-km. Trains are considerably heavier than planes, but last considerably longer which outweighs the weight difference. Their production effort per passenger-km will be higher as long as their occupancy rate is lower. Long distance trains in Europe have occupancy rates between 40-70% so you might have to consider a bit more production effort CO2 per passenger-km, not more than 0.5 g per passenger-km.
Not working or at least discussing the UBA data assumptions leads to vaguely founded or simply wrong assumptions. One example: Rademacher considers that the infrastructure effort for tracks must be higher than for streets, because trains need more tunnels and because the transportation capacity of the road system is so much higher than of the rail system. But he did not consider that even high speed rails just need one tunnel where for motorways typically two are needed and the same goes for the concrete volume needed for bridges. This outweighs the reduced capacity of high-speed train tracks to do bends. Looking at transport capacity, of course, you cannot compare the systems capacity when calculating environmental cost per km. Then you need to compare transport capacity per km. You need to compare a two track per direction motorway with a two track high speed line. A busy two track motorway like the A 10 north of Potsdam can handle up to 40.000 cars per day. With 1,5 passengers (the EU average) this represents 60.000 transported persons per day (both directions). This passenger number needs 132 ICE trains per day running with their average occupancy rate of 55% (at DB Fernverkehr), 66 per direction. Distributed over a 18 hours timeframe less than 4 trains per hour, far below the maximum capacity.
But the key point is: Rademacher, who elswhere seems to be eager to get the complete picture, leaves the quantification of all other climate-related emissions out of the equation, which consequently leads to wrong assumptions. The radiative forcing effect of non-CO2 emissions is merely mentioned in a footnote, which documents that he could not follow or prefers not to follow the scientific discussion. His footnotes leads to this article by Robert Sausen, who currently keeps mentioning that the application of a general radiative forcing factor lacks a steering effect, certainly not in order to ignore radiative forcing of non-CO2 emissions. This applies to the calculation of the emissions of single flights, e.g. in emission trading. When comparing means of transport there is no alternative to applying a single radiative forcing factor. So – as long as you don’t know the distance – CO2 emissions in aviation must be multiplied by 3.0 to get the current global warming effect as outlined in a study of Lee et al. which Rademacher cited, seemingly without even reading the abstract.
It is correct that driving with 5 persons in a battery electric car can be better for the environment than taking the train if the train connection needs diesel or when the electricity for the trains comes to a large part from coal or gas plants.
But with any radiative forcing factor applied a plane will never be better for the environment particularly not for the climate. Not even in hypothetical cases.
And whereas diesel combustion trains and cars are on the way to be replaced by battery electric or hydrogen powered versions and the source mix of electricity for trains contains more and more renewable energy – all these develoopments are in a distant future for planes. Another aspect Rademacher preferred to ignore.