FAQ about short-haul flights

It is true: Worldwide, air traffic accounts for around 3% of CO₂ emissions. It is also true that industrial construction or agriculture cause significantly more CO₂ emissions than flying, and changes in these areas would really help us protect the climate. Therefore, we gladly invite those who manage to massively reduce CO₂ emissions in those industries (e.g., politicians) to treat themselves to a Munich-Cologne flight!

However, CO₂ is not the only greenhouse gas. The aerosols and nitrogen oxides released during the combustion of kerosene contribute significantly to the climate effect. And due to the so-called altitude effect, the climate-damaging effect of flying is far higher than one would expect from emissions on their own.  According to the Federal Environment Agency, the negative effect is two to five times as high as the effect of CO₂ alone. Hence, atmosfair assumes an impact of 7% in terms of CO₂ equivalents worldwide. Prof. Volker Quaschning has calculated that in Germany up to 10% of the harmful effects of greenhouse gases are caused by flying.

It is an ethical question as well: More than 90% of the world’s population have never boarded an airplane. Among them are those who will suffer the most from the consequences of climate change.

Ultimately, the abandonment of short-haul flights is a measure by which everyone can begin to demonstrate his or her willingness to change everyday habits for the sake of the climate. Along with other important individual measures – such as reducing meat and energy consumption, using public transportation, etc. – these changes may also improve one’s quality of life.

Of course, the climate damage of a long-haul flight to Los Angeles is higher than that of a short-haul flight from Vienna to Munich. However, flying short distances is particularly problematic from an environmental point of view for at least the following reason: The high CO2 pollution caused by short-haul flights is completely superfluous since travelling by rail is a good alternative with a much better climate balance – i.e., the climate damage caused by flying can easily be avoided on the Munich-Berlin route, but hardly on the Berlin-Los Angeles route. The Austrian railway ÖBB has calculated that on some connections an aircraft emits up to 30 times more CO2 than a night-train connection (as these night trains run on 100% green electricity).

Since there are different definitions of “short-haul” (up to 400 km, up to 1000 km, up to 1500 km, German domestic), it is difficult to relate the different numbers used in the discussion regarding short-haul flying. In any case, there were 311,000 domestic flights in 2018, i.e., 4% more than in the previous year. In the decade before that, the number of flights up to 400 km had decreased in Germany, while the number of flights between 400 and 600 km had increased significantly. There is therefore more need for action now than ever before.

Domestic flights are mainly used for business trips and for connecting flights. That is why the focus of the commitment initiative on business travel is at the heart of the problem.

The idea is right. In theory the system is flawed. In various sectors (e.g., cement industry, flights within the EU/EEA – but not car traffic), an emission rights certificate must be acquired for every tonne of CO2 emitted when trading certificates in the EU. The amount of available allowances determines how much CO2 can be emitted. The idea is to reduce the amount of pollution rights issued annually. Once the upper limit is reached, a saving in one area (e.g., short-haul flights) results in the saving industry selling its emission rights – at a high price – to others. In this respect, savings in flying, for instance, do not necessarily reduce overall CO2 emissions.

However, there have been many certificates on the market since emissions trading began – in February 2017, the surplus of certificates was 1.5 times the annual emissions rights requirement – so, in practice, emissions trading is not happening. Only when there are really fewer certificates on the market than correspond to the actual CO2 emissions is the perspective expressed in the question relevant.

In addition, flights affect the climate not only through CO2 emissions, but also through the nitrogen oxides and aerosols released at high altitudes, which are not included in emissions trading (unlike laughing gases and perfluorinated hydrocarbons), even though they more than double the climate effect of flying at high altitudes as the CO2 emitted unfolds. It is therefore questionable whether emissions trading make voluntary commitment initiatives superfluous.

If you are not using your own Lear Jet for a short-haul flight, you are using aircraft which are part of our infrastructure. Since the weight of aircraft and fuel clearly outweighs that of passengers, and gross weight is decisive for fuel consumption, relinquishing an individual flight hardly reduces the CO2 emissions of the aircraft.

Nevertheless, the climate protection effect comes about as an indirect result. The less people fly, the less it pays off to offer certain flights and the more likely it is that the flight schedule will eventually be thinned out or the respective flight connection cancelled altogether (as has already happened for the Hamburg-Berlin or Berlin-Nuremberg flights). So it is like voting: the sum of many individual decisions results in an effect. If many, perhaps even the majority, act as an individual does, then change can and will succeed – but only then. Many of the larger changes of the past have begun with individuals who found it necessary for themselves to act differently. Consistent action can be contagious!

Of course you do not like to be the only one or the “foolish one” when you travel 7 or 8 hours by train and everyone else is flying. But most people actually want to do something for the climate, and it is easier for them if they coordinate with each other, know about each other, and can therefore assume that the commitment is not in vain.

This is exactly the charm of the self-obligation initiative: one knows that individual changes of behavior do not fizzle out because so many others are doing the same!

In 2018, there will be 24 million air passengers in domestic traffic in Germany and approximately 150 million passengers in long-distance Deutsche Bahn rail traffic. Deutsche Bahn plans to expand its capacity to 200 million passengers by 2030. The numbers show that the adjustment is feasible. If you use the train, you know that the challenges, e.g., travel on Friday afternoons, will certainly be very “sporty” for the Deutsche Bahn. Nevertheless, this is one of many necessary structural changes which must be accompanied by greater investment in climate-friendly infrastructure. Initial changes in this direction can be found in the German government’s current climate package. [1]

[1] Link to the current climate package.

How much of an institution’s CO2 emissions originates from aviation and how much comes from elsewhere – e.g., electricity from coal – depends, of course, on the respective university or research institution. ETH Zurich, for instance, has calculated that almost 50% of its greenhouse gas emissions are attributable to business aviation [1], and the situation is similar at other institutions. Air traffic is an essential area for adjustment.

However, it is also clear that in most cases the share of flights on short-haul routes (e.g., domestic flights) is less than 10%. Our initiative – and your commitment – is only the beginning for a long-term transition to climate-friendly travel!

[1] Link

This is one of several recurring myths. §4 of the Bundesreisekostengesetz says: “If you use a standard means of transportation, you have to take the lowest class of this means of transportation.” This means no first or business class on, e.g., an airplane; importantly, second class on a train is permitted – and the law even allows the use of first class for train travel when the trip takes longer than 2 hours (if this is not blocked by administrative regulations, as in Brandenburg)! Nowhere does it say that you have to take the cheapest means of transportation. In fact, that would typically be with Flixbus or Ryanair. Nowhere does it say that you are forced to use a no-frills bus or airline.

For 50% or more of domestic flights in Germany, a train alternative with a travel time of about 4 hours is available. If travel to and from the airport, waiting times, security checks, etc., are all taken into account, half of all domestic flights can be replaced by train travel without any loss of time.

To counter climate change, however, we must leave our comfort zones – it is important to set an ambitious goal because only ambitious targets will enable us to achieve the 1.5 degree limit! The voluntary commitment sets a target of 1,000 km – up to 12 hours travel time by train – and this can be associated with a noticeable loss of time. Since one can often work well in a train (unlike in an airplane), this loss of time is in part compensated.

Therefore, almost all destinations in Germany, Austria, and Switzerland are covered by the voluntary commitment, as are many other destinations in neighboring countries, depending on where the journey begins. Because this is only a first step, the voluntary commitment does not cover feeder flights unless the destination of the journey itself is in the 1,000 km or 12-hour range.

While it is quite easy to determine whether the destination is less than 1,000 km away, train journey times often vary considerably depending on the day of the week and the time of day. Since the voluntary commitment does not establish a legally-assessable commitment, we do not want to establish complicated rules in this respect. In case of doubt, each person should decide for him- or herself which behavior corresponds to the spirit of the self-commitment.

Especially for parents of small children, or those with relatives in need of care, the 12-hour mark may be too high. Scientists who otherwise show exemplary environmental behavior are often affected here. There are unfortunately some life situations which preclude the commitment being upheld – in which the use of an aircraft cannot easily be avoided.

Entering into the self-commitment can lead to conflicts, the resolution of which cannot be regulated for all conceivable cases. An illness in the family may give rise to an obligation to return home quickly, urgent official obligations may arise unexpectedly, or rail strikes may restrict one’s options. The Romans had a saying, ultra posse nemo obligatur, what one cannot do, one cannot be obligated to do. The single most important thing for making the commitment is that, if it is clear you cannot uphold the commitment due to other obligations, then you should not make the commitment in the first place.

The main objective of the entire campaign is to begin by questioning and, whenever possible, avoiding everyday routines that are taken for granted while being harmful to the climate. This also applies to using a car when travelling by bicycle is just as easy, or thoughtless energy consumption in the household. That said, in individual cases it may be necessary and justifiable to make exceptions to the default rule that climate-friendly action should be the first choice.

With the self-commitment you bind yourself to yourself. You do not have to justify your choices to your university or research institution – especially to the travel expense offices – for decisions made in exceptional situations. At most, you may personally feel you should justify your choices to the people in your life to whom you have announced your commitment.