Burning jet fuel causes the release of various gases that affect the climate and contribute to global warming. As well as CO₂, it produces other emissions consisting of H₂O, NO_x and SO_x, which are particularly critical if they are released at an altitude of more than 9,000 meters. This makes planes one of the most environmentally harmful means of transport per kilometer traveled. The exact climate impact of a kilometer traveled by plane depends on the aircraft’s capacity utilization, age and type, among other things.

Global air traffic has risen significantly in recent years.^[1] In countries with a high per capita income, people take disproportionately more flights. In Switzerland, air travel accounts for at least 18% of the country’s entire climate impact, and in 2018 produced approximately 11.57 million metric tonnes CO₂eq.^[2] The exact value is highly dependent on what is known as the radiative forcing index (RFI), which is used to describe the stronger effect of non-CO₂ emissions at an altitude of more than 9,000 meters.

In 2022 air travel was responsible for 30% of the recorded greenhouse gas emissions of the University of Basel (energy: 62%; catering: 7%). In 2019, the university emitted 3,362 metric tonnes CO₂eq into the atmosphere due to air travel alone. On average, that corresponds to 1.1 metric tonnes CO₂-eq per full-time employee. After the pandemic-related decline in flights in 2020 and 2021, air travel increased significantly in 2022. In order to stabilize greenhouse gas concentrations in the atmosphere, the total per capita emissions for all areas of life (energy, consumption and nutrition, as well as transportation) should be no more than 600 kg CO₂eq per person.^[3] In addition, the impact of a reduction in air travel goes beyond the direct reduction of climate damage, as the university can demonstrate that excellence in research and teaching can be reconciled with sustainable travel habits.

^[3] Bundesamt für Umwelt (2020): https://www.bafu.admin.ch/bafu/de/home/themen/klima/inkuerze.html

The aim is to achieve the target reduction as quickly as possible after the package of measures is introduced by the university units. Annual monitoring of flight-related emissions will allow the effectiveness of the measures to be reviewed and, if necessary, further adjustments to be made in order to achieve the reduction target.

Professor Jens Gaab (Associated Vice President for Diversity and Sustainability) and the Sustainability Office prepared a proposal based on the greenhouse gas balance for 2017–2019. The reduction target was adopted by the President’s Board and discussed with the deans at the President’s Conference. In September 2020, the Senate of the University of Basel discussed and approved the reduction target. The target is similar to those set by other higher education and public institutions (e.g. ETH Zurich, federal administration).

The flight data for 2017 to 2022 was collected retroactively based on accounting documents and includes all flights taken by staff, students and guests, provided that the costs were covered by the University of Basel. For example, if a professor is invited to an external conference and the flight is paid for by the conference, this does not appear in the University of Basel’s greenhouse gas balance. Similarly, most student excursions are not reflected in the data for expenses claims, as the students generally book and pay for the excursions themselves. The boundaries chosen for this system are coordinated with other Swiss universities.

Proven alternatives to flying already exist; for example, train travel reduces emissions of CO₂eq by up to 90% for the same distance traveled – and it is easier to put the time spent traveling by train to productive use. Virtual meetings allow travel to be dispensed with altogether, in particular for collaborations and smaller meetings. This technology increases the availability of all participants, the productivity of all meetings (by dispensing with travel time), and the frequency with which discussions can take place (by reducing the cost of meetings). A selection of measures is presented at the "less for more" website.

The extraordinary situation caused by the coronavirus crisis has indeed pushed the University of Basel’s emissions due to air travel down to almost zero. Now, it is important to further strengthen the virtual collaboration skills gained and to redouble our efforts to switch from planes to trains. When the number of people traveling rises again after the pandemic, it is important that we continue to meet the reduction target.

Field research in South Africa, an academic conference in Japan, or a physical experiment in California – sometimes, there is no real alternative to plane travel. An academic institution cannot therefore dispense with air travel altogether. Rather than seeking to ban anything, the new air travel project “less for more” aims to prompt people to reflect on their travel habits. Is flying to Paris really necessary, or can I take the train instead and work more comfortably and efficiently while I travel? Academics can demonstrate that they base their behavior on scientific insights. Moreover, initial studies have shown that academic air travel has no impact on academic success. ^[4]

^[4] Wynes et al. (2019). "Academic air travel has a limited influence on professional success" https://bit.ly/2CJIdKC

Emissions reductions should be based on an effective reduction in air travel – in other words, they should not include carbon offset measures. The offsetting of flight-related emissions should be a complementary measure, as it does not lead to the necessary reduction in global greenhouse gas emissions. If we theoretically tried to reduce the emissions of industrial nations solely through offset measures, it would not be possible to reduce global emissions to the necessary extent by 2050 or to meet the two-degree target adopted as part of the Paris Agreement in 2015. ^[5]

^[5] Gössling et al. (2007). "Voluntary Carbon Offsetting Schemes for Aviation: Efficiency, Credibility and Sustainable Tourism." https://bit.ly/2YArl1n