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Air travel

The following subpage provides information about the process of flight data collection
Data collection

Relevance, target setting and monitoring

Greenhouse gas emissions (t CO2e)

The Executive Board of the University has decided that UZH's flight-related greenhouse gas (GHG) emissions may increase to a maximum of 60 percent of the pre-pandemic level (average of 2018/2019 as baseline) in 2022 and must be reduced by at least 3 percent annually thereafter compared to the previous year. This corresponds to a total reduction in emissions of at least 53 percent by 2030. In addition, the university management recommends that the faculties set more ambitious reduction targets.

The University of Zurich is actively and consistently committed to the global goal of sustainable development. It has set itself the goal of climate neutrality by 2030 in the Implementation Strategy ("Umsetzungsstrategie") 2030 for the Sustainability Policy.

Air travel causes a large share of GHG emissions in UZH's regular operations. Before the Covid-19 pandemic, this share was around 35 percent (2018/2019) of UZH's total GHG emissions; due to the measures taken, this share has decreased and is now smaller than the share of UZH's electricity and heat purchases.

All flights that were at least half financed by UZH are taken into account. Around 85 percent of these emissions come from long-haul flights, although these only account for around one third of flights. Every avoided long-haul flight is therefore a considerable relief for the climate.

In 2022, flight-related GHG emissions were allowed to rise to a maximum of 60 percent of the 2018/19 level.

Bar chart showing the development of flight-related greenhouse gas emissions from 2018 to 2030, up to 2022 with actual values, afterwards with the targeted reduction path to at least 53 percent; the targeted reduction path is shown as a red line; the actual values are shown as blue bars (2018 above 6000 tons of co2, 2019 over 7000 t co2, 2020 under 2000 t co2, 2021 under 1000 t co2, 2022 under 4000 t co2); in the background the Zurich skyline and an airplane are shown as gray silhouettes

Measures of the faculties and other units

According to the decision of the Executive Board of the University, the faculties define own measures to reach the reduction target.

Faculty of Theology and the Study of Religion

At the Faculty of Theology and the Study of Religion, flight costs are only covered if the following conditions are met:

  • The public transport connection (train/bus) takes 
    • for "outgoings" more than 10 hours (more than 14 hours on night trains). 
    • for "incomings": more than 8.5 hours (more than 12 hours on night trains).
  • It is not a short stay (outside Europe the minimum is two nights, intercontinentally the minimum is three nights on site). 
  • The Dean's Office has authorised the flight. An application must be submitted for this. If the applications exceed the available CO2e budget, the approval or rejection of the application will be decided by lot.

Faculty of Law

  • Restriction of short-haul flights; incentive tax (CHF 100 per tonne of CO2e) used to offset CO2e emissions. Upon request, waiver of the incentive tax for people with disabilities/chronic illnesses; in addition, upon justified request, an exemption can be applied for a maximum of once per year (for research and participation in UZH teaching events).
  • More information can be found on the website of the faculty.
    Faculty of Law

Faculty of Business, Economics and Informatics

  • Incentive tax that is used to compensate for all CO2e emissions and is based on the market price for certificates (amount corresponds to the price of the certificate provider in each case).

Faculty of Medicine

  • Incentive fee (amount determined annually by the Faculty Board). A reduced steering fee shall apply to junior researchers.

Vetsuisse Faculty

  • Incentive tax for all continental flights (flat rate of CHF 100 for flights with less than one tonne of CO2e); in addition: CO2e compensation for all intercontinental flights. Annual one-off waiver of the incentive tax for young researchers.

Faculty of Arts and Social Sciences

  • Incentive tax (CHF 130 per tonne of CO2e, but minimum tax CHF 130, of which CHF 30 goes into compensation projects and CHF 100 into a fund to promote train and bus travel).
  • Upon request, waiver of the incentive tax for people with disabilities/chronic diseases; upon justified request, an exemption can be applied for once per year (e.g. for field research).
  • More information can be found on the website of the faculty.
    Faculty of Arts and Social Sciences (German)

Faculty of Science

  • All flights are subject to an incentive tax of CHF 200 per tonne of CO2e emitted. The money is collected in a fund. There are no exceptions. 
  • Each department receives back 20 per cent of the levies paid by the departments' profit centres. This money ("Justice Fund") can be used at the discretion of the institute, but must prioritise the needs of young researchers (e.g. networking) and must not lead to practices that favour one particular person over another (e.g. gender). 
  • Train journeys by MNF members are paid from the incentive tax. Expenses are only paid for train journeys if the place of origin or destination is outside Switzerland or if the costs within Switzerland amount to more than CHF 100. The money can also be used for other sustainability projects. 
  • More information can be found on the website of the faculty.
    Faculty of Science

Digital Society Initiative (DSI)

  • The DSI has decided that the lump sum contributions paid to candidates of the "DSI Excellence Program" may not be used for long-distance flights (longer than 3,500 km). Furthermore, they may not be used for air travel to places that can be reached within seven hours by train.

Pilot project: CO2 compensation

Four faculties and one division of the Executive Board of the University want to offset their GHG emissions of flight-related emissions (or part of them), in addition to introducing their reduction measures . The Sustainability Team took over the coordination in this regard and has selected an offset provider for the years 2023 and 2024 as part of this pilot project. This is atmosfair.

In the selection process, it was particularly important that the credits are of a very high quality (including additionality and permanence as well as co-benefits, e.g. promotion of biodiversity), so that the ecological benefit is secured.


Travelling fewer air miles is the most important lever for reducing GHG emissions. Basically, there are the following options:

  • Use virtual presence as an alternative to air travel. This applies to their own travel as well as to inviting speakers and examiners at UZH's expense. The environmental impact of the IT infrastructure required for video conferencing and other forms of virtual exchange, while not negligible, is generally much lower. A video conference would have to take 8,700 hours to offset a flight from Zurich to New York and back in CO2 equivalents
    Factsheet Business Travel. (PDF, 364 KB)
  • Reduce the number of people travelling. Selectively choose which person in a team travels to an event and then inform the rest of the team about the exchange.
  • Travelling by bus or train. When travelling in Europe, rail and long-distance coaches are the more environmentally friendly options. For some destinations there are night trains.
  • Combine several reasons for travelling. If possible, plan the trip in such a way that it fulfils several purposes at the same time and thus replaces several individual trips (e.g. by combining several visits).

For unavoidable air travel, the following measures help to significantly reduce the environmental impact:

  • Choose economy class. By doing without Business Class, 5 to 10 percent of flight-related greenhouse gas emissions could be saved annually at UZH. The emission contribution of a flight in business class is arithmetically (due to the larger proportion of the aircraft used) at least twice as high as that of a flight in economy class.
  • Choose relatively efficient airlines. By choosing an efficient airline, up to 50 per cent of flight emissions can be avoided. For a distance of 6,550 km, one tonne of CO2 can be saved for a return flight (efficiency class C: 1,600 kg CO2, efficiency class G: 2,600 kg CO2).
  • Prefer non-stop flights. A non-stop flight in Europe is preferable to a flight with a stopover, as the take-off phases are particularly emission-intensive. It is also worth replacing feeder flights with rail journeys.

Other initiatives at UZH

"Air Miles Monitoring" at the Department of Geography

The Department of Geography is playing a pioneering role in reducing flight-related emissions at UZH. In order to obtain data tailored to its own needs, the department collects information on employees' reasons for travelling in addition to the flight travel data. This makes it possible to develop specific recommendations for action to reduce emissions at the department. The department is also active in the area of community building – for example by organising workshops – and thus promotes exchange among researchers on the topic of flight-related emissions.
Department of Geography

"Green Travel Top Up" by Global Student Experience

Global Student Experience raises awareness among students about sustainability in the context of mobility during semesters abroad, summer schools or internships by providing tips on its website and by sending out information sheets. The suggestions are aimed at both outgoing and incoming students. Those who travel there and back by train receive financial support of 100 francs as a so-called "Green Travel Top Up".
Global Student Experience
"Green Travel Top Up"


Since May 2021, UZH employees have been able to declare voluntary commitments to reduce their flight-related GHG emissions and other sustainability measures on an online plattform. This option is increasingly being used.
Voluntary commitment


UZH is a member of two networks related to air travel:

  • "Swiss Network for Sustainable University Business Travel": In this network, representatives of the largest Swiss universities exchange information in order to jointly reduce emissions from business travel. In addition to UZH, the network includes ETH Zurich and EPFL, the universities of Basel, Bern, Fribourg, Geneva, Lausanne, Lucerne, Neuchâtel, St. Gallen, the Università della Svizzera italiana, ZHAW and ZHdK.
  • "FlyingLess": In the network, approaches to reducing flight emissions in the academic sector are discussed and developed.

Universities and researchers around the world are also working towards a scientific environment with fewer GHG emissions from air travel, for example in these international networks:

The universities of Edinburgh and Lund. Other universities and their efforts are shown in this interaktive map  created by a doctoral student at ETH Zurich.
University of Edinburgh
University of Lund
interaktive map  

Other information



  • An overview of European night train connections:, German).
  • An overview of travel times by train (one to eight hours):, German).

Support at the UZH

  • The event management of the UZH offers ideas, examples and advice for planning virtual or hybrid events.
    Event Management
  • Multimedia and E-Learning Services of the UZH assists with infrastructure procurement for video conferencing in offices, lecture halls and seminar rooms.
    Multimedia and E-Learning Services 

Weiterführende Informationen


Emissions and time

How does travelling by train, car, plane and virtual meetings differ in terms of greenhouse gas emissions and net time spent?

Assistance for virtual events

UZH's event management supports you in organising virtual or hybrid events.

Bild für Vorschläge

Misaligned incentives recognised?

If you know of regulations or processes that create an incentive or even compulsion to choose the more climate-damaging option – please report!