Within the ZHAW’s carbon accounting, no single area carries as much weight as mobility, with air travel emissions being particularly prominent. When it comes to staff business travel, more than 90% of emissions are attributable to flying. Travel by car, train and bicycle accounts for a significantly smaller share. Since 2020, the ZHAW has been systematically recording these air travel emissions, with data extending as far back as 2017. To also reflect the climate impact of emissions released at altitude, the ZHAW applies a Radiative Forcing Index (RFI) of 2.7, which is based on the recommendations of an internal study. The peak level before the COVID-19 pandemic of around 2,720 tonnes of CO₂-eq in 2019 became a reference point for reviewing performance and developing a reduction pathway.
Aaron Ehrat
Operational Sustainability Manager, ZHAW sustainable, President's Office
“Each School implements the shared reduction target with its own measures. This decentralised approach is proving effective. However, part of this progress is simply a consequence of the high pre-pandemic baseline. Starting from a very high level makes the first reductions easier to achieve. The hardest part of the journey still lies ahead.”
Behavioural changes caused by the pandemic
The COVID-19 pandemic then brought travel to a halt. In 2020 and 2021, emissions fell to a fraction of their previous levels, largely because very little travel took place due to mandatory home working and widespread uncertainty about travel. This raised the question: would previous travel patterns return once travel restrictions were lifted? To explore this question, the ZHAW conducted a series of internal focus groups involving both frequent and occasional travellers. The aim was to better understand what drives travel activity at the university and which measures could be implemented to reduce it.
As a result of this work, and following an internal consultation process, the ZHAW resolved at the end of 2023 to reduce its travel emissions by 50% by 2030 compared with pre-pandemic levels (average for 2017–2019). To support this goal, the university introduced an air travel emissions budget that allocates emissions allowances to each School, the President’s Office and Finance and Services. Allocations are based on historical emissions and historical emissions per FTE. Students are not yet subject to these measures, which are reviewed annually by the Executive Board.
A significant reduction achieved together
In 2024, the ZHAW recorded 1,732 tonnes of CO₂-eq,well below pre-pandemic levels, though still leaving room for further improvement. The following year marked a turning point. In 2025, air travel emissions fell by a further 21% to 1,364 tonnes of CO2-eq.On an FTE basis, this equates to 0.47 tonnes, which is less than half the figure for the 2017–2019 baseline period of 1.06 tonnes per FTE.
The reduction pathway envisages a linear reduction of 50% by 2030. As early as 2025, however, the ZHAW was already 45.8% below its allocated emissions budget – a figure that the pathway was not expected to reach until 2029. The university is therefore several years ahead of its own schedule.
A significant reduction achieved together
In 2024, the ZHAW recorded 1,732 tonnes of CO₂-eq, well below pre-pandemic levels, though still leaving room for further improvement. The following year marked a turning point. In 2025, air travel emissions fell by a further 21% to 1,364 tonnes of CO₂-eq. On an FTE basis, this equates to 0.47 tonnes, which is less than half the figure for the 2017–2019 baseline period of 1.06 tonnes per FTE.
The reduction pathway envisages a linear reduction of 50% by 2030. As early as 2025, however, the ZHAW was already 45.8% below its allocated emissions budget – a figure that the pathway was not expected to reach until 2029. The university is therefore several years ahead of its own schedule.
Francesco Bortoluzzi
Head of Sustainability Programmes, ZHAW sustainable, President's Office
“The reduction in air travel emissions is substantial and is being achieved across all ZHAW Schools. However, most of the realistic levers, including travelling more selectively and choosing lower classes of travel, have already been implemented. Maintaining intercontinental links remains important – it is an integral part of being an internationally oriented university. It remains to be seen how far we can go in this regard.”
Fewer flights, different travel classes
Two developments explain the reduction. First, ZHAW staff are simply travelling less: around 1,200 trips per year compared with just over 1,500 in the baseline period. Second, there has been a marked shift in travel-class choices, yielding a substantial effect. The share of emissions attributable to business class travel fell from 14 to 3.9%, while economy class travel rose from 81 to 92.5%. The reason is straightforward: a business class seat generates up to three times more emissions than an economy class seat because it represents a larger share of the aircraft's weight and capacity.
What has remained the same
One pattern has remained unchanged over the years: the majority of emissions are generated by long-haul flights to overseas destinations. Although these flights account for only 26.6% of all trips, they are responsible for 63.2% of total emissions – roughly the same as in the baseline period. ZHAW staff most frequently fly within Europe to destinations such as Amsterdam, Frankfurt or Madrid. However, most emissions come from intercontinental destinations, including San Francisco, Los Angeles and Singapore. It remains to be seen how much further reductions can be achieved in the long term without restricting the university's international character.
At present, the ZHAW is not planning to use either offsetting or negative emissions measures to achieve net zero, although such options have been examined and discussed.
