The ETH Zurich flight emission project: Emissions 2016-2019

Abstract

The following report shows the evolution of the greenhouse gas emissions from flights from business trips undertaken by ETH Zurich staff and guests, provided that the expenses are covered by ETH Zurich, and by students as part of their curriculum for the period 2016 to 2019. Overall, the flight emissions have decreased in 2019 compared to the base period 2016-2018, and more than half of the departments have already met their pledged 2025 reduction targets. This conclusion should be interpreted with care since year-to-year variations in the flight activity and therefore emissions are large. The data however show that in 2019 almost all employment categories contributed to this decrease, but overall less burden for emissions reductions are put on early career researchers (doctoral students) compared to more established researchers and professors, and emissions from guests have been cut the most (in %). For the base period, long-haul flights caused most of the emissions (86 %) although these only come from 38 % of the flights. For 2019, these numbers are 86 % and 41 %, respectively. Policies addressing or discouraging short distance flights are often aimed at flights that can be replaced by other means of transport. For the period 2016-2018, 38 % of the long-haul flights were also related to non long-haul flights, and 34 % of all short flights are related to a long-haul flight. Even thought most (94 %) flights recorded during the base period are economy class, 19 % of the emissions come from business and first class flights. This number decreased to 16 % in 2019. These numbers show that there is still potential for halving the emissions from business (and first) class flights just by changing flight class, and by cutting short flights that are not connected to other flights.