One of the steps towards environmental sustainability is carbon-free or low-carbon transport. To work or to conferences.
Public transport has a lower carbon footprint than driving (around 180 g/km CO2eq if you drive alone, 90 g/km if you drive two) (80-100 g/km CO2eq bus) with even lower emissions when walking (around 55g/km CO2eq, depending on how fast you go and the carbon footprint of what you eat) or cycling (around 25-35 g/km CO2eq, depending on your bike, your diet, and your training) when walking. Train travel can have the lowest carbon footprint (6-40g/km CO2eq, depending on the source of electricity).
Commuting to our campus by bike is popular. There are rides throughout the year, but every May, there are regularly several teams joining the Bike to Work competition on campus. It’s not about winning but promoting cycling in the city and also getting to know fellow cyclists, as the competition is organized as a team event. The campus management supports cyclists in various ways. For example, by providing space for storing bikes at the main gatehouse (although the maximum capacity was already reached during this May ́s competition). The management of the Institute of Experimental Medicine even pays the entry fee for all its participants and gives out prizes to the most active cyclists. This year, 2023, a record number of cyclists from the four largest institutes on campus have participated. A total of 67 people in 17 teams cycled 17,902km and, according to the competition system, saved 2,257kg of CO2eg (presumably relative to car transport). If we rode like this for a whole year, we would save 27t of CO2eq, or an average of 404 kg CO2eq per person.
Conference transport, especially air transport, has an even bigger carbon footprint. Because the biggest burden is the take-off, longer flights have a smaller carbon footprint than shorter flights per km. Even so, greenhouse gas emissions range between 190 and 250 g/km CO2eq. Attending one conference ‘costs’ on average about 1t of CO2eq per attendee, but one flight across the Atlantic produces over 4t of CO2eq. This is why some scientists are committed to limiting their own air travel (see, for example, https://noflyclimatesci.org/ or http://flyingless.org).
You can calculate the ecological footprint of your transport, for example, in the online EcoPassenger calculator, which includes travel by plane, car, or train, but not by bike.