The Carbon Footprint of the Consortium

Part of my motivation to join the Pioneer project was the environmental topic. The chance to contribute to tackling the challenge of climate change captivated me. On the other hand, here I want to be very honest with you, another part of my motivation came from the prospect to travel around a lot in Europe and even the world. These contradicting feelings bothered me for a while. Eventually, I came to the conclusion that the benefit of research is worth a distinct amount of traveling. However, in my opinion we scientists have to act as role models even more if the research is dealing with an environmental topic like it does within the Pioneer project. We must take responsibility and try to reduce our CO2 emission as much as possible.

Of course, others have already thought about this issue. Didier Barret presented a carbon footprint calculator for large research consortia [1]. It can be found on Before using the calculator let’s have a look at the background. The tool focuses on aviation since flights are the biggest contribution to a scientist’s carbon footprint. Basically, it calculates the carbon footprint of round trips, so traveling from a city of origin to a destination and back. This calculation is performed individually or for a group of origins and destinations. The latter is handy to assess the footprint of consortium meetings or conferences and even allows to determine an environmentally preferred meeting location.

For this purpose, the tool on the one hand calculates the distance between a given pair of cities. Deviations from the shortest possible path are considered. On the other hand the tool uses seven different publicly available methods to calculate the carbon dioxide emission as a function of the flight distance. The results of the methods may yield estimates that differ by a factor of five due to uncertainties in the flight related emissions. The environmental impact of aviation is not limited to the combustion of fuel and by this producing radiatively active substances (RAS) such as CO2. Furthermore, planes release material in the atmosphere that produce/destroy RAS such as NOx or substances that trigger the production of aerosols. These non-CO2 effects are considered (or not) in the methods by multiplication factors on the carbon dioxide emission. When choosing multiple models an average is formed. For the calculation economy class is assumed. Higher classes can be included by an additional multiplication factor. Finally, another input is the minimum distance for flying. For shorter travel distance a journey by train is assumed.

The usability of the calculator is now illustrated at the example of the Zaragoza Catalysis School combined with the annual project meeting. Due to the corona pandemic we didn’t meet in person but online. Let’s see how much CO2 we saved, shall we? The calculator on needs the origin and destination as pairs of city name, land in US English without diacritics. For the Pioneer consortium it would now look like this:

Origins     Destination  
City Country Number City Country
Eindhoven Netherlands 6 Zaragoza Spain
Antwerp Belgium 2    
Paris France 5    
Caen France 2    
Trento Italy 2    
Lisbon Portugal 4    
Zaragoza Spain 4    
Bucharest Romania 1    
Krakow Poland 2    
Liverpool Great Britain 2    
York Great Britain 1    

For multiple people starting from the same origin (e.g. ESR + Supervisor) the number of identical entries for that respective origin in the csv file given to the calculator has to match the number of people. The minimum flight distance was set to the default of 500km. The combination of the methods of ADEME, MyClimate and DEFRA that all use multiplication factors to account for non-CO2 effects yield an emission of 17.3t of CO2 Equ. as can be seen in Fig. 1. The ICAO method that is not using any multiplication factors and is therefore not recommended by Barret yields 6.7t CO2 Equ. There is need for a commonly accepted standard on flight emissions!

Fig. 1: CO2 emission for traveling to Zaragoza, Spain from different origins calculated with the ADEME, MyClimate and DEFRA method.

Barret argues that videoconferencing takes about 7% of the carbon yield of an in-person meeting. This would make 1.211t CO2 Equ. Eventually we saved 16.089t of CO2. Now I feel better even though I couldn’t go to Spain…

Even when traveling will be allowed again in the hopefully not so distant future we should try to keep our footprint as small as possible. Barret advises to limit conference attendance to the absolute minimum, use videoconferencing as often as possible or combine smaller meetings into a big one to reduce the amount of traveling. He sums up this whole issue very nicely:

“Traveling will not be banned but optimized.”

This text was written by Maik Budde

[1] Barret, D. Estimating, monitoring and minimizing the travel footprint associated with the development of the Athena X-ray Integral Field Unit. Exp Astron (2020).

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