This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1088/1748-9326/ad30a6. This is version 2 of this Preprint.
Flight quotas outperform focused mitigation strategies in reducing the carbon footprint of academic travel
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Abstract
The carbon footprint of academia has become a prominent concern and a burgeoning research area, with a notable focus on greenhouse gas emissions (GHG) from research-related travels. Mitigation strategies often promote alternatives, such as developing virtual communication or adopting sustainable transportation modes for short distances. While more ambitious strategies involving the transformation of research practices are increasingly discussed, these mitigation solutions are rarely subjected to rigorous quantitative assessments or meaningful comparisons. This study analyzes a unique database of about 130 000 travel segments by car, train and plane in 159 research entities across a wide array of disciplines in France. We investigate the patterns and associated carbon footprint of these research travels and explore a diversity of mitigation options. Our analysis shows that air travel overwhelmingly outweighs the carbon footprint of research travel, representing more than 96% of GHG emissions. Intercontinental flights are infrequent (less than 10% of all plane trips) but dominate GHG travel emissions, accounting for over 64% of total emissions. In contrast, domestic and continental flights are the most common but their mitigation potential by modal shift to train is limited (e.g. less than 15% for trips under 1000 km). Similar reductions can be achieved by targeting a small subset of travels, for example by modulating the frequency of conference attendance. The greatest and possibly most robust mitigation potential lies in combining modal shift with moderating air mileage (e.g. reducing travelled distance or number of flights). Strategies focusing on electrification or modal shifts for cars, proposed in official guidelines, are found to have negligible impact. In the absence of low-carbon alternatives for long-haul flights, we contend that only comprehensive strategies and policies which include moderating air travel distance or frequency can achieve a robust significant reduction in the GHG emissions from academic travel.
DOI
https://doi.org/10.31223/X5WD5H
Subjects
Sustainability
Keywords
carbon footprint, academia, Air travel, Mitigation policies
Dates
Published: 2023-10-02 10:55
Last Updated: 2024-04-26 16:25
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CC-By Attribution-NonCommercial-NoDerivatives 4.0 International
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Database composed of Research Unit information, not fit for publication for the time being
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Comment #129 Olivier Ridoux @ 2023-10-24 18:50
I wonder whether a "inertia-collapse effect" should be taken into account. My reasoning is as follows.
The ultimate goal of all these efforts is to decrease European GHG emissions by about 55 % by 2030, and academic travels is a really tiny part of the problem to solve. Assuming that all actors take their parts, the world will be very different by 2030! In particular, all potential flyers will have drastically reduced their usage of planes. This probably means bankrupt for many actors of air transportation, which probably means less planes, less plane constructors, less airports, less air connections, etc. So, the real question for an academic by 2030 will not be to fly or not to fly, but rather how to work with a distant colleague who is now out of reach. I cannot see how a 55 % GHG abattement cannot have this sort of effect.
Almost certainly, air transportation will first try to resist the reduction of passenger-kilometers, so that the actual plane-kilometers will not change much, hence the emitted GHG. How long will they resist? I do not know, but recall that next rendez-vous is in 6 years. So, if they can resist more than 6 years, it is probably the sign of a general failure of the ultimate goal. How can air transportation be such a proxy of failure? It is simple. Air transportation is a very fragile industry. If it can resist more than 6 years, then all more robust industries will resist too. Hence the failure of the ultimate goal. This is the inertia part.
At some time, air transportation will not be able to resist any longer. This means less traffic, less planes, etc. Worldwide, there are only two long-haul plane builders. How can both resist? How even one (which one?) can resist? Will they be able to convert to building short- and medium-haul planes? That seems difficult since the market is already occupied by other builders. This draws a landscape in which every long distance travel will be done in several badly-connected shorter segments. Attending a conference will no longer be worth the travel disconfort. Hence a natural collapse of the demand.
It is not as if we had our first rendez-vous in 20 years, and we could go day-dreaming clean planes and flights. We are speaking of a 55 % GHG emission abattement in 6 years. I really think that should be taken into account in such short-time projections.