[Paper Review] Estimating, monitoring and minimizing the travel footprint associated with the development of the Athena X-ray Integral Field Unit -- An on-line travel footprint calculator released to the science community

D. Barret|PubMed|Apr 12, 2020

Conferences and Exhibitions Management1 references4 citations

TL;DR

This paper presents an open-source online travel footprint calculator designed to estimate, monitor, and minimize the carbon emissions from scientific travel associated with the Athena X-ray Integral Field Unit (X-IFU) project. Using seven distinct emission factors, the tool quantifies CO2-equivalent emissions—including non-CO2 effects—enabling researchers to compare travel modes and select low-impact meeting locations, with the X-IFU project’s annual footprint estimated at ~500 tons CO2 eq, primarily from consortium meetings and reduced via video conferencing and optimized travel planning.

ABSTRACT

Global warming imposes us to reflect on the way we carry research, embarking on the obligation to minimize the environmental impact of our research programs, with the reduction of our travel footprint being one of the easiest actions to implement, thanks to the advance of digital technology. The X-ray Integral Field Unit (X-IFU), the cryogenic spectrometer of the Athena space X-ray observatory of the European Space Agency will be developed by a large international consortium, currently involving 240 members, split over 13 countries, 11 in Europe, Japan and the United States. The travel footprint associated with the development of the X-IFU is to be minimized. For that purpose, a travel footprint calculator has been developed and released to the X-IFU consortium members. The calculator uses seven different emission factors and methods leading to estimates that differ by up to a factor of 5 for the same flying distance. These differences illustrate the lack of standards and regulations for computing the footprint of flight travels and are explained primarily, though partly, by different accounting of non- CO2 effects. When accounting for non-CO2 effects, the flight emission is estimated as a multiple of the direct CO2 emission from burning fuel, expressed in CO2-equivalent (CO2eq), with a multiplication factor ranging from 2 to 3. Considering or ignoring this multiplication factor is key when comparing alternative modes of transportation to flying. The calculator enables us to compute the travel footprint of a large set of travels and can help identify a meeting place that minimizes the overall travel footprint for a large set of possible city hosts, e.g. cities with large airports. The calculator also includes the option for a minimum distance above which flying is considered the most suitable transport option; below that chosen distance, the emission of train journeys are considered. To demonstrate its full capabilities, the calculator is first run on one of the largest scientific meetings; the fall meeting of the American Geoscience Union (AGU) gathering some 24000 participants and the four meetings of the lead authors of the working group I of the Intergovernmental Panel on Climate Change (IPCC) preparing its sixth assessment report. In both examples, the calculator is used to compute the location of the meetings that would minimize the travel footprint. Then, the travel footprint of a representative set of X-IFU related meetings is estimated to be 500 tons of CO2eq per year (to place this number in perspective, it is equivalent to 2 billion kilometers driven by an average passenger vehicle). Of this amount, each annual consortium meeting accounts for 100 tons, being located at a site of minimum emission and for a minimum distance for flying of 700 km. Actions to reduce the X-IFU travel footprint are being implemented, e.g., the number of large consortium meetings has been reduced to one per year and face-to-face working meetings are progressively replaced by video conferences. As the on-line travel footprint calculator may be used to all scientific collaborations and meetings, the calculator and its methodology described in this paper are made freely available to the science communitycommunity(https://travel-footprint-calculator.irap.omp.eu).

Motivation & Objective

• To estimate and monitor the carbon footprint of international scientific travel for the X-IFU space mission development.
• To minimize the environmental impact of large-scale scientific collaborations by providing a transparent, standardized tool for travel emission calculation.
• To support the science community in reducing aviation emissions through data-driven decisions on meeting locations and travel modes.
• To promote sustainable research practices by enabling the calculation of CO2-equivalent emissions, including non-CO2 effects from aviation.
• To release a freely accessible, web-based tool for broader scientific use, supporting climate-conscious planning of international meetings.

Proposed method

• The calculator uses seven different emission factors and methods to estimate CO2-equivalent emissions from air travel, accounting for non-CO2 effects such as contrails and NOx through a multiplier ranging from 2 to 3.
• It incorporates a minimum flying distance threshold (700 km) below which train travel is considered instead of air travel, based on emission comparisons.
• The tool computes the total travel footprint for a set of participants by aggregating individual travel emissions based on origin-destination pairs and transport mode.
• It includes an optimization engine to identify the meeting host city that minimizes the total travel footprint across all participants.
• The calculator is implemented as a web application hosted at https://travel-footprint-calculator.irap.omp.eu, with source code and methodology made publicly available.
• The system was validated using real data from large scientific events, including the AGU Fall Meeting and IPCC Working Group I lead author meetings.

Experimental results

Research questions

• RQ1 What is the total annual travel footprint of the X-IFU project, and how is it distributed across meetings and travel modes?
• RQ2 How do different emission factors and methods for calculating aviation emissions vary, and what explains the up to fivefold differences in estimates?
• RQ3 Which meeting location minimizes the total travel footprint for a given set of participants, and how can this be systematically computed?
• RQ4 To what extent can video conferencing and travel reduction strategies lower the overall carbon footprint of large scientific collaborations?
• RQ5 How can non-CO2 effects from aviation be consistently accounted for in travel footprint calculations, and what is their impact on total emissions?

Key findings

• The X-IFU project’s annual travel footprint is estimated at approximately 500 tons of CO2 equivalent, equivalent to driving 2 million kilometers in a passenger vehicle.
• Each annual consortium meeting contributes about 100 tons of CO2 eq, assuming a 700 km minimum flying distance and optimal host city selection.
• The calculator reveals that emission estimates can vary by a factor of up to five depending on the method used, primarily due to differing treatments of non-CO2 effects such as contrails and ozone formation.
• Including non-CO2 effects increases the emission estimate by a factor of 2 to 3 compared to CO2-only calculations, highlighting the importance of this correction in travel planning.
• The tool successfully identified low-footprint host cities for the AGU Fall Meeting and IPCC Working Group I meetings, demonstrating its utility in real-world applications.
• The project has reduced its footprint through measures including limiting annual in-person meetings to one and replacing face-to-face meetings with video conferences, with further reductions expected.