The current exploitation of natural resources is putting the foundations of human civilization at risk. Planetary boundaries are increasingly transgressed, suggesting that Earth is now well outside of the safe operating space for humanity[1]. In particular, ongoing extensive emission of greenhouse gases (GHGs) leads to a rise of global temperatures with unforeseeable negative effects on nature, humans, and societies. In order to limit the effects of the accelerating climate crisis for life on Earth, it is imperative to drastically reduce the emission of GHGs. The 2018 IPCC Special Report on “Global Warming of 1.5 °C” (SR15) concluded that global warming must be limited to 1.5°C by the end of the century. Any pathway aiming at the SR15 goal requires immediate and massive changes in our energy usage and production away from fossil fuels. Technological innovation alone is not sufficient for this. The SR15 stresses that it is not only the energy production, but our entire lifestyle that have to be changed to mitigate environmental crisis.

Astronomical research itself contributes to a significant level to the emission of GHGs. To quantify the impact of the CRC we have to obtain a detailed assessment of our activities as one of the activities of the CRC sustainability board. A rough estimate is, however, already possible based on studies at comparable institutions. The graph shows the emissions in tons of CO₂ equivalents per astronomer per year attributed to different sources, based on studies for the MPIA in Heidelberg and the IRAP Toulouse. Qualitatively, our numbers will be similar.

Figure based on Jahnke et al. (2020) and Knödlseder et al. (2022)

We see that telescope construction provides the largest contribution, asking for extended research based on archival data and coordinated efforts within the whole astronomical community. The next big block stems from flights, mainly to conferences. With all effects included, aviation contributes 7% to the global human-made climate forcing across all sectors[2]. This asks for virtual conferences, ground transportation and regional hubs[3]. Electricity is used to a large degree for computing so that we need to care about the efficiency of our simulations[4]. Finally, we need to discuss with the university how to improve the energy efficiency of our buildings to reduce in particular the amount of CO₂ emitted when heating the buildings. 

[1] Richardson et al. (2023)

[2] IATA  sustainable fuel roadmap (2021)

[3] Burtscher et al. (2020)

[4] Zwart et al. (2020)

There is no one-fits-all solution for sustainability but all measures must be based on a thorough evaluation of the local situation. Any approach needs to follow a scheme as described e.g. by the UNFCCC “Climate Neutral Now” Initiative:

(UNFCCC, CC BY-NC-SA 2.0)

Individual steps can be further split up, like in the Eco-Managment and Audit Scheme (EMAS) of the European community, but it is clear that any measure that is not purely cosmetic must be based on a transparent evaluation and reporting of numbers on the environmental impact[5]. Therefore we have to start with quantitatively assessing all fields that we can directly influence and measure. 

For individual measures to reduce our environmental impact, we can build on a long list of measures already derived in the Hoch-N network of German universities (now DG Hoch-N). Most relevant for us are the three areas

They cover the actual research, operations, and our educational activities within the CRC. For the operational part we can also build on the long list of measures specified in the Catalogue of Recommendations for Sustainability in the Max Planck Society. Detailed implementation plans in an academic environment exist for instance for the ETH Zürich, the Ghent University  or the University of California. They cover the main areas of

• Energy
• Mobility
• Biodiversity & Food
• Supplies & Waste

Obviously, these are fields that are equally relevant to our efforts. To close the cycle of the general sustainability scheme all steps need a continuous assessment and monitoring to evaluate the measures with respect to 

• Feasibility
• Environmental effectiveness
• Budget and effort

At the end the transformation to sustainability in our research and in the society needs to build on support and engagement of all members. It requires a cultural change in many of our practices[6,7]. This cannot be commanded top-down although it needs to be supported top-down [8]. Instead it must profit from the daily engagement of everyone in the CRC, from project leads to students. Currently there is an clear mismatch between awareness of the sustainability crisis and daily action[9,10,11]. For the French example Blanchard et al. (2022) have shown that this is even worst in astronomy when looking at the eventual numbers of CO₂ emission. Therefore, communication and transparency are keys towards any sustainability efforts. A main task of the sustainability board therefore is to inform about possibilities of behavioral changes, give advice on alternatives to conventional approaches., and collect feedback from the members with respect to activities that can be done in-house to minimize the environmental impact of our work.

[5] Sweke et al. (2022)

[6] ALLEA Report  2022: Towards Climate Sustainability of the Academic System in Europe and beyond

[7] Crumley-Effinger & Torres-Olave (2021)

[8] Dobbelaere et al. (2023)

[9] Blanchard et al.  (2022)

[10] Whitmash et al. (2020)

[11] Schrems & Upham (2020)

With the application for the CRC to the DFG the CRC members already committed to immediately implement a  number of “no-regret” measures directly from the start. They are expected to reduce the amount of green house gas emissions from travel, in particular from flights, but also from telescope operations:

• Members of the CRC generally travel by ground-transport to destinations which can be reached in 6 hours door-to-door.
• CRC members assess the climate impact of the scientific events they organise (including visitor invitations) in their planning stages.
• If the impact on climate is high, scientific meetings, workshops, and conferences organised by the CRC will incorporate the possibility of online participation for speakers and participants.
• An estimate of the carbon footprint must be submitted together with each travel request.
• Our aim is to compensate for the CO₂ emission through atmosfair or equivalent projects with procured certificates according to the DFG guidelines for compensation payments.
• The Sustainability Board will come up with a strategy of how to measure the “success” of our efforts.The APEX telescope will switch to green energy via solar power in the very near future. The current estimate shows that this measure will pay off after only two years of operation. We intend to push toward similar measures for FYST.

In the constitutional members assembly of the CRC1601, the following persons were elected as members of the sustainability board: Volker Ossenkopf-Okada, Sven Thorwirth, Frank Lewen, Josefa Großschedl. Current non-voting members are Vittoria Brugaletta, Parit Mehta, Wonju Kim, Isabelle Breloy. More members from the CRC institutions other than the University of Cologne are still strongly desired.

The Sustainability Board is responsible for coordinating the evaluation of the environmental impact of the CRC activities, i. e. measuring, in particular, the carbon footprint of the research, with the aim to reduce it. This is done with the support of the sustainability offices of the partner institutions (e. g. the Sustainability Office of the University of Cologne). Based on this assessment, the board proposes measures to reduce the environmental impact to the CRC Executive Board. 

Moreover, the Sustainability Board proposes and establishes a series of talks and workshops for the sensitisation of the CRC members towards sustainability issues and for establishing practical solutions in the daily work, like sustainable conferencing techniques. 

The board will give advice on alternatives to conventional approaches. and collect ideas of the CRC members how to to minimize the environmental impact of our research. It will clearly communicate to efforts and progress to the CRC members and the general public.

The board meets monthly, every second Tuesday. All meetings are open to all CRC members. New contributors are always welcome. As described above openness and transparency are a key in our work for a transformation of the research towards sustainability.