An astronomical institute's perspective on meeting the challenges of the climate crisis
Knud Jahnke, Christian Fendt, Morgan Fouesneau, Iskren Georgiev, Tom Herbst, Melanie Kaasinen, Diana Kossakowski, Jan Rybizki, Martin Schlecker, Gregor Seidel, Thomas Henning, Laura Kreidberg, Hans-Walter Rix
aa r X i v : . [ a s t r o - ph . I M ] S e p An astronomical institute’s perspective on meetingthe challenges of the climate crisis
Knud Jahnke , Christian Fendt , Morgan Fouesneau , Iskren Georgiev , TomHerbst , Melanie Kaasinen , Diana Kossakowski , Jan Rybizki , Martin Schlecker ,Gregor Seidel , Thomas Henning , Laura Kreidberg , and Hans-Walter Rix Max Planck Institute for Astronomy, Heidelberg, Germany * [email protected] + these authors contributed equally to this work ABSTRACT
Analysing greenhouse gas emissions of an astronomical institute is a first step in reducing its environmental impact. Here, webreak down the emissions of the Max Planck Institute for Astronomy in Heidelberg and propose measures for reductions.
Humanity’s production of greenhouse gas (GHG) emissions is threatening our own habitat, our physical and mental health,and the chances of long-term survival of human society as we know it . The greenhouse gases emitted as we burn fossil fuelsfor energy have already resulted in a mean surface temperature rise of more than 1 ◦ C since the late 19th century . To furtherlimit the temperature rise to less than 1.5 ◦ C as per the Paris agreement requires all sections of human society to reduce theirGHG emissions to net zero by 2050. The scientific profession is not exempt. It is our responsibility to analyse the origin ofour work-related emissions, to identify solutions for reducing emissions, and to determine the responsibility on a personal,institute-, community-, and society-wide level for implementing the necessary changes.As astronomers of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, we have assessed our work-related GHG emissions. The MPIA is a well-funded, international astronomy research institute with ∼
150 researchers and ∼
320 employees in total. A wide range of research is conducted at the institute, including the development of astronomical in-strumentation, analysis of observational data, and theoretical modeling of astrophysical phenomena with computing facilities.The institute is scientifically well connected both within Europe and internationally, which, in combination with the broadrange of research departments, makes it a good test case for the analysis of research-associated GHG emissions. This reportcan therefore serve as a template for other institutes. Our analysis provides a complementary, European perspective to the anal-ysis by the Australian astronomical community , the Canada France Hawaii Telescope , the annual European AstronomicalSociety conference , and an earlier analysis of US astronomy . MPIA greenhouse gas emissions
We assessed the MPIA’s GHG emissions in seven categories; business flights, commuting, electricity, heating, computerpurchases, paper use, and cafeteria meat consumption. These categories were selected either because they were likely tohave a large contribution or because we had no prior gauge of their significance. For this first assessment, we omitted otherpurchases, including materials and components for instrumentation, additional office supplies, and IT hardware other thandesktop and laptop computers.The GHG emissions associated with some categories were easily determined, for example from electricity and heating oilbills, computer expenses, and paper purchases and recycling amounts. However, other categories proved less straightforward.Assessing the emission from flights required both a manual transcription of invoices and a questionnaire to all employeesabout self-booked business trips, as there was no automated and accessible list of itineraries, carriers or classes. Nevertheless,all numbers quoted here (see Table 1) are capturing the MPIA’s 2018 emissions quite well. We estimate the major contributorsto our greenhouse gas emissions, that is, flying and electricity, to be accurate to within 20%.Table 1 summarizes the emission sources and the associated quantities. We have converted the units for each source intotons of CO -equivalent emissions (tCO eq). The term “equivalent” denotes that these values are normalized to the GHGimpact of CO . In particular, the numbers in this table account for flight emissions at altitude (e.g. soot, sulphates, nitrogenoxides, and cirrus clouds from contrails), as well as methane emissions from meat farming.The MPIA’s total GHG emissions for 2018 amount to 18.1 tCO eq per researcher. Alternatively, the contribution per refer-eed science publication, of which there were 583 either authored or co-authored by MPIA astronomers in 2018, is 4.6 tCO eq.1 ource Amount CO eq CO eq/researcher Percentage (%) Travel (air) 1030 flights 1280 t 8.5 t 47Electricity (on/off campus) 3,400,000 kWh 779 t 5.2 t 29Heating (oil) 150,000 l 446 t 3.0 t 16Commuting (car) 792,000 km 139 t 0.9 t 5Paper / cardboard 0.15 / 7 t 35 t 0.2 t 1Computer (desk-/laptops) 57 purchased 29 t 0.2 t 1Meat (canteen) 1000 kg 16 t 0.1 t < Total ∼
100 %
Table 1.
Summary of the MPIA’s GHG emissions in 2018. Note that electricity includes both consumption at the MPIAcampus, as well as in external supercomputing centers used by MPIA.However, regardless of the chosen denominator, these metrics have caveats in attribution. For example a substantial part of theinstitute’s emissions results from instrumentation projects that will lead to future publications but at the same time, we also donot account for the emissions associated with the construction of observing facilities used in the 2018 papers; also simulationscan take months to years.The MPIA’s astronomy-related GHG emissions per researcher in 2018 were an alarming ∼ . Moreover, the per-researcher emissions are ∼
60% higherthan for the average German resident, whose annual 2018 GHG emissions (by consumption) were 11.6 tCO eq (GHGemissions by consumption per adult resident were 14.0 tCO eq ). Of course, these numbers just compare the work-relatedcontributions of MPIA researchers to the Paris target and German averages, neglecting the additional emissions associatedwith non-research related “private” emissions by MPIA researchers, as for example housing, clothing, private mobility, orfood.Few comparisons exist in the astronomical context. We therefore compare the MPIA’s emissions to the assessment bythe Australian astronomical community . The MPIA’s per astronomer emissions are approximately half that of the Australianastronomer, which amount to 42 tCO eq per capita (see Figure 1). Note that we calculated flight emissions using the model byatmosfair.de , which estimates approximately double the emissions of the Qantas calculator used for the original Australianassessment . Adjusting the reported Australian number by this factor, the MPIA’s flight emissions are similar or somewhatlower than that for the Australian astronomical community. The second major contributor to the MPIA’s GHG emissionsis our electricity consumption, at ∼ eq per astronomer. In contrast, the electricity-related emission, at 22 tCO eq perastronomer, dominated the Australian astronomer’s GHG emissions. The MPIA’s electricity consumption mainly results fromour computing needs, which for 2018 also included the use of supercomputing facilities in Garching (Max Planck Computingand Data Facility), and at the University of Stuttgart for a specific large-scale simulation project. However, the difference toAustralia in electricity-related emissions is almost completely due to the different carbon intensity for electricity production:Whereas fossil fuel sources contributed 83% to Australia’s generation of electricity in 2018 , the contribution in Germanywas ∼ , and MPIA’s delivery contracts have a carbon intensity even substantially below that. Thus, for the Australian,community the electricity usage for computing is calculated to require 0.905 kgCO /kWh, whereas MPIA’s electricity con-tracts average 0.23 kgCO /kWh. Lastly, we note that the MPIA’s heating oil emissions in 2018 are comparable to the “campusoperation" emissions derived for the Australian community (both 3 tCO eq per researcher), which are extrapolated from thebuilding power requirements of one institute. Potential measures to reduce emissions
To reduce our astronomy-related GHG emissions, we need to identify which measures will be effective and need implemen-tation at which level, i.e. at the level of the individual researchers, the MPIA, the Max Planck Society, the astronomicalcommunity, or human society in general. Each institute will face its specific challenges. For example, we have identified thehigh carbon intensity of MPIA’s heating, which needs to be addressed at the institute level, but other measures need changesacross the astronomical community. Measures and responsibilities can only be identified once the GHG emissions have beenquantified.
Flying
Flight-related GHG emissions dominate the MPIA’s total emissions. Since there is no technology on the horizon that wouldreduce flight emissions to anything approaching carbon-neutral by 2050, much less 2030, the only way to reduce flight-relatedemissions is to reduce this form of travel. To do so, we need to identify the destinations and reasons for the air travel. . . Commuting: 0.9Others: 0.50 5 10 15 20 25 30 35 40yearly CO eq / researcher [t]AustraliaMPIAGermanpledge2030 . . . Greenhouse gas emissions per researcher in 2018
Figure 1.
Average annual emissions in 2018 for an Australian and MPIA researcher in tCO eq/yr, broken down by sources.The sources include electricity, flights (converted to the same emission model, see text), observatory operation, office heating,commuting, and ‘others’, a category that combines office desktop and laptop hardware, paper and cardboard use, and meatconsumption. Electricity related emissions include both computing and non-computing consumption, where for Australiacomputing is accounting for 88% of electricity emissions; we estimate a similar fraction for MPIA. In the plot, the smallerhatched part of the ’Electricity’ bar indicates non-computing electrical power. Observatory operation is only given forAustralia, while heating, commuting, and sources captured by the ‘others’ category are only given for MPIA. Therefore,emissions can only be compared between Australia and MPIA for electric power consumption and flights, which amount to37.0 and 13.7 tCO eq/yr for Australian and MPIA researchers respectively. The major difference lies in the amount of GHGemissions per kWh electricity, which differs by a factor of ∼ eq/yr and researcher are also compared to the German pledge of a 55% reduction of the 1990emissions by 2030, plotted per capita in dark green, which is close to 6.8 tCO eq/capita per year .In Figure 2, we break down the MPIA’s emissions by destination. A negligible fraction of emissions originates from flightsinside Germany, and only 9% from flights with destinations inside Europe (including the Canary Islands). Though small, thisEuropean component can be further reduced by replacing air with train travel . Changes to the German public servant’s travellaw in early 2020 ensure that train trips to well-connected European destinations are now reimbursed, even if they are moreexpensive than a flight . Moreover, at the individual level, many German researchers have pledged not to fly distances under1000 km . However, the vast majority of the MPIA’s flight emissions ( > are an excellent starting point. They are providing an in-depth analysis of conferencingcarbon emissions and an overview of options. Their analysis shows that GHG emissions for in-person meetings will stronglydepend on the meeting location relative to the origin of the participants, and they make cases e.g. for fully online meetingsand hybrid models with continental in-person meeting “hubs”, combined with online connections between hubs, as well asother changes that would drastically reduce the conference-induced emissions. These and other models in combination with adrastically lower number of conferences promise to be an effective measure.In contrast, we identify reasons for flights for which we have no immediate alternatives. These include, for example,extended in-person collaborative visits, that prove very effective for initiating new projects, and the installation or commis-sioning of instruments at telescopes including the LBT (Arizona) or the ESO VLT (Chile). Hardware built by the MPIA must uropeGermany North AmericaSouth AmericaAsiaAustralia Flight emissions by destination
Figure 2.
Relative GHG emissions broken down by flight destination for MPIA employees. Intercontinental flights thatcannot be easily replaced by alternative means of transport make up about 91% of flying emissions. This is due to thenumber of flights, and the high climate impact of each intercontinental flight, primarily due to distance traversed, but also dueto greater time averaged emission altitude, for example for nitrogen oxides.be mounted at a telescope site, tuned, and put into science operations, and as a result expert engineers and astronomers haveto be physically present for a larger number of commissioning runs. Hypothetically, some runs could be combined, but thisimmediately impacts engineering timescales and family boundary conditions that might be complex to solve. The instituteand the astro community have to search for measures to address these cases, which at this point are unsolved.
Computing-related Emissions
The second major contributor to the MPIA’s GHG emissions resulted from the electricity production needed for our computingresources – estimated to be 75–90% of our electricity consumption – particularly our use of super-computing facilities. Sincelarge-scale simulations will continue to be an important part of astrophysics also in future decades, we need to identify effectivemeasures to reduce the associated emissions. Note that we did not assess the emissions associated with the manufacture ofcluster hardware, only their use.As is evident from the comparison of the computing-related emissions from the MPIA versus Australian astronomers,the source of electricity generation has the greatest impact on the computing-related carbon footprint. Thus, it is imperativethat super-computing facilities be run with renewable energy, and that the electricity required for cooling is minimised. Thesources of national/regional energy production are decided at a political level, but the astronomical community, and indeedindividual citizens, can collectively campaign for this change. As a mid-term option, super-computing facilities may be movedto locations where renewables are available and less electrical energy is needed for cooling, for example, to Iceland, whichhas an average of 0.028 kgCO eq/kWh emission for produced electricity in August 2020. Additionally, potential idle times,and hence the required amount of hardware, could be reduced by switching to more cloud computing, because there, capacityutilization is generally higher than for local computers . As a community, we should guarantee an efficient use of super-computing resources. This applies both to code efficiency, as well as regarding the computing architecture that we build up orrent . All these options will require changes at the institutional and astronomy-community level. Heating and local energy production
Finally, we briefly touch on the MPIA’s buildings. The use of oil for heating at 446 tCO eq is the third largest contributor to theMPIA’s GHG emissions. Oil has been used since the institute’s buildings were inaugurated in 1976, due to their distance fromthe city’s district heating and gas network. For the future, the only viable and sustainable option for heating the institute isto use ground heat, in combination with an electrically-operated heat pump. This type of heating system is already employed t the House of Astronomy, the astronomy education and outreach center built on the MPIA campus in 2011. Not only canthis heating system save 50% of energy compared to oil/gas-based systems, but also it can be run carbon-neutral on renewableelectricity. Installation of such a heating system can, in principle, be implemented at the institute level, as can improvementsto building insulation, which reduce the heating needs. These changes have been proposed for the MPIA and are currentlyunder review.MPIA’s electricity is consumed both on campus for a mix of computing (including cooling), workshops, cleanrooms, andgeneral office consumption, and to a large part in external high-performance computing centers as described above. While theassociated carbon emissions will decrease along with Germany’s decreasing use of coal and gas for electricity generation, thisprocess will take a long time. We note that the MPIA’s utility contracts have a carbon intensity about half that of the Germanaverage, and in principle, for a relatively small extra cost, these contracts could be changed to provide 100% renewableelectricity. However, many such contracts would not actually lead to more renewable energy being produced, but instead, onlyformally redistribute renewable electricity volumes or emission certificates between contracts. Thus, in reality other measureswould have a greater de facto impact. We proposed a photovoltaic installation on MPIA’s roof, also currently under review,which would initially produce ∼
10% of MPIA’s on-campus electricity consumption at zero additional cost.
Conclusion
We have assessed and summarised the MPIA’s research-related emissions for the year 2018, finding that the average MPIAastronomer produced at least 18.1 tCO eq of research-related GHG emissions in that year, a sobering 3 times the emissionsneeded for Germany to meet its 2030 goals set in accordance with the Paris agreement. We identified the areas in which weproduced the most GHG emissions and urge other institutes to conduct their own assessment. Each institute will face a uniqueset of challenges, depending on its location, funding structure, and fields of research. These challenges can only be addressedonce quantified . However, many of the challenges will overlap, as is apparent from our comparison of the MPIA’s emissionsto those of the Australian astronomical community.We identified a high carbon cost associated with astronomy-wide issues, but also a few that were institute specific. Overall,work-related travel dominates our carbon footprint and must be addressed as a community. If we continue to travel by air aswe do now, we will not meet the required global reduction in CO emissions. The astronomical community should adopt someof the recommendations of Klöwer et al. , and go beyond them in some respects. The second dominant contribution is theelectricity generation for computations on clusters. Changes in the production of electricity are required to address this in thelong term, but we can start to partially address this at the institute level with on-site, renewable means of energy production.For example, we have proposed the installation of solar panels on the flat and vacant MPIA roof space. The third highestcontribution, which was institute-specific, was the high carbon footprint associated with heating. We have recommended thatthe heating system be changed to a ground heating system in the future.We require both a local and community-wide approach to reduce the GHG emissions associated with astronomy research.For this, we need the lead of both our professional organisations (e.g. International Astronomical Union, European and Amer-ican Astronomical Societies) and funding agencies, as well as the development and leading by example of larger institutes orcommunities. The political landscape is unlikely to adapt rapidly enough to the evolving climate crisis situation. Instead, weas astronomers need to ‘own’ our emissions and adapt the culture and technology we use to conduct our research. In doing so,we can set an example for others to follow. References McMichael, A. et al. Climate change and human health: Risks and Responses (World Health Organisation, 2003). Edenhofer, O. et al.
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