The impact of astronomy on climate change

Australian astronomers generate more greenhouse emissions than the average Australian citizen, thereby exacerbating the climate crisis. By quantifying contributions from different activities such as supercomputing and air travel, as presented here, astronomers can focus on reducing emissions by changing their practices in the most critical areas.

Astronomical research facilities, such as space telescopes, space probes or ground-based observatories, are the largest contributor to an astronomer’s carbon footprint, well beyond other activities such as flying to conferences or running computer simulations.

Conflicting methodologies for estimating the CO₂ intensity of the space sector are beginning to emerge because of a lack of publicly available data, resulting in extensive variations that undermine the credibility of reported results.

Averting the imminent climate crisis requires large reductions in greenhouse gas emissions within this decade. To provide a benchmark for reduction and to identify the main sources, we estimate the carbon footprint of astronomy research in the Netherlands over 2019.

Analysing greenhouse gas emissions of an astronomical institute is a first step to reducing its environmental impact. Here, we break down the emissions of the Max Planck Institute for Astronomy in Heidelberg and propose measures for reductions.

The development and use of research infrastructures accounts for more than 70% of the carbon footprint of the Institute for Research in Astrophysics and Planetology. Our community needs to rethink this crucial facet of astronomical research to engage in effective and perennial reduction strategies.

Measuring the carbon emissions of the CFHT in 2019 reveals that the per employee emissions are 16.5 tCO₂e, six times above the recommendation of the Paris Agreement, with ~63% due to the electricity consumption of the summit facility and ~25% to out-of-state air travel. Concerted efforts are underway to reduce this figure.

The 2019 carbon footprint of the W. M. Keck Observatory is estimated at 3.0 tonnes of CO₂ equivalent per science night and that figure will move towards net zero over the next decade or so by decarbonizing the Observatory’s vehicle fleet, aviation footprint reductions and other measures.

The annual meeting of the European Astronomical Society took place in Lyon, France, in 2019, but in 2020 it was held online only due the COVID-19 pandemic. The carbon footprint of the virtual meeting was roughly 3,000 times smaller than the face-to-face one, providing encouragement for more ecologically minded conferencing.

The climate crisis is no longer a prediction for the future, it is happening here and now. Astronomers have realized that they need to become part of the solution and are working towards reducing their own carbon footprint as well as communicating an astronomical perspective.

Climate change is affecting and will increasingly affect astronomical observations, particularly in terms of dome seeing, surface layer turbulence, atmospheric water vapour content and the wind-driven halo effect in exoplanet direct imaging.

Computer use in astronomy continues to increase, and so also its impact on the environment. To minimize the effects, astronomers should avoid interpreted scripting languages such as Python, and favour the optimal use of energy-efficient workstations.

The 2020 COVID-19 pandemic forced a string of cancelled conferences, causing many organizers to shift meetings online, with mixed success. Seizing the opportunity, a group of researchers came together to rethink how the conference experience and collaboration in general can be improved in a more virtual-centric future.

A recent survey suggests that reducing the number of meetings and conferences is a viable way to address concerns about the effectiveness of the modern scientific collaboration process, its effects on the environment and the well-being of the community.

Astronomers are trusted voices in the communication of science; our community should resist inundating people with facts and figures but use its advantage to encourage the public to listen to climate change experts and encourage the need for urgent cross-sectoral systemic change.

Astronomers are used to advocating for (financial) support for their future endeavours, but how should they go about lobbying for support for issues such as the climate emergency? Join forces with those experienced in effecting policy change.

The impact of astronomy on the Earth’s climate is being increasingly discussed, not least in Chile, home to many astronomical observatories, during the seventeenth annual meeting of the Chilean Astronomical Society (SOCHIAS) in January 2022.

Quantitative estimates presented in this issue demonstrate that astronomers contribute more to climate change than the average global citizen. Concerted actions are needed to reduce the ecological impacts of our occupation.

As the world recovers from one global crisis, it must steel itself for the coming of a far greater one: the climate crisis. Astronomers and planetary scientists have roles to play as trusted scientific experts, but should seek partnerships with domain experts when venturing outside their areas of knowledge.

In-person conferences have typically resulted in a large carbon footprint while limiting inclusivity of those who can attend. This analysis uses the pandemic to gauge like-for-like environmental and demographic outcomes for virtual conference attendance.

Biennials, regional hubs and virtual attendance can slash emissions, new calculations show.

Conferences are a pivotal part of the scientific enterprise, but large in-person meetings have several disadvantages. As the pandemic experience has shown, online meetings are a viable alternative. Accelerating efforts to improve conferences in virtual formats can lead to a more equitable and sustainable conference culture.

Climate scientists recommend ways to boost the value of virtual conferences and reduce carbon footprints even when travel curbs ease.