Reducing carbon emissions in astronomy

Many aspects of being an astronomer result in the emission of greenhouse gases that contribute to climate change. These include direct emissions from flights, and indirect emissions from the electricity required to power supercomputers, observatories and other facilities.

A study published in Nature Astronomy sheds light on carbon emissions produced by the Australian astronomical community and makes recommendations for how astronomy and other industries can carry out cutting-edge research with a reduced impact on our planet. 

The new study, led by Swinburne alumni Dr Adam Stevens and Dr Sabine Bellstedt, and including Professor Michael Murphy from the Centre for Astrophysics and Supercomputing (CAS), found that the work-based emissions of the average Australian astronomer are equivalent to around 37 tonnes of carbon dioxide per year.

On a per-capita basis, this is 40 per cent higher than the average Australian adult and five times the global average.

Carbon emissions at the Centre for Astrophysics and Supercomputing

The study found that the use of Swinburne’s OzSTAR supercomputer – used for astrophysical simulations and processing astronomical data – was by far CAS’s largest carbon emissions source, followed by air travel, then emissions from electricity use in on-campus workplaces.

Another important factor, but one that is difficult to estimate, Professor Murphy says, is the carbon emissions from CAS’s use of world-wide astronomical observatories.

At the time of the study, the OzSTAR supercomputer was being powered by electricity from Victoria's brown-coal-dominated grid. It is now powered by 100 per cent renewable electricity.

“Members of CAS were strong proponents of the move to 100 per cent renewable electricity in Swinburne, primarily because our supercomputing needs have such large electricity requirements,” Professor Murphy says. “This single action has likely reduced CAS's carbon emissions by more than 80 per cent, based on pre-COVID–19 figures.”

Reducing air travel emissions will be more difficult. Professor Murphy says that a positive outcome from the current pandemic may be the long-term reduction of air travel for conferences and meetings as the quality and experience of virtual conferences improves.

He adds that every profession has a responsibility to understand and reduce its carbon footprint, and astronomy is no exception.

“We've now completed an initial audit of Australia's astronomy carbon emissions, so we know very well how to reduce them. We just need to get on with it and many astronomy institutes around the country are well on their way."