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Can astronomers limit climate change?

Can astronomers mitigate climate change? This is what Leiden astronomer Leonard Burtscher and his colleagues discussed at the annual meeting of the European Astronomical Society. For the second year in a row, the meeting was online. And according to Burtscher, it should stay that way. During a special session, he explained what else astronomers could do to combat the climate problem. A summary has now been published in Nature Astronomy.

‘How can we convincingly tell the general public and policymakers that “there is no planet B” while hopping onto the next intercontinental flight for a conference at a fancy location?’, the auteurs wonder. Together with several more astronomers, they founded Astronomers for Planet Earth (A4E) in 2019. This organisation wants to make the field more sustainable and helps astronomers communicate about the climate crisis. They do this for example through workshops, conferences and campaigns.

Start with yourself, but where?

In order to take concrete steps, A4E calculated the CO2 footprint of various astronomical entities, such as observatories, institutes and conferences. ‘This enabled us to identify the biggest culprits,’ says Burtscher. ‘They are electricity, (intercontinental) flights, new purchases such as computers, heating and cooling of buildings and building materials.’ There are regional differences - one country generates energy more sustainably than another - and differences per institute - not all institutes are easily accessible by train, for example. Also interesting: senior astronomers have a larger footprint than starting astronomers. This is because they go to conferences more often, for example.

The carbon footprint of astronomical research activity as determined for the International Centre for Radio Astronomy Research (ICRAR) in Perth, (top left), for the Max Planck Institute for Astronomy (MPIA) in Heidelberg, (top right), for the annual meeting of the European Astronomical Society (EAS) 2019 in Lyon, (bottom left), and for the European Southern Observatory (ESO) (bottom right)

What astronomers can do

Based on this inventory, A4E comes up with two main ways to reduce emissions: 
1.    Switching to renewable energy
2.    Flying less

Burtscher: 'We have to get rid of electricity that runs on fossil fuels. Institutes and universities can buy their own solar panels, for example. Combined with another sustainable energy sources such as wind or water, green energy can become available around the clock.’

And secondly: astronomers should step on the plane less often. ‘Flights to conferences, for example, account for 25 to 50 per cent of the institutions' emissions,’ says Burtscher. But if you have to go to the other side of the world, taking the train is quite a challenge. ‘However, in the last year and a half, we have proved that we can also meet without flying,’ the authors say. ‘It is not only better for the environment, but also more inclusive, more accessible, more honest and safer.’ Yet the authors do understand that meetings with international colleagues are a great asset of the profession. 'We will have to normalise a culture shift from ‘face-to-face, unless not possible’ to ‘online, unless face-to-face is a necessity’.’ A4E wants to accelerate this movement.

Convince the general public

‘We have an obligation to use wide reach to warn the people of the damage done to our only home.’

But A4E wants to go a step further. How nice it would be if we could also highlight the severity and urgency of the climate crisis to the wider public, politicians and other decisionmakers,' they write in Nature Astronomy. ‘Thanks to the wide interest from the public in the universe, our reach extends beyond that of many other scientific disciplines. We therefore have an obligation to use that reach for the good. We should inform the public about the damage done to our planet. We are not climate scientists, but that gives us a neutral standpoint, the public trusts us. That is why we must use our voice to call for action and support climate scientists.’

Back to a better normal

According to the authors, we must use the changes forced upon us by the corona pandemic to define a new and better normal. ‘A normal that is ecologically sustainable, inclusive and fair.’ In order to be equitable to researchers at all career levels and from all countries, it is critical to collectively agree on a new path at all levels: institutional, national and international. ‘We must embrace virtual tools to enhance scientific collaboration, advocate for a just transition to renewable energy sources, and refuse a return to our wasteful practices of the past. We are the discipline that understands most keenly that there is no planet B: our actions must be consistent with this truth.’


Burtscher, L., Dalgleish, H., Barret, D. et al. Forging a sustainable future for astronomy. Nat Astron 5, 857–860 (2021). https://doi.org/10.1038/s41550-021-01486-x

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