What if astronomy reduces its carbon footprint?

For the first time, researchers have tried to estimate the amount of greenhouse gases produced by 30,000 astronomers and their working instruments, which are ground-based radio telescopes, probes and rovers sent into space.

Based on initial findings published on Monday, March 28, 2022. Astronomy of naturethe total activity of these instruments since their inception has produced at least 20.3 million tonnes of CO2, equivalent to the annual carbon footprint of Estonia or Croatia.

According to astronomical data, this would mean annual emissions of 1.2 million tons. The study highlights that the number is nearly “five times higher” than the amount created by air travel by astronomers when they travel for professional reasons. “The astronomy community is currently discussing reducing the carbon footprint associated with transportation as well as supercomputing activities,” Jürgen Knodlseder, director of research at CNRS and lead author of the study, told AFP. “That’s good, except they don’t see an elephant in the room: a matter of infrastructure.”

To estimate the size of the “elephant”, the researcher went through 50 space missions and 40 ground-based observation devices: the Hubble and Max Planck telescopes, the Insight research missions (Mars), the Rosetta probe (Churi comet), the Very Large Telescope (VLT). ) in Chile…

“We must think about reducing greenhouse gas emissions in our infrastructure”

Ideally, building materials, operating costs, electricity consumption should have been taken into account, but these data were often not available, sometimes due to a lack of transparency on the part of the space agencies, explains Jürgen Knödlseder, who works at the Institute for Research in Astrophysics and Planetology in Toulouse.

To fill in these gaps, his team used a method developed by Ademe (Environmental and Energy Agency) and the Association for Carbon Balance (ABC): the so-called money ratio method, according to which the carbon emissions of an activity are proportional to its cost and mass.

Thus, by their calculations, the $10 billion James Webb Space Telescope and the upcoming Array of Square Kilometers giant radio telescope in South Africa and Australia alone would be responsible for the equivalent of at least 300,000 tons of CO2.

“We must think about reducing greenhouse gas emissions in our infrastructure”, says Jurgen Knodlseder. As well as “everyone has to contribute, including astronomers who are not in an ivory tower”commented Annie Hughes of the Max Planck Institute, one of the authors of the study, during a press conference.

“Like any activity, astronomy has a significant carbon footprint”

“I know this may come as a shock, but we have to slow down the car if we want to cut emissions by almost 50% by 2030.”his colleague astronomer Luigi Tybaldo abounded.

“Like any activity, astronomy has a significant carbon footprint, so our job is to slow down the construction of infrastructure while continuing the search for perfection.”calculated by Eric Lagadec, president of the French Society for Astronomy and Astrophysics, who was not involved in the study.

But the methodology is controversial: valuation by monetary ratios generates a high degree of uncertainty (up to 80%), which can “damage the reliability of the results,” writes Andrew Ross Wilson in a commentary published in the margins of the study.

“Lacking details of what the plant is consuming, they calculated +at random+” for her part surprised by the astrophysicist Françoise Combe of the Paris-PSL observatory. Who also disputes the fact of dividing the total cost by the number of astronomers: “When you build an observatory, it is for science, it benefits millions of people! It’s like dividing the cost of the opera only by those who go there,” scientist comments.

“The method is debatable, but the approach is a first step worthy of thought.”concludes Eric Lagadec.

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