Is James Webb too polluting? “We have to stop wanting new toys”


Astronomy is a polluting science. In particular, the research centers responsible for the emission of more than one million tonnes of CO2 every year. But solutions exist to make it a more sustainable area.

Exploring new worlds, discovering the secrets of stars, galaxies, finding extraterrestrial life… So many goals that make you dream, and rightly so. But we must not forget that behind all this astronomical research, there are important technological developments which are accompanied by a certain pollution.

This is pointed out by a study published on March 21, 2022 in Nature Astronomy. French researchers have sought to find out to what extent astronomy is a polluting science. And their verdict is resounding: the carbon footprint of this area of ​​research is disastrous with no less than 1.2 million tonnes of CO2 issued each year, which is five times higher than previously estimated.

For a long time now, the astronomical community has been looking at its carbon footprintdetails the main author Jürgen Knödlseder, CNRS researcher from the University of Toulouse. But we wanted to focus more specifically on observatories on the ground and in space. »

Observatories more polluting than all the rest

With his team, the astronomer studied the emissions of around fifty space missions as well as forty ground research centers, taking into account the construction of the installations, the electricity consumption, as well as the cost of the launches for the missions. spatial. By their own admission, the team did not come up with an accurate measurement of the rate of CO2 released into the atmosphere, but considers that its study can serve as a starting point before further evaluations.

What we are surepromises Jürgen Knödlseder, it is that these observatories represent the first polluter in the field of astronomy, well beyond all the other causes. Because this is not the first time that this field of research has been the subject of climate self-criticism. In September 2020, a whole series of studies appeared in Nature with the aim of probing the carbon impact of astronomy, but also of providing solutions to reduce it.

The authors then concluded that several margins of progress existed:

  • First track, multiply videoconferences and avoid air travel as much as possible to attend meetings. A change that has been encouraged with the health crisis;
  • Use renewable energy to power the supercomputers responsible for calculations and data processing. These are extremely energy-intensive computer systems which, in addition, are called upon to expand further as the data to be received are more numerous every day.

At the time, these studies were rather well received by the scientific community, which welcomed this position and promised efforts to reduce the environmental impact of the discipline.

The Vera-C.-Rubin observatory under construction. // Source: Wikimedia/CC/Frossie (cropped photo)

However, Jürgen Knödlseder’s study is much more unpopular. ” We offer solutions too, but not everyone likes that… Basically, we’re asking researchers to stop messing around with their toys and always want more. Which is hard to accept. »

James Webb, a disastrous toy for the planet

The symbol of these very (too?) polluting toys would be the James Webb Space Telescope (JWST). Launched at Christmas 2021, Hubble’s supposedly revolutionary successor, a true gem of technology, is also responsible for emitting at least 300,000 tonnes of CO2 : this is an estimate for its entire mission, from its construction until the next 5 years (a low estimate, because the high estimate rather foresees 1 million tons ofCO2). And even now that it is launched, the research centers intended to receive its data continue to pollute, whether they are offices, antennas or computers. ” This is a large-scale project made to last for yearssays Jürgen Knödlseder. Its carbon footprint is enormous, especially since it does not really replace an old telescope, since no other device has been retired. »

Not only does the JWST produce CO2, but in addition, it is added to old telescopes still in operation. If it pollutes so much, it’s because it took years to build, but also because the amount of data it sends is literally astronomical. More than 200 gigabytes per day will circulate between the telescope and the Earth when it is fully operational.

The study does not call for dropping James Webb, but the solutions put forward are quite radical for the astronomy community. ” Efforts to reduce the use of fossil fuels will be for naught if we build more centers. Currently, the Square Kilometer Array, a radio telescope project, is in development in South Africa and Australia, and will produce as much CO2 than the JWST. And as stopping such a project seems quite complicated, the researcher proposes instead to eliminate other older telescopes.

We don’t need so much datadeplores Jürgen Knödlseder. We receive so many that we can’t even process them and we have to train artificial intelligences to do it for us! You have to know how to slow down. »

Is James Webb too polluting?  “We have to stop wanting new toys”
The Hubble Space Telescope. // Source: Flickr/CC/Nasa in The Commons (cropped photo)

A decline in science would be a solution, according to the astronomer who calls for doing less, and above all to be content with what we already have. ” There are dozens of years of untapped archives where treasures may be hidden. At the moment, I’m only working with this old ample data. Maybe I’m going slower, maybe a little less far, but we don’t always need to have everything right away. »

The researcher recognizes that the progress of science is important, but not at any price. ” Today, the emergency is climate change. We cannot ignore it. »

Because if tomorrow, major discoveries can be attributed to the JWST, it has not always been so. In 1995, the first exoplanet discovered was the result of a study based on the observatory of Haute-Provence, a material far from being at the cutting edge of technology. Science can therefore perhaps be done in sobriety.



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