To stop global warming, should we send a giant parasol into orbit ?

© Technion Israel & ARIS

The Earth has just experienced the hottest year in its history in 2023. Over the past decade, seven years have been among the 10 hottest on record. Faced with this reality, the latest IPCC report mentions a “climate emergency” which does not seem to find any echo in the political world.

Despite the signing of a treaty on the end of coal in the world during the last edition of COP 28, in Dubai, there are still many efforts to be made. Fortunately, dozens of solutions exist, both on Earth and in space.

A parasol in orbit

Indeed, our orbit could very soon host a test of small satellites. By placing themselves thus between the daylight body and our planet, they would cut off part of the Sun's rays. If this idea may seem fanciful, it is slowly infusing itself into the scientific world as a “reasonable” to fight against global warming.

In a published study on the subject, researcher Istvan Szapudi, who works at the University of Hawaii's astronomy center, explains that it would not be necessary to cover all the rays of the Sun. Creating a 2% shadow would already be enough to reduce global warming by 1.5°C. In other words, it would still be possible to return to the starting point, before the industrial revolution.

How to carry out such a mission< /h2>

Nevertheless, the launch of such a project raises many questions. Indeed, depending on the position of the space umbrella, certain parts of the world could be more or less impacted by its shadow. Another very important fact must be taken into account, the financing of such a mission.

To cover 2% of the Sun's rays, by placing the parasol on the Lagrange point L2 (a place in the solar system where gravitational forces are balanced, which allows it to remain static), several billion dollars would have to be spent.

No private company would be ready to carry out such a mission, especially since the installation of such a giant parasol presents no source of profitability. A government agency like NASA would therefore have to agree to dip into its budget to carry out such a mission.

In order to convince them of the potential of’ 8217;a space parasol, a team of Israeli scientists led by researcher Yoram Rozen plans to carry out a demonstration mission at lower cost in a few months. It is thus planned to send a square space parasol measuring 30 meters on a side for 100 to 200 million dollars.

According to the calculations of Doctor Rozen, for cutting 2% of the Sun's rays as Istvan Szapudi suggests in his study, it would be necessary to build a parasol measuring 1.6 million kilometers on each side. The structure would then be as large as Argentina and weigh 2.5 million tons (5 times the Burj Khalifa).

When we know that the SLS rocket, which is today one of the most powerful in the world, can only place 81 tons of payload per launch, our technology still seems far from the mark.

Hide poverty

But humanity's technological delay in setting up such a system does not ;#8217;is not the only obstacle to the idea of ​​a space umbrella. Indeed, scientists, particularly climatologists, fear that this solution is just a “bandage that hides the wound”.

Placing a parasol between the Sun and the Earth will not make global warming go away. The atmosphere would still be overloaded with carbon dioxide and other greenhouse gases. The health risks linked to pollution will therefore always be there. In short, this option cannot work alone.

It is impossible to place such a structure in orbit. However, the idea of ​​a space umbrella can work on smaller scales. By using this method, and reducing our environmental footprint, the Earth still seems to have a chance. We still have to manage to grab it in time.

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