In a legendary episode of the animated series The Simpsons (the 25th of season 6, to be precise), Mr Burns, owner of the nuclear power plant that employs half of Springfield, Homer Simpson included, decides to block out the sun. To do so, he has an enormous disc installed that eclipses the star and plunges the small town into darkness. There is something atavistic about the desire of a powerful figure – a king, an emperor, a billionaire – to control the surrounding environment, to the point of hiding the sun: it is pure, superhuman, divine power, one might say.

The powerful and the control of sunlight

In recent years, however, the idea of dimming the sun – using methods very different from those of Burns, of course – has been widely discussed in light of the ongoing environmental and climatic upheavals, which are a consequence of human use of fossil fuels and other polluting substances. The rising concentration of CO2 (carbon dioxide) in the atmosphere, which affects the greenhouse effect, as well as the warming and acidification of the oceans, together with the melting of glaciers and the increasing extremity of weather events: all of this represents an enormous risk for human beings and for terrestrial ecosystems. And while some are attempting to solve this longstanding problem through a radical and certainly more affordable energy transition and transformation in favour of clean and renewable sources, others are proposing more radical solutions. "It's too hot? What if we stopped the sun, somehow?".

What geoengineering is and who wants to dim the sun

At the end of June, the outgoing head of European Union climate policy Frans Timmermans opposed geoengineering projects applied to the changing climate, arguing that "no one should be conducting experiments on our planet alone." From a technical standpoint, even a dam or a structure like the Venice MOSE can be considered works of geoengineering, since they modify the Earth's geological environment to achieve certain outcomes. What concerns Timmermans is obviously something else, such as the – in many cases experimental – projects in climate and especially solar geoengineering. The first category includes technologies for the capture and storage of greenhouse gases, such as CO2, which have been discussed for some time now: these are machines capable of, precisely, capturing CO2 molecules from the atmosphere and transforming them into something else. Such as, for example, waste products or resources that can in turn be used in other ways.

Bill Gates and the others

It is a sector in full transformation, with many investing in it to mitigate the effects of the gas in the atmosphere (one of the main causes of rising temperatures). A recent discovery by a team at the University of Sydney appears to have doubled the capacity to "extract" CO2 from the atmosphere. Sam Altman, co-founder of OpenAI (the company behind ChatGPT), Bill Gates and George Soros are just some of the billionaires who have invested in companies in the sector. Last March, the European Union itself set an ambitious target: to reach 50 tonnes of CO2 removed from the atmosphere and stored underground. The decision was designed to inspire competition among energy companies and those in the sector.

The two gases used for geoengineering

We do not yet know when the capture of CO2 – which itself consumes a great deal of energy – will become a sustainable endeavour capable of having a beneficial impact on the environment. What is certain is that it is not the most concerning form of geoengineering: with his words, Timmermans was in fact referring to solar geoengineering, that is, precisely, the shielding of the sun. In 2021, Gates backed a Harvard project that sought to spray calcium carbonate (CaCO₃) over Scandinavia to measure its capacity to reflect solar rays and counteract rising temperatures. Other ventures are running tests with another gas (again, non-toxic), sulphur dioxide.

Geoengineering: for many, an unacceptable risk

This type of "solar" geoengineering is regarded by some of its proponents as an uncomfortable and risky ally, but one that is necessary for the survival of humanity. Above all, it is seen as a supplementary solution to a deeper energy transformation. As the magazine New Yorker wrote in an article on the subject: "Blurring the sun to cool the Earth is a desperate idea, but we're getting close to trying it." The European declaration must therefore be placed within a broader debate on the environment, one that starts from the premise that "geoengineering is being discussed and explored in many parts of the world," even though it is "a matter with significant risks and global implications." It must therefore be treated "in the right way and at the highest possible international level." Not left to individual companies.