Elon Musk (photo), who leads the U.S. private space company SpaceX, argued for launching numerous satellites that function as mirrors into Earth orbit to reflect sunlight back into space and thereby stop global warming.

Proposals to artificially reflect sunlight are taboo in the mainstream scientific community because they could disrupt Earth’s climate system. However, with Musk wielding considerable political and economic clout, his raising such an idea is drawing attention to the possibility that related technologies could become a reality.

On the 3rd (local time), Musk posted on his X that “a large constellation of AI-based satellites could finely adjust the amount of solar energy reaching Earth and stop global warming.”

His post appears to advocate launching many satellites that act as mirrors into Earth orbit to reduce the amount of solar energy that reaches the surface. In academia, this is called ‘solar radiation management (SRM).’

SRM stems from the assessment that global warming is moving into an uncontrollable phase. Because national interests around the world are preventing carbon dioxide from falling quickly, the idea is to reduce the very amount of solar energy reaching the surface instead.

Some researchers have proposed releasing large quantities of aerosols (fine particles) into Earth’s atmosphere or spreading reflective materials on land and sea. These are short-term responses to defend against warming.

However, SRM has problems. We cannot accurately predict how the Earth’s climate system will respond when sunlight reaching the surface is artificially reduced, because the climate system is extremely complex. If sunlight is blocked to lower temperatures in some regions, unprecedented natural disasters could strike elsewhere.

If SRM were to be implemented, another issue is who would have the authority to block sunlight over particular regions. Countries that suffer unintended impacts from SRM could push back.

On Musk’s X, where he made his SRM-related proposal that day, one comment said there was “a possibility of geopolitical conflict.” Because of such issues, there is a strong tendency in the mainstream scientific community to treat discussion of SRM itself as taboo. As a result, none of the related technologies has reached commercialization.

But Musk is the world’s richest man and the CEO of SpaceX, which possesses cutting-edge launch vehicle and satellite manufacturing technology. SpaceX has launched as many as 10,000 satellites for ‘Starlink,’ which provides internet service worldwide, from 2019 through this year. In other words, SpaceX has the potential to turn Musk’s idea into reality. For that reason, the local scientific community is focused on what moves Musk will make following this proposal.