Can we dim the sun? (Photo 12/Universal Images Group via Getty)

We live in an age of climate doomerism, and culture has responded in kind. One of its best avatars is Bong Joon-ho’s 2013 film Snowpiercer, set on a Snowball Earth created when scientists released aerosols into the sky in a last-ditch attempt to stop global warming. The plan catastrophically backfires, wiping out most life on the planet, and leaving Chris Evans and Ed Harris in 2031, trapped on board a train bearing the last remnants of human life and ceaselessly circumnavigating the Earth. When I first saw the film, I remember thinking: “Thank God no one would be crazy enough to try something like that in real life.”
I was wrong. Over the past six months, several governments and international organisations — including the White House, the EU, the British research agency ARIA, the Climate Overshoot Commission, and various UN bodies — have produced reports that cautiously advocate the very same idea: releasing aerosols into the atmosphere in order to block sunlight from hitting Earth’s surface. The concept is known as solar engineering, or solar radiation modification (SRM), and it’s a specific type of geoengineering aimed at offsetting climate change by reflecting sunlight (“solar radiation”) back into space.
The idea of solar engineering is not new, but for a long time it was relegated to the fringes of the scientific community — and the realms of science fiction. However, as the very existence of these reports makes clear, the concept has been attracting more and more attention in recent years, largely thanks to the growing panic over climate change. And much of the interest in solar engineering stems from the fact that, unlike other climate mitigation policies, which require decades to yield any significant results, “SRM offers the possibility of cooling the planet significantly on a timescale of a few years”, as the White House report claims, even to “the preindustrial level” according to “highly idealised modeling studies”.
That report followed on from a 2021 study by the US National Academies of Sciences, Engineering, and Medicine (NASEM), “Reflecting Sunlight”, which suggested that “the US should cautiously pursue solar geoengineering research to better understand options for responding to climate change risks”. Mark Symes, director of the UK’s research agency ARIA, agrees: “Through carefully-considered engineering solutions it may eventually be possible to actively and responsibly control the climate and weather at regional and global scale.” Earlier this year, more than 100 scientists signed an open letter calling on governments to increase research into solar geoengineering.
Scientists point to large historical volcanic eruptions — which result in massive quantities of sulfur dioxide and dust particles being spewed into the atmosphere — as examples of the effectiveness of “stratospheric aerosol injection”. They’re not wrong: the 1815 Tambora eruption cooled the Earth by 0.7°C and led to a “year without summer”; more recently, the eruption of Mount Pinatubo, in 1991, cooled the planet by about half a degree Celsius on average for many months. So, the idea goes, by spraying a certain amount of sulfur dioxide into the atmosphere, we could replicate the effects of a major eruption and cool the Earth. Problem solved?
Not quite. All the reports acknowledge that there are serious risks associated with solar radiation modification, which could affect human health, biodiversity and geopolitics. That’s because modifying sunlight could alter global weather patterns, disrupt food supplies and in fact lead to abrupt warming if the practice was widely deployed and then halted. But despite such caveats, the very existence of these reports represents a huge opening of the Overton window when it comes to the issue of geoengineering. Indeed: “The fact that this report even exists is probably the most consequential component”, Shuchi Talati of the Alliance for Just Deliberation on Solar Geoengineering crowed after the White House’s report.
Join the discussion
Join like minded readers that support our journalism by becoming a paid subscriber
To join the discussion in the comments, become a paid subscriber.
Join like minded readers that support our journalism, read unlimited articles and enjoy other subscriber-only benefits.
Subscribe