They War-Gamed Dimming the Sun. It Went Even Worse Than You Think

When it comes to deciding the fate of the planet, Dr. Colleen Golja always thought science and reason would have a seat at the table. That was until one morning last September in London, when the climate researcher took part in the first in a series of war games. The goal: to prevent an uncontrolled global race to develop a technology aimed at cooling the planet but that comes with vast, unknown risks that could reshape life on Earth.

“I thought that would be such an easy thing. Like, we can all agree to do ethical research and make sure it’s for the better of all humans,” she told WIRED. “And boy, was I wrong.”

The simulation, titled Exploring Geopolitical Tipping Points and Climate Cooling Strategies, saw a couple dozen foreign-relations experts, scientists, military personnel, and former government officials from across the world convene in a meeting room at Queen Mary University of London. After making introductions over coffee and little yogurts, they sat at tables arranged in a square with the name of the country or organization each person was playing: national governments, climate NGOs and nonprofits, indigenous groups, and tech companies. Golja was assigned to provide technical advice to help participants make scientifically literate decisions.

The point of the game was to stress-test the world’s response to a group of prospective technologies known collectively as solar radiation modification. These technologies promise to reverse global warming by reflecting away a portion of the sunlight reaching Earth, for example by spraying particles of sulphur dioxide or some other manufactured substance into the atmosphere. The cooling effect of this kind of solar geoengineering is widely accepted. It would mimic the well-known impacts of large volcanic eruptions, which temporarily cool the planet by half a degree or more. But the fallout is less certain—and less equal. Some regions will suffer: Models predict drying in sub-Saharan Africa and more intense tropical storms in the Atlantic. The cooling effect would also last only as long as the geoengineering continued; after that the global temperature could shoot back up with wild and hard-to-predict effects.

Until recently, the idea of solar radiation modification was a speculative niche of climate science. That has changed fast. Private firms are exploring solar geoengineering as a commercial opportunity: Last year, a US-Israeli startup called Stardust Solutions raised $60 million, and in May it released details of a suite of new inventions it claims would give humans the ability to dial down the global temperature as desired. In August, Elon Musk, whose company SpaceX might be a candidate for delivering geoengineering interventions, threw his voice behind solar geoengineering, writing on X: “Space satellites to control temperature and massive geo-engineering will be needed or it will be game over.”

The world is going to have to make decisions about how to govern this technology much sooner than most policymakers imagine, Cynthia Scharf, a former UN advisor, told WIRED. “It’s not 15 years from now; it’s in the next decade, easily.”