Solar geoengineering governance war game exposes deep mistrust

Solar geoengineering would spray tiny particles, such as sulfur dioxide or a manufactured alternative, high into the atmosphere so they bounce sunlight away. Scientists broadly accept it would cool the Earth. Big volcanic eruptions do the same thing naturally; the 1991 Mount Pinatubo eruption cooled the planet by about half a degree Celsius for more than a year.

The side effects are the problem. Climate models predict some regions would lose out, with drying in sub-Saharan Africa and stronger tropical storms in the Atlantic. The cooling only lasts as long as the spraying continues, so stopping suddenly could send temperatures shooting back up.

And it’s no longer just theory. Stardust Solutions, a US-Israeli startup founded in 2023, says it has raised $75 million and has designed particles made from amorphous silica (a common food additive) and calcium carbonate (the main ingredient in eggshells). Its CEO, Yanai Yedvab, estimates each million tons released would cool the planet by 0.9 degrees Fahrenheit and cost roughly $10 billion a year. In August, Elon Musk publicly backed the idea on X, and his company SpaceX has been mentioned as a possible delivery partner.

The exercise, called Exploring Geopolitical Tipping Points and Climate Cooling Strategies, was designed by Danielle Young, an assistant professor of international relations at Leeds University. Its research was sponsored by the UK government-funded Advanced Research and Invention Agency.

A couple dozen foreign-policy experts, scientists, military officers and former officials took on roles as national governments, climate groups, indigenous groups and tech companies, including SpaceX and Stardust. The setting was an emergency UN committee that met first in the present day, then in September 2027, then again in September 2028. At each stage, organizers introduced new advances in the technology, and no player had the full picture.

Climate researcher Colleen Golja was given the job of offering scientific advice. She expected that everyone would quickly agree on ethical research. That expectation didn’t survive the first morning.

The first session set the pattern. Players for both the US and China said they couldn’t sign anything that limited research in their national interest, or that let the other superpower take the lead. Jeffrey Nielsen, a US Army major playing a US security attache, summed up the stance this way: “any deal that favors China” was worse than no deal at all.

Then came the false alarms. Organizers gave Russia an intelligence report about a plane near the Bering Strait tied to a US research program; the US, which really was flying research missions, called it disinformation. China tried to add language protecting past experiments from punishment and quietly approached the SpaceX player about sharing technology. That player reported it straight to the Americans, who demanded an investigation, and the talks fell apart. The Canadian player called it a “humiliating defeat.”

Nielsen saw it as a big win for his team. But Young later revealed China wasn’t actually running experiments in the game. Everyone left convinced their rivals were racing ahead, which is exactly how an arms race starts.

The last sessions added a darker twist. A mystery plume of particles turned out to be a joint US-Saudi test of Stardust’s technology. A climate NGO offered Golja money to fund a satellite monitoring network, then was exposed as secretly backed by the fossil fuel industry, which wrecked her credibility. Several players had figured out the group’s backing and kept quiet because it suited them. By the end, Golja was in tears.

The game’s verdict is blunt. The organizers’ final report concluded that strategic competition and national sovereignty drove the talks, not climate worries. Reports of disasters barely registered, and Golja’s demonstration of how weather patterns would shift in different regions went ignored. European countries and Canada pushed for safeguards and open research, but delays and standoffs blocked every proposal.

For ordinary people, the stakes are concrete. Whoever controls this technology could change rainfall and storm patterns far from their own borders, and right now there are no international rules on who gets to decide. A game like this can’t predict the future, and many players lacked hands-on diplomatic experience. But it shows how easily mistrust between Washington and Beijing could turn a climate tool into a strategic weapon.

Real-world events have echoed the game. Two US think tank papers have urged the Trump administration to lead on the technology to counter China, and the UK Ministry of Defence paid a consultancy to research sunlight reflection. The British government then released its first official policy paper on the subject, backing more research but saying it doesn’t support deployment and has no plans to do it.

Stardust says it won’t run large outdoor experiments before global rules exist and will test outdoors only under government supervision. Past attempts show how fraught that step is: a Harvard test flight plan in Arctic Sweden was dropped in 2021 after local opposition, and a rogue startup release in 2022 led Mexico to ban solar geoengineering experiments.