They played the war game Dimming the Sun. It went even worse than you think.

Solar geoengineering could buy humanity time against climate change, or ignite a dangerous new arms race. The first simulation of its kind offers a glimpse of what happens when geopolitics takes the controls.

"I thought it would be very easy. Like, we could all agree to do ethical research and make sure it's better for all human beings," he told WIRED. "And boy, was I wrong?"

The simulation, titled Exploring Geopolitical Tipping Points and Climate Cooling Strategies, saw two dozen foreign affairs experts, scientists, military personnel and former government officials from around the world convene in a meeting room at Queen Mary University of London. After introductions of coffee and small yogurts, they were seated at tables set up in a square with the name of the country or organization each person played for: national governments, climate NGOs and nonprofits, indigenous groups, and tech companies. Golja was entrusted with providing technical advice to help participants make scientifically literate decisions.

The purpose of the game was to stress test the world's reaction to a group of futuristic technologies known collectively as solar radiation modification. These technologies promise to reverse global warming by reflecting some of the sunlight that reaches Earth, for example by sprinkling sulfur dioxide particles or some other synthetic material into the atmosphere. The cooling effect of this type of solar geoengineering is widely accepted. This could mimic the known effects of large volcanic eruptions that temporarily cool the planet by half a degree or more. But its outcome is less certain and less equal. Some areas will suffer: models predict drying in sub-Saharan Africa and more intense tropical storms in the Atlantic. The cooling effect will also last only as long as the geoengineering continues. Global temperatures could then rise with wild and unpredictable effects.

Until recently, the idea of ​​solar radiation modification was a speculative topic in climate science. That has changed rapidly. Private companies are exploring solar geoengineering as a business opportunity: Last year, an American-Israeli startup called Stardust Solutions raised $60 million and in May released details of a series of new inventions that it claims will give humans the ability to lower the Earth's temperature at will. In August, Elon Musk, whose company SpaceX may be a candidate for geoengineering interventions, threw his voice behind solar geoengineering, writing in X: "Space satellites will be needed for temperature control and massive geoengineering or it's game over."

Cynthia Scharf, a former UN adviser, told WIRED that the world will have to decide how to govern this technology much sooner than most policymakers think. It's not 15 years from now, it's easily the next decade.

It was against this backdrop that Daniel Young, Assistant Professor of International Relations at the University of Leeds, organized the war game. In its place was a hastily formed UN committee charged with coordinating the international response to developments in solar geoengineering. The game took place in simulated sessions at three points in time: now, September 2027, and September 2028. Each stage raises the stakes, with the game's developers introducing new developments in sun-reflecting technology. As in real life, no one knew all the facts, and players had to react to events that brought the world closer to a full-scale attempt to deploy solar geoengineering technology, even when they might not have a full picture of what really happened - or what others had done.

The first session set the tone. Mistrust and misinformation prevailed. As participants debated the rules governing outdoor testing in an attempt to agree on an international agreement, players representing both the United States and China told the group they could not sign an agreement that would limit their pursuit of research deemed to be in their "national interests." They also could not accept a deal where their superpower rival had the upper hand in terms of technology. Speaking to WIRED, U.S. Army Maj. Gen. Jeffrey Nielsen, who served as the U.S. national security attaché, summed up the position: "Worse than no deal is any deal that favors China."

Tensions escalated when the team running the simulation gave Russian officials an "intelligence report" suggesting they had found an aircraft near the Bering Strait believed to be involved in a US geoengineering research program. The US team - which was actually flying on research missions - accused Russia of disinformation.

Meanwhile, the United States became convinced that China was also conducting research and development of its own program. Beijing's representatives had tried to insert language into a proposed agreement that would guarantee no retroactive punishment for past tests. Then, China approached a player representing SpaceX to pitch the idea of ​​a technology sharing program. In a private chat away from the group, the SpaceX player immediately reported the approach of the Chinese to the US team. America called for an international investigation. The finger-pointing continued and countries abandoned negotiations. Canada's representative called it a "humiliating defeat".

By the end of the session, Nielsen was pumped. He had destroyed China and derailed any prospect of a global accord. In terms of gaming, he told WIRED, it was a "big win" for Americans. But Yang, the researcher who designed the scenario, said the Chinese weren't actually testing the game. Mutual suspicion meant that all parties left the room, believing that the others were moving as quickly as possible to build their geoengineering capabilities.

What happened in the first meeting reflected "the possibility of a geoengineering arms race," Nielsen said, explaining that he was speaking privately to WIRED and did not represent the views of the actual US government. Most experts believe that a superpower would be needed to ensure the safe passage of the planes needed to deliver the dust cargoes. The stratosphere in a geoengineering exercise But, Nielsen says, neither the US nor China will slowly cede control of the global thermostat, and mistrust and poor communications are a significant risk: "Any related action by one actor could be perceived as disorder by another."

A former British diplomat with a national security background told WIRED that the threat of falling behind a competitor is "a very strong driver for research and development of capabilities." "But this is not at all like an establishment." There are parallels with the dynamics of nuclear weapons—although solar radiation management, unlike nuclear weapons, has more obvious advantages as well as downsides, many of which are poorly understood. "There is an interdependence here," said the former diplomat, who was not involved in the game and spoke on condition of anonymity to preserve ties. "It's not an inherently zero-sum game."

Scharf, who represented the US government alongside Nielsen at the game, told WIRED that a "transparent international scientific cooperation" between China and the US "may be the best thing we can do in terms of preventing a very dangerous competition between the two. But I certainly can't imagine that happening under the Trump administration."

Exacerbating the problem is the lack of information. Geoengineering has historically been viewed with suspicion and often ignored by mainstream science. One researcher told WIRED that she experienced rejection and barriers to academic progress because of her interest in technology; He no longer works in this field.

This lack of academic interest greatly frustrated Golja, who spent most of the game watching the audience while political stances prevailed. Given the low level of knowledge about solar radiation modification and its side effects, he was one of the few experts who could have helped the participants understand the climate impacts of what they were discussing - but was largely ignored.

In subsequent meetings, the organizers tried in vain to steer the talks towards the realities of climate change. Participants received frequent notifications of weather disasters. These were hardly registered. Golja had prepared a "simulator," a real-world demonstration of the best available science on how solar radiation management might affect climate patterns in different regions. was ignored If the country's representatives asked him anything, it was usually a leading question, looking for data that would serve their purposes or calling a rival's proposal frivolous.

Then, the other day, players were trying to find a way to respond to reports that a large mass of aerosols had been detected. In the game, this was due to the United States and Saudi Arabia jointly testing Stardust technology, although not everyone knew this. Finally, scientific advice came first. Countries need to know how to monitor satellites and other surveillance tools to prevent such tests from being carried out in secret. A player on behalf of an NGO called Future Weather Cooperative approached Golja and offered to finance such a project.

"Great. Great. Why not?" He remembers thinking

But it soon became clear that the future climate cooperative was actually sponsored by the fossil fuel industry. Organizers noted that fossil fuel companies and major producing countries such as the United States and Saudi Arabia have a clear interest in removing barriers to the development of technology that can combat climate change without immediately stopping the burning of coal, oil and gas. The shadowy NGO expertly spent the game getting their vibe out and working on the process – though mostly they just sat back and let it burn. Some players—Russia, the United States, SpaceX and Stardust—realized that CFC was not what it seemed, Yang says. But they evaluated it in their favor and did not pay attention to it." The CFC then chose its moment to present Gulja with money so that his credibility would be reduced and the voice of science in the room isolated and fragmented.

That last lesson in the real politics of fossil fuels was about all Golja could take. By the end of the last day, she was in tears.

Despite numerous proposals, the countries present in this game did not agree to an agreement at any point. European countries and Canada tried to build support for safeguards and open scientific research, but talks were constantly mired in delaying tactics and turned into tense confrontations over dueling strategic interests. In their final report, the researchers running the simulation - whose work is supported by the UK government's Advanced Research and Innovation Agency - concluded that "strategic competition and government dominance drove the simulation, not climate concerns."

Simulations like this are not meant to predict the future. The results depend on the game design and the relative personality and experience of the players. Many in the room lacked first-hand diplomatic and national security experience. The UN assembly, which the organizers chose as the venue, may not be as effective as negotiations between smaller groups of major countries. But in the real world, London's experiment reverberated and reverberated in the months it ran and afterward.

In March, two articles from conservative US think tanks called on the Trump administration to take the lead in fixing solar radiation and countering the threat from China. One memorably coined a new term codenamed MAGA: "climate sovereignty." This month, the Observer newspaper in London revealed that Britain's Ministry of Defense had hired a deep-tech security consultancy to conduct research into sunlight reflection. Then, last week, the British government published its first official policy paper on the matter, backing further research but insisting it had not done so. It supported deployment and had "no plans to do so." Stardust has continued to lobby the United States and governments around the world. It's getting easier because unlike before, "most policymakers are already aware of the technology," WIRED CEO Yanai Yadavb told WIRED.

Stardust has always said it won't do any major outdoor testing, let alone full deployment, before global governance. "We are developing a very powerful tool," Yadav says. "When you develop this kind of powerful technology — and you have a lot of records — there's a national interest. We're not naive about that."

Meanwhile, the factors of climate crisis are intensifying. During the game's time frame, efforts to limit the use of fossil fuels were undermined by rising energy costs and political hostility. Week after week, an incredible summer of drought and heat hit Europe. In the last week of August, a glacier collapsed on the Tibet-Nepal border, fulfilling decades of predictions by climate scientists and killing more than 1,450 people.

In the months since the simulation ended, Golja has reevaluated many things. On a cork board behind his desk, he has pinned a note to himself, in which he paints a vision for life in a world dominated by narrow geopolitical self-interest rather than science, evidence, and reason. His answer: He plans to return to the small Connecticut beach town where he grew up and use his expertise to help local climate groups build seawalls and coastal erosion protections to cope with the inevitable. "To make a difference where I feel really stretched," she says. After what he saw, pursuing science in hopes of informing global decisions no longer held much appeal. It feels a little more personal now."