From cloud seeding to injecting aerosols into the atmosphere: The risks of trying to control the weather

This week, the UK’s Advanced Research & Invention Agency (ARIA) announced £56.8m to fund 21 geoengineering projects around the world over the next five years. As a cautious fan of science fiction, this news shook me to the core.

A few years ago I read Kim Stanley Robinson’s Ministry for the Future, and this week’s news brought me back to those pages. The announcement felt less of a scientific milestone and more like a plot point for that dystopian novel, which opens with catastrophic heatwaves I hope we never live to see, but increasingly fear we might.

If you’re unfamiliar with the term, geoengineering refers to large-scale technological interventions in the Earth’s climate system, designed to counteract the effects of climate change. This can include techniques such as cloud seeding to increase rainfall, or more radical proposals such as injecting aerosols into the atmosphere to reflect sunlight and cool the planet. While this week’s announcement is among the most significant geoengineering experiments funded by a government ever, unfortunately these kinds of experiments to manipulate the weather are not new, and currently largely unregulated.

Australia has been experimenting with cloud seeding at different scales since 1947. This has involved releasing aerosols or silver iodide into clouds at different scales, hoping to induce rainfall. Saudi Arabia has been using silver iodide to induce rainfall for the past 20 years. Malaysia started cloud seeding in 2024 to combat drought, and earlier this year, Thailand began spraying dry ice into the air above Bangkok to disperse smog and encourage rain. But these efforts are relatively small-scale compared with China, which currently runs cloud-seeding projects to reduce drought risk across an area larger than India.

As the impacts of drought only get worse, there is a chance that these weather manipulation experiments, and potentially far worse, will become far more common around the world. Scarier still is that the world’s billionaire class, rather than governments alone, could become rogue weather makers of their own.

Take, for example, California businessman Russ George, who, in 2012, dumped more than 100 tons of iron sulfate into the Pacific Ocean in the hope it might save the world. At the time, he hoped he might stimulate a phytoplankton bloom that might absorb carbon dioxide, and he did so before being accused of violating several global agreements, and setting off alarm bells over the potential ecological consequences.

Soon after, a massive plankton bloom was noticed from space – it is debatable what caused it, but what’s not debatable is that Canadian authorities also reported a significant increase in concentrations of neurotoxins in the water off the coast. George, who said at the time he did not believe his actions violated any international resolutions, became a global pariah shortly after – though he said he had been unfairly held under a "dark cloud of vilification" and in years since has hit back at the “inaccurate claims” by critics.

The reality is that we simply don’t know what type of side effects these experiments will cause, and many countries such as Kenya, Colombia, Mexico and Fiji believe it’s a risk we just can’t take. At the UN Environment Assembly last year, they pushed for a non-use agreement on these types of geoengineering experiments, known as solar radiation management, out of fear that it could unintentionally shift monsoon patterns or intensify droughts.

For others, the risk is that it becomes a distraction, or even a moral hazard. They would argue that geoengineering will become an excuse that is seeking to deal with the symptoms of the climate crisis, its droughts and heatwaves, and not the actual cause. Considering that last year’s Production Gap Report found that governments are planning to produce more than twice the amount of fossil fuels in 2030 than we can afford to stay under 1.5C, I can understand their concern.

But in other ways, I worry that even though the global expansion of geoengineering parallels that of AI, both tread a fine line between the potential for global benefits and dystopian horror, and both have split their respective scientific communities. While it might seem like a lifetime ago, it was only in 2023 that many of the world’s leading AI researchers and advocates, including Elon Musk and Steve Wozniak, signed an open letter alongside thousands of others highlighting the need for a moratorium on AI expansion.

At the time, they warned against the existential threats of an “out of control” global AI arms race. Since then, the AI genie has well and truly broken out of its ethical bottle, and who knows if there’s any way to put it back. ChatGPT now reports more than 400 million active weekly users worldwide, with nearly half accessing AI tools directly from their smartphones. Calls for a moratorium only two years ago have now been drowned out by projections of insatiable future growth, even if it comes at the price of half our jobs.

As the climate crisis, air pollution, and global droughts escalate, geoengineering technologies are unlikely to emerge as a sudden, centralised wave like AI. Instead, they are likely to roll out in a quietly unregulated patchwork of crises, one country at a time.

Even though I may have been naive to the reality, geoengineering has been happening in a fragmented, ad hoc manner for decades. It’s incredibly scary, but what’s perhaps scarier is that countries are already rolling out their own experiments around the world without real international coordination or clear regulations.

Given the long and diverse history of cloud seeding, the UK government’s push to expand research in this area with the promise of built-in oversight, safety protocols and reversibility, feels somewhat measured.

The Labour government has confirmed that it’s not in favour of rolling out geoengineering at this stage; instead, it hopes that these experiments will lay the groundwork for shaping global regulations around these emerging technologies by 2030.

Until then, it’s safe to say geoengineering will remain in the spotlight. The urgency to reduce fossil fuel emissions could not be greater, but as the climate crisis leads to more unpredictable weather events around the world, the temptation for a quick techno-fix will only grow greater, regardless of whether it addresses the cause of this climate crisis we’re now in.

I just hope that over the next few years we approach this existential risk with more foresight and restraint than we ever managed with AI.