Enter Stardust Solutions. The company has been working under the radar for a few years, but it has started talking about its work more publicly this year. In October, it announced a significant funding round, led by some top names in climate investing. “Stardust is serious, and now it’s raised serious money from serious people,” as James puts it in his new story.

That’s making some experts nervous. Even those who believe we should be researching geoengineering are concerned about what it means for private companies to do so.

“Adding business interests, profit motives, and rich investors into this situation just creates more cause for concern, complicating the ability of responsible scientists and engineers to carry out the work needed to advance our understanding,” write David Keith and Daniele Visioni, two leading figures in geoengineering research, in a recent opinion piece for MIT Technology Review.

Stardust insists that it won’t move forward with any geoengineering until and unless it’s commissioned to do so by governments and there are rules and bodies in place to govern use of the technology.

But there’s no telling how financial pressure might change that, down the road. And we’re already seeing some of the challenges faced by a private company in this space: the need to keep trade secrets.

Stardust is currently not sharing information about the particles it intends to release into the sky, though it says it plans to do so once it secures a patent, which could happen as soon as next year. The company argues that its proprietary particles will be safe, cheap to manufacture, and easier to track than the already abundant sulfur dioxide. But at this point, there’s no way for external experts to evaluate those claims.

As Keith and Visioni put it: “Research won’t be useful unless it’s trusted, and trust depends on transparency.”

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