In an influential cli-fi novel, a desperate government ignores international consensus and pumps aerosols into the atmosphere to cool the world. Could it happen for real? //

This January, more than 440 scientists signed an open letter calling for a non-use agreement on solar geoengineering – including for small-scale outdoor experiments, like the unauthorised test conducted by a San Francisco start-up in Mexico earlier this year. They argue that the side-effects are unpredictable, the current global governance system is "incapable" of guaranteeing fair and effective control, and that development might encourage "normalisation" of the technology as part of the world's climate policy. Its cooling effect could create a "moral hazard", numerous researchers and civil society organisations warn, by taking pressure off efforts to cut the underlying CO2 emissions.

Such concerns have so far resulted in a de-facto moratorium on deployment, while a planned field test over Sweden was cancelled in the wake of objections.