Eli Klintisch reports that some scientists who'd previously adhered to the anti-geoengineering consensus are now giving it a second thought as they grow increasingly pessimistic that countries will reduce carbon emissions enough to stave off catastrophe. Unfortunately, this superficially promising path remains full of pitfalls. Brad Plumer, for example, raises an issue I'd never thought of:
Cloud-seeding in the United States has led to all sorts of lawsuits from farmers complaining about stolen rain. Chinese cities experimenting with this stuff have been warring over "cloud theft." The U.S. Air Force has drafted a report, "Weather as a Force Multiplier," discussing ways to use weather-modification as a weapon. If someone does come up with a way to cool the earth—say, giant space mirrors—there would be all sorts of tricky debates about who decides how it's used. It's hard to imagine that the international talks over that would be any less difficult than reaching an agreement on reducing carbon emissions.
Right. You can't actually get around the need for a hard-to-achieve level of international coordination. The Air Force isn't wrong to think that weather control could be a weapon, after all.