BBC: From the twilight zone of science fiction, the idea of “geo-engineering” is emerging into the harsher daylight of science fact – and I’m going to risk the prediction that we’ll hear a lot more about it in the coming years. Only a few years ago, the very notion of planetary-scale projects to tackle climate change was derided by many as too nutty to bother with. Mainstream media coverage tended to gently poke fun at the images of galaxies of mirrors in orbit or fleets of giant …