An inside tour of the incredible—and probably dangerous—plans to counteract the effects of climate change through experiments that range from the plausible to the fantasticDavid Battisti had arrived in Cambridge expecting a bloodbath. So had many of the other scientists who had joined him for an invitation-only workshop on climate science in 2007, with geoengineering at the top of the agenda. We can't take deliberately altering the atmosphere seriously, he thought,...