San Jose Mercury News: You know about global warming and carbon footprints. Now get ready to hear more and more about “geoengineering.” As the warming of earth’s climate nears what experts say is a crisis point, a panel of scientists in San Francisco on Thursday said it’s time to get serious about studying tinkering with the atmosphere to counteract harmful carbon dioxide emissions. While such geoengineering might sound like something out of a science fiction novel — seeding clouds, for example, …