Crazy-sounding ideas for saving the planet are getting a serious look from top scientists, a sign of their fears about global warming and the desire for an insurance policy in case things get worse. There's the man-made "volcano" that shoots gigatons of sulfur high into the air. The space "sun shade" made of trillions of little reflectors between Earth and sun, slightly lowering the planet's temperature. The forest of ugly artificial "trees" that suck carbon dioxide out of the air. And the "Geritol solution" in which iron dust is dumped into the ocean.
I think the future will be filled with what people currently consider to be crazy technology. Molecular nanotechnology, large scale Quantum computers, effective space travel, radical life extension, metamaterials, genetic control, radiation spectrum control etc... As I track in the articles on my site, many precursor to full blown crazy technology are starting to have impact. Molecular technology and other technologies that radically transform rapid production will eliminate the bottlenecks for infrastructure replacement.