Here are 20 bold/crazy ideas that could save the world...most of them related to energy and climate change.
A relatively small piece of the Sahara could theoretically provide electricity for the entire planet if it were covered in solar thermal mirrors. Plus think of all those jobs to build a solar plant the size of Britain. The new transmission grid would be quite a project as well...
Update: Hmm, the site appears to be down and redirected to same squatter spam thing. I'll put the link back up when the site (hopefully) returns.
Update: The Infrastructurist site is still down but I found the original link on the Guardian.