A $25 million V-prize

Virgin's millions are up for grabs. What's a biologist to do? Tycoon Richard Branson offered another $25 million to combat global warming (he pledged $3 billion in September). This time he's taking a page from X-prize folks, offering the money as a prize for the best design of a plan for removing ?significant volumes of anthropogenic, atmospheric greenhouse gases.? Although the official rules are a bit hazy on what a ?significant amount? means (they are far less hazy on publicity rights and s