Multi-millionaire and space enthusiast Sir Richard Branson [wiki] is now offering $25 million to the first person who can come up with a way to clean the atmosphere of greenhouse gases. 

The prize will initially only be open for five years, with ideas assessed by a panel of judges including Branson, Gore and Tickell as well as U.S. climate scientist James Hansen, Briton James Lovelock and Australian environmentalist Tim Flannery.

The winner will have to come up with a way of removing one billion metric tons of carbon gases a year from the atmosphere for 10 years -- with $5 million of the prize being paid at the start and the remaining $20 million at the end.

If no winner is identified after five years the judges can decide to extend the period.