The Guardian has asked The Observer's experts how the world is going to change in the next 25 years. Answers are really worth reading.

How about: 'We'll play games to solve problems' or 'What constitutes a 'city' will change'?

Regarding energy issues, Chris Llewellyn Smith from Oxford University says: 'Disappointingly, with the present rate of investment in developing and deploying new energy sources, the world will still be powered mainly by fossil fuels in 25 years and will not be prepared to do without them.'

20 predictions for the next 25 years