Some really interesting reads over at The Edge annual question 2007, asking a huge range of scientists and thinkers ‘What are you optimistic about? Why? Surprise us!’.
There’s lots of interesting stuff there and I’ve only read a tenth, I particularly liked George Dyson talking about the potential for a return to sail powered cargo ships:
The trade winds constitute an enormous engine waiting to be put to use. When oil becomes expensive enough, we will.
This is a fascinating example of the bright green thinking which says we can manage the environmental and energy problems we face without having to step back into the ways of the past.
Also: New Scientist article on modern sail powered ships.