I only reluctantly admit this -- because I foolishly believe in people doing the right thing without being bribed to do so -- but the economy, if handled correctly, could possibly save the planet. In February, Pavan Sukhdev held the annual Earthwatch Lecture here at Oxford and explained how an appreciation of the real value of natural resources left intact (e.g. south american rainforest as a water pump for the Argentinian cattle industry) could shift the balance so far that preserving wild nature would appear as a sound investment rather than a financial burden.
With this in mind I have looked at two examples of finance deals aiming to save rainforests -- one in Ecuador, coupled to (non-exploration of) crude oil, and the other in Guyana -- and written a news feature for Current Biology which is out today:
Ransom for rainforests
Current Biology, Volume 20, Issue 5, R217-R218, 9 March 2010
summary and restricted access to pdf file