We know how to reduce deforestation – so where's the money?

Paying people not to cut down trees works, evidence shows - so can we really afford not to do so?

For years some environmentalists and economists have argued that you could pay people to keep their forests standing, maintaining carbon sources and habitat for threatened species. Yet, the idea - known as payments for ecosystem services or PES - has faced critics, who argued it wouldn't live up to the hype. A new study in Science this week may make them think twice.

"We needed better evidence about how well this approach worked in order to know if we should be scaling it up or rethinking it," said Seema Jayachandran, lead author and development economist with Northwestern University.