The U.S. Environmental Protection Agency (EPA) is collaborating with the National Geographic Society and the World Resources Institute to develop tools that will help to fully account for the value of ecosystem services.

Planting and protecting trees-which trap and absorb carbon dioxide as they grow-can help to remove carbon dioxide from the atmosphere. But a new study suggests that, as a way to fight global warming, the effectiveness of this strategy depends heavily on where these trees are planted. In particular, tropical forests are very efficient at keeping the Earth at a happy, healthy temperature.