For Mozambican conservationist Gabriela Curtiz, the key to making a new plan for carbon credits work in the remote mountains of Gorongosa National Park, ravaged by civil war in recent decades, is to involve the community living there.

"Listening is the first part of changing people's minds — then they will hear you, too," Curtiz said.

The park management wants to make it financially worthwhile for villagers to grow and protect indigenous trees alongside their coffee crops, while helping companies elsewhere slim their carbon footprints by buying offsets generated from the park.