arrived, Nolwo was standing in front of a makeshift arch, fashioned from a palm leaf, next to a handwritten sign that said: “Welcome! Welcome! To the land of ‘untouchable virgin forest’ the land of fresh oxygen (O2) the purifier of green house gases” (sic). A sing-sing – a ceremonial celebration – was under way. The men and women of Igai wore feathers, and had bright turquoise and yellow dots painted on their faces.

Nolwo led the procession up to the centre of Igai, away from the river. According to Papua New Guinean custom, the men gathered in the main village hall, known as a haus, while women, children and teenagers stood or sat on the ground. After five years of hearing about carbon trading, this was the first timein Igai’s history. It was still early afternoon, though, and at first there was nothing to see. People drifted away. A man climbed a tree to bring down coconuts. But then darkness came, as it does in Papua New Guinea, with the speed and confidence of something quite permanent. And on the hill, out of the alchemy of the money and the trees, four lights shone, hard against the night.