The quest for black gold

How powerful can a steaming pile of rotting food be? One third of the world’s food is lost or wasted, greenhouse emissions are warming our planet, and about a third of the world’s soil is degraded. Composting our food waste can help with all of this. But does it make economic sense and does it deserve it’s moniker ‘black gold’? Emily Thomas meets people in the compost business to ask whether composting at scale will ever turn a profit without government money. And why, if compost is so good for the land, are farmers still so reluctant to use it? For the compost business to thrive, people need to separate their food waste - but how can they be persuaded to do so? We hear from Seoul in South Korea, where the solution lies in a talking bin, and from Colombo in Sri Lanka, where a failure to address the problem has had devastating consequences. (Picture: Plants growing in a pile of compost. Credit: Getty Images)