Around the world, most of the 1.4 billion tonnes of food thrown away each year goes to landfills. As it rots, it pollutes water and soil and releases huge amounts of methane, one of the most potent greenhouse gases. But not in South Korea, which banned food scraps from its landfills almost 20 years ago. Here, the vast majority of it gets turned into animal feed, fertilizer and fuel for heating homes. Food waste is one of the biggest contributors to climate change, not only because of the methane but also because the energy and resources that went into its…