San Francisco, which already diverts 72 percent of its waste away from landfills and into recycling and composting programs, is passing the nation’s most ambitious recycling law today. Mayor Gavin Newsom is expected to sign a new mandatory composting ordinance. On the Huffington Post, he writes,
We recently conducted a waste-stream analysis and discovered that about two thirds of the garbage people throw away–half a million tons each year–could have been recycled or turned to compost. If we were able to capture everything, we’d be recycling 90 percent–preventing additional waste material from going to the landfill, and creating hundreds of green-collar jobs.
When food scraps break down in an oxygen-starved landfill it creates large quantities of methane gas, a greenhouse gas 72 times more potent than carbon dioxide when measured over a 20 year period. It also creates acids that can leach toxins from the landfill.
Composting food scraps produces little to no methane because there is sufficient oxygen in the process. And using the resulting compost reduces greenhouse gases by returning carbon to the soil, increasing plant growth, and reducing emissions associated with chemical fertilizers, pesticides and irrigation. Recent studies show that farming one acre of land using conventional industrial methods releases 3,700 pounds of carbon into the atmosphere each year. Farmed sustainably, with compost and cover crops, that same acre will put 12,000 pounds of carbon back into the earth.