THE BLOG

The Compost Revolution

05/25/2011 12:05 pm ET

You don't drive or fly much, you heat your home with renewable energy, eat meat rarely and already changed every light bulb you reasonably could. Your carbon footprint is admirably faint, but have you looked into your kitchen trashcan lately?

In the United States, food scraps account for 12 percent of the waste stream; in cities where food disposals aren't common, that percentage is even higher. Things are even worse in Hong Kong, where food makes up about one third of the tonnage dumped into landfills daily. That's a lot of weight in trucks, which means a lot of money in landfill tipping fees. In response, some Hong Kong restaurants have begun to charge customers at all-you-can-eat buffets for leaving food on their plates. One place fines diners 64 cents an ounce for leftovers; another, $1.28 for each uneaten piece of sushi.

If the fees cut waste they'll save the restaurant some dough, but they'll also help save the earth. How's that? It's simple: inside a landfill, food waste -and grass clippings, leaves, paper, and wood--breaks down and generates methane, which is about 21 times more powerful at warming the atmosphere than carbon dioxide. Landfills are the single largest man-made source of methane in this country. Some dumps capture this gas, mostly because it has a habit of migrating and exploding, while others scrub it up and use it to generate energy. Still, some experts believe these vacuum systems capture only a small fraction of the stuff wafting from our trash heaps.

What's a better way to deal with biodegradable resources? Compost, says a new generation of waste managers. Hong Kong is now experimenting with a composter that's turning four tons a day of unwanted food into a soil amendment. Could we do something like that here? San Francisco already is. Food scraps from commercial establishments and private homes are trucked to Vacaville, where they're cooked into compost that's spread on nearby organic farms and on vineyards. Boulder, Seattle and Portland, Oregon, also compost food scraps and food-soiled paper.

Sure it's easier - and cheaper - to dump everything into a hole in the ground, but that doesn't mean it's right. Twenty-three states - and the European Union - already ban yard trimmings from landfills: this stuff takes up space, it generates acidic leachate, and then there's the matter of changing the climate. Farmers in Vermont, California and Texas are composting cow poop and generating electricity; even NoImpactMan, in New York City, is getting into the act, composting his locavore scraps in a counter-top worm bin. According to the EPA, more than sixty percent of the stuff in landfills designed to hold residential waste has the potential to be composted.

So let's review: Why should you bother to separate food waste and compost it? Because you'll avoid generating methane. You'll make something nice to tuck around your tomato plants. You'll buy less fertilizer and fewer pesticides; you'll improve soil structure, control erosion, and get better plant growth. All that, and you're sequestering carbon, too. Extra credit, should it come that.