Many people compost their food scraps and yard waste because they think it is the right thing to do. In some places, like San Francisco and Seattle, there is curbside pickup available to have these organic materials composted.
A recent study by the University of Washington looked at the environmental benefits of composting these materials instead of sending them to landfills. Landfills are a major source of methane emissions, which are extremely potent greenhouse gas sources.
In the U.S., about 95% of food scraps still end up in landfills. Yard waste – grass clippings, leaves and branches – do much better. About half is diverted to compost facilities instead of landfills.
According to the study, the benefits of composting yard waste vary significantly by location. Yard waste in Florida in December breaks down far more quickly than yard waste in Minnesota during the same month.
Food scraps, on the other hand, behave about the same everywhere. Even on a snowy day in Minnesota, the temperature inside a food-laden landfill is likely to be over 70 degrees.
The study concluded that composting food scraps is far better for the environment than disposing of it in other ways. The reductions in methane emissions are significant. People who do their own composting are justified in feeling good about what they are doing. And U.S. cities and counties that offer composting services prevent food trash from decomposing in landfills and dumping methane into the atmosphere. Where carbon credits are available, these places earn them as well, which provides a financial incentive to establish composting programs.
Photo, posted March 17, 2007, courtesy of Joi Ito via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio.