In 2010 an estimated 31% of the food in U.S. stores and homes went uneaten, and Americans shipped approximately 34 million tons of food waste to landfills. When food decomposes under anaerobic conditions—for instance, buried beneath other waste in a landfill—it produces methane, a highly potent greenhouse gas. According to the U.S. Environmental Protection Agency, landfills are the third largest producer of methane in the United States, accounting for about 18% of methane emissions in 2013.2