"Landfills are a large source of methane. Methane is a potent GHG emission, with 23 times the global warming potential of carbon dioxide. Methane is emitted from landfills when biodegradable materials such as paper, yard trimmings, or food are placed in an anaerobic or oxygen-starved environment like a landfill. The amount of methane produced by these materials can be reduced either through technological improvements to the landfill or by preventing waste from ever reaching it. The City has intervened by requiring that paper be recycled. It collects yard waste through a City composting program. However, this program was first slated for elimination during the 2008 budget cuts, which troubled many community gardeners who received the compost produced by the program. Food waste is the exception – there are no efforts on the part of the City to divert food from landfills. This might be less problematic if food waste was a small part of the city's waste stream. In 2006, a study by the Department of Sanitation found that organic waste makes up 41.1 percent of the city's residential waste stream. Of that, 17.1 percent is food, four times the national average. The reason New Yorkers generate more food waste than the rest of the country remains unclear. We can be certain that most New Yorkers do not examine their food waste and adjust their actions and purchases to reduce their footprint. Taking these measures is an effective and important first step. The list of challenges to diverting a substantial amount of food waste from landfills is long. The City does not have a municipal facility to manage organic waste; nor are there mandates for businesses or residences to compost. In contrast, San Francisco became the first city in the United States to mandate that all residents and businesses separate their food waste from trash for recycling in 2009. New Yorkers, however, are left to create their own composting bin or pay for the export of waste.