According to the EPA, Americans send an average of 4.5 pounds of garbage per person per day to landfills. The organic material in that garbage decomposes in an oxygen-free environment, which produces landfill gas, a mixture of two potent greenhouse gases, methane and carbon dioxide. Landfill gas is the largest human-related source of methane in the United States, making it a significant contribution to global warming.
Both methane and carbon dioxide are greenhouse gases, but methane has 21 times the global warming potential of carbon dioxide. While there are EPA regulations designed to curb methane emissions, and some landfills have begun to convert their gases into energy, a huge amount still escapes into the atmosphere. Also, food waste in landfills contributes to leachate, the potentially toxic liquid that results from accumulated moisture and rainwater filtering through the garbage. This liquid is difficult to contain, and can lead to groundwater contamination.
Instead of sending all of that useful biodegradable material to a landfill, why not try composting? Unlike the anaerobic decomposition process that takes place in a landfill, a properly managed aerobic composting system that gets plenty of oxygen will reduce the amount of greenhouse gases released into the atmosphere. The compost you will make is much better for the environment than chemical fertilizers, and the plants you eventually grow with it will help take carbon dioxide out of the air.
Even people in small apartments can keep their kitchen scraps in a compost pail. Any stainless steel pot with a tight fitting lid will do, or you can just put it in a container in the freezer until you can take it to your local community garden or Whole Foods compost trash can. More intrepid folks could also try a worm bin, since vermicomposting is a great way to compost your scraps indoors, when you don't have a yard, or if your outside space is limited.