Americans throw away millions of CDs every year, the Environmental Protection Agency says. Who needs the clutter when you can organize your music files in a neat database on your computer? Even though consumers made the shift long ago to downloadable music files, recording powerhouses like Sony ( SNE), Warner Music Group ( WMG) and EMI still rely heavily on CD sales. They're incented to keep pumping out plastic instead of embracing the green technology their customers prefer. There isn't a lot of data about the music industry's carbon footprint. What's available is incomplete and fairly self-serving. A British nonprofit called Julia's Bicycle contends that CDs are responsible for 26% of the greenhouse gases created by the U.K. music industry. But those numbers are somewhat misleading. The group attributes the largest portion of greenhouse gas emissions to something beyond the industry's control: audience travel to live shows. Half of the gases music companies directly produce come from making and shipping CDs. Touring generates the other half, the group says. I would expect the data for the U.S. to be comparable, but on a larger scale. It's not hard to see why CDs are wasteful. Besides the energy it takes to make and ship them, consider the materials that go into the discs themselves. They're cooked up from a batter of gold, silver, aluminum and nickel, and petroleum-derived plastic. Back Thru The Future, a New Jersey-based company that recycles electronic devices, estimates that it takes 300 cubic feet of natural gas, two cups of crude oil and 24 gallons of water to make a pound of plastic, which is enough for 30 CDs.