Earth Policy Institute - Between 2007 and 2011, carbon emissions from coal use in the United States dropped 10 percent. During the same period, emissions from oil use dropped 11 percent. In contrast, carbon emissions from natural gas use increased by 6 percent. The net effect of these trends was that U.S. carbon emissions dropped 7 percent in four years. And this is only the beginning. 
The U.S. Department of Energy projects that residential electricity use per person will drop by 5 percent during this decade as light bulbs are replaced and as more-efficient refrigerators, water heaters, television sets, and other household appliances come to market.
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