National Geographic: As Earth Day approaches, a new report finds that the United States is on track to breeze past Germany within two years as the world leader in installed capacity to spin the wind into electricity. Globally, wind-power capacity rose 27 percent in 2007 to 94,100 megawatts, according to the report from the Washington D.C.-based Worldwatch Institute. The U.S. led the charge with a record-breaking 5,244-megawatt increase for a total of 16,818 megawatts–enough to power 4.5 million …