Associated Press: Americans love tearing down buildings. We rip up our homes to the studs, scrape them down to their foundations and are riveted by the ultimate demolitions: imploding skyscrapers. It’s all part of a cultural need to make way for the new and improved. But the construction and operation of buildings send up twice as much greenhouse gas emissions as the entire U.S. transportation sector, according to the National Trust for Historic Preservation. (Analysts with the federal Energy …