Reuters: Cities often blamed for producing most of the world’s greenhouse gas emissions actually generate just two-fifths or less, according to a study published on Friday. U.N. agencies, former U.S. President Bill Clinton’s climate change initiative and New York Mayor Michael Bloomberg have all said that 75 to 80 percent of total emissions come from cities, the paper in the journal Environment and Urbanization says. But using data from the U.N. climate change panel, it estimates the …