7 billion people on Earth? How do they know?
Friday, October 28, 2011 - 20:00
in Earth & Climate
Science editor Alan Boyle's Weblog: The United Nations is set to mark the 7 billionth click of the population counter, but in reality, no one knows when that click will actually come. We may well have already passed the 7 billion mark, or it may be months away.
