Alan Weisman asks, 'How many people can the Earth sustainably hold?'

May 19, 2014

(AP Photo/Ben Curtis, File)
In this Jan. 19, 2012 file photo, children line up to receive a meal at a food distribution center for those displaced by last year's famine or by conflict, in Mogadishu, Somalia.

Alan Weisman's latest book is Countdown: Our Last Best Hope for a Future on Earth. It considers how many people the planet can sustainably hold. Medical advances and revolutionary leaps in food technology has caused humanity to swell in number, far-outpacing any species on the planet. He’ll talk with us about the stress on our resources and ecosystems.