How many people have ever existed?
Today there are over eight billion people on Earth. That\u2019s an awe-inspiring figure\u2026 but how does it compare to the vast numbers who came before us? Listener Alpha wants to know how many people have ever existed, so CrowdScience sets out to do a historical headcount.
The Population Reference Bureau in the USA estimated this number back in the 90s, and have been updating their calculations ever since. Demographer Toshiko Kaneda explains how their model works, the assumptions it makes \u2013 and the huge uncertainties around the number it comes out with.
We first need a date for when \u2018humans\u2019 first began, so Caroline travels to the Natural History Museum in London to meet human evolution expert Chris Stringer, and marvel at his collection of replica fossil skulls. Chris demonstrates how to distinguish our species, Homo sapiens, from other species like Neanderthals. When did these species first appear - and which of them count as human?
And once you know where to start the clock, how do you estimate the numbers of people alive at different points in history? For a population demographer like Walter Scheidel, it helps that some ancient civilisations kept detailed censuses, a few of which have survived to the present day. Caroline and Walter pour over one of these census fragments, and learn how to combine them with other archaeological clues to get some very rough numbers.
And finally: what does the future of our population look like? Poonam Muttreja from the Population Foundation of India discusses developments in the world\u2019s most populous country, as well as the big demographic trends ahead for humanity.
Presenter: Caroline Steel \nProducer: Phil Sansom \nAdditional Recording: Umaru Fofana \nEditor: Cathy Edwards \nProduction Co-ordinator: Connor Morgans \nStudio Manager: Sue Maillot
Featuring:\nToshiko Kaneda, Technical Director of Demographic Research, Population Reference Bureau\nChris Stringer, Research Leader in Human Evolution, Natural History Museum London \nWalter Scheidel, Professor of Classics and History, Stanford University \nPoonam Muttreja, Executive Director, Population Foundation of India