I know much of this is guesswork, and that you can "prove" anything with statistics, but this is thought-provoking. In the last 50,000 years around 107 BILLION humans have lived, as opposed to the 7 Billion estimated to be alive right now, so the dead would appear to outnumber the living. "The population of the planet reached seven billion in October, according to the United Nations. But what's the figure for all those who have lived before us? It is often said that there are more people alive today than have ever lived - and this "fact" has raised its head again since the UN announcement about the planet's population reaching a new high. The idea helps fuel fears that the population is expanding too fast. It is true that if you delve back into the mists of time, the population of Earth was tiny in comparison to today and logically it might seem plausible that the living outnumber the dead. It is agreed by most demographers that the UN figure for the number alive today is reasonably accurate. The problem is, how do you calculate how many have ever lived, and where do you start? One group to have done the work is the Population Reference Bureau in Washington. Wendy Baldwin from the Bureau says that the normal starting point is when Homo sapiens first walked the earth, about 50,000 years ago. So you have a starting point and an end figure but it's the time in between that causes the problems. "For 99% of that time there is no data," she says. This means experts have to make an educated guess." BBC News - Do the dead outnumber the living?