How many cumulative years have people lived

population How many people have ever lived on earth?

We don't know for sure, but estimates put 90 to 110 billion people. Sometimes one comes across the rumor that because of the population explosion, more than half of all people who have ever lived are now alive. Thats not right. Assuming that around 100 billion people have lived so far, the 7 billion today is 7 percent of that.

Doesn't it also depend on when you start counting, i.e. when you set the beginning of mankind?

That too: Do ​​we calculate, for example, from the point in time when the evolution of humans and apes developed? Or later, at the stage at which the researchers speak of the genus Homo? Or only with modern Homo sapiens? Depending on which one is talking about the last 6 million years or only about the last 50,000 years. Since evolution is a continuous process, every point in time at which the beginning of humanity is set is arbitrary. The interesting thing is: Because only very few human beings populated the earth at that time, this does not play a major role in the overall view. Of course, in one case it would be a few billion more than in the other, but since we're talking about a hundred billion, and even this estimate is very rough, it makes no difference in magnitude.

The last 10,000 years are particularly decisive - namely the time after the beginning of agriculture. Because for the first time it triggered a large population growth. Back then there were around 5 million people - today there are more than a thousand times as many. This makes it clear: the vast majority of people who have ever lived have lived in the last 10,000 years.

How can one even determine the numbers from the past?

Essentially, by taking the numbers you have available - there were censuses in ancient times; the Bible reports about it - and then to a certain extent calculates it back. We know that over seven billion people live on earth today. A hundred years ago it was less than two billion. Population scientists can roughly determine how big the population growth was in each case, how quickly the generations reproduced, but they also know the great slumps - like in the times of the plague - when the population temporarily shrank dramatically. And so one can estimate that around 300 million people lived at the time of Christ's birth. And if you add these numbers together, you get around 100 billion people. It is true that there are more people living on earth today than ever before.

If you only look at the bare numbers, you still have to say: The “turnover” from people used to be much higher. Life expectancy was shorter, and with it the duration of a generation. Women had children earlier, they gave birth to more children - if only because child mortality was very high. But you have to count all these children who died early if you want to determine how many people have ever been born. For this reason, earlier millennia also play a role and not just the last 200 years, in which the world population has grown from one billion to seven billion people.