By 2100, over 13 billion people could be walking the planet. That's the conclusion of a new study published on Friday in Science, which employed UN data to explore the probability of various population scenarios. The new study further demolishes the long-held theory that human population growth will quit growing by mid-century and then fall.

 

It's worth noting that 13 billion is at the very high end of the researcher's projections and, therefore, unlikely, but hardly impossible. The scientists estimated that there is an 80 percent probability the global population fall somewhere between 9.6 and 12.3 billion in 2100, meaning there is a ten percent chance that population will be above 12.3 billion.

 

Going further, there was a 95 percent probability that the population will be between 9.0 and 13.2 billion, putting the chances of a population exceeding 13.25 billion at 2.5 percent.

 

The results follow a revision by the UN last year of population projections, which first reported that global population rates were not behaving as expected, due largely to stubbornly high fertility rates in Africa.

 

"What's new is that we are able to quantify the confidence that underlie the projected population growth. Earlier projections were strictly based on scenarios, so there was no uncertainty," explained lead author Patrick Gerland with the Population Division at the United Nation. "This work provides a more statistically driven assessment that allows us to say how likely particular outcomes are."

 

So, the most likely scenario? Around 10.9 billion, which is a 55 percent increase over today's current population.

 

Prior to recent revisions, many demographers believed global population would essentially take care of itself. Due to declining fertility rates, populations would peak somewhere between 2050 and 2100 before dropping slowly. Increasingly, experts say that's no longer the case.

 

 

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