38
Oops, Scientists May Have Severely Miscalculated How Many Humans Are on Earth
(www.popularmechanics.com)
TL;DR The estimate of 8 billions humans on Earth might be underestimated. Because in specific areas where a dam is built and relocated population is precisely counted, they realized that they were underestimated.
But this is just one publication that does not convince other scientists that the estimation would be too way off. So until further notice were still 8 billions.