How did we get here? And where are we heading? Every two years, the United Nations makes  projections  for future population growth. Its latest medium projection – the most likely scenario – is a population of  9.7bn in 2050  and  10.4bn in 2100 . Because many factors affect population growth, it makes a range of projections depending on different assumptions. Within its 95% certainty range, the difference in population in 2100 from the highest to lowest projection is 3.5 bil