2007 Volume 41 Pages 23-49
Considering that existing estimates of world historical population are based on fragile evidence,a new method using city population is proposed here to further clarify the past population trend. Different from "urban population" which keeps increasing, city population defined as top x cities'population is found to be a stable indicator in proportion to the total population. At the global level, the city population ratio is stable since 1950 to the present and in the country/regional level it was stable until the onset of modern times (around the 19^<th> century). Assuming the stability of city population ratio, the total population of the world was calculated for the past 2000 years.The result shows the discontinuous trend of population both globally and regionally and a relatively low figure for medieval European population. The stability of the city population ratio can be explained by the generalized rank-size rule by which the total population is the function of the top city population, slope of the rank-size distribution and number of the communities.
