Human population growth and the demographic transition.

摘要: The world and most regions countries are experiencing unprecedentedly rapid demographic change. obvious example of this change is the huge expansion human numbers: four billion have been added since 1950. Projections for next half century expect a highly divergent world, with stagnation or potential decline in parts developed continued growth least regions. Other processes also undergoing extraordinary change: women's fertility has dropped rapidly life expectancy risen to new highs. Past trends mortality led very young populations high developing increasingly older world. Contemporary societies now at different stages their transitions. This paper summarizes key population size, mortality, age structures during these focus on from 1950 2050, which covers period global transformation.