Populations

Abstract

Demographic transition has been completed everywhere except for large parts of Africa. Steady decline of traditionally high fertilities and mortalities brought temporarily high rates of population growth (globally peaking during the 1960s), as the worldwide count rose from about 1 billion in 1800 to more than 7.8 billion by 2020. The new prevailing pattern of population dynamics is characterized by very low infant mortalities, fertilities well below the replacement level, increasing longevities, and aging, even decline, of many populations. Generations of high growth rates and productivity gains in agriculture and abundance of fossil fuels led to an unprecedented pace of urbanization. More than half of humanity now lives in cities, including a rising number of megacities, each with more than 10 million people.