when did earth's population reach 1 billion
World population milestones It is estimated that the population of the world reached one billion for the first time in 1804. It would be another 123 years before it reached two billion in 1927, but it took only 33 years to rise by another billion people, reaching three billion in 1960. Thereafter, the global population reached four billion in 1974, five billion in 1987, six billion in 1999 and, by some estimates, seven billion in October 2011 with other estimates being in March 2012.[3] It is projected to reach eight billion by 2024–2030. According to current projections, the world's population is likely to reach around nine billion by 2035–2050, with alternative scenarios ranging from a low of 7.4 billion to a high of more than 10.6 billion.[4] Projected figures vary depending on underlying statistical assumptions and which variables are manipulated in projection calculations, especially the fertility variable. Long-range predictions to 2150 range from a population decline to 3.2 billion in the 'low scenario', to 'high scenarios' of 24.8 billion. One scenario predicts a massive increase to 256 billion by 2150, assuming fertility remains at 1995 levels.[5]
Millennials Millennials (also known as Generation Y) are the demographic cohort following Generation X. There are no precise dates for when this cohort starts or ends; demographers and researchers typically use the early 1980s as starting birth years and the mid-1990s to early 2000s as ending birth years.
One-child policy Effective from January 2016, the one-child policy was replaced by a two-child policy, allowing each couple to have two children.
World population World population has experienced continuous growth since the end of the Great Famine of 1315–17 and the Black Death in 1350, when it was near 370 million.[3] The highest population growth rates – global population increases above 1.8% per year – occurred between 1955 and 1975, peaking to 2.06% between 1965 and 1970.[2] The growth rate has declined to 1.18% between 2010 and 2015 and is projected to decline to 0.13% by the year 2100.[2] Total annual births were highest in the late 1980s at about 139 million,[4] and are now expected to remain essentially constant at their 2011 level of 135 million,[5] while deaths number 56 million per year and are expected to increase to 80 million per year by 2040.[6] The median age of the world's population was estimated to be 30.1 years in 2016, with the male median age estimated at 29.4 years and female at 30.9 years.[7]