the human population reached 1 billion in 1804.
the human population reached 1 billion in 1804.
when did the human population reached 1 billion?
1804
section::::history.:milestones by the billions.









































it is estimated that the world population reached one billion for the first time in 1804. it was another 123 years before it reached two billion in 1927, but it took only 33 years to reach three billion in 1960. thereafter, the global population reached four billion in 1974, five billion in 1987, six billion in 1999 and, according to the united states census bureau, seven billion in march 2012. the united nations, however, estimated that the world population reached seven billion in october 2011.
world population
bullet::::- 1773 — william bartram, "(1739–1823)". american naturalist sets out on a five-year journey through the us southeast to describe wildlife and wilderness from florida to the mississippi. his book, "travels", is published in 1791 and becomes one of the early literary classics of the new united states of america.









































bullet::::- 1798 – thomas robert malthus publishes an essay on the principle of population, an evolutionary social theory of population dynamics as it had acted steadily throughout all previous history.









































section::::19th century.









































bullet::::- 1820 — world human population reached 1 billion.
timeline of history of environmentalism