A Selected Chronology of the Earth
Years Before 
Present (bp)
Human 
Population
Event
4.5 billion years Earth formed
4.4 by Oceans formed
3.2 by First life appears
1.5 by Ozone layer forms
900 million years Sexual reproduction accelerates evolution
400 my First land plant; Age of Fishes
220 my Dinosaurs rules; first mammals
65 my Asteroid impact-dinosaur extinction
45 my Himalayan Mountains formed
3.7 my First human-like creatures
2 my Tool use
360,000  Controlled use of fire
40,000 Complex language
25,000 Peopling of the Americas
10,000 Agricultural revolution; last ice age ends; (there have been perhaps 35 previous ice ages).
3,000 50 million Writing, Bronze Age, Pyramids; Sahara is grasslands
2,000 100 million
1,000 BC 150 million First Olympics; Confucius, Homer
600-400 BC Buddha, Socrates, Old Testament
200 BC Great Wall of China
200 million Roman Empire; birth of Christ
600 AD Mohammed, Mayans, Byzantines
1000 AD 250 million Crusades
1200 AD 300 million Genghis Khan, Marco Polo; wood is predominant energy source
1500 AD 500 million Renaissance, Columbus, Incas & Aztecs
1600 AD 600 million Gallileo, microscope, America.  Takes 2 years to circumnavigate the globe.
1700 AD 700 million Newton, Bach, Mozart
1800 AD 900 million Mendel
1850 AD 1 billion Darwin, evolution; 2 months to circumnavigate; coal is predominant energy source
1900 AD 1.7 billion Einstein, Freud, Curie; cars, Panama & Suez Canals
1920 AD 1.85 billion Airplanes; another galaxy found; oil is predominate energy source
1940 AD 2.25 billion Information Revolution; A-bomb; two weeks to circumnavigate
1950 AD 2.5 billion Two days to circumnavigate
1960 AD 3 billion Green Revolution; 90 minutes to circumnavigate (by rocket); energy consumption has doubled since 1950
1970 AD 3.7 billion Man on the Moon; equality and ecology movements
1980 AD 4.4 billion Energy consumption has quadrupled since 1950
1990 AD 5.3 billion Circumnavigation by fax, nearly instantaneous
1993 AD 5.6 billion
1994 AD 5.7 billion
2001 AD 6.2 billion