Millennia: |
|
---|---|
Centuries: |
Holocene Epoch |
---|
↑ |
Holocene |
The 4th millennium BC spans the years 4000 through 3000 BC. Some of the major changes in human culture during this time included the beginning of the Bronze Age and the invention of writing, which played a major role in starting recorded history.
The city states of Sumer and the kingdom of Egypt were established and grew to prominence. Agriculture spread widely across Eurasia. World population in the course of the millennium doubled, approximately from 7 to 14 million people.
farming, animal husbandry
pottery, metallurgy, wheel
circular ditches, henges, megaliths
Neolithic religion
Based on studies by glaciologist Lonnie Thompson, professor at Ohio State University and researcher with the Byrd Polar Research Center, a number of indicators shows there was a global change in climate 5,200 years ago, probably due to a drop in solar energy output as hypothesized by Ohio State University.