4th millennium BC

World population was largely stable in this time at roughly 50 million, growing at an average of 0.027% per year.

[1] Sub-Saharan Africa remains in the Paleolithic period, except for the earliest neolithization of the Sahel following the desiccation of the Sahara in c. 3500 BC.

[8][9] As the grasslands of the Sahara began drying after 3900 BC, herders spread into the Nile Valley and into eastern Africa (Eburan 5, Elmenteitan).

The desiccation of the Sahara and the associated neolithisation of West Africa is also cited as a possible cause for the dispersal of the Niger-Congo linguistic phylum.

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.

Ġgantija Warka Vase Bronocice pot Kish tablet Narmer Palette
From top left clockwise: The Temple of Ġgantija , one of the oldest freestanding structures in the world; Warka Vase ; Bronocice pot with one of the earliest known depictions of a wheeled vehicle; Kish tablet , an example for proto-writing ; Pharaoh Narmer is credited with uniting Upper and Lower Egypt and is depicted as such in the Narmer Palette .
Monte d'Accoddi is an archaeological site in northern Sardinia , Italy , located in the territory of Sassari near Porto Torres . 4th millennium BC.
Sumerian priest-king from Uruk , Mesopotamia, circa 3300–3000 BC
Shengavit Settlement , c. 3300 BC
Pharaoh Scorpion II on the Scorpion Macehead , c. 3200 BC
Bronze Age spread of Yamnaya steppe pastoralist ancestry into two subcontinents—Europe and South Asia—from c. 3300 to 1500 BC. [ 5 ]
The Ġgantija temples are the earliest of the Megalithic Temples of Malta
Tustrup-dysserne, the largest passage grave in Eastern Jutland , is an example of Funnelbeaker culture circa 3200 BC
Fertility figurine from Mehrgarh , Indus Valley , c. 3000 BC