Changes

In the 4th millennium BC, the Nile, became less predictable. From around 3700 BC, the Nile may have periodically flooded more than expected while in other years floods were too low. Although the patterns of the annual Nile flood, which was critical to agriculture, had set in, the timing and fluctuations were not stable. This could have been due to fluctuating monsoon rains in central Africa that was were influencing Nile flooding. It was during this time we begin to see settlements becoming larger but also more distant from the flood areas of the Nile. The settlements around Naqada become among the most important areas for Egypt in at this time and develop early proto-kings that influence much of Egypt. Hierakonpolis also arose as a possible rival to Naqada.  The limitation of resources that were once found in the deserts along with less predictable flooding has led some to speculate that these could have been the triggers to the social stratification and inequality that led to the rise of pharaohs or at least proto-kings that would have held some regional power as they competed with potentially other actors. While the Nile became more drydrier, this could have made the river less marshy and thus more useful for both agriculture and settlement. In other words, in earlier periods there may have been too much water, while during the the 4th millennium BC it became now suitable for major towns and cities to begin to form.  There were likely some brief wet episodes during this time but in general , the climate became more dry drier and resources and people began to be concentrated along the Nile, leading to the great social stratification and hierarchy that became associated with Egyptian civilization.<ref>For more on Nile flooding and unpredictable climate conditions, see: Hassan, F.A., 2008. Africa, North | Egypt, Pre-Pharaonic. <i>Encyclopedia of Archaeology</i>, p. 45-50. </ref>

After 3500 BC, the last remaining margins outside of the Nile were mostly abandoned, with the exception of a few oases. Nile records soon began to be recorded by the now rapidly arising Egyptian societies along the Nile that happened between 3500-3000 BC. From around 3000 BC, the stability of the Nile became more evident. The floods were more predictable and providing the fertility and water needed for crops to be grown in the Nile valley. The first unifying pharaohs arose by around 3200-3100 BC. The combination of predictable flooding and concentrations of populations in the Nile valley made it easier for pharaohs to rule a larger population, but this was also made possible by the increasing aridity that had occurred over the previous millennia. Stability through the benefaction of the gods and pharaoh became a key theme in Egyptian civilization, which was influenced by the largely predictable climate of Egypt as climate stabilized for a period.<ref>For more on increased social complexity triggered by climatic change, see: Newton, C., Midant-Reynes, B., 2007. Environmental Change and Settlement Shifts in Upper Egypt

However, stability was not always that long -lasting. By around 2400 BC, rainfall in the equatorial regions of Africa, which affected the annual flooding of the Nile that was needed for agriculture, began to diminish. Around 2200 BC, conditions became even more arid arider and this may have contributed to the crisis of the late 3rd millennium in ancient Egypt with the fall of Old Kingdom Egypt. Once again, climate may have played some role in shaping Egyptian civilization, this time creating a famine or some loss of stability for the state authorities that challenged their ability to control the population. Rebellions against the state developed and Egypt broke into multiple kingdoms. It would reemerge as a unified state after 2000 BC, but climate continued to influence Egyptian civilization in the centuries to come.  Egypt, at times, would emerge as the breadbasket for major empires, such as the Roman Empire, but at other times would experience famine and breakdown of central authority. So long as the monsoon rains were stable, Egypt thrived, but once there was disruption to the summer monsoons then it often began to crumble as a central, unified state.<ref>For more on changing climate conditions affecting Egyptian civilization, see: Yletyinen, J. (2009). <i>Holocene climate variability and cultural changes at River Nile and its Saharan surroundings</i>. Institutionen för naturgeografi och kvartärgeologi. Stockholm. https://www.diva-portal.org/smash/get/diva2:400169/FULLTEXT01.pdf </ref>