Climate change and the rise and fall of civilizations

Egyptian civilization is the gift of the Nile. But it is also the result of climatic change since the last ice age (Fagan 2004). During the last 10,000 years or so, desertification, punctuated by temporary reversals, has driven people out of what was once a well-watered savannah covering vast areas of the present Sahara into smaller areas fed by rivers and near-surface groundwaters. In Egypt, the result was a relatively large population in a relatively small area, the Nile Valley (Barich 1998). 

This has led to ideas that this population required organization in order for it to survive and allow complex regimented societies to develop; exemplified by the early Pharaonic period with its huge public works projects—the pyramids and associated monuments (Wilkinson 2003). But did complex societies evolve during this organization or was the organization a pre-requisite for the complex societies; did it take place before the constriction of society into the Nile Valley; and did it begin in one area and then spread?

 A popular view is that increasing social complexity occurred during the development of agriculture, made possible by a benign climate while severe climatic change interrupted this development (Burroughs 2005). On the other hand, there is increasing evidence that social complexity developed during climatic deterioration (Brooks 2006). Such questions require objective analysis of the timing of development of different social systems related to climatic change in different parts of Egypt and adjacent areas.

The Sahara was not always a desert; in fact, it was once a fertile region with grasslands, lakes, and rivers. This period is known as the Green Sahara or the African Humid Period and it occurred from approximately 10,000 to 5,000 years ago, during the Holocene epoch.
https://www.quora.com/Were-there-civilizations-in-the-Sahara-when-it-was-still-green

Vocabulary:

• Savannah

• Climate Change

• Glacial Period: A geological epoch characterized by the presence of extensive ice sheets, glaciers, and colder global temperatures, also known as an ice age.

• Interglacial Period: The warmer intervals or periods of relative warming that occur between glacial periods within an ice age.

• Glacier: A large, slow-moving mass of ice formed from compacted snow, typically found in mountainous regions or polar areas.

• Milankovitch Cycles: Long-term variations in Earth's orbit and axial tilt that influence its climate and are thought to play a role in the timing of ice ages.

• Pleistocene Epoch: A geological epoch that lasted from approximately 2.6 million to 11,700 years ago and is associated with multiple glaciations.

• Ice Age Extinction: The phenomenon in which many species of plants and animals became extinct or evolved during and after ice age periods due to changing environmental conditions and competition with other species.