The Kingdom of Egypt prospered for 3,000 years—in the desert. Its success depended on strong leadership, written language, mathematics and engineering… but most importantly, on the flooding of the Nile, which happened each June through September.

Farmers developed an irrigation system that trapped floodwaters in their fields using dams. They let the water recharge the soil for a few months while the organics settled out, providing nutrients to the earth.

They’d then release the water to the receding river and plant their crops. In this way, year after year, the fields could produce enough food to sustain a large population living in the desert.

The floods were the direct result of African monsoons, which fell on the highlands of Ethiopia, the headwaters of the Nile. If the rain didn’t fall, the Nile wouldn’t flood. And there were some years that it didn’t.

Volcanic activity in the region filled the atmosphere with ash and gas, reflecting the sun’s heat, reducing evaporation and, therefore, rainfall.

Geologic and historical records now allow us to closely correlate volcanic eruptions with reduced Nile flooding, reduced crop production, reduced tax revenue for the state, and higher incidence of famine and revolt from the populace.

Especially high volcanic activity in the last 300 years of the Egyptian Kingdom contributed to its eventual fall to the Romans.

Yet another example of how connected human civilization has been, and continues to be, to freshwater supply, weather patterns, and the geology of Earth.