6 Civilizations Impacted by Climate Change

Onset of City Civilizations (3200 BC)

- Unusually cold and dry period globally that forced together more dispersed agricultural communities towards more concentration populations near rivers

- Egyptian cities along the Nile River Valley as the Sahara became a desert and forced people to live along the river together

Fall of the Mesopotamian Akkadian Empire (2150 BC)

- Evidence of rapid collapse found in spike in arid eolian sediments which indicates a drought; isotopic signatures of eolian sediments suggest a variety of sand sources indicating the drought was extensive

- Empire most likely collapsed due to drought-induced food shortage

Fall of the Roman Republic (44 BC)

2 years following the massive eruption of Alaska's Okmok volcano in 43 BC it led to extreme cooling-induced famine

Fall of the Mediterranean Western Roman Empire (479 AD)

- Roman empire was flourishing until a 100 year cold wet period

- Led to mass migrations in Europe which led to decreased agriculture and thus less deforestation

Collapse of Anasazi Culture (1350)

- Population collapse was coincident with decreased summer rain

- Precipitation from SW U.S. tree wing widths indicate the collapse of the Anasazi Culture occurred at the transition from the wetter Medieval Warm Period (MWP_ to the drier Little Ice Age (LIA)

Transitions in Andean culture (200-1600 AD)

- Transition from MWP to LIA caused a shift of Andean cultures from coast to the mountains (the Inca)

- Cold and dry coastal cultures from 200-600 AD

- Warm and wet highland cultures from 600-1000 AD

- Cold and Dry coastal cultures from 1000-1450 AD

- Warm and wet highland cultures from 1450-1700 AD