Climatic Change The Anasazi, Tiwanaku, Akkadians, Mayan, and Roman Empires all fell due to abrupt climatic changes. Droughts severely impacted agriculture, disrupting water supplies and societal stability. The Anasazi abandoned villages around A.D. 900 due to sustained dry spells. The Tiwanaku in Bolivia collapsed when Lake Titicaca's water levels dropped, […]