There’s an interesting article in The Conversation today which suggests that climate change may have been responsible for the collapse of the Mayan civilisation in central America. The authors refer to a study in Science authored by Douglas J. Kennett et. al., in which they studied rainfall patterns from stalagmites inside Yok Balum Cave in Belize and compared them with historical clues carved into local monuments. While anomalously high rainfall had allowed the population to expand considerably, the following warming and drying trends which extended for several hundreds of years led to droughts which shattered and eventually destroyed the civilisation.
There is also evidence that contemporaneous civilisations fell prey to the same problem. The Khmer, who covered much of South-East Asia and built the famous Angkor Wat temple, suffered first from the deluge, which badly damaged their extensive network of canals and reservoirs, then from the succeeding centuries of drought. The civilisation never recovered. Other civilisations that suffered include the Nazca in Peru, who turned a land of fertile oases into a sandy desert, and the Anasazi in the American south-west.
Much older civilisations have succumbed, too: the oldest known civilisation, the Akkadians of Mesopotamia, succumbed to the effects of long harsh drought and overpopulation. So, too, did the Minoans on Crete, who deforested their island for ship-building, the Sumerians in southern Iraq, and the Harappan civilisation in the Indus valley.
While non-manmade weather events occurred, there’s little doubt that the actions of the civilisations played a substantial part in their own decline. In particular, expanding populations considerably over the carrying capacity of the land, and extensive deforestation, both contributed to the eventual societal collapse. Let’s hope that our current civilisation can learn from the plethora of past examples.