John Michael Greer: The unnoticed technologies

…The cyclic interaction between settled urban societies and desert nomads depended on the maintenance of irrigation technologies first put into place by the ancient Sumerians. The slow march of climate change made irrigation more difficult and more necessary at the same time, and most desert civilizations had to direct a fair proportion of their economic output into maintaining the canals and waterworks on which survival depended. This, as ibn Khaldun pointed out, became their Achilles


One of the wrinkles of catabolic collapse