The food-water-energy nexus defeated the Romans. It could defeat us too - The Ecologist
▻http://www.theecologist.org/blogs_and_comments/commentators/2673820/the_foodwaterenergy_nexus_defeated_the_romans_it_could_defeat_us_too.h
The Romans developed networks of trade and food supply that enabled them to escape local water constraints, in a way that is explained in a new study in the journal Hydrology and Earth System Sciences.
Fertile regions such as southern Spain or Italy’s Po valley would grow lots of food and ship it back to Rome or to the drier outposts of the Empire.
Embedded within this is a what geographers call a virtual water trade - an indirect way of shifting this precious resource from wetter, less populated areas to those regions with more people or a less consistent climate.
The map shows this in action. The amount of virtual water imports (a) and exports (b) in different parts of the Empire are illustrated by the size of the circles. The numbers express this in tonnes of grain.
Rome is by far the largest water importer, followed by Alexandria and Memphis in Egypt, and Ephesus and Antioch in modern-day Turkey. Spain and Egypt were the biggest exporters.
The paper’s primary author, Brian Dermody at the University of Utrecht, suggests this sophisticated water economy ultimately contributed to its own downfall as it enabled urban populations to boom beyond sustainable levels.
Does this sound uncomfortably familiar? In the next 30 years we are facing a critical combination of inter-related stresses on the core resources that keep our civilisation running.