virtual water trade.... sounds ridiculous
It happens today as well — before the current water shortage (which is partly natural in origin, but also political), Israel was an exporter of virtual water in the form of fruits and vegetables sold into the European market. Thanks to population increases, prosperity, and the aforementioned water shortage, Israel now is a net importer of virtual water as fruits and veggies. The Roman version shown in the article is wheat, but they also shipped around wine, olive oil, and other ag products.