Virtual Water to the rescue!
Hi Everyone! I've heard of a concept called "virtual water"... it has to do with water conservation. Can you guys guess what that could be? They are using the concept in China right now to justify the building of immense irrigation ways from the south to the north of China!
Virtual water is used as a proxi (an approximation made by measuring something else) to know how much water was used in different geographical zones. These types of tricks are used when the thing you are trying to measure is difficult to measure well.
In this case, the use of water could be measured in two main ways: (1) you count how much water was used by certain activities in a region; or (2) you count how much water is needed for a certain activity and you multiply that by the total amount of that activity. Virtual water is the second strategy, used because of how difficult it is to directly measure the use of water by certain activities (if you don't have a machine reliably measuring water at every point of use) in certain places... as in China right now.