Is Agriculture Sucking Fresh Water Dry?

sciencehabit writes "The average American uses enough water each year to fill an Olympic-sized swimming pool, and global agriculture consumes a whopping 92% of all fresh water used annually. Those are the conclusions of the most comprehensive analysis to date of global water use, which also finds that one-fifth of humankind's water consumption flows across international borders as 'virtual water' — the water needed to produce a commodity, such as meat or electronics, if the ultimate consumers were to make it themselves rather than outsource its growth or manufacture."

Comments

It's all to do with pricing

[Colin Smith]

The perception is that when something is cheap, it is of low value so it doesn't matter if you consume too much of it.
If you look at areas where water is scarce and where wars are fought over it, or where it has to be desalinated i,e, it's expensive, you'll find the users are a lot more careful over how much is used and how it is used.

Compare US irrigation methods:
http://en.wikipedia.org/wiki/File:Irrigation1.jpg

with Persian Qanat methods:
http://en.wikipedia.org/wiki/Qanat

Definitions - Tricky Things

[DeathToBill]

This study borders on sleight-of-hand to my mind. At least the way it is presented is misleading.

The headline says that 92% of freshwater use is in agriculture. What it doesn't mention is that the vast majority of that "use" of water is rain that happens to fall on farmland. We could increase that number by converting land use to arable land without changing any natural flow of water. For instance, the city of Adelaide is about the same area as the county of Cornwall and is built largely on prime agricultural land. Moving the city 100 miles North East onto unfarmable land and resuming agriculture there would noticeably increase the agricultural use of water - but it would actually be an environmentally good thing.

When it comes to diverting the natural course of water (extraction from rivers, building dams, draining lakes etc - what you might call exploiting the natural resource), the use of water in agriculture is much less - the majority here supplies water for urban residences and industry.