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

Water is not consumed

[goombah99]

Agriculture does not consume water it uses water. Virtually all the water is returned to the eco system after use.

However there are different sources of water. Ground water versus surface water. Depletion of ground water is not sustainable as water table levels are dropping. Surface water use is sustainable but also has consequences as stream dry up as they are diverted or become filled with water so contaminated it can't be re-used down stream.

Re:Water is not consumed

[Sique]

Not exactly. Agriculture can consume locally available water. And that's all what counts.
If you pump water from ground depots which are not fully refilled, then most water used in agriculture ends up as clouds which the wind blows somewhere else. This water is completely lost for local use. For most of the Central U.S., the amount of water that comes in via rain or rivers, is less than the amount of water lost due to evaporation. And most of the water gets lost due to the amount of water used for agriculture. In this case, agriculture literally sucks the earth dry, because ground water, water from lakes and water enclosed in the last ice age in natural reservoirs below the surface is pumped up and evaporates. Those resources are not unlimited, and they will dry up sooner or later.
The case is different for the East Coast or for most of Europe, where more fresh water comes in via rainfall or rivers, than gets lost due to evaporation. Here you can use as much water as you want, the resources will never dry up, you just have to make sure that used water will not intoxicate fresh water wells, so you have to build an extensive drainage system and water treatment plants.

Re:The real questions should be different

[Bert64]

The corn farmers lobbyists are too influential in the US...
They want to continue producing corn, and won't even consider changing their business model...
So instead of looking to produce appropriate products to meet demand, they are looking for ways to force their existing products onto the market, even when they are not the best choice...

Case in point high fructose corn syrup, it is a terrible sweetener and requires considerably more processing than sugar, making it more expensive to produce...
In the US, high taxes on sugar force the use of HFCS...
In other countries without such manipulative taxes, market forces result in sugar being used because its a more suitable product.

The situation is so ridiculous, that people in the US actually go out of their way and often pay more to buy Coke that's been imported from Mexico because it uses real sugar instead of HFCS.

There is an easy way to help

[gr8_phk]

Most farmers do everything they can to get rain water to run off the fields so they don't flood and over-water the crops. Then they pump water out of the ground and apply it to the fields as needed. The rain water then dumps very quickly into the rivers and causes flooding down stream. A simple way to take care of this is to dig a large basin (1-2 percent the area of the fields and say 20-30 feet deep) to collect the rain water, then pump that back onto the fields as needed and only when it's dry would they need to pump water from the deep aquifer. It would help all of the problems, but would cost a bit to set up. Oh, and this would re-apply the fertilizer that washes away when it rains - which is another problem both down-stream and as a cost to farmers and a natural resource issue (phosphorous).

All those problems come down to poor resource management.