Agribusiness and Water Use

I expected to find some high grade mendacity in this article about an agribusiness sustainability summit, and I did. Though this argument walks away with the prize by far:

... Dr. Brian Kiepper, an engineer and professor in the college of agricultural and engineering sciences at the University of Georgia, talked about water use, explaining that there are two kinds of uses: "non-consumptive use" in which water is returned to the basin from which it was drawn to be used again and "consumptive use" in which water is not returned and not used again.

Agriculture is criticized for high levels of water use, he said, but agriculture is mostly a non-consumptive user. "We put it back." ...

Ouch. I guess it's not technically a bold-faced lie if you have a very broad-minded interpretation of the word "back." Like for instance, if that sentence read, 'We put it back into circulation in the planetary biosphere, eventually,' okay. I could almost give him that.

But it matters where you got the water from in the first place, where that water goes when you're done with it, and what condition it's in when it gets there.

Since agriculture uses almost three quarters of the fresh water accessed by humans, it's especially answerable for these questions. Consider grain as a proxy for water:

... In an increasingly integrated world economy, water shortages are crossing national boundaries via the international grain trade. Since it takes 1,000 tons of water to produce 1 ton of grain, the most efficient way for water-deficit countries to import water is to buy grain from elsewhere.

... Grain exporters are, in effect, water exporters. Canada, where water exports are a politically sensitive issue, is one of the world's leading exporters of water in the form of grain. The 18 million tons of grain, mostly wheat, that it ships abroad each year embody 18 billion tons of water. Similarly, U.S. annual grain exports of 90 million tons of grain represent 90 billion tons of water, an amount that exceeds the annual flow of the Missouri River. ...

Where it comes from, ...

Fresh water from deep aquifers, sometimes called fossil water, is about as renewable as fossil fuel at the rate humans are using it.

Consider the Ogallala aquifer in the US, which supports "14 million acres of crops that represent one-fifth of the country's total agricultural harvest, this primary source of groundwater affects everything from the food we eat to the clothing we wear. Deep enough to fill Lake Erie nine times over, it is immense, but it is not infinite, and this precious aquifer is going dry."

Shallower aquifers could in theory replenish themselves fairly quickly, but they, also can be drained faster than they can be replenished and polluted faster than they can be naturally purified.

Across Asia, and acutely in major grain producing nations, India and China, the water tables are sinking rapidly as they're drained for the agricultural uses of well over 2 billion people.

... where it goes ...

The water used for agriculture is plainly not going back into the aquifers and ground water tables from whence it often came. Most of it runs off to the sea or evaporates.

Natural ecosystems hold onto more water for longer periods of time, and often filter it. Water budgets tend to produce maximum biomass, and often cycles through the bodies of a greater diversity of local plants and animals before eventually evaporating or running off.

Simplified agricultural ecosystems are comparatively wasteful of water, decreasing the amount and diversity of biomass a given amount of water can support. More of that biomass may be food for us than would be the case in a natural ecosystem, but the costs to the local water cycle are quite high.

... and what condition it's in.

Only a paltry 2.5% of the world's water is fresh and about 70% of that is locked up in ice caps. When the fresh water available to land ecosystems gets contaminated with toxic substances, like pesticides or high concentrations of fertilizer, its value and ability to support life is greatly diminished.

Agriculture very often takes clean water and makes it dirty. And no one at all wants dirty water put back where their clean water came from.

Agricultural runoff is a major source of pollution for many rivers, not that it stops there. It also poisons the ocean, with agricultural runoff largely responsible for the 405 oceanic dead zones reported in 2008:

... Fertilizer contains large amounts of nitrogen, and it runs off of agricultural fields in water and into rivers, and eventually into oceans.

This fertilizer runoff, instead of contributing to more corn or wheat, feeds massive algae blooms in the coastal oceans. This algae, in turn, dies and sinks to the bottom where it is consumed by microbes, which consume oxygen in the process. More algae means more oxygen-burning, and thereby less oxygen in the water, resulting in a massive flight by those fish, crustaceans and other ocean-dwellers able to relocate as well as the mass death of immobile creatures, such as clams or other bottom-dwellers. And that's when the microbes that thrive in oxygen-free environments take over, forming vast bacterial mats that produce hydrogen sulfide, a toxic gas. ...

In the Chesapeake Bay and Gulf of Mexico alone, these events destroy nearly 300,000 tons of marine life every year, dramatically cutting the potential commercial fish catch. As the article notes, the species hardest hit are the ones that can't leave, including marine plants, clams and oysters.

In what way is this, or any of these other consequences, "non-consumptive"?

There's got to be a better way to feed ourselves. And if there is, ostrich-like apologists for the current system aren't going to help us find it.

(Photo credit: Soil-Science.info on Flickr.)