Peak Water?

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Courtesy of HVR Water Purification AB

Agriculture used to mean unexciting investments in commodities. Now Silicon Valley, for instance NewSeed Advisors and KPCB, are looking for the “next great idea” in farming efficiency. It’s Agriculture 2.0, a.k.a. “ag” app. At the same time companies like Goldman Sachs and several sovereign funds are investing in agricultural land.

Why is this!? Populations grow, living standards grow, water supply declines, productive land is in short supply.

One of the consequences is that the share of irrigated land is increasing. About one fifth of present world agriculture already depends on irrigation.

According to International Atomic Energy Association (IAEA) “about 20% of irrigation worldwide, producing 40% of the food supply, is dependent upon groundwater”. Other sources say that half the water used for irrigation is surface water and the other half is ground water.

This means that a large part of global food production depends on non-renewable fossil water. A well-known example of fossil groundwater is the Ogallala Aquifer situated under the “corn basket” in the Mid West of the US. This huge underground lake presently supplies close to 30 percent of the irrigated land in the US and it is drying up. Ever since large scale irrigation began some decades ago, water levels in the aquifer have fallen 10 to 20 meters and according to some estimates it may dry up entirely in as little as 25 years.

Much other water used for irrigation is also – not technically, but practically - nonrenewable. Some rivers have already dried up. Many lakes are at risk. Overuse has already taken its toll. The best known example is the Aral Sea which has decreased to half in size, fallen 19 meters and had its salinity tripled.

Even at some places where ground water is replenished profusely by annual rains, water tables are falling because of irrigation. This may ultimately make the groundwater in such locations unfit for irrigation because of sea water intrusion and/or upward diffusion of deeper (fossil) saline water.

Groundwater depletion and surface water depletion commonly leads to salinization. But also normal irrigation, especially with ground water, adds salts to the soil because, unlike rain, both surface and ground water contain minerals. Irrigated soils are therefore slowly becoming more saline. Up to a point, salinity is no problem. After a while, the choice of crops becomes limited and in the end the soil may become barren.

Pollution also reduces the amount of water that can be used for irrigation - Love Canal and Citarum River are well known examples. On top of it all, farmers who today use 70 percent of the world’s fresh water are facing increasing competition for water from industrial users.

The world population has grown from less than 2 billion one hundred years ago to more than six billion today. Billions who are still undernourished push towards a passable living standard. Other billions strive to increase their basic living standards.

The amount of water needed per kilogram of potatoes has been calculated to 160 litre, corn 450, milk 900, wheat 1200, soybean 2300, rice 2700, chicken 2800, eggs 4700, cheese 5300, pork 5900 and beef 16000. (World Water Council).

Food sufficiency in the future will require an increase in water supply. Some of it will be secured by re-use and some from desalination of sea-water.

That’s why there is a present boom in the water industry where mammoth players like GE, Siemens, Veolia and many others are in fierce competition and many start-ups emerge.

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