It's a problem so widespread, so obvious, so immediate and so perilous to so very many people in every corner of the world that it speaks to the paralysis of our political leadership that they have all but ignored it. It is what's now being called "Peak Water."
Anyone who has listened to the warnings from people like Maude Barlow over the past many years knows that the freshwater crisis setting in around the world is a threat to our civilization that rivals that of climate change itself.
Some nations are nearing Peak Water, the point at which their supply of freshwater is in inexorable decline. Other nations have already reached that point.
Think of it this way. Water insecurity is food insecurity and food insecurity is political instability and chaos.
Peak oil has generated headlines in recent years, but the real threat to our future is peak water. There are substitutes for oil, but not for water. We can produce food without oil, but not without water.
We drink on average four quarts (4.5 litres) of water per day, in one form or another, but the food we eat each day requires 2,000 quarts of water to produce, or 500 times as much. Getting enough water to drink is relatively easy, but finding enough to produce the ever-growing quantities of grain the world consumes is another matter.
Grain consumed directly supplies nearly half of our calories. That consumed indirectly as meat, milk, and eggs supplies a large part of the remainder. Today roughly 40% of the world grain harvest comes from irrigated land. It thus comes as no surprise that irrigation expansion has played a central role in tripling the world grain harvest over the last six decades.
...beginning with the Sumerians some 6,000 years ago, irrigation water came from building dams across rivers, creating reservoirs that then enabled them to divert the water onto the land through a network of gravity-fed canals. This method of irrigation prevailed until the mid 20th century, but with few remaining sites for building dams the prospects for expanding surface irrigation faded. Farmers then turned to drilling wells to tap underground water resources.
In doing so, they learned that there are two types of aquifers: those that are replenishable through rainfall, which are in the majority, and those that consist of water laid down eons ago, and thus do not recharge. The latter, known as fossil aquifers, include two strategically important ones, the deep aquifer under the North China Plain and the Ogallala aquifer under the US Western Great Plains.
Tapping underground water resources, which got seriously underway in the mid-20th century, helped expand world food production, but as the demand for grain continued climbing the amount of water pumped continued to grow. Eventually the extraction of water began to exceed the recharge rate of aquifers from precipitation, and water tables began to fall. In effect, overpumping creates a water-based food bubble, one that will burst when the aquifer is depleted and the rate of pumping is necessarily reduced to the rate of recharge from precipitation.
Today some 18 countries, containing half the world's people, are overpumping their aquifers. Among these are the big three grain producers – China, India, and the United States – and several other populous countries, including Iran, Pakistan and Mexico.
In Mexico – home to a population of 109 million that is projected to reach 129 million by 2050 – the demand for water is outstripping supply. Mexico City's water problems are well known. Rural areas are also suffering. In the agricultural state of Guanajuato, the water table is falling by 2m or more a year. In the northwestern state of Sonora, farmers once pumped water from the Hermosillo aquifer at a depth of 35ft. Today they pump from 400ft. Mexico's water supply appears to have peaked. Peak grain may be imminent.
...now aquifer depletion also threatens harvests in the big three grain producers – China, India and the United States – that together produce half of the world's grain. The question is not whether water shortages will affect future harvests in these countries, but rather when they will do so.
Among the big three, dependence on irrigation varies widely. Some four-fifths of China's grain harvest comes from irrigated land, most of it drawing on surface water. For India, three-fifths of its grain is irrigated, mostly with groundwater. For the United States, only one-fifth of the harvest is from irrigated land. The bulk of the grain crop is rain-fed, produced in the highly productive midwestern corn belt, where there is little or no irrigation.
India's grain harvest has been expanding rapidly in recent years, but in part for the wrong reason, namely massive overpumping. A 2005 World Bank study reports that 15% of India's food supply is produced by mining groundwater. Stated otherwise, 175 million Indians are now fed with grain produced with the unsustainable use of water. As early as 2004, Fred Pearce reported in New Scientist that "half of India's traditional hand-dug wells and millions of shallower tube wells have already dried up, bringing a spate of suicides among those who rely on them. Electricity blackouts are reaching epidemic proportions in states where half of the electricity is used to pump water from depths of up to a kilometre."
As India's water table falls, well drillers are using modified oil-drilling technology to reach water, going down a half mile or more in some locations. In communities where underground water sources have dried up entirely, all agriculture is now rainfed and drinking water must be trucked in. Tushaar Shah, who heads the International Water Management Institute's groundwater station in Gujarat, says of India's water situation: "When the balloon bursts, untold anarchy will be the lot of rural India."
In the United States, farmers are over-pumping in the Western Great Plains, including in several leading grain-producing states such as Texas, Oklahoma, Kansas and Nebraska. In these states, irrigation has not only raised wheat yields but it has also enabled a shift from wheat to corn, a much higher-yielding crop. Kansas, for example, long known as the leading wheat state, now produces more corn than wheat.
Irrigated agriculture has thrived in these states, but the water is drawn from the Ogallala aquifer, a huge underground water body that stretches from Nebraska southwards to the Texas Panhandle. It is, unfortunately, a fossil aquifer, one that does not recharge. Once it is depleted, the wells go dry and farmers either go back to dryland farming or abandon farming altogether, depending on local conditions.
In the states that draw their irrigation water from the Ogallala aquifer, wells are starting to go dry. In Texas, a large grain and cattle state, which is located on the shallow end of the aquifer, irrigated area peaked in 1975 and has dropped 37% since then. In Oklahoma, irrigation peaked in 1982 and has dropped by 25%. In Kansas the peak did not come until 2009, but during the three years since then it has dropped precipitously, falling nearly 30%. Nebraska, now also a leading corn-producing state, saw its irrigated area peak in 2007. Since then its grain harvest has shrunk by 15%.
The message is plain. Mankind has employed conjuring acts to allow it to increase massively not only in total numbers but also in per capita consumption. This has been achieved by recklessly over-exploiting our finite freshwater resources far beyond their sustainable limits. When the hydrological cycle failed to meet our water needs, we turned to mining water out of the ground at volumes vastly exceeding recharge rates. As we have done in many other areas, we allowed ourselves to become dependent on something essential that was both unreliable and irreplaceable.
But we always have rainwater, right? Wrong. Global warming has broken the hydrological cycle that has sustained mankind since our inception and upon which our entire civilization has been built. It's broken.
We've lost a great deal of that usable water. More of our freshwater resource now lies over our heads in the form of water vapour. A warmer atmosphere holds more water that previously would have been down here where we need it.
The far worse aspect of our broken hydrological cycle is that it no longer reliably brings usable amounts of rainwater where it's needed as it's needed. Farmers need predictable, steady supplies of rainwater. Too much rain at the start of the growing season and they can't get on the land to plant their crop. Too much rain during the growing season and their crop may rot in the fields. Too little rain during the growing season and the crop may wither and die. Too much rain late in the growing season and they may not be able to get on the land to harvest.
Agriculture has always been at the mercy of the hydrological cycle. But now, new forces are at play. The broken hydrological cycle brings deluge and drought as we have never experienced them. The warmer, moister atmosphere fuels severe storm events of steadily increasing frequency and intensity.
We have also messed with the jet streams. In the northern hemisphere, the loss of Arctic sea ice and warming of the Arctic ocean waters has unleashed a very powerful Polar Jet Stream that brings atmospheric Rossby waves that meander slowly both farther north and south, plunging ordinarily mild Europe into an Arctic deep freeze in February while delivering 96F heat to mid-Alaska in June. These waves don't migrate west to east the way they did before. Now they tend to stall and park over regions bringing sustained drought or floods to the areas affected.
It's not hard to figure out that you can't wipe out the Arctic sea ice without triggering major atmospheric and hydrological impacts. While our governments napped, the Arctic has warmed, heated actually, at twice the global average. Did we really not expect to get one upside the head from that?
And now we have research demonstrating a recent, major change in the ENSO - El Nino Southern Oscillation that triggers floods and droughts that virtually span the world. And, based on examination of 700-years of evidence, the researchers conclude the new ENSO is also linked to global warming.
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