Wednesday, March 19, 2008

Peak Water

(See previous article "The Emerging Global Freshwater Crisis"[10] in the blog.)

The real impact of the peaking of any finite resource is that long-established demand continues to rise while the supply goes into terminal decline. This is the nexus of a crisis. In our growth-addicted global society to it means that growth of whatever sectors of the economy and society rely on that resource must cease. There is much discussion and debate about peak oil and the broad impact it will have on our energy-hungry global society. But we are facing another peak which will ultimately have even more devastating consequences.

Peak water!

There is a not unreasonable tendency to think of water as a renewable resource. Seventy-five percent of the earth's surface, after all, is covered with it. And the planet has a very efficient hydro-cycle where water is constantly recycled and recirculated. The rain that falls on a field of Kansas corn rose as water vapour from the vast warm waters of the Gulf of Mexico or the Atlantic Ocean. But salt water is largely unusable and the surface freshwater contained in lakes and rivers is only a minuscule 0.3 percent of the water on the planet and about ten percent of the total freshwater which is only 2.5% of the planet's total water supply. Ninety percent of the world's freshwater is locked up in ice caps and glaciers or sequestered in deep underground aquifers. In fact, according to the Worldwatch Institute "Some 97 percent of the planet's liquid freshwater is stored in underground aquifers."[9]

Over half the freshwater usage in the world (estimates are as high as 75% and growing) comes from these underground aquifers, water that is replenished, if at all, over slow geological time frames, not seasonal replenishment like surface water. "Water that enters an aquifer remains there for an average of 1,400 years, compared to only 16 days for rivers."[9] Many of the world's major aquifers that are heavily relied upon for agriculture, like the Ogallala Aquifer in the western U.S. (about 400-million cubic meters of drawdown per year)[1], the Arabian Aquifer and the deep aquifer under the North China Plain (the shallow aquifer is replenishable but has largely been sucked dry)[7], are non-replenishable, fossil aquifers mostly formed during and after various ice ages. Once such an aquifer is depleted it is gone, forever. With replenishable aquifers there is generally at least the potential for aquifer recovery if the aquifer has not been contaminated and the rate of drawdown is reduced to below the replenishment rate. Coastal aquifers, however, can become increasingly contaminated, not surprisingly, from salt-water intrusion if the drawdown exceeds the natural replenishment rate. Once that happens, as is the case in much of the middle east and central Asia, the aquifer, though it may be full of water, is no longer usable.

But there is increasing concern that vital aquifers everywhere are becoming contaminated with toxins. A new study from the Worldwatch Institute reveals that "this first global survey of groundwater pollution shows that a toxic brew of pesticides, nitrogen fertilizers, industrial chemicals, and heavy metals is fouling groundwater everywhere, and that the damage is often worst in the very places where people most need water."[9] "Sixty percent of the most hazardous liquid waste in the United States-34 billion liters per year of solvents, heavy metals, and radioactive materials-is injected directly into deep groundwater via thousands of "injection wells." Although the EPA requires that these effluents be injected below the deepest source of drinking water, some have entered underground water supplies in Florida, Texas, Ohio, and Oklahoma."[9] And the U.S. EPA estimates "that about 100,000 gasoline storage tanks are leaking chemicals into groundwater. In Santa Monica, California, wells supplying half the city's water have been closed because of dangerously high levels of the gasoline additive MTBE."[9] A close personal friend in Australia with a permaculture farm found the groundwater below their property contaminated from just such a source, a petrol station just up the road with leaky storage tanks.

Over the last century while the world population has tripled global freshwater usage has increased more than six-fold with the bulk of that increase being ground water from deep aquifers. And it is estimated that as much as 90% of the global population increase to the middle of this century will be in areas that are already facing critical freshwater supply constraints[5] either as a result of surface water contamination ("Some two million tons of waste per day are disposed of within receiving waters, including industrial wastes and chemicals, human waste and agricultural waste" according to the UN)[1] or aquifer depletion[9].

Where the minimum daily water availability per person established by the United Nations is ten gallons, these water-challenged areas have daily water availability now of less than three gallons per person, many of them 1.5 gallons or less. "Unless population growth can be slowed quickly by investing heavily in female literacy and family planning services, there may not be a humane solution to the emerging world water shortage." states the report Water Shortages May Cause Food Shortages.[5] Nearly 1.7 billion people do not have access to sufficient water for basic personal hygiene. "Infectious waterborne diseases such as diarrhea, typhoid, and cholera are responsible for 80 percent of illnesses and deaths in the developing world, many of them children. One child dies every eight seconds from a waterborne disease; 15 million children a year."[1]

On average agriculture is responsible for over seventy percent of the freshwater a nation consumes. It is reliably estimated that with current agricultural irrigation practices every ton of wheat or corn produced, for example, consumes 1000 tons of freshwater. About sixty percent of that usage, however, is wasted through losses from leaky irrigation ditches, run off and field evaporation.[1]

When nations begin to run into serious water constraints they have to make up lost agricultural production with imports, particularly of grains. "This can be seen with Iran and Egypt, both of which now import more wheat than Japan, traditionally the world's leading importer. Imports supply 40 percent or more of the total consumption of grain--wheat, rice, and feedgrains--in both countries. Numerous other water-short countries also import much of their grain. Morocco brings in half of its grain. For Algeria and Saudi Arabia, the figure is over 70 percent. Yemen imports nearly 80 percent of its grain, and Israel, more than 90 percent."[5] As the report Water Shortages May Cause Food Shortages says, "Since a ton of grain equals 1,000 tons of water, importing grain is the most efficient way to import water. World grain futures will soon in effect become world water futures."[5]

But grain imports are already becoming increasingly problematic. The numbers involved are massive. According to the report, Aquifer Depletion, "Overall, China’s grain production has fallen from its historical peak of 392 million tons in 1998 to an estimated 358 million tons in 2005. For perspective, this drop of 34 million tons exceeds the annual Canadian wheat harvest."[7] With the combined impact of global warming, surface water pollution, aquifer depletion and continuing population increases the ability to make up agricultural shortfalls in the world market is diminishing. The global emergency food grain reserves, on which the poorest of the world's poor are dependant, have over these past several years fallen from a marginal 119-day supply to a critical 53-day supply and those reserves are still declining. In fact, with the increased demand for seed grains driven by the rush for biofuels that decline is accelerating.

Agriculture, of course, is not the only use we make of fresh water. Industry consumes 20% and residential consumption accounts for ten percent. In the arid nations currently experiencing or facing near-term critical freshwater shortages, however, agriculture is responsible for ninety percent of all freshwater usage. With the combination of demand for agriculture and that of domestic and industrial use in growing cities, the aquifers - many of them non-replenishable - underlying the larger cities in many developing countries - on which those cities are totally dependant - are depleting at rates of 3-8 meters per year and may be totally exhausted within the next 20-25 years.[5] "Nearly one third of all humanity relies almost exclusively on groundwater for drinking, including the residents of some of the largest cities in the developing world, such as Jakarta, Dhaka, Lima, and Mexico City."[9]

As surface water in lakes and rivers becomes increasingly polluted and as surface water sources dry up under the impact of global warming future generations may have to increasingly rely on groundwater sources for their very survival. It is our responsibility to protect it for both those future generations and ourselves. "Groundwater contamination is an irreversible act that will deprive future generations of one of life's basic resources," said Payal Sampat, author of Deep Trouble: The Hidden Threat of Groundwater Pollution. "In the next 50 years, an additional 3 billion people are expected to inhabit the Earth, creating even more demand for water for drinking, irrigation, and industry. But we're polluting our cheapest and most easily accessible supply of water. Most groundwater is still pristine, but unless we take immediate action, clean groundwater will not be there when we need it."[9]

The following were important sources of material and research for this article.

1) UN Highlights World Water Crisis
2) A Global Water Crisis
3) Water Crisis - World Water Council
4) Water Deficits Growing In Many Countries
5) Water Shortages May Cause Food Shortages
6) The Ogallala Aquifer Depletion
7) Aquifer depletion
8) Report: Water crisis hits rich countries
9) The Hidden Freshwater Crisis
10) The Emerging Global Freshwater Crisis

1 comment:

Leon said...

Thank you for your excellent and informative contributions to this urgent dialog. Although it plays out in complex scenarios, the underlying metaphor is simple: the pie is shrinking and the numbers of those seeking a share of that pie are increasing. I know you see a rapid crash rather than a slow decline. Whether something is considered rapid or slow can be rather subjective. Now in my sixties, I started preaching to friends and extended family a couple of years ago that sources I had been reading on the peak oil issue had some pretty compelling arguments that the shit was going to hit the fan in as early as two or three years. To me two or three years was just around the corner, but to my twenty-something nieces and nephews and children, I might as well have been talking about the next century. Well, to use another well worn phrase, the perfect storm now seems primed to break over us. But not yet. I keep wondering what event or crisis will have to happen before a critical mass of the population gets it and we start mounting a collective response.