Science News reports that all over the world, people are pumping more water out of the ground than is being put back by rain, snow, or other natural processes.
Groundwater levels have dropped in many places across the globe over the past nine years, a pair of gravity-monitoring satellites finds. This trend raises concerns that farmers are pumping too much water out of the ground in dry regions.
Water has been disappearing beneath southern Argentina, western Australia and stretches of the United States. The decline is especially pronounced in parts of California, India, the Middle East and China, where expanding agriculture has increased water demand. [emphasis added]
Unlike global warming, for example, these data appear to be pretty much beyond dispute.
The measurements are made by a pair of satellites which share an orbit. They are designed to be insanely sensitive to fluctuations in the strength of the gravity that keeps them in those orbits. They're pulled apart and pushed together as they fly over regions of ever-so-slightly higher or lower gravity.
Large concentrations of mass such as mountains have consistent results each time the satellites pass over. After subtracting for snowpack, rivers, lake levels, and other variable phenomena, the satellites can detect ground water changes of roughly a centimeter spread over an area about the size of the state of Illinois. Bigger changes can be detected in smaller areas, of course.
The conclusion is inescapable: farmers are using too much water.
An agricultural boom in northern India has helped to squeeze nearly 18 cubic kilometers of water from the ground every year (SN: 9/12/09, p. 5). That’s enough water to fill more than seven million Olympic swimming pools. And in California’s Central Valley, which supports about one-sixth of the nation’s irrigated land, the ground has been sinking for decades as landowners drill more wells and pull out almost 4 cubic kilometers of water per year (SN: 1/16/10, p. 14). [emphasis added]
As water levels drop, wells will have to get deeper and deeper and it will take more and more energy to lift water to the surface. Eventually you run out entirely.
This is one of those problems which anyone can see coming a long way off. There will come a point when there simply isn't any more water no matter how deep we go. At that point, California will lose the agricultural output of the Central Valley and India will lose the food output of their northern region.
Although the satellites can tell how much water has been taken out without being replaced, they can't tell how much is left. The only way to get even a vague idea is to drill lots of wells deep enough that they don't find water and hope you've sampled the underground geology adequately.
Some of the techniques for analyzing rocks for oil provide hints, but as with oil, the only way to be sure is to drill, baby, drill! This is expensive, so data are scant. Nobody knows when the aquifers will hit the wall, so "business as usual" carries on. We'll never miss the water 'til the well runs dry.
Water resources are being depleted all over the world and agriculture is the primary culprit. Not coincidentally, agriculture is one of the most heavily regulated activities in the world, all over the world. Just about all government actions with respect to agriculture distort markets in one way or another.
In India the government not only provides free pumps so farmers can bring up ground water, they also provide free electricity to run the pumps. The wealthiest farmers with the best political connections get preferred access to these free resources, of course. One can only imagine what else they do with their free power.
With so much electricity being given away, the electric companies can't make a profit. They've been taken over by the government, which runs them so inefficiently that there's a perpetual electricity shortage all across India. This makes it harder to industrialize, which would use less water than subsistence farming. Farmers and factories are battling over electricity, but they haven't yet realized that the battle over water will be much more important and much more contentious when it comes.
The Imperial Valley in California is naturally a semi-desert because it receives only 3 inches of rain per year. It's been transformed into a billion-dollar farming area, however, thanks to Colorado River water which is brought to the valley via the All-America Canal.
When the canal was built nearly a century ago, Imperial Valley farmers were gifted in perpetuity the right to about 20% of the water in the Colorado River, which was more than Arizona and Nevada combined. The farmers didn't have to pay much for their water; their political clout allowed them to get it far below cost. Like the Indian farmers who receive free electricity to pump water, they have few incentives to use water efficiently.
Efforts to save water don't always work as expected. Lining the canal with concrete meant less seepage, but the seepage had been replenishing an aquifer that fed Mexican farms. Saving California water caused suffering in Mexico.
Now we've entered a dry era, and over the past century, other states which border the Colorado River have greatly increased populations. They're starting to want more water for their people to drink, but giving the new cities more water will put farmers out of business. As Mark Twain said, "Whiskey is for drinking and water is for fighting over."
What's worse, NPR reports that Lake Mead, which stores Colorado River water before it's fed into the canal, has a 50% chance of drying up in 10 years. If that happens, the only way to get water for crops will be to drill for it. That can only increase strain on the aquifers.
Yemen is in the midst of just such a water crisis. The LA Times reports that the city of Sana was able to draw on 180 wells a decade ago, but only 80 wells still give water. As China grows wealthier, the Chinese will demand better food which will require more water.
The world's great and good are well aware of the problem of water shortages and meetings are held all 'round the globe in desperate attempts to have governments solve the problem from On High. Unfortunately, the basic problem is that governments all over the world have subsidized water, particularly for farming. In other words, government intervention in the market created the problem in the first place.
Unless the government changes water prices so that people pay for what they use, waste will continue and the shortage will get worse. The best way to do this would be an open and free market for water so that the water will go to whoever pays the most for it, so we can get the maximum amount of benefit from the water we have available. But on those rare occasions where private provision of water have been tried, the thundering herds of protestors rush in to demand free water for everyone who needs it - exactly the opposite of what's required.
We have the technology to use water far more efficiently; Israel is a sterling example of how green you can make a place using minimal water. The UN reports that Israeli-style drip irrigation can cut water use by 50%, but it requires capital investment to install the water conservation systems and reasonably technical people to maintain it. The problem is that our government-enforced pricing structure doesn't make efficient water use worthwhile.
Unlike the energy crisis where we don't have any good substitutes for oil and nuclear power, we do know a lot of ways to save water in farming. It just doesn't make any economic sense to do so because governments the world around have intentionally distorted water markets.
The best way to encourage more efficient water use would be to price water based on supply and demand instead of letting farmers have so much of it for free. Once that's done, existing technology will reduce water use, by the free and rational choices of individual market participants, not be government fiat.
For precisely that reason, it's not likely to happen anytime soon. Better drink up while you can.