Water, water everywhere …by fiona.rae
… but we need to be careful how we manage it, says public policy and law professor Robert Glennon.
In front of the Bellagio Hotel and Casino, 1200 jets shoot water from a 3ha artificial lake high into the desert sky. The fountains, choreographed with a light show and classic music hits, are a tourist attraction in Las Vegas, the city of nearly two million people in the middle of Nevada’s Mojave Desert.
The Las Vegas hotels, with their fountains, faux Venetian canals and pirate lagoons, display some of the “most ostentatious water use imaginable”, says Robert Glennon. A public policy and law professor from Arizona University and the author of Unquenchable: America’s Water Crisis and What To Do About It, Glennon is in New Zealand to lecture on America’s water crisis (Las Vegas is one of many American cities where supply no longer keeps up with demand) and meet scientists and officials to discuss our water management.
But hold on. Glennon spent his first three days in New Zealand fly-fishing in the “gin-clear waters” of the Tongariro River. We don’t have any real deserts and we’re not ostentatious water users. But, Glennon points out, it’s not the Las Vegas hotels and casinos that are the problem in Nevada. “It’s all a mirage,” he says. The fabled casino strip, the powerhouse of the Nevada economy, uses only 3% of Las Vegas’s water; in response to some tough demands by the local water authority, the hotels and casinos have installed low-flow showerheads and use recycled water. About 80% of the state’s water is used by farmers. The New Zealand stats are similar: agriculture consumes 70-80% of our water.
“I was struck by the number of similar problems you folk are facing,” says Glennon, citing agricultural and urban discharges, eutrophication of lakes and over-allocation of river water. “It looks to me like you’re doing some of the same things that we’ve done, which is dole out water on a first-come, first-served basis, basically willy-nilly, and now you’re suddenly realising the catchments are over-allocated.” The problems, says Glennon, all stem from the mistaken notion that water is a limitless resource. But in many parts of New Zealand, it’s hard to think otherwise.
“We have got an embarrassment of riches in New Zealand,” says Brent Clothier from Plant and Food Research, who organised Glennon’s Agmardt-sponsored visit, “but we’ve got to make sure we don’t stuff it up.” Clothier has been calculating the water footprints of different industries and says there’s room for improvement. New Zealand’s per capita water footprint – the amount of water used to produce the goods and services a person consumes – is 1589 cubic metres a year, lower than the American figure of 2842 but higher than the global average of 1385. A big driver for New Zealand producers to be more efficient in their water use, says Clothier, is access to overseas markets.
“The big supermarket chains where we sell our premium wine and food products are asking questions not only about carbon footprint but about water footprint. You have to answer the questions if you want the product on their shelves. So using water sustainably in our food products will get us continued shelf access to the top supermarkets with premium prices.”
As well as warning us how not to manage our water resources, Glennon has ideas of how things should be done. “I would recognise a modest quantity of water as a human right,” he says, but beyond that water for domestic users should be subject to increasing block rates “to ensure that everyone uses water carefully”. For other uses – farming, industry, conservation – Glennon says the market will set the price. Existing users have a right to use the water they are using – they played by the rules and got their permits – and anyone with a competing use for the water can buy rights from an existing user.
In the United States, this system has involved conservation groups paying farmers to take less water for irrigation in order to protect valuable habitat, and developers paying farmers to retire low value agricultural land. When the farmers use this money to install more-efficient irrigation systems, everyone wins. The key, agree Glennon and Clothier, is to manage the resource we have in a sustainable way so it can continue to provide water to domestic, industrial and agricultural consumers, while maintaining the natural environment for recreation and conservation.
“Water is our future,” adds Clothier. “In Australia you can dig a hole and send minerals around the world. In New Zealand, we can use the water we have to produce products the world wants – food.” And in Las Vegas, one of the fastest-growing cities in the United States, some of that food might end up on the supermarket shelves.
Question: I understand that scientists can measure the passage of time very accurately by using the periodic oscillation time of the caesium atom. But how do they know the absolute time of day? How do they know when it is exactly midday – the time the sun has reached its zenith – at Greenwich? John S, Whakatane.
Answer: Rebekah Higgitt, curator of history of science and technology at the Royal Observatory at Greenwich, responds: "Before atomic clocks, time was determined astronomically. Astronomers regularly observed a range of stars as well as the Sun, working out the exact moment of zenith by observing the Sun as it reached the same height either side of the meridian. The length of time between one solar zenith and the next varies, so it is averaged out into mean time.
At Greenwich, from 1851 until 1957, the main instrument for making such observations was the Airy Transit Circle telescope, which is accurate to within tenths or hundredths of a second and defined the international Prime Meridian. After 1957, Greenwich time was determined by an instrument called the Photographic Zenith Tube, which allowed automatic recording of stars transiting near the zenith. All such instruments are now obsolete; we now use satellites and atomic clocks to track the Earth's rotation with much greater precision.
The question is now whether we continue to use the slightly variable and generally slowing rotation of the Earth as our ultimate arbiter of time, or cease to correct our atomic clocks by adding leap seconds and allow the two to drift – extremely slowly – apart."
Robert Glennon interview on Saturday Morning with Kim HIll:
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