Water debate is about quality, not quantity
Take this week’s ‘‘revelation’’ that New Zealand dairy farms use water equivalent to that used by 60 million people. Sounds terrible, right?
Well, if it is, then what about every other aspect of agricultural production that uses water, the quantities of which sound criminal if they’re unfamiliar.
Take, for example, a kilogram of chocolate. That takes 17,196 litres of water to produce, according to the Institute of Mechanical Engineers (IME). A kilo of beef? That’s 15,415 litres.
Some will argue that chocolate and beef are respectively a luxury and an animal product that could be replaced in a vegetarian diet; that neither is strictly necessary.
They are right. Indeed, the potential for meat and milk substitutes to be produced in factories instead of from animals within a few years represents a huge challenge to New Zealand’s economic dependence on pastoral farming. Those processes will still use water, but far less of it.
However, staple foods – vegetables, fruit, and bread – also take oodles of water to produce.
A kilo of bananas? According to the IME, that’s a 790-litre proposition. A loaf of bread takes 1608 litres of water to produce – including the water required to grow the ingredients as well as making the bread.
Producing 1kg of cabbage uses about the same amount of water as a full cycle in a top-loading washing machine – about 200 litres.
The same issue arises in the debate over water bottling. A royalty on water use is justified, arguably long overdue. But the debate about water royalties is not assisted by alarmist arm-waving about the quantities involved.
According to water bottlers, a total of 26 million litres of water was exported last year – equivalent to a couple of minutes’ flow over the Huka Falls or 90 minutes of water use by Aucklanders.
If 26 million litres still sounds like a lot, consider this: Total volumes of water coursing through New Zealand lakes and rivers annually total perhaps 350 billion cubic metres – an unimaginably large quantity.
Of which perhaps 2 billion cubic metres is used by people to do everything that humans here do, including making food.
Just to confuse things, a cubic metre, or cumec, measures water in far greater volumes than litres. Cumecs are measure of flow rates. A 1-cumec-per-second river flow is equal to 1000 litres per second.
In other words, the water debate is mired in both the tyranny of big numbers and the tyranny of expert jargon.
As a result, it’s meaningless to claim that human water use is a tiny fraction of the total and that the vast majority flows ‘‘unused’’ into the sea. If that wasn’t the case, we wouldn’t have rivers.
None of this helps to address the urgent need to improve New Zealand’s freshwater quality.
The fact that human use is such a small proportion of total ‘‘available’’ water but has caused such significant degradation proves that the big numbers are a distraction. Rather, the questions are, how should we regulate and how should we value the water that we do use?
Labour’s proposed water tax – in reality an attempt to stop further agricultural intensification by discouraging irrigation schemes – is a crude and imperfect beginning.
The Government’s national policy statement on freshwater management, while confusing and derided, is better than its critics would have us believe.
But these are only a start. Whoever becomes the next government will need to work harder, faster and far smarter than either the 1999-2008 Labour-led government or the National-led administration of the last nine years to find solutions.
Getting sidetracked by mindboggling numbers won’t help at all.
Staple foods – vegetables, fruit, and bread – also take oodles of water to produce.