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| PLANET STATUS HOW IS WATER DISGUISED AS FOOD ? |
HIDDEN WATER
By Fred Pearce, environmental author and correspondent of New Scientist
COURTESY OF THE UNITED NATIONS ENVIRONMENTAL PROGRAMME
INEQUALITY comes in litres. While most of the poor have too little water to meet their needs, the relatively well-off consume enormous amounts.
Indeed, few realize quite how much water someone living a Western urban lifestyle – whether in Europe or North
America, or among the middle classes in developing countries – actually uses.
It’s not the obvious uses that really add up. On average, each person drinks not much more than 5 litres of the
stuff daily. Even after washing and fl ushing the lavatory, it increases to only around 150 litres each. But that is just the start. The numbers begin to soar when the water needed to produce food and drink is added in.
It takes between 2,000 and 3,500 litres of water to grow a kilo of rice. That is more water than many families use in aweek. It takes 1,000 litres to grow a kilo of wheat, and 500 litres for a kilo of potatoes.
And when you start feeding grain to animals to make meat and milk and cheese, the numbers become even more startling. It takes 11,000 litres – that’s 11 tonnes – to grow the food for enough cow to make one hamburger; and between 2,000 and 4,000 litres for it to produce a litre of milk.
Every teaspoonful of sugar in a cup of coffee requires 50
cups of water to grow it. That’s a lot, but not as much as
the 140 litres of water (or 1,120 cups) needed to grow
the coffee itself. Growing cotton for clothes is no better.
On the Internet you can buy jokey T-shirts with slogans
like ‘Save water, bath with a friend’. It’s a good message,
but please don’t buy the T-shirt. You could fi ll roughly
25 bathtubs with the water needed to grow the cotton
to make it.
In all, an average citizen of the United States consumes
2,483 cubic metres a year – about three times as much
as a Kenyan or a Chinese. For myself, I reckon that, as a
typical meat-eating, milk-guzzling European, I account
for as much as a hundred times my own weight in water
every day.
WHERE DOES IT ALL COME FROM?
Some of that water falls as rain on fi elds. But most of the
food and all the cotton consumed around the world is
grown using water collected from rivers or pumped
from underground. In some places, two, three or even
four times more water is taken to irrigate crops than a
generation ago – and as a result these once abundant
sources are drying up.
Many places are in danger of running out of water. In
India, farmers are taking 100 cubic kilometres more
water from underground sources every year than the
rains replace. That’s six times more water than Britain,
for example, uses in a year.
As rivers run dry and underground water tables fall,
countries have tried to get round such local crises
through trade. Not in water itself – which is too heavy
and expensive to transport far. Instead, more and more dry
and densely populated countries are importing thirsty crops
rather than growing them themselves.
Economists call the water needed to grow these traded
crops ‘virtual water’. Think of it this way: every tonne of
wheat arriving at a dockside carries with it, in virtual form,
the 1,000 tonnes of water needed to grow it. All sorts of
traded products require water for their production: it takes,
for example, about 400,000 litres of water to manufacture
a car. But about 90 per cent of the ‘virtual water’ trade is
in food and cotton.
The biggest exporters are the United States of America,
Australia and Canada, while major importers include Japan
and Europe and, increasingly, China, which no longer
has enough water to grow the food it needs. In one way
this trade is good news. The Middle East, for instance,
ran out of water to feed itself some years ago, the fi rst major
region ever to do so. Without the trade, Jordan, Iran, Egypt
and Algeria would starve. There would be water wars.
VIRTUAL WATER: REAL SHORTAGE
Virtual water carries risks because not everyone can be a net
importer; someone has to do the exporting. Water prices have
soared round the world in the last two years, partly because
Australia, a major source of thirsty crops, had a drought. Its
exports of rice, sugar and wheat fell by more than half.
Climate change means that more and more countries are
likely to suffer droughts in future. Who will feed them? In
such a world, countries that rely on importing virtual water
could be in trouble.
What can be done to provide enough water? There are
some technical solutions. Coastal regions can desalinate
seawater, for instance. That is OK for providing drinking
water, but too expensive for the big users – like farmers.
Some countries will build more reservoirs to catch the
water in their rivers. But in more and more places, the
rivers are already drying up. A global study published
recently showed that a quarter of the world’s people live
in river basins where the water is already fully used.
So what else? Moving water over the hills from one river
basin to another – from wet regions to drier regions – is
possible. China is spending $60 billion on a series of vast
canals to move water from the wet south to the arid north.
India is talking about an even bigger project to pump water
from the great monsoon rivers of the north, like the Ganges,
to the dry south and west. But it is very costly, because
water is heavy and expensive to pump uphill.
GETTING IT RIGHT
First, we need to get better at catching the rain where it
falls. I have visited villages across India and China where
they are doing just this – reviving ancient methods of
capturing the rain and pouring it into their wells to be used
during the dry season.
The water-rich, like me, also need
a revolution to use water more efficiently in their daily
lives. Huge gains can be made by such simple measures
as turning off the tap while brushing teeth, using a bucket
rather than a hosepipe to water the garden or wash the car,
or not always flushing the lavatory.
But agriculture, as the biggest user of water, especially in
the driest countries, can contribute most. Tens of millions
of farmers worldwide still irrigate their crops simply by
fl ooding their fields. Most of the water evaporates and
little, in practice, reaches the plants. But cheap, modern
systems of drip irrigation can deliver it drop by drop close to
the crop roots, cutting demand by 50 per cent or more.
So there are solutions. If water is used right, everyone can
be fed and have water. But fi rst it must be properly valued.
It must be treasured, not wasted.
THE ‘NEW OIL’?
Some say that water is the ‘new oil’ – that it will be the
cause of wars in the 21st century, as ‘black gold’ was
the cause in the last one. Maybe so. But water is even
more important than oil: after all, the world’s people
could manage without oil, if we had to. But no one
can manage, even for one day, without water.
Carrie Cizauskas |
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National Geographic Image Collection/Annie Griffiths Belt |
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