UN experts concerned by water footprint|
By Arthur Max, Associated Press
DELFT, Netherlands — It's not only our carbon footprint we
should worry about, U.N. experts say. They warn about our growing
Nearly half the people on Earth, about 2.5 billion, have no access
to sanitation, many of them in urban slums. The world's cities are
growing by 1 million people a week, and soon their aging water systems
will not cope. Farming demand on water is increasing.
"What we are doing now can't keep up with the issues we already
have," said Carol A. Howe, an expert working for a UNESCO-led water
development project called Switch.
"Something needs to change. It needs to change quickly, and it
needs to be fairly dramatic," she told a symposium for journalists
The threat of climate change has drawn attention to the carbon
footprint, the amount of greenhouse gases produced by human activity.
Now scientists have begun calculating a water footprint, the amount of
water needed to produce goods or services.
A report published this month by UNESCO's Institute for Water
Education in Delft said it takes 70 to 400 times as much water to
create energy from biofuels as it does from fossil fuels.
It said 262 gallons of water is needed to produce crude oil that
provides the same amount of energy from biomass grown in Brazil —
primarily sugar cane used for ethanol — that requires 15,972
gallons of water. Biomass grown in the Netherlands needs 6,284 gallons,
the report said.
Engineers are experimenting in a dozen cities from Lima, Peru, to
Beijing to find ways to ease the pressure on water resources.
The projects, run by the U.N. Education, Scientific and Cultural
Organization and funded by the European Union, include turning rooftops
into gardens, capturing and recycling rain, recharging underground
reservoirs with waste water, and swapping traditional flush sanitation
for dry toilets.
Birmingham, England, is monitoring the effects of green roofs on
reducing flooding during storms, cutting energy needs and capturing
run-off to reduce water needs in buildings and surrounding areas, Howe
A project in Tel Aviv, Israel, channels treated waste water into an
aquifer through the natural filtering system of the soil, and is
testing whether it can be reused for drinking water, she said.
Waterless toilets, using either chemicals or composting, are being
tested in Ghana, Kenya, Peru, Egypt and elsewhere. They also enhance
the possibility of separating human waste, using liquid waste as a
rich source of nutrients for crops, said Gary Amy, a professor of
urban water supply and sanitation with the institute.
"If we captured all the urine in Africa, it could match all the
nitrogen and phosphates used for agriculture," he said.
Howe said standard mechanisms consume about 25% of all residential
water — drinking water that is literally flushed down the toilet.
"It takes a lot of energy and money to bring in the water, to treat
it, to put into the toilet, to treat it again, and to put it into the
river system," she said.
Original article: USA Today
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