Too much water means flooding, too little and the result is
drought and our planet has both in abundance.
According to the latest estimates there are 1386 million km3
(cubic kilometers) of water in the world. 97.7%
of this is salt water. Only
2.5% of this is fresh water (about 55 million km3). Of
this, 68.7% is permanent ice in the Arctic, Antarctic and Alpine
mountains and 29.9% is ground water, mostly deep seated. That
leaves 0.26%, or 64,000 km3, of accessible fresh water.
On a Worldwide scale we withdraw about one tenth of this water per
year. 65% of this water is used in agricultural irrigation.
SO, WHAT'S THE PROBLEM?
Between 1960 and 1997, the per capita availability of freshwater
worldwide declined by about 60% and
another 50% decrease is projected by the year 2025 (Hinrichsen,
1998). The global demand for water is now doubling every 21 years.
Currently there are half a billion people (the collective population
of 31 countries) experiencing severe and chronic water shortages. This figure
may reach 2.7 billion (nearly one third of the world's population) in 50
countries by the year 2025. Most of these people will live in
Africa and South Asia.
Water tables are now falling in China, India, and the United
States, which together produce half the world's food. Water
extraction from rivers is reaching crisis point in many places.
During the dry season in India, the Ganges River has little water
left when it reaches the Bay of Bengal. India is currently pumping
up underground water at twice the rate that it is replenished by
rainfall. In China, where water tables are falling by 1.5 m per
year, the Yellow River runs dry before it reaches the Sea for more
than half the year. It may or may not surprise Americans that the
Colorado River is used so heavily by Colorado, California,
Arizona, etc., that it is usually no more than a
trickle by the time
it reaches the Sea of Cortes.
HOW CAN THIS BE?
Well, there are three reasons:
Firstly that the water isn't in the right places (arid areas
account for 40% of the Earth's land masses).
Water demands already far exceed supplies in over 80
Secondly there is
waste. Consider the following:
The minimum basic water requirement for human health, including
drinking water, is 50 litres per person per day but in the United
States the average for domestic usage is 400 litres per person per
day - EIGHT times higher.
The minimum amount of water required per capita for food is about
400,000 litres per year.
In the USA, the average annual water consumption in food
production is 1.7 million litres per capita, 325% more than the
Thirdly, a lot of the water is unclean. Nearly half the world's major
rivers are going dry or are badly polluted. In China, 80 per cent
of major rivers are so degraded they no longer support fish life.
Much of the pollution is the result of overuse of pesticides in
crop production, untreated sewage and toxic chemicals allowed to
enter our rivers and lakes. In the developing countries it is
estimated that 95% of their untreated urban sewage is discharged
directly into surface waters. In the USA the Environmental
Protection Agency reported in 1994 that 37% of U.S. lakes were
unfit for swimming due to runoff pollutants and septic discharge.
WHAT PROBLEMS DOES THIS CAUSE?
The largest single consumer of water is agriculture (using 65% of
all water abstracted from the Earth) and the bottom
line is that when water runs out the crops die and people starve.
Also, sanitation in water deprived areas is poor and preventable
water-related diseases in these areas kill an estimated 10,000 to
20,000 children every day. Just give a thought to all that human
AN IMPORTANT ASIDE
One kilogram of grain requires around 1000 litres of water to
grow. It takes 16 kg of grain to produce 1 kg of beef. That's
16,000 litres of water per kg of beef. So, next time you look at a
16 ounce steak on a plate think "That's over seven cubic
metres of water!"