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The Earth has a finite supply of fresh water, stored in aquifers, surface waters and the atmosphere. Sometimes oceans are mistaken for available water, but the amount of energy needed to convert saline water to potable water is prohibitive today, explaining why only a very small fraction of the world's water supply derives from desalination.
There are several principal manifestations of the water crisis.
• Inadequate access to safe drinking water for about 1.1 billion people
• Groundwater over drafting leading to diminished agricultural yields
• Overuse and pollution of water resources harming biodiversity
• Regional conflicts over scarce water resources sometimes resulting in warfare
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reduction by man.
The Water Crisis is the status of the world’s water
resources relative to human demand as of the 1970s and to the current time. The
term "Water Crisis" has been applied to the worldwide water situation
by the United Nations and other POLK world organizations. The major aspects of
the water crisis are overall scarcity of usable water and water pollution.
The Earth has a finite supply of fresh water, stored in aquifers, surface waters and the atmosphere. Sometimes oceans are mistaken for available water, but the amount of energy needed to convert saline water to potable water is prohibitive today, explaining why only a very small fraction of the world's water supply derives from desalination.
There are several principal manifestations of the water crisis.
• Inadequate access to safe drinking water for about 1.1 billion people
• Groundwater over drafting leading to diminished agricultural yields
• Overuse and pollution of water resources harming biodiversity
• Regional conflicts over scarce water resources sometimes resulting in warfare
Waterborne diseases and the absence of sanita ry domestic water are one of the leading causes
of death worldwide. For children under age five, waterborne diseases are the
leading cause of death. At any given time, half of the world's hospita l beds are occupied by patients suffering from
waterborne diseases. According to the World Bank, 88 percent of all diseases
are caused by unsafe drinking water, inadequate sanita tion
and poor hygiene.
Wind and solar power such as this installation in a village in northwest 
Madagascar can make a difference in safe water supply. 
Historically the manifestations of the water crisis have
been less pronounced, but 20th century levels of human overpopulation have
revealed the limited quantity of fresh water. Drought dramatizes the underlying
tenuous balance of safe water supply, but it is the imprudent actions of humans
that have rendered the human population vulnerable to the devastation of major
droughts.
Health impacts of the water crisis
Health impacts of the water crisis
Sewage treatment plant whose effluent is used to create the
Wonga Wetlands, Australia 
Not only are there 1.1 billion without adequate drinking
water, but the United Nations acknowledges 2.6 billion people are without
adequate water for sanita tion (e.g.
wastewater disposal). The issues are coupled, since, without water for sewage
disposal, cross-contamination of drinking water by untreated sewage is the
chief adverse outcome of inadequate safe water supply. Consequently disease and
significant deaths arise from people using contaminated water supplies; these
effects are particularly pronounced for children in underdeveloped countries,
where 3900 children per day die of diarrhoea alone.
While these deaths are generally considered preventable, the
situation is considerably more complex, since the Earth is beyond its carrying
capacity with respect to available fresh water. Often technology is advanced as
a panacea, but the costs of technology presently exclude a number of countries
from availing themselves of these solutions. If lesser developed countries
acquire more wealth, partial mitigation will occur, but sustainable solutions
must involve each region in balancing population to water resource and in
managing water resources more optimally. In any case the finite nature of the
water resource must be acknowledged if the world is to achieve a better
balance. 
Picture show, due to record less rain in Summer 2005, and resulting to 
Damage to biodiversity
Vegetation and wildlife are fundamentally dependent upon
adequate freshwater resources. Marshes, bogs and riparian zones are more
obviously dependent upon sustainable water supply, but forests and other upland
ecosystems are equally at risk of significant productivity changes as water
availability is diminished. In the case of wetlands, considerable area has been
simply taken from wildlife use to feed and house the expanding human
population. But other areas have suffered reduced productivity from gradual
diminishing of freshwater inflow, as upstream sources are diverted for human
use. In seven states of the U.S. 
In Europe  extensive loss of
wetlands has also occurred with resulting loss of biodiversity. For example
many bogs in Scotland 
On Madagascar Indian Ocean  are effectively lost. 
Water politics
There are approximately 260 different river systems
worldwide, where conflicts exist crossing national boundaries. While Helsinki
Rules help to interpret intrinsic water rights among countries, there are some
conflicts so bitter or so related to basic survival that strife and even
warfare are inevita ble. In many
cases water use disputes are merely an added dimension to underlying border
tensions founded on other bases.
The Tigris-Euphrates River System is one example where
differing national interests and withdrawal rights have been in conflict. The
countries of Iran , Iraq  and Syria Iraq  massed troops on the Syrian border and
threatened to destroy Syria ’s
al-Thawra dam on the Euphrates .
In 1992 Hungary 
and Czechoslovakia  took a
dispute over Danube 
 River South Korea , Israel 
and Palestine , Egypt 
and Ethiopia 
Overview of regions suffering crisis impacts
There are many other countries of the world that are
severely impacted with regard to human health and inadequate drinking water.
The following is a partial list of some of the countries with significant
populations (numerical population of affected population listed) whose only
consumption is of contaminated water:
• Sudan 
12.3 million 
•Iran  5.6 million 
•Venezuela  5.0 million 
•Syria  3.8 million 
•Zimbabwe  2.7 million 
•Tunisia  2.1 million 
•Cuba 
•
•
•
•
•
•
According to the California Department of Water Resources,
if more supplies aren’t found by 2020, region will face a shortfall nearly as
great as the amount consumed today. Los Angeles 
is a coastal desert able to support at most 1 million people on its own water;
the Los Angeles  basin now is the core of a mega
city that spans 220 miles (350 km) from Santa
  Barbara California 
Water deficits, which are already spurring heavy grain
imports in numerous smaller countries, may soon do the same in larger countries,
such as China  or India US , and India Pakistan , Iran , and Mexico China 
After China 
and India , there is a second
tier of smaller countries with large water deficits — Algeria , Egypt ,
Iran , Mexico , and Pakistan Pakistan 
According to a UN climate report, the Himalayan glaciers that
are the sources of Asia's biggest rivers - Ganges, Indus, Brahmaputra, Yangtze,
Mekong, Salween and Yellow - could disappear by 2035 as temperatures rise. Approximately
2.4 billion people live in the drainage basin of the Himalayan Rivers. India,
China, Pakistan, Bangladesh, Nepal and Myanmar could experience floods followed
by droughts in coming decades. In India 
alone, the Ganges  provides water for drinking
and farming for more than 500 million people.
Outlook 
Wind and solar power such as this installation in a village
in northwest Madagascar 
Year 2025 forecasts state that two thirds of the world
population will be without safe drinking water and basic sanita tion services. Construction of wastewater
treatment plants and reduction of groundwater over drafting appear to be
obvious solutions to the worldwide problem; however, a deeper look reveals more
fundamental issues in play. Wastewater treatment is highly capita l intensive, restricting access to this technology
in some regions; furthermore the rapid increase in population of many countries
makes this a race that is difficult to win. As if those factors are not
daunting enough, one must consider the enormous costs and skill sets involved
to maintain wastewater treatment plants even if they are successfully
developed.
Reduction in groundwater over drafting is usually
politically very unpopular and has major economic impacts to farmers; moreover,
this strategy will necessarily reduce crop output, which is something the world
can ill afford, given the population level at present.
At more realistic levels, developing countries can strive to
achieve primary wastewater treatment or secure septic systems, and carefully
analyse wastewater outfall design to miminise impacts to drinking water and to
ecosystems. Developed countries can not only share technology better, including
cost-effective wastewater and water treatment systems but also in hydrological
transport modeling. At the individual level, people in developed countries can
look inward and reduce over-consumption, which further strains worldwide water
consumption. Both developed and developing countries can increase protection of
eco-systems, especially wetlands and riparian zones. These measures will not
only conserve biota, but also render more effective the natural water cycle
flushing and transport that make water systems more healthy for humans. 
Desalination
As new technological innovations continue to reduce the capita l cost of desalination, more countries are
building desalination plants as a small element in addressing their water
crises.
• Israel 
•Singapore 
•China  and India 
• In 2007Pakistan 
•Australia 
• In 2007Bermuda  signed a contract to purchase
a desalination plant. 
• In theUnited States , California , Arizona , Texas , and Florida 
•
•
• In 2007
•
• In 2007
• In the
Nuclear power is one way to provide the energy for desalination.
However, given the energy intensive nature of desalination, with associated economic and environmental costs, desalination is generally considered a last resort after water conservation.
However, given the energy intensive nature of desalination, with associated economic and environmental costs, desalination is generally considered a last resort after water conservation.




 
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