A precious resourceIt has not any color, smell, taste or calories, but water is a vital element for all life forms. No human, animal or plant can live without it. From elephants to bacteria, water is essential and nothing can replace it. A human must consume 2.5 liters of water from food and beverage to remain healthy. No water means no life.
Without water, no livestock can be grown and land cannot be cultivated. There's no food without water. Fortunately, there's a lot of water on Earth: seen from space, our blue planet could be called Water, not Earth. If water covered neatly the Earth's surface, the whole planet would be covered by a global ocean 2.5 km (1.5 mi) deep. All the land surface would fit into the Pacific Ocean.
But most of the water on Earth is found on seas and the seawater is salty. A human drinking seawater would die dehydrated, as its body could not eliminate the extra salt. Crops cannot be irrigated with this water and if used in industry, it quickly oxidizes any machinery. Removing its salt is very costly.
Only 3 % of the Earth's water is freshwater. Almost all the freshwater (99 %) is stored in glaciers and polar caps or on table waters at great depths. Humankind has access just to 1 %. Even this 1 %, if uniformly distributed and rationally used, would be enough to sustain a human population two-three times more numerous than the current one.
The water quantity on Earth is very constant and this is the water that dinosaurs drank, the whole water that ever existed or will ever exist. The water on Earth is on a continuous cycle from oceans to atmosphere, than on the ground, rivers and back on the oceans. But in many areas water is a scarce resource.
In US, the consumption is over 350 liters of water daily, as much as for filling 2.5 bath tubes. Imagine the showering, consumed tap water, flushing toilets. In developed countries, water is at the reach of a tap and always available. Compare this to a common situation in Africa, where the closest water source can be a river kilometers away and coming back with a big recipient of water can take up to four hours daily. For an hour, the water must be filtered for eliminating the parasites and then put in three canteens: one with drinking water, one with water for domestic use, and a third with water for the evening bathing. When they have to wash clothes, women must go to the river. You can imagine the economical loss, when a woman spends the entire morning bringing water.
While Asia contains 36 % of the world's lakes and rivers, it harbors 60 % of the world's population. Instead, the Amazon river detains 15 % of the water contained by the world's rivers, still only 0.4 % of the world's population lives close enough to it for using its waters.
Earth's clime also varies a lot: while some regions are dry all year round, others only during determined drought periods. But people can influence this. Deforestation, excessive agriculture and grazing lead to desertification. These factors increase the amount of light reflected into the atmosphere; this gets heated, clouds are dispersed and it rains less.
Large amounts of rainfall in the forested areas is water evaporated from the vegetation. Vegetation acts like a huge sponge absorbing and maintaining humidity. When trees and bushes are cut, water amounts forming the clouds decrease.
One thing is certain: the water crisis is getting more severe. The lack of water menaces the economy and people's health in 80 countries. 40 % of the world's population does not have access to clean water or hygienic conditions.
Developed countries manage the water crisis through funds for building dams, expensive technologies for recycling water or even desalinizing seawater. Developing countries cannot do this. They have to choose between rationalizing water, a fact impeding economical development and the reduction of food production and reuse of the untreated water, a fact that favors the spread of diseases. And for the moment, the water requirements are increasing everywhere. This is also linked with the growth of the population. By 1990, 1.2 billion people could not drink water without being menaced by severe diseases. This number is larger today, as rainfall does not 'grow' at the same time with the growth of the human population. In the last century, the water consumption doubled and in ten years it could be double again.
The growth of the megacities in the developing countries occurred explosively and in a chaotic manner. The poor people live crowded in huts lacking salubrization and hygienic conditions. Without state paid salubrization, they must buy water, often dirty, from particular sellers who ask for a lot of money.
Population growth also means a growth in necessary food supply. This requires more water, but agriculture must compete with the food requirements of the industry and people. The extending cities and industrial zones steal terrain from crop lands. Moreover, the demographic growth occurs in the developing areas, where in most cases, water is scarce and they have the least financial and technological possibilities to cope with this.
To all this, another issue can be added: pollution. Many rivers are now rivers of death. The wastewater, from industrial and municipal use, damped in the rivers worldwide bypasses 450 cubic kilometers. Many rivers are polluted from springs to mouth. In developing countries, the drain off of the untreated wastewaters contaminates almost all rivers. 80 % of the Russian rivers have dangerous levels of bacterial and viral load. The table waters and rivers in developed countries are often poisoned with toxic chemicals coming from fertilizers employed in agriculture. Almost all coastal countries discharge in shallow waters untreated waste waters, contaminating severely the beaches.
And we still do not know the effects on the long term of what we discharge in the water. Experiments revealed that estrogen mimicking chemicals from wastewater cause reproductive issues in fish and amphibians.
At each 8 seconds, a child dies because of a disease transmitted through the infected water. In developing countries, 80 % of the diseases are spread through the consumption of infected water. Pathogens transmitted through water kill annually 25 million persons, like those causing amoeba-linked diarrhea, cholera and typhoid fever, especially on the tropics. Still, in 1993, 400,000 persons from Milwaukee (Wisconsin, US) got sick by consuming tap water contaminated with a microbe resistant to chlorine. In the same year, in the sewage system of Washington, New York and Cabool (Missouri) dangerous microbes were found, a fact that determined people to boil the tap water.
The water crisis leads to tensioned situations and conflicts. It can be said that water is a real luxury. A major issue is the distribution of water coming from the great rivers. 40 % of the world population lives on rivers crossing several countries, like Brahmaputra, Indus, Mekong, Niger, Nile and Tiger and each country wants to use as much water as possible, a fact that triggers issues. The increasing water need will just aggravate these problems.
Some solutions have been proposed for the water crisis. Desalinizing fabrics would extract the salt from the seawater, by pumping water in low-pressure chambers, where it is heated to the boiling point. The water evaporates and it is headed towards other directions, leaving behind the salt crystals. This is costly and most developing countries cannot afford it.
Glaciers from Antarctica have been proposed to be molten. They would be dragged by special tracker ships and would ensure water for the arid countries in the Southern Hemisphere. The problem is that half of the glacier would melt before reaching its destination.
Another solution would be the capture of aquifer layers. These are rocks containing water located at great depths in the ground. From them, water could be pumped even in the driest deserts. Still, this is costly and leads to the lowering of the table water. Moreover, most aquifer layers are renewed after long periods of time or never.