Freshwater: The 21st century gold - Revista Planeta

Freshwater: The 21st century gold
No. Edition: 438 Text: By Eduardo Araia 01/03/2009
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World consumption of water rose about six times in the last five decades. The World Water Day on 22 March, is the net synonymous with life at a crossroads: overfishing reduces the stocks available in plain sight, but the man is still reluctant to adopt measures to ensure its preservation. Of all currencies, water is the one that will determine peace or war between nations in our century





It is in the arid and rocky area of ​​Wadi ("stream" in Arabic) Faynan in southern Jordan, which British and Jordanian archaeologists studying a precious historical find. Evidence indicates that there, between 11,600 and 10,200 BC, men and women were established not for a season or season, but permanently. If the hypothesis is confirmed, it is one of the oldest settlements in the world final in which its inhabitants have learned to work the land and raise animals. Ie: it was one of the first times when the man left nomadism to become sedentary - one mudançachave in the course of civilization.

But why such a dry area would have been chosen by these pioneers? The archaeologist Steven Mithen of the University of Reading (UK) and one of the research leaders, explains that the local landscape was very different back then. There was vegetation, including figs, vegetables and cereals; there were wild goats, whose meat would be an alternative food; the very climate was cold and wet; and, of course, no water.



Of all the water on the planet, only 3% is fresh, and most of that percentage is in glaciers. But the rest, although used, can supply the nature and man.

Comparison of Wadi Faynan today with what would have been there more than 10,000 years refers to a very current issue: the use of water. An area that perhaps has never had abundance of this liquid, the demands caused by a growing population may have helped dry out the source that made life possible. This unsustainable pattern remains in place in various latitudes and makes the water shortage a worldwide danger.

According to the researchers, the original inhabitants of Wadi Faynan should have followed a roadmap well known to us. They first fell trees to make shelters and use them as fuel. Rough clearing, however, has led to a point where it rains, rather than infiltrating aquifers and groundwater, soil devastated. Then the sources were drying up. Meanwhile, the need to produce more food led farmers to divert water from springs that resisted to irrigate crops. And the damp, mild climate from the beginning was becoming drier and hotter.

To Mithen and colleagues, the settlement of Wadi Faynan was abandoned at least twice. A major climate change was the reason for the first change; worsening pollution justified the second. Today, the Bedouins inhabiting the area are required to wear ducts beneath the dry bed of the stream to suck the remaining water to irrigate their tomato fields. This task, however, is becoming more complicated: the good rains, which were already in alternate years, have dumped less water than in the past.

"The start of sedentary communities is the start of the need to manage fresh water supplies," says Mithen. "This is a starting point for our great modern dilemma. Of concern of individuals, moved to cities, nations, and today is a global issue. "

The United Nations (UN) estimates that about 1 billion people lack access to safe water and at least 2 billion can not adequate water to drink, wash up and eat. Living with water scarcity is a condition attached to millions of deaths a year caused by disease, malnutrition, chronic hunger. By removing school boys and girls, it prevents children and their relatives and friends have access to information that will give them a better life.

Water scarcity and poverty create a trap from which escape is difficult. About two-thirds of people who do not have water for their basic needs live on less than $ 2 a day. "The variation in water availability is strongly and negatively related to per capita income," said Jeffrey Sachs, author of Common Wealth: Economics For a Crowded Planet and Special Advisor to the General Secretary of the UN.

Deranged stocks

The effects of global warming and the planet's water

More variable rainfall

More flooding

Drier

Glaciers melting of which 1 billion people depend on behalf of river flows in summer

Rising sea level, at risk of flooding of coastal communities, freshwater aquifers, river deltas and mangroves

Currently, the lack of water is no longer characteristic of poor countries. In California, Gov. Arnold Schwarzenegger said in 2008 the first state drought in 17 years. The news is not surprising because much of the Californian territory is desert. More amazing was the drought in the humid southeastern United States in 2007, which led the City of Orme, Tennessee, to release water consumption of municipal reservoirs for only three hours. In May 2008, the city of Barcelona, ​​pressed by the worst drought in its history, imported water from other cities (including the French Marseille) to supply its 3.2 million residents.

In the last 50 years, the increase in population and the needs derived from it made the water consumption up six times. But mismanagement of this resource has decreased the usable stocks.

Six consecutive years of severe drought, which began in 2002, has decreased by 98% and rice production in Australia, and a local government report predicts that the human supply system may go into crisis if the situation does not improve this year. According to the text, since 1986 droughts occur in the country on average every two years, and the increasing heat waves and changes in rainfall patterns may become dry permanent part of the Australian landscape.

Population growth and the need to supply people with water - including around a crucial activity, agriculture - are key factors in question, that global warming is only exacerbate. Only to meet the food production, the World Bank estimated that water consumption will increase 50% by 2030. Experts anticipate that if nothing is done, billions of people will join those who already suffer from water shortages. The moves that will be disease, hunger, migration and wars.

According to experts, the amount of freshwater on earth that is not caught in the glaciers of Antarctica and Greenland is about 10 million cubic kilometers, moving between the atmosphere and the earth in evaporation and precipitation cycles, and findable in deposits as rivers, lakes, glaciers, aquifers and wetlands. This tiny fraction of the whole is more than enough, according to scientists, to supply the 6.5 billion inhabitants of the planet. The geographer John Anthony Allan of King's College London, estimates that all earthly need "only" 8000 km3 of water annually.

By UN calculations, each person needs five liters of water to survive in a moderate climate, and at least 50 liters a day for drinking, cooking, bathing and use in hygiene. Domestic consumption accounts for 10% of the volume of water used by humans. The industry uses twice that, and agriculture, seven times.

The increase in human population and the demands he made originates water consumption up about six times in the last five decades. Mismanagement of water, in turn, has reduced the usable stocks. To interrupt the free flow of water courses that are located about 845 thousand dams worldwide restrict the passage of water and sediment into the downstream communities and increase evaporation. The leaky waste reaches 50% of water. According to the UN, chemicals and heavy metals dumped in the water for industries and farms are poisoning more than 100 million people. And rainfall is changing for the worse in many areas.

The UN considers "water scarcity" the availability of less than one thousand cubic meters per year of fresh water for each person. This measure puts about half the world's population in countries with water shortages. Jordan is among the hardest hit: the average there is 160 m3 per year of fresh water per person. The result is a severe rationing. The 2 million inhabitants in the metropolitan area of ​​the capital, Amman, and nearby agricultural areas have only water one day a week.

Finally, there is a growing threat conflict by possession of water. The net is a crucial component in the Middle East scenario, for example, former President of the Soviet Union Mikhail Gorbachev declared the 3rd World Conference on Water in 2003, which in recent history had been locked out 21 armed clashes involving water, 18 of which in Israel. According to the Secretary-General of the UN, Ban Ki-Moon, the war in Darfur (Sudan), which already has killed more than 200,000 people, began with an "ecological crisis caused by climate change."

If the liquid synonymous with life already acquired size value, which continues to be wasted? The first reason is obvious: those who have money get preference. Oil-rich countries in the Persian Gulf have desalination plants, while Palestinians suffer from scarce water. The rich Southern California and the mecca of gambling, Las Vegas, are in desert areas but bears numerous pools and fountains. While the population of Amman suffers from water rationing, tourists staying at major hotels in the city do not have any limitation due to consumption.

Another important factor is the belief of most people that water is a "common good", which belongs to no one in particular. A farmer is not shy about divert some of the nearby river flow to irrigate his crops because they will pay little or nothing for it. The same belief is behind gestures like washing the sidewalk with hose or running the tap while brushing your teeth. The low cost of the service encourages waste and discourages investments in the area.

The third reason is the subsidies of rich countries to their farmers whose grain production, thus driven, gives huge stocks at lower prices. The impact of this feature was envisioned by John Anthony Allan. He wondered why Middle Eastern nations with scarce water showed no more obvious signs of a crisis in relation to the net and found that they "imported" water within the food that they bought for its supply. The concept of "virtual water" is created by Allan the formula that calculates the amount of water needed for the production of any food or manufacturing (see table at p. 49).

Finally, there is an obvious disproportion between what is extracted and the amount of available spare, especially from the last century. Lack of attention to this detail has claimed, for example, the health of the Aral Sea in Central Asia, which began to dry up in the 1930s with the diversion of water from its tributaries to irrigate cotton fields. The emergence of powerful suction pumps in the second half of the 20th century further worsened the situation. The result is a substantial drop in water supplies in major agricultural regions, such as North China Plain, the Punjab, India, and the US southern Great Plains. Reducing the amount of water in these reservoirs also affects the nature: according to the UN, the number of freshwater fish fell 50% between 1970 and 2000.

Shortage of effects

The lack of adequate water for drinking and hygiene is used mainly responsible ...

... The death, every year, 11 million children under five years, caused by diseases and malnutrition

... By chronic hunger around 1 billion people

... The "food insecurity" that, according to FAO, affects 2 billion people whose nutrition is not considered appropriate for an "active and healthy life"

... For helping to keep more than 60 million girls away from school

Global warming brings other variables (see table on p. 45). According to scientists, the increase of one degree centigrade in global average temperature will increase the volume of rain 1% - a result of absorbing more moisture by warmer air. There would be no change in the total volume of water on Earth, but it would be recycled more quickly, causing breakdowns in world agriculture. Aware of the negative effects of excessive water consumption over nature, some countries have established laws that guarantee "minimum environmental flows". There are other recommended measures, whose implementation depends on the various structures involved - from the individual to the international.

Properly price water

Sao Paulo paid nothing by 31,000 liters of water removed per second of the Cantareira System (corresponding to the eastern portion of the Piracicaba river basin) between 1974 and 2006. This year, the enactment of the law collection of water use has forced the city to annually disburse R $ 11 million for this purpose.

The money raised goes to the steering committee of the Piracicaba basin and is applied in the preservation of rivers. Other basins, such as the Paraiba do Sul river and the metropolitan region of Curitiba, also charge for water extracted from their beds.

Domestic efficiency

Simple measures help a lot in reducing consumption. A dripping tap wastes 1380 liters per month. A two millimeters hole in the pipeline causes the leakage of 3,200 liters per day.

Efficiency of vendors

It is estimated that, in the Greater São Paulo, Sabesp leaks in the network take away 18% of the collected water. The percentage corresponds to 1 billion liters per day, which, with the discount losses, could supply 3.7 million consumers.

Efficiency in agriculture

There are three main ways: get versions seeds able to grow in drier and salty environments, improve the performance of irrigation and exchange cultures, planting more compatible with the current state of the land and climate vegetables.

Reuse

The potential of water reuse is gigantic. To give you an idea, it is possible to make drinking water polluted by waste (the inhabitants of the rich Orange County, in Southern California, consume recycled sewage water since the 1970s).

Aquifers threatened

Brazil has a privileged position - 12% of the world's fresh water reserves are here - thanks to its huge underground springs.

The Guarani Aquifer, for example, is the world's largest. It extends over 1.2 million km2, the south of the country until the beginning of the Amazon Basin, penetrating in Paraguay, Uruguay and Argentina. The total thickness of the aquifer ranges from 50 to 800 meters; considering an average thickness aquifer 250 meters and effective porosity of 15%, it is estimated that the permanent reserves of the Guarani (water accumulated over time) is 45,000 cubic kilometers. But even such reserves are threatened by environmental pollution by pesticides at unsustainable deforestation, the artificial irrigation of agricultural areas and changes in rainfall patterns due to factors such as global warming.

Desalination

This costly alternative is feasible in countries with precarious water supplies. According to the English newsletter Global Water Intelligence, desalination capacity will more than double by 2015.

Trade

Agricultural grants represent a severe trade distortion, but in certain cases it is preferable import food and industrial goods internally to produce them in a cost prohibitive water. According to the organization International Water Management Institute (IWMI), the demand for irrigation would be 11% higher without trade - a percentage that would rise to between 19% and 38% by 2025.

Traditional techniques

Some methods used previously remain atualíssimos: replant trees, especially near water sources; boot exotic trees whose survival requires a lot of water; collect rainwater with lakes and ponds; erect stone walls to contain erosion.

Vegetarian diet

Producing a kilogram of beef requires 17,100 liters of water, while a kilo of pork demand 5250 liters. On the other hand, there are 1000 liters of "virtual water" in one kilogram of vegetables or root crops (see table opposite). So being a vegetarian helps a lot in water conservation.

At least some of these alternatives is being adopted around the world. But there are still considerable hurdles to overcome. Poverty, as stated Jeffrey Sachs, is one of them. The vision of water as a cheap or free is still well rooted in many places, and many farmers are reluctant to revise their crops and planting methods. Thus, it forms a certain scenario similarly to global warming: the diagnosis exists and is well-made, but the measures to solve the problem are slow to be taken - and the delay could cost us dearly. The US biogeographer Jared Diamond, author of Collapse - How Societies Choose to success or failure (Editora Record) says that societies that persisted had a long-term vision and showed flexibility and will power to change their values ​​when they did not serve them anymore. Does contemporary humans have these characteristics