It is commonly assumed that the worlds water supply is huge and infinite. This assumption is false. In fact, of all the water on Earth, only 2.5 percent is freshwater, and available freshwater represents less than half of 1 percent of the world’s total water stock. The rest is seawater, or inaccessible in ice caps, ground water and soil. This supply is finite.
“The issue today, put simply, is that while the only renewable source of freshwater is continental rainfall (which generates a more or less constant global supply of 40,000 to 50,000 cubic km per year), the world population keeps increasing by roughly 85 million per year. Therefore the availability of freshwater per head is decreasing rapidly.”
Most disturbingly, we are diverting, polluting and depleting that finite source of freshwater at an astonishing rate. Today, says the United Nations, 31 countries are facing water stress and scarcity and over one billion people lack adequate access to clean drinking water. By the year 2025, as much as two-thirds of the world’s population-predicted to have expanded by an additional 2.6 billion people-will be living in conditions of serious water shortage and one-third will be living in conditions of absolute water scarcity.
World Resources, a publication of the United Nations Environment Program, the World Bank and the World Resources Institute, has a dire warning “The world’s thirst for water is likely to become one of the most pressing resource issues of the 21st century…ln some cases, water withdrawals are so high, relative to supply, that surface water supplies are literally shrinking and groundwater reserves are being depleted faster than they can be replenished by precipitation.”
Groundwater over-pumping and aquifer depletion are now serious problems in the world’s most intensive agricultural areas. In the U.S., the High Plains Ogallala aquifer, stretching some 800 miles (1,300 km) from the Texas panhandle to South Dakota, is being depleted eight times faster than nature can replenish it. The water table under California’s San Joaquin Valley has dropped nearly ten meters in some spots within the last 50 years. Twenty-one percent of irrigation in the U.S. is achieved by pumping ground water at rates that exceed the water’s ability to recharge (and most water used for irrigation cannot be recycled).
In the Arabian peninsula, groundwater use is nearly three times greater than recharge and, at the current rate of extraction, Saudi Arabia is running toward total depletion in the next 50 years; Israel’s extraction has exceeded replacement by 2.5 billion meters in 25 years and 13 percent of its coastal aquifer is contaminated by seawater and fertilizer run-off; current depletion of Africa’s non-recharging aquifers is estimated at 10 billion cubic meters a year; water tables are falling everywhere throughout India; land beneath Bangkok has actually sunk due to massive over-pumping; and northern China now has eight regions of aquifer overdraft while the water table beneath Beijing has dropped 37 meters over the last four decades. In fact, so severe is the projected water crisis in Beijing, experts are now wondering whether the seat of power in China will have to be moved.
In Mexico City, pumping exceeds natural recharge by 50-80 percent every year and experts are saying the city could run out of water entirely in the next decade. In the maquiladora free trade zones all along the Mexican-U.S border, water is a precious commodity, delivered weekly in many communities by truck or cart. In early 2001, the National Water Commission reported that the border area, thick with industrial and human waste and strapped for funds, only treats about one-third of its waste water and sewage. Ciudad Juarez, growing at a rate of 50,000 people a year, is running out of water; the underground aquifer the city relies on has declined at about five feet a year. At this rate, there will be no usable water left in 20 years.
This means that instead of living on water income, we are irreversibly diminishing water capital. At some time in the near future, water bankruptcy will result. In addition to depleting supplies, groundwater mining causes salt water to invade freshwater aquifers, destroying them. In other cases, groundwater mining actually permanently reduces the earth’s capacity to store water. In California, for example, overuse of the underground water supplies in the Central Valley has resulted in a loss of over 40 percent of the combined storage capacity of all human-made surface reservoirs in the state. In 1998, California’s Department of Water Resources announced that by 2020, if more supplies are not found, the state will face a shortfall of water nearly as great as the amount that all of its towns and cities together are consuming today.
Further, the global expansion in mining and manufacturing is increasing the threat of pollution to these underground water supplies. (In most Asian countries, for example, these aquifers provide more than 50 percent of domestic water supplies.) World Resources reports that as developing countries undergo rapid industrialization, heavy metals, acids and persistent organic pollutants (POPs) are contaminating aquifers.
At the same time, over-exploitation of the planet’s major river systems is threatening another finite source of water. “The Nile in Egypt, the Ganges in South Asia, the Yellow River in China, and the Colorado River in America are among the major rivers that are so dammed, diverted, or overtapped that little or no freshwater reaches its final destination for significant stretches of time,” In fact, the Colorado is so over-subscribed on its journey through seven U.S. states that there is virtually nothing left to go out to sea. The flows of the Rio Grande and upper Colorado rivers are in danger of being reduced by as much as 75 percent and 40 percent respectively over the next century.
Perhaps the most devastating analysis of the global water crisis comes from hydrological engineer Michal Kraveik and his team of scientists at the Slovakia non-governmental organization (NGO) People and Water. Kraveik, who has a distinguished career with the Slovak Academy of Sciences, has studied the effect of urbanization, industrial agriculture, deforestation, dam construction, and infrastructure and paving on water systems in Slovakia and surrounding countries and has come up with an alarming finding. Destroying water’s natural habitat not only creates a supply crisis for people and animals, it also dramatically diminishes the amount of available freshwater on the planet.
Kraveik describes the hydrologic cycle of a drop of water. It must first evaporate from a plant, earth surface, swamp, river, lake or the sea, and then fall back down to earth as precipitation. If the drop of water falls back onto a forest, lake, blade of grass, meadow or field, it cooperates with nature to return to the hydrologic cycle. “Right of domicile of a drop is one of the basic rights, a more serious right than human rights,” says Kraveik.
However, if the earth’s surface is paved over, denuded of forests and meadows, and drained of natural springs and creeks, the drop will not form part of river basins and continental watersheds, where it is needed by people and animals, but head out to sea, where it will be stored. It is like rain falling onto a huge roof, or umbrella; everything underneath stays dry and the water runs off to the perimeter. The consequent reduction in continental water basins results in reduced water evaporation from the earth’s surface, and becomes a net loss, while the seas begin to rise. Kraveik issues a dire warning about the growing number of what he calls the earth’s “hot stains”- places already drained of water. The “drying out” of the earth will cause massive global warming, with the attendant extremes in weather drought, decreased protection from the atmosphere, increased solar radiation, decreased biodiversity, melting of the polar ice caps, submersion of vast territories, massive continental desertification and, eventually, “global collapse.”
By Jenny WaterMicronWorld