Water crisis
From Wikipedia, the free encyclopedia
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.[1] The term "water crisis" has been applied to the worldwide water situation by the United Nations and other world organizations.[2][3] 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[4].
There are several principal manifestations of the water crisis.
- Inadequate access to safe drinking water by over 1.1 billion people
- Groundwater overdrafting 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 sanitary domestic water is the leading cause of death worldwide and may account for up to 80 percent of human sickness.[5]
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 man that have rendered the human population vulnerable to the devastation of major droughts.
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[edit] Health impacts of the water crisis
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 sanitation (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 diarrhea alone[6].
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[7]. 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.
[edit] Groundwater overdrafting
Even in many wealthy western countries the drafting of groundwater beyond sustainable yield is endangering maximum agricultural productivity. One of the false assumptions of the Green Revolution is the limitless availability of water to foster crop growth. Most regions of the world are presently faced with choices between extraction of quantities of water desired for short term satisfaction, versus limiting groundwater use to maximize future steady state agricultural yields[8]. As early as the 1970s the U.S. Army Corps of Engineers identified a number of groundwater basins where overdraft was a significant concern[9].
By the mid 1990s developing countries on the whole were in a state of overdraft[10]. Some of the biggest deficits accrued in India and China; for example, on the North China Plain, overdrafting reduced the depth to groundwater by 50 meters in a span of 35 years, whilst in India a net overdraft of 56 percent had taken place.
Even in advanced countries like the United States, there are numerous regions where striving for maximum agricultural output has placed aquifers in overdraft, producing adverse water quality and questionable sustainable yields. One of the USA’s largest groundwater basins, the Ogallala Aquifer, is in substantial overdraft, compromising the likelihood of sustainable crop yields in America’s heartland[11]. Smaller, but important watersheds like Sonoma Valley in California have also begun to display overdraft, presently limiting the amount of otherwise arable land that can be farmed.[12].
[edit] 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 acreage 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. over 80 percent of all historic wetlands were filled[13] by the 1980s, when Congress acted to create a “no net loss” of wetlands.
In Europe extensive loss of wetlands has also occurred with resulting loss of biodiversity. For example many bogs in Scotland have been drained or developed through human population expansion. One example is the Portlethen Moss in Aberdeenshire, that has been over half lost, and a number of species which inhabited this moss are no longer present such as the Great Crested Newt.
On Madagascar’s central highland plateau, a massive transformation occurred that eliminated virtually all the heavily forested vegetation in the period 1970 to 2000. The slash and burn agriculture eliminated about ten percent of the total country’s native biomass and converted it to a barren wasteland. These effects were from overpopulation and the necessity to feed poor indigenous peoples, but the adverse effects included widspread gully erosion that in turn produced heavily silted rivers that “run red” decades after the deforestation. This environmental generated effect removed a large amount of fresh water from usable water for people, but also destroyed much of the riverine ecosystems of several large west-flowing rivers; several fish species have been driven to the edge of extinction and some coral reef formations in the Indian Ocean are effectively lost.
[edit] Regional conflicts
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 inevitable. 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 each present valid claims of certain water use, but the total demands on the riverine system surpass the physical constraints of water availability.[14] As early as 1974 Iraq massed troops on the Syrian border and threatened to destroy Syria’s al-Thawra dam on the Euphrates.[15]
In 1992 Hungary and Czechoslovakia took a dispute over Danube River water diversions and dam construction to the International Court of Justice. This case represents a minority of disputes where logic and jurisprudence may be the path of dispute resolution. Other conflicts involving North and South Korea, Israel and Palestine, Egypt and Ethiopia, may prove more difficult tests of negotiation.
[edit] 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[1]:
- 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 1.2 million
[edit] Outlook
Year 2025 forecasts state that two thirds of the world population will be without safe drinking water and basic sanitation services. Construction of wastewater treatment plants and reduction of groundwater overdrafting appear to be obvious solutions to the worldwide problem; however, a deeper look reveals more fundamental issues in play. Wastewater treatment is highly capital 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 overdrafting 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 treatement systems but also in hydrological transport modeling. At the individual level, people in developed countries can look inward and reduce overconsumption, which further strains worldwide water consumption. Both developed and developing countries can increase protection of ecosytems, 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.
[edit] See also
- Intestinal parasite
- Malnutrition
- Overpopulation
- Water pollution
- 1998 Klang Valley water crisis
- China water crisis
[edit] References
- ^ Ron Nielsen, The little green handbook, Picador, New York (2006) ISBN 0-312-42581-3
- ^ United Nations statement on water crisis
- ^ UN World Summit on Sustainable Development addresses the water crisis
- ^ World Energy Outlook 2005: Middle East and North Africa Insights, International Energy Agency, Paris (2005)
- ^ Water Partners International: Global Water Crisis
- ^ http://www.nrdc.org/international/summit/summit3.asp
- ^ Lester R. Brown, Plan B 2.0, W.W. Norton & Co, New York (2006) ISBN 0-393-32831-7
- ^ Lal Lal, Rattan Lal, Sustainable Agriculture and the International Rice-Wheat System, Marcel Dekker, New York, 2004 ISBN 0-8247-5491-3
- ^ Groundwater recharge in Monterey County, California U.S. Army Corps of Engineers, prepared by Earth Metrics Inc. (1976)
- ^ Reengaging in Agricultural Water Management: Challenges and Options, World Bank, Washington DC {2006)
- ^ When the Wells Run Dry: The Ogallala Aquifer
- ^ Kenwood Press, Groundwater management study approved, Volume XVII, Number 12, page 1, July 1, 2006
- ^ William J. Mitsch, James G. Gosselink Wetlands,
- ^ Nurit Klio, Water Resources and Conflict in the Middle East, Routledge, Oxfordshire, England (2001)
- ^ Contested Environments. edited by Nick Bingham, Andrew Blowers, Chris Belshaw, John Wiley and sons, Chichester, UK (2003)
