Overuse of water resources on global, regional, and local scales is
causing rivers, wetlands, lakes, and aquifers to lose volume and even in many
cases to dry up. Based on data from NASA, the World Health Organization, and
other international agencies, the United Nations Environment Programme has
determined that by 2050 severe water shortages currently affecting at least 400
million people will affect as many as four billion people.[1]
While the world's population tripled
in the 20th Century, the use of renewable water resources grew six-fold. By
2050, world population is projected to increase by 40 to 50 percent. That growth,
coupled with industrialization and urbanization, is likely to result in increasing
demand for potable water.
If that population growth occurs as predicted, within less than 40 years
more than half of the Earth’s population will be living with inadequate water
supplies, depleted fisheries, and polluted aquifers, streams, and coastlines because
of water mismanagement on a global scale. The World Bank recently reported that
80 countries now have water shortages that threaten health and economies and
that 40 percent of the world’s population — more than two billion people — have
no access to clean water or sanitation. One of the most important causes of
global water problems is increasing world population, which places difficult to
meet demands for increasing water supplies for industrial/commercial,
agricultural, and individual uses.
But population growth is far from the only challenge with respect to
water shortages. According to the World Bank, world-wide demand for potable water
is doubling every 21 years. Since 1900, a two-fold increase in world population
was accompanied by a six-fold increase in water use, reflecting the effects of
rising standards of living on greater water use; e.g., diets containing less
unprocessed foods such as grains, fruits, and vegetables and more processed
food products, especially meat. That dramatic increase in population and
transition to more “modern” lifestyles has been accompanied by depletion of
groundwater supplies (the mining of “fossil” water that was deposited millions
of years ago); inadequate surface water supplies; land salinization;
eutrophication and algal blooms in lakes, inland seas, and even the open ocean
(see 6-21-11 post on Dead Zones) from agricultural chemicals; irrigation of
crops already in surplus; and conversion of agricultural land to other uses,
especially in hard surfaced urban areas. Land use change and habitat
modification have also led to widespread negative effects on lakes and rivers.
Those changes include removal of native vegetation, including forested
areas and wetlands (see 6-21-11 post on Deforestation), to permit agriculture
and grazing, conversion of mangroves and other tidal habitats to aquaculture
and recreation-oriented development (resorts as well as permanent and vacation
homes), large-scale irrigation schemes that are poorly designed and managed,
water diversion projects that dry up wetlands and lakes, and dams that decrease
stream load and cause the erosion of estuaries and other coastal areas. And we
can’t ignore the reality that about 95 percent of the world’s cities still dump
raw sewage and industrial effluents into their rivers and lakes, adding
microbial and chemical pollutants to the waters.
Other serious problems include accelerating pollution, desertification,
salinization, and human-induced climate changes that cause rapid melting of
winter snow pack and glaciers and fewer water supplies for agriculture and
urban uses during summer months when demand is the highest. Many climatologists
expect temperatures to rise by 5-7° C by the end of the century and rainfall to
decrease between ten to twenty percent, which will greatly increase
evaporation, vegetation loss, wind erosion, and dust storms. Global warming is
expected to cause glaciers in the mountains of south Asia are to decline by 40
percent to 80 percent in the next hundred years with profound effects on large
populations in countries that depend on the water for agriculture, human and
animal consumption, and sanitation, especially Nepal, India, Pakistan, China, Bangladesh, Myanmar, Thailand, Laos, and Vietnam.
However, many water resource experts believe that the main problem associated
with fresh water is poverty, not supply or the lack of it. Their view is
influenced at least in part by the inescapable reality that the far greater
majority of severe water shortage problems are in developing nations, where
poor irrigation management and water supply practices result in wasting vast
quantities of water and the lack of proper sanitation results in heavily
polluted water sources. Added to that, developed nations such as the U.S. and the nations of Western
Europe have a much different water problem: government welfare
given to large agri-businesses in the form of enormous water subsidies and
protections accounts for 85 percent of fresh water consumption.
Real World
Examples: In the past several decades, the Aral Sea
has lost about 60 percent of
its volume. For almost 40 years, water has been diverted from the rivers
supplying the Aral Sea (Amu-Darya and the Syr-Darya) to irrigate millions of
acres for cotton and rice production, resulting in the Sea shrinking from over
65,000 km² to far less than half that size, exposing large areas of the lake
bed to wind erosion, increasing the salt concentration from ten percent to more
than 23 percent, and changing the regional climate to hotter, drier summers and
colder, longer winters. Lake Chad presents
another powerful example of the effects of human agency on the environment. In
the 1960s, with an area of more than 26,000 km², the Lake was the fourth
largest in Africa ; it is now one-twentieth the
size it was 35 years ago. Overgrazing in the surrounding savannas and
large-scale irrigation projects along the Chari and Logone
Rivers , which originate in the
mountains of the Central African Republic ,
combined to divert water from the two main rivers that empty into the Lake .[2]
Given the unsettled political situation that currently exists in the nations
that border the Lake, it is possible that the Lake
will disappear before the end of the 21st Century. Lastly, in Jaipur State
south and west of New Delhi in central India India
Author’s Note: Solutions to the
growing water shortage are many and varied and include such technological and political fixes as government imposed
water conservation regulations, slowing population growth in critical areas,
more efficient irrigation management, elimination of government subsidies (a
form of welfare to the well-off) to agricultural users (especially those in
arid or semi-arid regions such as California and the American Southwest), a
push for more government-sponsored desalination research, adoption of regional
water management regulations, pollution reduction, and better management of
present supply and distribution systems (in some large, older European cities
as much water is lost every day from leaky pipes as is consumed). Another
approach much beloved by conservatives is to make water supply a function of
the market by assigning monetary values to fresh water. Imagine the results of
that free market environmentalism in places where a centuries-old landed gentry
controls the land and water and the far greater majority of the resident population
are tenants who historically have had no rights whatsoever. That should work
just fine.
[1] United
Nations Environment Programme, Challenges to International Waters; Regional
Assessments in a Global Perspective. February, 2006; ISBN 91-89584-47-3;
available online at http://www.giwa.net/publications/finalreport/.
[2] Michael
T. Coe and Jonathan A.Foley. “Human and natural impacts on the water resources
of the Lake Chad Basin
No comments:
Post a Comment