Geography Reference
In-Depth Information
WATER IN GLOBAL CONTEXT
It is difficult to imagine a more precious resource or one more central to human survival
and well-being than water. According to recent reports from scientific organizations and
multilateral agencies, the world's freshwater supplies are under increasing stress (Palaniap-
pan and Gleick 2009). Of the total water resources on the planet—which measure about 1.4
billion cubic kilometers, a figure that is impossible for most people to contemplate—only
about 2.5 percent consist of freshwater, and most of this precious resource is locked away
in glaciers, groundwater, or vegetation, leaving only about 0.1 percent of the earth's water
readily accessible for human use at any given time (Clarke and King 2004). Anthropogenic
stresses such as population growth, urbanization, industrial pollution, rising consumption
patterns, and inequitable distribution policies result in what has been termed the “global
water crisis,” which relates both to the quantity and quality of available freshwater (Cain
and Gleick 2005; Gleick 2003). This crisis presents a particular challenge to economic de-
velopment and human well-being in the developing world and constitutes one of the most
pressing social and environmental problems of our time.
The problem stems from distribution as much as from simple supply and demand. The
concept of “peak oil” has been used since the 1950s to describe the rate of oil production
in relation to consumption levels. The pattern follows a bell-shaped curve, with time on the
horizontal axis and annual production on the vertical axis: as demand rises, discovery and
exploitation of additional sources rise to meet it. But this process causes costs to escalate,
which makes further exploration prohibitively expensive, causing the rate of production to
fall. The world has reached “peak oil” when at least half of the known stock of petroleum
has been depleted and the rate of production begins to fall, driving prices ever higher. 7
Water-resource experts have posed the question of whether water consumption follows
a similar bell-shaped curve (Palaniappan and Gleick 2009). Are we facing an era of “peak
water”? Like oil, water is essentially a fungible commodity: whether it is running through
surface channels, seeping through bedrock, or coursing through vegetation as “green wa-
ter,” as long as two hydrogen molecules are bonded with one oxygen molecule, it is water.
Unlike oil, however, the earth will never “run out” of freshwater because the hydrologic
cycle ensures a continuous supply. But on a local or regional scale, people can and often
do run out of freshwater. The North China Plain aquifer, which sustains a population of
more than 100 million in and around the megacities of Beijing and Tianjin, has been tapped
and used at a rate that far exceeds its natural recharge rate. 8 This trend is unfortunately true
for surface water, too: some of the world's great rivers—the Colorado, the Rio Grande, the
Nile, and the Yellow—are reduced to little more than a trickle by the time they reach the
sea, overtaxed by agricultural irrigation, industrial use, and residential consumption.
The concern about the earth's water supply, therefore, is not simply about the consump-
tion of a scarce resource. Rather, it is a concern about the distribution of that resource at the
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