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As World Water Day
approaches, new Worldwatch Institute study examines global water use and steps
to address water scarcity
wateronline.com
Washington,
D.C. -- Some 1.2 billion people-almost a fifth of the world-live in areas of
physical water scarcity, while another 1.6 billion face what can be called
economic water shortage.
The
situation is only expected to worsen as population growth, climate change,
investment and management shortfalls, and inefficient use of existing resources
restrict the amount of water available to people, according to Worldwatch
Institute's Vital Signs Online service (www.worldwatch.org).
It is
estimated that by 2025, 1.8 billion people will live in countries or regions
with absolute water scarcity, with almost half of the world living in
conditions of water stress.
Water
scarcity has several definitions.
Physical
scarcity occurs when there is not enough water to meet demand; its
symptoms include severe environmental degradation, declining groundwater, and
unequal water distribution.
Economic
water scarcity occurs when there is a lack of investment and proper management
to meet the demand of people who do not have the financial means to use
existing water sources; the symptoms in this case normally include poor
infrastructure. Large parts of Africa suffer from economic water scarcity.
World
population is predicted to grow from 7 billion to 9.1 billion by 2050, putting
a strain on water resources to meet increased food, energy, and industrial
demands.
But
there are many other pressures, including increased urbanization and
overconsumption, lack of proper management, and the looming threat of climate
change.
According
to the United Nations Food and Agriculture Organization and UN Water, global
water use has been growing at more than twice the rate of population increase
in the last century.
At the
global level, 70 percent of water withdrawals are for the agricultural sector,
11 percent are to meet municipal demands, and 19 percent are for industrial
needs.
These
numbers, however, are distorted by the few countries that have very high water
withdrawals, such as China, India, and the United States.
Agricultural
water withdrawal accounts for 44 percent of total water withdrawal among
members of the Organisation for Economic Co-operation and Development (OECD),
but this rises to more than 60 percent within the eight OECD countries that
rely heavily on irrigated agriculture.
In the
four transitional economies of Brazil, Russia, India, and China, agriculture
accounts for 74 percent of water withdrawals, but this ranges from 20 percent
in Russia to 87 percent in India.
Policymakers
must introduce a variety of measures to address global water scarcity. One
important initiative is to support small-scale farmers.
Much of
the public investment in agricultural water management has focused on
large-scale irrigation systems.
Farmers
can also use water more efficiently by taking a number of steps, including
growing a diverse array of crops suited to local conditions and adopting
irrigation systems like "drip" lines that deliver water directly to
plants' roots.
Climate
change will affect global water resources at varying levels.
Reductions
in river runoff and aquifer recharge are expected in the Mediterranean basin
and in the semiarid areas of the Americas, Australia, and southern Africa,
affecting water availability in regions that are already water-stressed.
In
Asia, the large areas of irrigated land that rely on snowmelt and high mountain
glaciers for water will be affected by changes in runoff patterns, while highly
populated deltas are at risk from a combination of reduced inflows, increased
salinity, and rising sea levels.
And
rising temperatures will translate into increased crop water demand everywhere.
To
combat the effects of climate change, efforts must be made to follow an
integrated water resource management approach on a global scale.
This
involves water management that recognizes the holistic nature of the water
cycle and the importance of managing trade-offs within it, that emphasizes the
importance of effective institutions, and that is inherently adaptive.
Further
highlights from the report:
· A region is said to face water scarcity when supplies fall below
1,000 cubic meters per person, and absolute water scarcity is when supplies
drop below 500 cubic meters a year.
· About 66 percent of Africa is arid or semiarid, and more than
300 million people in sub-Saharan Africa currently live on less than 1,000
cubic meters of water resources per person.
· According to UN Water, each person in North America and Europe
(excluding former Soviet Union countries) consumes at least 3 cubic meters per
day of virtual water in imported food, compared with 1.4 cubic meters per day
in Asia and 1.1 cubic meters per day in Africa.
https://www.wateronline.com/doc/the-looming-threat-of-water-scarcity-0001
https://www.wateronline.com/doc/the-looming-threat-of-water-scarcity-0001
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