Environmental Engineering Reference
In-Depth Information
Discussion
International transfers of water in virtual form are substantial and likely to increase with
continued global trade liberalization (Ramirez-Vallejo and Rogers, 2004). Intensi
fi
ed
trade in water-intensive countries o
ers both opportunities and risks. The most obvious
opportunity of reduced trade barriers is that virtual water can be regarded as a possibly
cheap alternative source of water in areas where freshwater is relatively scarce. Virtual-
water import can be used by national governments as a tool to relieve the pressure on their
domestic water resources. This import of virtual water (as opposed to real water, which is
generally too expensive) will relieve the pressure on the nation's own water resources. For
water-abundant countries an argument can be made for export of virtual water. Trade can
physically save water if products are traded from countries with high to countries with low
water productivity. For example, Mexico imports wheat, maize and sorghum from the
USA, which requires 7.1 billion m 3 of water per year in the USA. If Mexico were to
produce the imported crops domestically, it would require 15.6 billion m 3 of water per
year. Thus, from a global perspective, the trade in cereals from the USA to Mexico saves
8.5 billion m 3 /yr. Although there are also examples where water-intensive commodities
fl
ff
ow in the opposite direction, from countries with low to countries with high water pro-
ductivity, the available studies indicate that the resultant of all international trade
ows
works in a positive direction. We showed that international trade in agricultural com-
modities reduces global water use in agriculture by 5 percent. Liberalization of trade
seems to o
fl
ff
er new opportunities to contribute to a further increase of e
ciency in the use
of the world's water resources.
A serious drawback of trade is that the indirect e
ects of consumption are external-
ized to other countries. While water in agriculture is still priced far below its real cost in
most countries, an increasing volume of water is used for processing export products. The
costs associated with water use in the exporting country are not included in the price of
the products consumed in the importing country. Consumers are generally not aware of -
and do not pay for - the water problems in the overseas countries where their goods are
being produced. According to economic theory, a precondition for trade to be e
ff
cient
and fair is that consumers bear the full cost of production and impacts. Another down-
side of intensive international virtual-water transfers is that many countries increasingly
depend on the import of water-intensive commodities from other countries. Jordan
annually imports a virtual-water volume that is
ve times its own annual renewable water
resources. Other countries in the Middle East, but also various European countries, have
a similar high water import dependence. The increasing lack of self-su
fi
ciency has made
various individual countries, but also larger regions, very vulnerable. If for whatever
reason food supplies cease - be it due to war or a natural disaster in an important export
region - the importing regions will su
er severely. A key question is to what extent
nations are willing to take this risk. The risk can be avoided only by promoting national
self-su
ff
ciency in water and food supply (as Egypt and China do). The risk can be
reduced by importing food from a wide range of trade partners. The current worldwide
trend, however, facilitated by the World Trade Organization, is toward reducing trade
barriers and encouraging free international trade, and reducing interference by national
governments.
The current global trade pattern signi
uences water use in most countries of
the world, either by reducing domestic water use or by enhancing it. Future national and
fi
cantly in
fl
Search WWH ::




Custom Search