The costs of cleaning up the mistakes of the past
have been rising and are likely to continue to do
so. There have been many of these mistakes,
some of them discussed elsewhere in this chapter.
The reclamation of salinized land, and the revival
of economies that once depended on that land,
already consume large sums, and could consume
much more. By far the best-known case has
been the Aral Sea basin (Figure 5.5), which will
take decades to restore (if it is ever achieved).
The existing recovery programme will only save
one basin of the former sea, and reduce only
a proportion of the dust that damages health
(Kingsford and others 2005).
The Aral is not unique. "Salinization and
waterlogging have affected 8.5 million ha or 64 per
cent of the total arable land in Iraq; [.] 20-30 per
cent of irrigated land has been abandoned due to
salinization" (UNEP 2002). In the Tarim River basin of
China, more than 12 000 square kilometres of land
was salinized between the 1960s and 1990s (Feng
and others 2005). In both countries, degradation
is expanding. Because salinization slowly and
incrementally affects yield well before it precipitates
complete failure, the problem may take years to
become apparent to anyone but the local farmers.
Collapse of the whole may then be sudden. This is
what is said to have happened in Iraq, 3 000 years
ago, where the legacy of salinized soils is almost as
great today as it was then (Jacobsen and Adams
1958). Dealing with accumulated salt may take
centuries, if not millennia.
The prospect of wars over water (Bulloch 1993)
has not materialized. Countries that compete for
water, like India and Pakistan, have kept strictly
to their agreement about sharing water (in their
case, the Indus Waters Treaty), even if they have
resorted to war over other things. Perhaps water
is too important to fight over (Alam 2002). This
is not to say that water is not a source of local
conflict, as it has been recently in Cochabamba in
Bolivia, and continues to be in Israel and Palestine.
Reclamation may not, then, be violent, but it
will not be cheap. Communities and economies
will need to be relocated; national and regional
economies have to be adjusted - some of them
for the better in the long-term, if we believe Reisner
(1986); more will have to be spent on supplying
water, and on international treaty obligations.
Dust, as from the Aral Sea and the Owens Lake
in California, has to be controlled. Sedimenting
reservoirs have to be managed more carefully and
on a longer-term basis.
Accounts of the collapse of the Iraqi and Indus
Valley (above) and other desert collapses, such as
that of the irrigation system in Chaco Canyon in
Arizona in the 12th century (Diamond 2005), show
that collapse is a common hazard in deserts. This
is largely because desert economies depend so utterly on water. In ancient water-supply systems,
withdrawal or degradation usually brought collapse.
Vulnerability may now be reduced, but it is not
eliminated, as the Aral crisis shows.