Environmental Engineering Reference
In-Depth Information
store of fresh water, its potable and irrigation appeal is inevitable but supplies are
restricted geographically and seasonally in the absence of storage schemes. The
feasibility of towing Antarctic icebergs to the Middle East was explored, given the high
cost of alternative desalinization strategies. Glacier meltwater is a major global source of
hydroelectricity generation but is released in high spring and early summer discharges
which still require reservoir storage (Plate 1). Jökulhlaups demonstrate that it does not
always come in manageable quantities.
Although meltwater supply is usually out of phase with demand, contemporary water
access is adjusted to contemporary regimes. These are sensitive to change and glaciers
are generally retreating, out of equilibrium with climate. Norway and New Zealand are
among the few regions experiencing glacier advance due to increased precipitation.
Forecast global warming will initially increase summer meltwater supply as glaciers melt
but glacier retreat will lead eventually to a more sustained reduction. There are two
worst-case scenarios. It is more likely that global warming will remove all alpine glaciers
this century but sustained ice advance may overrun the very societies they serve, where
increased precipitation outweighs melting.
Plate 1 Mauvoisin dam and reservoir, south-west Switzerland.
Global warming threatens the survival of waning glaciers such as
those above the dam. Readvance of similar glaciers above the
reservoir would, conversely, threaten the dam and its hydroelectric
installation.
Photo: Ken Addison.
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