replace bureaucratic systems of water allocation based on licenses with a unified
market system based on tradeable water rights to ensure that water was
allocated to its most socially valuable use.
By the early 2000s, it was apparent that policy had failed to generate
sustainable allocations of water. These problems were exacerbated by years of
severe drought. The severity of the drought is related, at least in part, to climate
change caused by human activity (Murray-Darling Basin Ministerial Council
2007). Climate models suggest, on the balance of probabilities, that precipitation
in the Murray-Darling Basin will decline as a result of climate change, and, with
high probabilities, that increased temperatures and evaporation will reduce
inflows for any given level of precipitation.
However, given the high levels of natural variability in precipitation, and the
apparent presence of multi-decade cycles, attribution of causes for the current
drought is subject to high uncertainty. Neverthless, the balance of evidence
suggests that climate change will be associated with reductions in rainfall in the
Murray-Darling Basin, and with more frequent and severe drought conditions in
the future (Wentworth Group 2006).
The failure of existing management policies in the Murray-Darling Basin has
produced a series of responses, each responding to the actual or perceived
deficiencies of its predecessors : the Living Murray Program (2002), the National
Water Initiative (2004), the National Plan for Water Security (2007) and the
Water for the Future Plan (Wong 2008).
Climate change projections
A variety of projections of rainfall, temperature, humidity and evaporation for
each catchment in the model were produced for the Garnaut Review of Climate
Change (Garnaut 2008). Since there remains considerable uncertainty about the
impact of climate change on rainfall patterns, the Garnaut Review presented
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