Terrestrial Biodiversity Adaptation Research Network

Annual rainfall averaged across 12 years is now the lowest, in the period since 1996, in the 110 year record for south-eastern Australia.
March to October rainfall since 1996 has declined ~20% since 1996, and is also the lowest across the 110 year record in south-eastern Australia; ~70% of the decline in rainfall across March to October since 1996 is occurring in autumn.
Changes in El Nino Southern Oscillation in the Pacific Ocean are unlikely to be contributing to the declines.
Changes in the Indian Ocean Dipole, and the Southern Annular Mode in the Southern Ocean are a contributor, but cannot explain the autumn declines.
Increases in strength of the sub-tropical ridge over southern Australia can explain the autumn rainfall decline, and are likely a result of global warming.
The South Eastern Climate Initiative is likely to continue into a second round to further explore the causes of the south-eastern Australian rainfall declines.
Recent drought conditions across south eastern Australia, seen in rainfall deficiencies since at least the late 1990's, are a major concern in regards water availability in South Australia.

Timbal, B. (2009) The continuing decline in SEA rainfall -update to 2009

From: South Australian Government, Premier's Climate Change Council, Expert Science Subgroup