APPENDIX 2 - BACKGROUND - CLIMATE IN AUSTRALIA
The Australian Bureau of Meteorology (BoM) records show that Australia's climate has been changing over the last half century, "Australia's temperatures have, on average, risen by about 1° Celsius with an increase in the frequency of heatwaves and a decrease in the number of frosts and cold days. Rainfall patterns have also changed - the northwest has seen an increase in rainfall...while much of eastern Australia and the far south-west have experienced a decline" (www.bom.gov.au/climate/change).
Of the four most severe droughts (in terms of rainfall deficits over a 1 - 2 year period) in recorded eastern Australian history, three occurred between the years 1982 and 2003 with the most recent drought increasing that number to four in the last 25 years (Year Book Australia, 2005 (cat. no. 1301.0).
A recent report on Australia's climate (Climate Change in Australia), jointly released by the BoM and the CSIRO, predicts that over the next 30 years temperatures will rise a further 1° Celsius with "changes in temperature extremes, fewer frosts and substantially more days over 35 degrees". Annual average rainfall in southern Australia is also expected to decline, although the rainfall we do get is likely to be more intense. Other changes predicted include greater frequency of drought, increase in evaporation rates, more high-fire-danger weather, more intense cyclones and further rises in sea levels. (www.csiro.au/news/ClimateChangeInAustraliaReport.html)
The map below from the Bureau of Meteorology shows rainfall percentages across Australia over the last 3 years. Generally, over this period, rainfall in the north and much of the west of the continent was above average while central and south eastern Australia experienced below-average rainfall.
AUSTRALIAN RAINFALL PERCENTAGES: 2003-04 TO 2006-07