Climate trends in Victoria
The Victorian Government’s ‘State of the Environment’ Report, released in 2013, provides an overview of both the current condition of Victoria’s climate and trends based on past climatic data. It is important in planning for the future that we learn from the past and the report provides an excellent basis for this. The report states that:
- Average temperatures in Victoria have risen by approximately 0.8°C since the 1950s
- The severity, duration and frequency of heatwaves have increased
- Between 1997 and 2009, Victoria experienced a record-breaking 13-year drought, the longest recorded period of rainfall deficits on record
- Over the past two decades, there has been a large decline in autumn rainfall, a small decline in winter and spring rainfall, a small increase in summer rainfall, and reduced frequency of very wet years
- Victoria experienced its highest summer rainfall on record in 2010–11. The record rainfall led to major flooding that affected a third of Victoria
- Since 1993, Victoria’s sea level rise has been similar to global averages of 3 mm per year
- Annual sea-surface temperatures in south-eastern Australia increased at approximately four times the global average.
Figure 1 illustrates that Victoria’s climate is steadily getting warmer with the state’s mean temperature anomaly increasing since the 1950’s.
Figure 1: Victorian Mean Temperature Anomaly 1910 – 2012 (Source: BoM)
Over the past two decades the average autumn rainfall has dropped significantly and when combined with declines in both winter and spring rainfalls, as well as reduced frequency of very wet years, it points towards a definite need to change how water is managed, especially when combined with projected further declines in annual rainfall and increasing temperatures.
Figure 2: Victorian Annual Rainfall Anomaly 1910 – 2012 (Source: BoM)
Monitoring of sea levels at a global scale has been conducted since 1870. Since the 1900s the sea had been rising at around 1.7 millimetres annually. However, since 1993, records are showing that this annual rise has climbed to 3.1 millimetres a year and is largely attributable to recent increases in ocean warming, expansion and the melting of land-based ice (CES, 2013).
Sea levels around Australia and indeed Victoria, are not rising equally due to factors such as prevailing winds and changes to ocean currents. For example, monitoring stations at Lorne and Stony Point in Victoria have recorded rises of 2.8 millimetres per year and 2.4 millimetres per year respectively since 1991 (CES, 2013).