Victoria is expected to warm at a slightly faster rate than the global average, especially in the north and east of the state. By 2030, annual average temperatures are expected to increase by around 0.8 °C (with warming likely to be greatest in spring and summer).
By 2070, the average annual temperature could increase by 1.4 °C (under a lower emissions growth scenario) or by as much as 2.7 °C (under a higher emissions growth scenario).
As well as changes in average temperature, the number of hot days (days over 35 °C) will increase in both frequency and intensity. The largest increases are expected in inland areas, while the smallest changes can be expected in coastal regions. Additionally, changes to the annual average number of frosts will also decrease across the state.
By 2030, the annual average rainfall is expected to decrease by around 4 per cent. With the decrease being more prominent in winter and spring, while it is likely heavy rainfall will increase in summer and autumn.
By 2070, the annual average rainfall is likely to decrease by 6 per cent (under a lower emissions growth scenario) or by as much as 11 per cent (under a higher emissions growth scenario). In addition to likely decreases in average rainfall, Victoria is also expected to experience an increase in the intensity of the highest 1 per cent of rainfall events. Therefore, there will be more dry days but the days when it does rain will be wetter and more intense. It is likely that these changes will be more prominent in autumn and winter.
As well as decreases in total rainfall, evaporation is expected to increase, enhancing the overall drying trend.
Global sea levels are not rising equally and this variation also occurs along the Victorian coast. Regions along the Victorian coastline that are considered highly exposed include the Western Port Region of Victoria.
Monitoring stations at Lorne and Stony Point in Victoria have recorded rises of 2.8mm per year and 2.4mm per year respectively since 1991 (National Tidal Centre, BoM, 2006).
The Future Coasts Program (being collaboratively led by the Victorian Department of Environment and Primary Industries and the Department of Transport, Planning and Local Infrastructure) is a $13.7 million investment the Victorian Government is taking in response to climate change, to help Victoria better understand and plan for the risks associated with sea level rise and storm surge.
A key aspect of this program is that it provides mapping and guidance tools for stakeholders (including local government) to gain a greater understanding about the potential risks from sea level rise along the Victorian coast. These tools include the Victorian Coastal Inundation Dataset (see Box 1) and the Victorian Coastal Hazard Guide and Digital Elevation Model data - which are currently available on the Program’s website.
Box 1 - Victorian Coastal Inundation Dataset
The Victorian Coastal Inundation Dataset provides a high level assessment of the potential risks from sea level rise and storm surge at a state-wide to regional scale, for four different time periods (2009, 2040, 2070 and 2100). The 2100 sea level rise combined with a storm surge event has been used for the purposes of this report.
The intention is for this tool to be used by stakeholders to assist in strategic planning and risk management at a regional scale as an indicative assessment of which areas are likely to be at risk over different timeframes.
The Victorian Government is also working closely with local government and other project partners to undertake more detailed local coastal hazard assessments at several priority locations along the coast, including Port Fairy, Bellarine Peninsula-Corio Bay, Western Port, Gippsland Lakes-90 Mile Beach. These local assessments will test a range of methods to analyse the impacts of sea level rise as well as provide practical information for planners and land and infrastructure managers to make decisions at a local scale.
The projected warmer drier weather described in this section is likely to increase the frequency and intensity of bushfires. Relative to the climate of 1974-2003, by 2020 it is expected the number of ‘extreme’ fire danger days will generally increase by between 5 per cent and 40 per cent.
By 2050 this is expected to further increase by between 15 per cent and 25 per cent (under a lower emissions growth scenario) or by 120 per cent and 230 per cent (under a higher emissions growth scenario).
Since the early 1970s, Australian droughts have become more intense as a result of the warmer than average temperatures. The projections for warmer temperatures and reduced annual rainfall are likely to increase the risk of drought.
The frequency of drought is also likely to increase by between 10 per cent and 80 per cent in the southern half of the state and by between 10 per cent and 60 per cent in the northern half by 2070.
Australia
Barwon South West
