Impacts of Climate change and extreme events
The Wimmera Southern Mallee economy is dominated by agriculture, which is highly dependent on favourable climatic conditions. Many parts of the region, including those most attractive to residents and visitors, are susceptible to extreme events such as flooding and bush fire. Future climate predictions suggest the region may experience longer periods of drought and that bush fire and high rainfall events will be more severe. Such changes have significant environmental, economic and social implications. Careful management of new land use and development is required to minimise risk to life and property and to ensure that environmental values are not compromised by inappropriate development (Wimmera Southern Mallee Regional Growth Plan, 2013). A report by the University of Melbourne commissioned by World Wildlife Fund (WWF) in 2015, suggests significant impacts to food production in Australia including our region. However, whilst often the negative aspects of climate change are the focus, it is also important to understand and take advantage of any opportunities or benefits it may bring.
With climate change and its associated events, it is vital that we build resilience of our natural assets so they can respond,
evolve and recover. Our community, on the other hand, has for many decades, adapted to a variable climate. For example, changes in farming techniques, plant breeding and fire management practices.
Climate change predictions
Lower winter rainfall, higher summer rainfall, temperature increases and extremes in all seasons, more hot days and fewer very cold days are all future predictions for the Wimmera region from the Victorian Climate Change Adaptation Program 2008. This has been confirmed in the CSIRO’s Climate change modelling for the Murray Cluster (CSIRO, 2013).
Key messages from the climate change projections under current emission rates to 2090 for the Murray cluster (CSIRO, 2013) area for rainfall and temperature include:
- Average temperatures will continue to increase in all seasons (very high confidence).
- More hot days and warm spells are projected with very high confidence. Fewer frosts are projected with high confidence.
- By late in the century, less rainfall is projected during the cool season, with high confidence. There is medium confidence that rainfall will remain unchanged in the warm season.
- Even though mean annual rainfall is projected to decline, heavy rainfall intensity is projected to increase, with high confidence.
- A harsher fire-weather climate in the future (high confidence).
- On annual and decadal basis, natural variability in the climate system can act to either mask or enhance any long term human induced trend, particularly in the next 20 years and for rainfall.
Climate change and frost
Current research suggests frost frequencies (and associated year-to-year variability) will remain largely unchanged until
at least 2030 irrespective of emission rates. It is also understood that across the southeastern parts of the continent the season for frosts has broadened. That is, they start earlier and end later in a season. CSIRO modelling suggests that depending on the emission scenarios, there is likely to be a strong reduction in frost incidences by 2090. While experts acknowledge that assessing frost using global climatic models can significantly under report frost occurrence, there is general consensus that if emission continue to accumulate in the atmosphere at current rates, that the resultant warming is likely to reduce the number of
frost events but there is uncertainty about changes in the length of the frost season and the severity of frost events. So while in the longer term the number of frosts may reduce, in the short term we will continue to have a similar frost number and season length. There is a need to continue to better understand frost occurrence and the impact of frost severity and to continue to develop management and technology to ensure our natural assets can cope with frost.