Salinity in Australia - Climate Change and Its Impact On Salinity

Climate Change and Its Impact On Salinity

There are mixed predictions in relation to climate change’s effect on salinity in Australia. Climate change can be seen to appease salinity in Australia in some circumstances, but in others it may have detrimental effects. It is predicted that in some instances climate change will result in the reduction in annual rainfall leading to a drier and warmer climate, which will ultimately reduce salinity. Conversely climate changes impact on the salt concentration in water bodies is expected to be unfavourable.

Where there is a reduction in rainfall it is expected that salinity will be reduced. This will occur as a result of the water table being recharged less often, reducing the chance of the water table transporting underground salts to the surface of the land. Climate change may also result in the offsetting of rainfall into different seasons, resulting in larger down pours and extreme weather events in some locations within Australia. In these instances as evaporation will not occur at a faster pace than rainfall, it is likely to result in excessive additions to aquifers, which is also known as deep drainage. This is an issue as dryland salinity is onset by additional deep drainage. In Australia this will be most evident in South Australia, Victoria and the lower half of Western Australia. However these changes are expected to be minimal as the water table may already be reduced from excessive periods of drought.

On the other hand the reduction of water in streams, rivers, water bodies and the like is likely to result in an increase of salt concentration in these water bodies. This will be particularly evident in groundwater flow systems of different catchments. Austin et al. of CSIRO have predicted that water in the Murrumbidgee will drop by up to approximately 48% by 2070 which will result in salt yields on the surface of the land falling by approximately 30%, however the stream salinity concentrations are predicted to increase by 11%.