ANSWER 1

Written response:

An important question when considering the impacts of climate change on ocean circulation patterns. So, both the Leeuwin Current (southward flowing western boundary current off Western Australia) and the East Australian Current (EAC) (southward flowing down the east coast of Australia) are really important highways that transport warm waters. Climate models suggest they’re both going to change as the planet keeps heating up — but in different ways.
Future climate projections suggests that the Leeuwin Current is likely to weaken under a warming climate due to shifts in the winds and pressure systems that drive it both across the Indian and Pacific Oceans. The Leeuwin Current has weakened in strength over the past 50 years by 10–30 %. The current is predicted to weaken further by 15 % by 2060 under no particular RCP model. However,  shorter term variability depends on seasonal climate drivers such as ENSO. Furthermore, a generally weaker Leeuwin Current in the future will be occurring against a background of much warmer ocean temperatures than what WA has historically experienced. So, the past relationships between Leeuwin Current strength and sea surface temperatures may not hold true under a warming climate.
The EAC is another powerhouse boundary current that is projected to further strengthen and extend further south towards Tasmania. This extension of the EAC is already underway and there is strong evidence to suggest that it is a major contributing factor for the south-east of Australia being a hotspot for ocean warming and for range extensions of species further south.