Taxation will make Australia "unsurvivable" for people faster than any climate change.
Taxation has been far higher in our past than now, and has been far higher internationally than it has ever been in Australia, and often coincides with economic booms and record low inequality.
edit: Also a big LOL to the thought that the Australian government raises more tax in a year than would cost the Australian economy per year to enact policies to ensure the ongoing survival of Sydney.
The difference is that Australians are, for the most part, paying the bills as they come due.