Answer: Australians emit 1.5% of the CO2 emitted by humans. So Australians, over the years, emitted at most about 1.5% of the 110 ppm increase in CO2 since pre-industrial times (that increase is is probably due to ocean warming, due to whatever has been heating the world since 1680), or 0.0000017% of the air (1.7 ppm).
Fallacy: impossible expectations