One thing that tends to characterise hung parliaments or even non-traditional coalitions in most countries is their ability to only pass popular spending sprees and not the unpopular new taxes (or more correctly, tax reform) that are possible with clear parliamentary majorities.
This is clearly not the case in Australia. Whether for or against a Carbon tax, one has to admit that it is bold, given the popular opinion of the moment.
The thing is, that the idea is to reduce CO2 at the *lowest* cost, which is still putatively an aspiration of a reduced majority. The Europeans have active policies that don't work, and the US has failed to pass legislation that wouldn't work anyway.