Finland. 60 Euro!
The problem is your figure of $23 and my figure of 60 are meaningless in isolation, as they're simply the rate of the tax. Unless we also know the base of the tax, we don't know how "big" the tax is, we don't know the impact on the economy or the impact on individuals.
This means your assertion that Australia is is completely unsubstantiated.
What we do know, in Australia the rate is $23 t/Co2, imposed on companies that emit over 25,000 t/CO2 per year (the base). From knowing the rate and the base, we can extrapolate the likely impact. At the macro level
some have estimated this to be an increase in CPI of 0.75% (as a comparison the introduction of the GST increased CPI by 2.5%). At a household level, the same study estimated it would add $7.87 p/w to the poorest 10% of households, $22.13 p/w to the richest 10% of households and an average of $13.18 p/w for all households. This is starting to tell us how "big" the tax is. Another indicator is that it will raise approximately $8 billion per year (although again this doesn't really tell us how big the tax is without knowing the size of the economy it was raised from).
Now lets look at Finland. 60t/CO2 is bigger than $23 t/CO2, but what does this mean. It means F-all!
60t/CO2 is the rate for traffic fuels. So we know that in Finland the base includes petrol, which is excluded in Australia. 30t/CO2 is the rate for coal and natural gas, except there is a 50% discount when used in combined electricity and heat production and no CO2 tax when used for electricity production. Again, the rate is higher and the base wider than in Australia, except in regards to electricity production. Overall the Finish carbon tax is quite
complex, and can't be described as a single flat rate.
So what do we know?
We know in Australia that at $23t/CO2 imposed on companies that emit over 25,000 t/CO2 per year, it will raise approximately $8 billion, from an economy of $1.57 trillion, from a population of 23 million people.
We know in Finland, their various environmental energy taxes will raise approximately $5.5 billion, from an economy of $187.6 billion dollars, from a population of 5.4 million people.
So yeah, I think saying Australia has the biggest carbon tax in the world is pure bollocks and to name just one country with a bigger tax, I give you Finland.