Don't sell yourself short. Amaroo was not the only one who wondered when we would hear from you again...
As regards the question at hand, climate science is something that is building up, but we do not yet have the same evidence base as we do in other areas of science, and the same applies to carbon taxes and pollution rates.
I am not sure that all the drop in pollution will have been due to the tax, some may relate to economic activity or other variables. But the tax may have created an environment where investment and production decisions were made against different variables than in the past, and the carbon tax may yet prove to have been the biggest driver.
I am sure Drron could point to instances in medical practice where changes in treatment have produced different outcomes, yet the reasons those changes may have worked are not agreed or fully understood. There will be a lot more analysis needed before all the facts can be elicited from the hypotheses, reasoned argument and conjecture. Makes for a great discussion point when you think you don't have much in common with others say at a function or party, but like any discussion of personal opinions I think we can have an interesting debate if we can tolerate a mix of views.