I would certainly agree that the carbon tax is a contributor to the inflation rate. I think it is obviously not responsible for the entire rate of inflation, but it is a contributor. It is a cost, so yes, this is a lever within government's control.
Inflation is a mixture of factors outside the government's control and decisions that the government makes, and the carbon tax is a decision that the government has made, so it is contributing to inflation. Assuming that the bank would have lowered rates at 2% and assuming that if the carbon tax wasn't present it would have brought the rate down to under 2%, which it seems by that math that it would, then yes, I would agree.