What revenue gov loses by killing the carbon tax

Far out. This is a Hockey shocker. From Wayne Swan's facebook page (click to enlarge):

Yes folks, but getting rid of all things to do with the carbon tax will cost $28billion in gov revenue. Why the fuck not keep it then? It's bringing in money. If they're so concerned about the budget bottom line surely keeping $28billion in revenue would be a good start? Not when it's about ideology.......