The Conservative government will refuse a carbon tax or a cap and trade system, because that would provide an industrial boost, in Canada, to concerns centered in Ontario (for instance, electric cars, wind turbines, electric power equipment, design and expertise, and, especially, the nuclear power industry), rendering that province's future job growth more independent of growth in the oil sands industries. This is also why they are intransigent internationally on this issue, and why they are shrinking the box into which AECL may grow, and shrivelling the nuclear industry from an international concern (in a sector poised for growth) to a Canadian rump.
The greater Ontario's economic jobs and growth is linked to the western provinces' growth, the more Ontarians will not want to disappoint the political sympathies of the westerners providing their supper. Keep them lean, hungry, and knowing who their masters are.
It's important to note that any hypothesized boost to Ontario from any sort of proper Canadian carbon accounting would not likely come at the economic expense to the Alberta or Saskatchewan. Even oil sands interests have called for a carbon tax (I don't think insincerely). Their major growth product, oil, for transportation and plastics, has a global market broadly separate from energy from electricity. It is a pet peeve of mine to emphasize this, since many left or centrist commentators assume that Harper, in rejecting any sane policy to account for climate change, is doing the bidding of oil companies. Not so. The simplest explanation of what Harper is doing is to assume he is just doing what is best for Harper.
A carbon tax or cap and trade regime could greatly affect the internal Canadian political scene. This, rather than economic concerns, is what is driving this issue now. Harper isn't a Marxist, but he'll make the trade of the country being worse off, long term, if it improves his personal fortunes today. Just like any run-of-mill controlling autocrat.