I think the question with cap and trade isn't a moral issue: current disparities in emissions can be accounted for by placing different caps on different countries and I don't see anything morally wrong with allowing people to purchase the right to emit more (CO2 being a well mixed gas and all). The question is whether it works once you include all the inevitable offsets for which it's difficult to ensure additionality.
Set up a system that works and I won't have a problem with the trading. I think it would be pretty hypocritical to buy into capitalism and then reject cap and trade as a bad, nasty, evil market.