I think prohibiting pollution of atmosphere at source is only way to go forward, trying to collect needles in haystacks is futile. Why emit the carbon just to collect it later? Any financial cost based scheme is morally problematic, if something is wrong and unethical it must not be done at all, making it expensive makes it only unavailable to people with less financial means, but the people with more financial means can pay the tax of their sins in a sense, and it is discriminatory.