Generally speaking "Cap and Trade" (C+T) is an environmental policy designed to reduce greenhouse gas emissions, which is created by fossil fuels (oil, coal). Naturally, lobbyists for those industries are going to be critical of such a policy. C+T is also called "allowance trading", which seems to emphasize the economics and flexibility elements of the policy over the goal of pollution reduction. Any good idea for reducing greenhouse gases and controlling pollution is accountable to intelligent implementation. This includes C+T policy. Implementation shouldn't just focus upon economic incentives for achieving reductions in emissions. Education can be the greatest influence on behavior.
Sadly though, economics is what usually drives implementation of C+T policy, which will thereby make it either effective or doomed for failure. Currently C+T policy is at the macro level (big companies) but what if it was brought down to the level of individual responsibility (micro level)? Would it be beneficial for a single guy (no family or business requiring such a vehicle) to be "responsible" for his Hummer's comparative excessive carbon emissions? If another guy purchased a pollution free liquid hydrogen vehicle (initially at higher cost), should Mr "Pollution Free Vehicle" be encouraged to trade/sell his carbon credits to Mr "11 MPG Hummer"? Would such a micro level plan be more effective for further reducing total carbon dioxide emissions? Likewise, would charging for those plastic grocery bags add an incentive to consumers to bring reusable bags to their grocery stores?
Currently, the macro level C+T policy, in place since 1990, has been effective for reducing targeted areas of emission pollution so better implementation, emphasizing the cap on emissions rather than the trade of credits, should prove effective. Unfortunately, discussions on the effective implementation bring in politics influenced by the aforementioned lobbyists and partisanship desiring power rather than a universal desire to promote the important goal of pollution reduction.
Education must become an essential element of any policy for reducing greenhouse gas emissions. When education on the importance of reducing polluting emissions is undertaken then the subsequent discussions on effective practices will become wiser and less partisan. It is essential for effective educators to be consumers and purveyors of knowledge related to global warming, greenhouse gas emissions, alternative energy, and government policy related to each.