People don't like carbon emissions, rather, they like energy which has a byproduct of carbon emissions. By taxing carbon emissions, you squeeze energy production from CO2-producing fuels to non-CO2-producing fuels.
This is a good description of what cap and trade COULD accomplish. However, we need to be realistic about the fact that what makes Cap and Trade necessary is that we have underprioritized clean energy research as a nation for far too long.
If we had known in advance that fossil fuels would damage the ecology of the planet, which of course we didn't for most of the 20th century, we could have chosen to put research dollars into clean energy and possibly develop those technologies to the point where they could compete with fossil fuels now, in 2011.
We didn't do that. Too bad! So now we need to intervene in the market to slow the environmental damage from overconsumption of fossil fuels. As economic conservatives will always (correctly!) point out, such interventions often have unforeseen and chaotic effects.
These interventions are necessary in the short and probably even the medium term. But long-term the task remains the same - we MUST prioritize clean energy research much more highly than we currently do, and undertake the long-term, serious and difficult process of finding the technologies that will provide for the energy needs of the 21st century.
The bit of cap n trade/carbon tax triumphalism I object to is the idea that it will somehow magically force the nation to develop clean energy technology. It won't. It will incent the use of existing clean energy technology. It's tempting to think that this would increase the basic research being done in that field, but in fact there is no market mechanism by which that can happen. Basic research in clean energy, like ALL basic research, must necessarily be a policy choice.
As Schumpeter pointed out many decades ago, capitalist markets chronically underinvest in basic research because its commercial benefits are too far in the future. A dynamic actor such as the state is able to correct this over the long term, but for the last 50 years we have focused almost all of our significant nonmedical high-tech research efforts on developing weapons, and we are now reaping the whilwind of that disastrous miscalculation in the form of an antiquated energy production system.