There are various ways to do it (like the cap and trade system several posters have mentioned). The key is to do something along those lines instead of trying to mandate peoples lifestyle changes or choices via direct government intervention. Even the system I envision will be unpopular in the short term due to higher costs for energy and transport…but I think anything the government attempts to dictate (like telling people they HAVE to use public transport, or set their thermostats to a certain level, or can only drive X miles a week or use Y gallons of gas or Z amount of energy) will not only be wildly unpopular but doomed to failure. While on the surface the two may seem the same, in reality people would much rather make their own decisions based on price than have their decisions dictated to them. Look how things changed with simply a dollar more a gallon of gas in the US in the last year. Now…project that to a like increase in the price of power in the home and you can see how the changing price will drive people to make re-evaluations of their energy use.
Of course, this kind of thing is going to hit the really poor harder than the middle class or upper classes, so some thought would need to be given to that as well…and in the short term it’s going to hit everyone fairly hard (as well as being unpopular with a lot of people in the US). But if we really want change I think this is the best bet on how to get it in a timely manner.
-XT