In my opinion, people will stop relying on oil when oil is more expensive than its alternatives. This is of course why oil is so predominant, more bang for your buck. For those of you who say you will never buy an electric car, I understand what you are saying, yes, current alternatives cannot compete with oil based engines in all niches. Some, yes, like the short commute car that isn't needed for long distances.
However, I think you guys need to look at what the scientists are saying. Not the environmentalists, the scientists. The combustion of oil produces NOx compounds, which is where smog comes from. Burning oil produces Sulfur dioxide, which produces acid rain. Burning oil produces CO2, a greenhouse gas.
Greenhouse gases absorb IR light. The IR light that is being absorbed by this carbon dioxide molecule makes the molecule jiggle more. This jiggling makes the molecule hit other molecules, which absorb some kinetic energy and they hit other molecules. So basically all the molecules in the air around this little CO2 are all moving a little bit more because the CO2 absorbed some IR light. This means that the temperature of that little area of air is higher.
Now, the actual atmosphere is a lot more complicated, so a localized increase in temperature on the molecular scale won't necessarily translate into a global temperature increase, but it will have some kind of impact, because the amount of CO2 put into the atmosphere is quite high. To be honest, I don't think the scientific community really knows what to expect, but what if it does turn out bad? This community seems to be pretty savvy on taking preventative measures on possible risks, being prepared for any situation. Well, here is something to be preventative about.