Mububban is largely correct. We should always be careful, though I've heard some people who are so keen on sacrificing everything for the planet, that they're willing to prosecute people who drive too much. Basically, they turn it into a scare tactic for whatever cause they have. Unfortunately, there are so many people on either side of this issue that are unwilling to listen to each other and realize that maybe not everyone who disagrees with them is wrong or of evil intentions. I am often guilty of that I know, and that's why I tried to carefully listen to scientists on either side of the issue.