Some philosopher ponders it
What would be the point when I know full well that halfway around the world there lives my evil twin, some carbon-footprint doppelgänger in Shanghai or Chongqing who has just bought his first car (Chinese car ownership is where ours was back in 1918), is eager to swallow every bite of meat I forswear and who's positively itching to replace every last pound of CO2 I'm struggling no longer to emit. So what exactly would I have to show for all my trouble?
Well, partly this points to a very important point about climate change. If westerners give up their hummers, the demand for and price of oil will drop (yay!) and, err, Chinese people will notice and buy more oil! Total consumption will drop but by way less than you hoped with your sacrifice.
That said this spectacularly misses another point, which is that some Chinese guy gets to drive his new car and the world is slightly better off too! I mean bloody hell! It's not a good thing that he's too poor to buy petrol. There's a big difference between fancy rich people voluntarily forgoing some stuff to heal the planet and getting all excited by the observation that poor people have a small carbon footprint. When he gets as rich as other fancy people he'll also start wringing his hands over his carbon footprint, but right now, pulling his rickshaw he doesn't give a shit. He and his kids are likely to make the transition much quicker than we did too, if only because in twenty years so many more cars will be hybrids regardless of his feelings.
Stupid question dude.