Well I think the other guy thought it would just be easier to insult me than to actually try to respond to the points I raised.
It's true - whether it is "our" environment or "no one's" environment really is a semantic issue. My interpretation of "our environment" is "that which surrounds us", but other people have been using it in a possessive sense, leading to all manner of emotional, senseless arguments. For the sake of discussion it would be most expedient to avoid labeling it altogether.
How about saying that the environment is a resource that needs to last humanity as long as it is incapable of settling elsewhere? Think about it that way and our responsibility to protect it comes clear. But obviously some people don't care about that. That's why other people push legislation through to control environmental destruction. How does this not make sense?
Banning plastic bags isn't a huge step, but it's something. I agree - better not to use any at all (since I usually bike everywhere I have to fit everything in my backpack).
By the way, becoming a vegetarian is probably the best thing a person can do for the environment. This is not controversial - the lower you consume on the food chain, the less byproduct (e.g. shit), the less water consumption (and contamination), the less energy. The numbers are absolutely staggering if you work it out. The production of one pound of vegetables consumes about 2% of the resources of one pound of beef.
The fact that liberals consume less has to do with a number of side correlations: mainly, all those people who live in cities and don't own cars? They split at least 80-20 for Democrats. Think about the cities where lots of people ride their bikes to work - they are liberal bastions like Boston, Minneapolis, Portland, San Francisco, etc. Or try taking a poll on any subway or bus. Do you honestly think that you'd get an even split? Vegetarians probably have even higher numbers - I've never met a conservative vegetarian, but I know plenty of liberal vegetarians. People living in cities (very liberal) also have smaller residences and smaller lots, as a matter of economics. All those McMansions in the suburbs (much more conservative) have enormous heating bills and huge lots with big lawns that get watered and fertilized.
Of course there are plenty of personal anecdotes to the contrary. I'm sure your grandfather was a fine man. And I won't support Edwards or Gore unless I have to.
And again - just because you personally don't feel compelled to steal, does that mean that we don't need laws against theft?