Inka, your point reminds me that the people who are probably the "real" environmentalists...the living ones, anyway...are going to be those who have no wish to have such a small footprint. I bet they'd like to drive a car, to eat meat, to live in a fancy house, etc. but poverty makes them closer to being carbon neutral.
The moral of the story, let's not pat ourselves on the back too much for having a reusable water bottle...I mean, it's a step in the right direction. If you really want to reduce your carbon footprint, take a vow of poverty. Live by the sun, rather than use a compact fluorescent bulb!