This nagging feeling is strengthened when I do carbon footprint calculations, and I still come up with 9 tons of CO2 (or 1.6 earths or 6 kilowatts per year or 50,000 kWh per year), which is about half the amount an average American uses, about equal the amount an average European uses, but is still more than I "should" get for keeping a lid on disastrous warming (2 ton CO2, or the 2 kW society).
This study, which looks at carbon footprints of a variety of lifestyles in the US, helps me put a finger on what's going on. They determine that there is an apparent minimum carbon footprint for a person living in the US--even a homeless person or a monk living in the woods half the time still has a pretty big impact, due in part to institutional factors such as using roads or libraries or police services. I also suspect there is a lot of hidden energy use in the manufacture of goods that must add up to a significant amount in the end.
I guess I'm bothered as well by the idea that if I, who am pretty committed to "the cause", struggle and ultimately fail at living a sustainable lifestyle, where does that leave someone with less, shall we say, enthusiasm?
*I find it a bit of a quagmire to understand my footprint. I think it's because there are two axes that I tend to confound. One is carbon, as in global warming, which has some obvious solutions (use less fossil fuel and more renewable energy). The other is a general ecological harm or lack of sustainability, which can be much harder to address. Things get tricky when you look at CF bulbs (less energy! good! more mercury! bad!) or solar panels (free energy! good! heinous toxic chemicals in manufacturing and disposal! bad!)