The Many Shades of "Green"

What does "Green" mean?

There are lots of things people have tried or recommended to be more "green". Here is a short list with my comments. Some "green" actions don't have the impact you might hope:

Action	Climate Impact
Walk instead of drive	Significant
Use shared transport instead of driving alone	Significant
Buy a hybrid vehicle	Depends on what mileage it gets and how much you drive (and maybe on what you do with your old vehicle)
Recycle	Negligible? Has anyone done the math on this?
Use recycled products	Depends. Some recycled products could be as energy-intensive as virgin-raw-material products.
Install some CFLs	Helpful but not huge.
Live in California or somewhere where electricity rates have been decoupled	Significant--Californians use significantly less electricity per capita.
Buy carbon offsets	Dubious. Much debate. Impact probably minor. (Anybody have a way to evaluate this?)
Buy locally produced agricultural products	Depends. Distance is a poor measure of emissions per pound in transport. Also need to evaluate energy intensity of production. Roses grown in New York are much more energy intensive than those grown in Colombia, even counting transport (I think).
Use more ethanol (by buying a flex-fuel vehicle and fueling it with E85)	1. Depends on the mileage and use of the vehicle. E85 is still 15% gasoline. 2. Depends on where you are. Ethanol produced from maize in North America probably doesn't reduce greenhouse gas emissions much compared to gasoline. In Brazil using cane ethanol the benefit is clear.
Become a vegetarian	I don't know. Anyone done the math on this one?
Move to Manhattan	Significant. New York City is the most energy efficient city in North America, by some measures.