Do individual actions matter?

One of the discussions in community organization and participatory democracy is do individual actions matter?

-- 'How Bad For The Environment Can Throwing Away One Plastic Bottle Be?' 30 Million People Wonder, from The Onion
-- Going Green but Getting Nowhere, from the New York Times

E.g., does my recycling really make a difference? Or does bringing my own bag to the grocery store make a difference (in a place where there isn't a bag tax)? Or picking up litter, since more people just throw more stuff the next day ("One piece of trash theory;" Don't Mess With Texas Research Results).

Does using public transit make a difference (umm, yes)?

Or getting an electric car over an internal combustion engine (in early stage of the technology, probably not, between the extra energy expended to create the car + greenhouse gas effects, maybe it will be better in late stages, + the induced driving effect--people believe that their driving of an electric car is less harmful, so they drive more,). Etc.

I know that I notice programs like the Certified Wildlife Habitat from the National Wildlife Federation. Communities in Maryland use it to be certified at the community and individual household level. Certified households get a yard sign, which is how I learned about it in the first place.

There is a "River Star Homes" project in the Elizabeth River Watershed in Virginia. Certified households get a yard flag.

I think these programs are important. Maybe feeling better about yourself because you buy an electric car isn't as good.

Although the overall impact is an issue. How much impact do you have? My street is cleaner because I pick up litter. But, seeing my examples, the households on the street that generate the most litter haven't changed their behavior. Or, Suzanne confronted someone who doesn't pick up after their dog. They just changed their route to avoid our block, and so now some other household gets to pick up after them, not just us...