John Quiggin asks about the " the relationship between cleaning up litter and environmentalism." I've heard the kind of arguments that he references as reflecting negatively on the relationship -- far-left warnings that little steps like picking up litter and recycling reduce the pressure to bring down the whole corrupt capitalist system. But I think John's conclusion that "the impact has been to reinforce support for environmentalism" is correct, for two reasons:

1) Cleaning up litter is empowering. If we see environmental problems as the result of global political-economic structures, there seems to be little we can do short of dedicating ourselves to some sort of socialist solidarity movement. This is not an option available or appealing to most people. There would be a tendency to give up on caring about the environment, since it seems like there's little we can do. I'm not saying that cleaning up litter is itself going to fix much of the negative impacts we have on the environment, but it still gives the litter-cleaner something.

2) Taking action makes you feel more committed to the side you're acting on behalf of. I've argued this point before with reference to protesting the war, and I think it holds here. While other forms of environmentalist empowerment like buying organic food may create a stronger commitment to the movement (which could in a sense be a negative, since it's harder to get people to take such a big step), picking up litter has a few important advantages. First, it's hard to argue that less litter is a bad thing -- while picking it up may be seen as a waste of effort, few people wish there were more McDonald's cups along the side of the road. Second, it appeals to an important human value -- cleanliness. And it connects the litter-picker to the strongest emotional/philosophical basis for environmentalism -- an appreciation of the beauty of nature. Right or wrong, preserving natural beauty is the most important motivation for public environmentalism.