> You're right, I should just throw my car in the sea. If I also throw out my computer, my grandchildren will be proud that I tried to help bankrupt the ecology-destroying companies that mine rare metals for these gadgets you and I use to waste time online. OR I could just be honest with myself and acknowledge that I'm selfish despite knowing that merely existing is a huge burden on the planet.
You can have a sense of proportion about the fun:ecological impact ratio of the activities you do, and make choices in the light of that. My instinct is that "driving three towns over to ride in a carousel ... just for the heck of it" is in the same category as "tossed all our rubbish in a nearby field": the cost to other people is all out of whack with the benefit to you. I don't know whether that's actually true or not, but going on a long drive for something frivolous triggers the same skin-crawling reaction in me that tossing litter out of a window would.
(My preferred solution would be carbon cap-and-trade (and land value taxes that would translate into road use fees and parking charges) so that car users bore the full costs of the externalities they were imposing, and then if you want to spend your discretionary income on frivolous car journeys that's up to you. But in the current regime I'd say there's a moral duty to minimize car travel or offset it somehow, because by taking a car journey you're imposing a cost on others, much more than just using a rare metal for a time)