I love my moped and I ride it because it's fun. But I don't try to justify my indulgence by claiming environmental friendliness. My machine, which runs very well, spews one hell of a lot of crap into the air. Fortunately, I don't use it that much, and there are very few of them out there.
We already had a spirited conversation on this in another thread (see "Is a moped good for me?" - 8 June 2002) so I'm not going to dredge it all up again. Suffice it to say that, "an automobile would have to drive 100,000 miles to produce the same amount of smog-forming pollutants as a two-stroke engine does in seven hours, according to the California Air Resources Board." (Sierra Club Planet Newsletter.)
By the way, I can't stand those Sierra Club weenies.
If everyone switched from cars to mopeds, we'd save one hell of a lot of energy, but the air would be thick with smog. For mopeds to become environmentally "correct" they'd have to switch to four-cycle engines with pollution controls, at the very least. Don't count on that happening anytime soon.