I suppose this subject isn't necessarily of great moment, but I couldn't resist. As a father whose youngest child is on the threshold of going diaperless 24/7, I still find that the Great Diaper Debate holds some interest for me, if only for the sake of nostalgia. At any rate, the Times of London is reporting on a study completed by the British government which seems to confirm that reusable diapers have a larger carbon footprint than disposable diapers. While it's possible to keep the difference to a minimum if you "take an extreme approach to laundering them," i.e. line-drying year round, washing in only hottish water and using them even on young children (presumably instead of pull-ups), it's hard to imagine the typical parent doing that. Here are the hard numbers:

The report found that while disposable nappies used over 2 1/2 years would have a global warming impact of 550kg [1,212lbs] of CO2 reusable nappies produced 570kg [1,257lbs] of CO2 on average. But if parents used tumble dryers and washed the reusable nappies at 90C [190F], the impact could spiral to 993kg [2,189lbs] of CO2. A [Department for Environment, Food and Rural Affairs] spokesman said the government was shelving plans for future research on nappies.

I love that last line. In fact, the fun part of this story involves a cover-up of the original report. Apparently, the government has been telling Britons for years that reusable diapers are better for the environment. Oopsie.

All that said, this study did not appear to address the carbon footprint of reusables if handled by a diaper service, though most services probably don't skimp on the hot water, the tumble drying or the bleach, for that matter. And of course, you still have to deal with the environmental impact of the chemicals that go into disposables (like that yucky but effective gel and all that chlorine) so I suppose it's still not a slam-dunk. However, it does suggest eco-diapers like 7th Generation's (sold at Weavers Way, of course) are a pretty good way to go.