It probably wouldn't but then again, my riding a bike all year versus driving the most huge, obnoxious SUV I could find doesn't really change anything either. But I try not to willfully create waste if there's a simple, reasonable and inexpensive alternative.

That said, our household of 4 people generates about 1 trash bag every 2 weeks on average. There are houses on our block that fill up two of the big wheelie bins every week, each of which would hold 4 or 5 of our bags, and I've seen them overflow two bins in a single week. One of the nice things about winter here is that I can go 3 or 4 weeks between garbage runs because the garbage doesn't spoil in the garage. We can make it 3 or sometimes even 4 weeks on a single black garbage bag.

Our household output is more than that of course, but the rest goes into the compost pile or into municipal recycling. The carts I assume could go into recycling as well.

I've never actually used CO2, just seeing the carts by the side of the road (which I stop, pick up, and put into recycling) made me assume that you use a cart and throw it away - do they actually hold for a week or three until you need more CO2? How many fills can you get from a cart over how much time?