In my garage there's a push mower. I don't mean one with a gasoline engine, or even electric. I mean a push mower, a heavy thing with spiral metal blades that looks not unlike the ones that get pushed around in old Peanuts strips. It's heavy, it's clumsy, and it's roughly a zillion years old, but if you keep the blades sharp and clean it cuts quite well.
Sadly, that mower was really for the tiny yard at my last house. At the current place I use a power mower that runs off little bottles of propane. It's a semi-green solution, but it's far from perfect, especially since I've been unable to get the propane tanks refilled and even have trouble turning in the empties for recycling. I'm still dreaming of a flock of solar-powered, electric sheep.
In the meantime, the guys at Autosherperd have taken another look at the environmental impact of gas lawnmowers, and as previous studies have indicated, making your yard green makes your lifestyle considerably less green. We've written before that a quarter of the gasoline that is put into small engines (i.e., lawnmowers) can come out the exhaust without being burned, which means that some riding lawnmowers can emit as much as 34 cars. See more in the video after the jump.