Gas-powered lawn mowers don't have the same pollution controls as automobiles, and according to the Environmental Protection Agency (EPA), each one produces as much air pollution in a year as 43 new automobiles being driven 12,000 miles each [source: Environmental Protection Agency].
Electric-powered lawn mowers don't emit pollutants by themselves, but the electricity needed to power them is often generated in power plants that burn fossil fuels. Solar-powered electric mowers require no external source of electricity, but they can only run for a limited time on each charge. Since push reel mowers are powered exclusively by the person doing the pushing and are much cheaper than solar-powered mowers, they're the mower of choice if you're concerned about the environment and don't have a lot of money to spend.
On the other end of the spectrum, two-cycle gas lawn mowers are inefficient and release 25-30 percent of their mixture of oil and gas unburned into the air [source: People Powered Machines]. A four-cycle lawn mower engine burns its fuel more efficiently, but it still emits hydrocarbons, carbon dioxide and other pollutants linked to global climate change.
Mulching lawn mowers are more friendly to the environment because their blades cut the grass into pieces small enough to rapidly decompose and return vital nutrients to the soil. This reduces the need for adding fertilizer to the lawn and saves space in landfills that might otherwise be taken up with bagged clippings. However, bagged clippings can be sent to municipal compost sites instead of being taken to the dump.
Another consideration is the environmental impact of a rotary mower on the grass it cuts. While reel mowers cut with a scissor-like action that helps the grass retain moisture, rotary mowers tear the grass unless the blade is kept sharp. That tearing action can expose the grass to more diseases.
What about new lawnmowers? Have there been any advancements in the technology?