You could create a lawn that doesn't need mowing.

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Planting trees and shrubs

They shade buildings and absorb CO2 and other greenhouse gases from the air.

Rethinking yard work

Leaf and snow blowers use gas or electricity, but raking and shoveling emit no greenhouse gases.

Replacing gas-powered lawn mowers

Replacing grass with other ground cover

create a "lawn" that doesn't need mowing.

Cutting back on recreational vehicles

Each gallon of gas burned emits 9 kilograms (20 pounds) of CO2; each gallon of diesel emits 10 kilograms (22 pounds).