I mean, the correct answer is MORE HOUSING. Yes, lawns are bad for the environment in their own right as a monoculture that requires dumping fertilizer and pesticides on it to maintain an “acceptable” quality. But if you are in the US, it is not unlikely that you have mandatory minimum lot sizes, minimum setbacks on all sides of the propety (especially large in the front), and a mandate that the front area must be grass. You also are not allowed to construct more structures on your lot for the purposes of housing, or run any kind of business on your property that might have customers physically visit the space or have any visible impact on the property.

The result is:

• More expensive housing, since each house is required to sit on more land than it physically takes up.
• More expensive cost of living, since finding sufficient new land requires building farther out, making commutes longer and therefore more expensive.
• Car dependency for daily tasks, since no one can build a gym or a corner store in your neighborhood.
• Reduced social cohesion, since even if a friend lives nearby, you will probably drive to their place since walking in a lawn-filled neighborhood is boring, and the gaps between homes mean their house is that much farther away