Make it legal to NOT mow your lawn.   American culture has caused us to deforest a vast area surrounding all of our houses and other buildings. There is no scientific reason to mow lawns and no defensible safety or other
reason.   It may be a mistaken instinct left over from the days when we reasonably feared lions.   It is impossible for most people to allow their lawns to return to a state of nature due to local ordinances which enforce lawn mowing.   We need a federal law enabling the reforestation of our lawns by the natural method of not mowing.   Trees will grow eventually, converting CO2 into wood.   Lawn mowers generate CO2.   Where I live in
Illinois, it rains every few days, making forest fires impossible.  In semi-desert areas, a concrete strip bordering the house and stronger fire codes may be required, or housing should be prohibited in semi-arid areas.