The same thing you burn anything with, fire
Which comes from a process called combustion via a fuel and air mixture from a wonderful and simple invention called a drip torch.
I left cause I had 10 acres of the K Bluegrass to burn. And speaking of your precious grass, those weak roots (photo below - numbers are in feet and your grass is the first on the left) couldn't compete in a
true sod - the kind found in tallgrass prairies. Deep rooted perennial prairie plants create healthier soil biota, as well as growing tall above ground biomass which can intercept and store and filter more precipitation before it runs off - up to 53 tons per acre during one 1" per hour precipitation event - which is the main way in which we get clean water from overland flow.
A Kentucky Bluegrass lawn's (and any other short turfgrass) interception rate doesn't come anywhere remotely in the ballpark of that figure - most water applied to lawns runs right off because people apply too much at once. And the vegetation is too short. Consequently, all those chemicals from fertilizers and herbicides, as well as your dog's and cat's fecal bacteria get carried with the water and into municipal stormwater drains. And eventually into that glass you fill up. Oh and it plays a big role in why the Gulf of Mexico has such a huge dead zone.
To simplify: More prairie = cleaner water. More lawns and farms = low-oxygen water. I can live just fine without corn and turfgrass.
It's not about being an "environmental whacko", it's just common sense to not use a mundane lawn. But like I said, basic ecology and knowledge of one's natural heritage is sadly lost among most people. Not my fault you're insecure about that.
There's also the issue of soil carbon and water. Water quality always follows soil carbon levels. Turfgrass provides almost no soil carbon when compared to prairies. Grasslands as a whole store almost 1/3 of the world's carbon in the root systems - and that
carbon is not lost during burning. It is lost, however, when prairies are plowed and converted to row crops and tame grazing pastures and lawns.
Oh, before I forget, if you've seen one square inch of non-native lawn, you've seen them all. If you've seen one square foot of prairie, you've got hundreds of billions more to see - and it changes every season!
Back to burning tomorrow!