For years, whenever I found myself in Miami with an afternoon to spare, I sneaked off west to where a road abruptly separates the urban grid from the Everglades. Depending on time, I drove as deep into the saw grass void as I could, parked, got out and gazed up at tropical clouds racing unimpeded by tree or building.

Then, usually, I burst into tears.

Sky and grass. Nothing else. It’s a bit embarrassing to admit that anything in Florida — with its postcard palms plastered against postcard sunsets, its coconut tanning oil and Lily Pulitzer pinks and greens, its schmaltz and buffoonery and hanging chads and “Florida Man,” with his love of Styrofoam, weapons and monster trucks — affects me this way. But it does.

“There are no other Everglades in the world. They are, they have always been, one of the unique regions of the earth; remote, never wholly known,” Marjory Stoneman Douglas wrote in her 1947 book, “The Everglades: River of Grass.” “The spears prick upward, tender green, glass green, bright green, darker green, to spread the blossoms and the fine seeds like brown lace,” she wrote. “The grass stays. The fresh river flows.”

Where it’s not diverted or blocked by human engineering, the water still trickles south at the rate of a quarter mile a day, as it has for millenniums. But it is profoundly imperiled by pollution, human schemes to drain and control it, animal and plant invasives and sea level rise. As salt water breaches the limestone bedrock around the Florida peninsula and enters the aquifer, this natural freshwater wonder is threatened like never before.