Florida has become a prime example of how Americans love-hate nature. A magnet for new people and industry, the beautiful, booming Sunshine State is also a monument to careless planning. Conservationists have just halted work on a Miami-area jetport that threatened to ruin Everglades National Park. But they are losing to despoiling highways, sprawling developments and coastal landfills that destroy estuaries, the breeding grounds of key marine creatures. The whole state seems to be flirting with ecological disaster.

Around Lakeland, phosphate miners are tearing huge holes in the earth that endanger the local...