Don't look now, but here comes Robert Christo again, trailing yards and yards of shocking pink plastic behind him. Six million square feet, to be fairly exact. By May this superfrill will surround each of 11 islands in Miami's Biscayne Bay, rather like a ballerina's skirt, if all goes well.
Alas, things tend not to go well when Mr. Christo sets out to embellish the environment. His 24 miles of ''Running Fence,'' delightfully meandering its nylon way to nowhere across the California countryside, took the public by surprise. But New York was ready when Mr. Christo offered to erect thousands of fabric ''gates'' throughout Central Park. Parks Commissioner Gordon Davis denied that fantasy, commenting crossly on ''the defects in the artist's grasp and understanding of Central Park.''
And now the Christo opposition is beginning to gather against the project he calls ''Surrounded Islands.'' This time our artist - a surrounded island himself - faces not only the usual Philistines but environmentalists as well. Even as a small Christo army of 45 artisans goes to work sewing the plastic to hundreds of anchors on what Mr. Christo figures to be a $2.25 million objet d'art , the Friends of the Everglades are grumbling: ''It makes about as much sense as saying, why don't we put blue food dye in Old Faithful and watch the nice colors bubble up?''
Pointing out that massive sheets of pink plastic will further harass endangered species in the area, such as the brown pelican, the bald eagle, and that gentle, curious sea cow, the manatee, a spokesperson for the National Wildlife Rescue Team has complained: ''I don't think the Everglades needs any gift-wrapping, particularly pink plastic.''
Even his fellow artists may have their reservations about Mr. Christo. In fact, there's something a little quaint about his innovations, as if he were the last avant-gardist in a world now turned to photorealism and computer graphics.
At this late date, does he think he can shock us - we who have made some sense of everything from junkyard sculpture to the tomato soup can to abstract impressionalism? It was just about 70 years ago now that Ezra Pound cried, ''Make it new,'' and surely novelty-for-novelty's-sake has long since been exhausted. After all the ''happenings,'' and just plain accidents, do we have to ask again the tired question, ''What is art?''
The answer, probably, is yes. And the Philistines who cry, ''Charlatan!'' and the environmentalists who cry, ''The earth is just fine, thank you, without this exterior decorator'' may be missing the point.
If Christo's creation does threaten the bald eagle, say, then a balance of interest must be decided. But if the particular act of wrapping a 300-foot pink plastic border about an island is being regarded as an arrogant presumption, then we must also question every other gratuitous human act, from planting a flower garden to exploring outer space.
The precedents of denial send out concentric waves and can make endangered species of us all.
Should Mr. Christo be inclined to cut out little pink plastic fringes for the lily pads in the pool in his backyard, he - and we - would have no problems. But no. He insists on bumping his art into our property and forcing us to make uncomfortable choices - and worse, forcing us to think about all the implications in the choice we finally do make.
Perhaps this is his gift.
If the Great Wrapper is foiled in Biscayne Bay, he is said to have plans to wrap the Reichstag and the Pont Neuf in Paris. Also, there's talk of a pyramid of oil barrels 49 stories high and five city blocks long, to be erected on a site not yet selected in the Middle East.
Evidently we can't keep Mr. Christo down. The novelist Andre Malraux, an art critic of some boldness himself, once observed that every man longs to carve his initials on the crust of the earth. Mr. Christo simply wants to do it literally - preferably with a cake-frosting gun, on top of Mt. Everest.
Color that frosting pink.