To celebrate Earth Day, Friday’s globe-hopping edition of ABC’s “20/20” was dedicated to “Seven Ways To Help Save the World,” which included turning the lights out on the top of the Empire State Building, the Arc de Triomphe, and even in ABC’s Times Square studio, where Diane Sawyer could briefly be seen waving a flashlight in the dark. Was this an oblique reference to Auden’s famous lines about “Ironic points of light” that “Flash out wherever the Just / Exchange their messages”? Probably not. Anyway, the lights soon came back on because, after all, there was a program to get through.

In fact, there will be a lot of programs to get through now that Mother Earth has become the biggest star on the planet, so to speak. Gaia is a hefty gal, solid as a rock and impossible to wrap your arms around, so one of the useful things about the “20/20” episode (there were lots of maps) was the lightning-quick lesson it provided for we Americans who are a bit vague as to where her various parts are located.

Ms. Sawyer began with the basics: “Tonight, on ‘20/20,’ an unprecedented report from all seven continents.” That was definitely useful information and I made hurried note of it (“number of continents = 7”) in case I ever end up on that terrifying quiz show, “Are You Smarter Than a Fifth-Grader?” Though I’m pretty sure there are also seven seas, I was hoping for a quick run-down on the number of oceans, the exact difference between a sea and an ocean, what the Antarctic has against the Arctic, etc. But I suppose that’s what PBS is for.

Anyway, it soon became apparent that the main thing afflicting the planet is that she is hot. Not hot in the Angelina Jolie sense, but more like she has a fever and all the ailments that come with it. For instance, the reporter-underwater for “20/20,” Bill Weir, disclosed that sections of Australia’s once dazzling Great Barrier Reef now look like bundles of old straw. It was a deeply depressing sight, and there were more to follow. The cause, apparently, is that the ocean has become too warm. We also learned that warm water expands, which leads to flooding, though, as it happens, Australia is suffering from drought. “Climate change means too much water in some places, not enough in others,” Mr. Weir explained … which did sort of sound like it means whatever you want it to mean, even if it’s true.

More global warming is on the menu this evening, including a special edition of PBS’s “Frontline.” On the Sundance Channel, there’s “Big Ideas for a Small Planet.” A 13-part documentary series about the environment that made its debut last week, “Big Ideas” is filled with chic-looking men and women, many of whom look as if they live in Santa Monica or SoHo, drinking organic tea and wearing clothes made of reconstituted seaweed and bamboo.

“To be environmentally responsible also means to embrace fashion and to be stylish and to be beautiful,” Simran Sethi, an environmental journalist, assures us in an upcoming episode. “You don’t have to sacrifice one for the other.”

That episode “Wear,” about environmentally conscious fashionistas, will show a fortnight from now and is worth checking out just for the sly cameo by Robert Downey Jr., who drops by the boutique of designer Linda Loudermilk to pick up an organically correct outfit that he can wear to an “amazing event in Hollywood.”

“All the companies that send us these fabrics,” Ms. Loudermilk, who does design very beautiful (and expensive) clothes, tells Mr. Downey, “are fair trade, fair wage.” To which, with the gravity of a Shakespearean prince, Mr. Downey replies: “I am most pleased.” I suspect he then went on to say, “And now, fair damsel, have thy slave fetch my eco-car and wrap these garments most hastily, for I must drive!” It was probably cut in the editing room.

“Big Ideas,” which is part of a larger environmental chunk of programming on Sundance under the name “Green,” provides an interesting, often amusing look at a mix of worthy causes, mechanical ingenuity, and what looks like the full-blown flowering of a major religious cult for which the planet, not any deity who might have created it, is the object of veneration. (As Ms. Sawyer said, quoting Marshall McLuhan and touching a giant globe as she did it, “There are no passengers on the Spaceship Earth. We’re all just crew.” Perhaps we should start wearing uniforms.)

“Why are these people so happy?” Alexandra Pelosi asked in her recent HBO film, “Friends of God,” about bornagain Christians. You could ask the same of a lot of the people showcased here. Theirs is a cooler, more urban form of bliss, but it too comes from the sense of having chosen the correct spiritual path. The overall message of the series, reinforced by imaginative graphics, lively backdrops, and colorful filmmaking, is that you can combine designer materialism with environmental rectitude.

Last week’s “Big Idea” was about carlovers determined to enjoy their autos without polluting the atmosphere. Colette Brooks, the founder of BioBling.com, described her Malibu-based company as “an online resource that connects conscious people with bio-ready cars.” Well, Ms. Brooks certainly looked conscious — enough to make most of us look dead, which she probably thinks we are. Equipped with a dancer’s physique, pop-up biceps, and a senorita mode of plumage (frilly black tank top and a long, lacy pink skirt she referred to as “The Superiority Dance BioBling Skirt”), she has found a way to unite her passion for cars with eco-righteousness, and she’s loving it.

We also met Joel Woolf, who designs twotank car engines that run mostly on vegetable oil. Joel is a lot more down-to-earth. Dressed in a plaid shirt and blue jeans, he spends most of his time mucking about in his garage in Ojai, Calif. I’m not sure how many Americans want to drive around in cars that smell like a cheap kitchen, but Joel is refreshingly unpretentious and, within a limited sphere, ingenious in his attempt to free Americans of their dependence on foreign oil.

Tonight’s episode, “Build,” is about three kinds of housing: prefab homes, or “sustainable modular houses built in a factory”; more traditional multifamily homes, newly outfitted with bamboo floors, recycled carpets, geothermal heating, etc., and “growing homes,” which are a bit more futuristic. Some appear to be giant beehives encased in trees. Mitchell Joachim, a graduate of MIT, displays an architectural model of what a “100% self-sufficient” Lower Manhattan will look like 300 years from now. I am here to tell you it will look like a plate of spaghetti garnished with multicolored golf balls. If someone offers you eternal life, do not accept.

bbernhard@nysun.com