Some say the world will end in fire, some say ice. From what I've tasted of the snowshoe-stomping eco-disaster flick The Day After Tomorrow, I hold with those who favor death by extravagant F/X and drizzly speechifying: tidal waves in New York City that swamp the Statue of Liberty, and admonitions that ''global warming can trigger an ice age!'' Tornadoes in Los Angeles that flatten the famous Hollywood sign, and a lecture about the oceans' ''critical desalinization point!'' If, as disaster master Roland Emmerich suggests in his latest, most politically heated escapist epic (at least since Mel Gibson went ballistic in ''The Patriot''), the end of the world is closer than we think, ecologically speaking, then that still leaves Emmerich and his young screenplay collaborator Jeffrey Nachmanoff a couple of hours to educate audiences about greenhouse gases and melting polar ice caps.
Not that there's anything wrong with the instinct for activism, of course; I'm all for Saving Our Planet, aren't you? But a classic, big-budget studio movie about widespread, dramatic, hand-of-God destruction and the few hardy characters who, to our satisfaction, improbably survive is no place for serious hectoring about the Antarctic ice shelf. Especially when the ecology lesson is coming from a director whose last two scorched-earth scenarios featured a lizard monster (''Godzilla,'' 1998) and aliens (''Independence Day,'' 1996). The weirdest climate shifts in ''DAT'' occur not when folks freeze to death in a split second (that part's cool), but when the air thickens and time slows so that some smarty-pants can offer a fact-packed monologue.
So let's set aside any serious consideration of the movie's superficial political timeliness. Let's ignore, too, this fiction's pleasant, cheap joke that the hardheaded Vice President (Kenneth Welsh) who harrumphs at ecological concerns (''our economy is every bit as fragile as the environment'') bears an uncanny physical resemblance to Dick Cheney, and that the President (Perry King) is played as a relatively clueless sportsman (when faced with impending disaster, he turns to his Veep and stalls, ''What do YOU think we should do?''). Any low-rent, unguilty-pleasure excitement in ''DAT'' lies in the sick-thrill sight of New York City succumbing to forces of nature (there's no chance of confusing this fun-scary fantasy with real danger). Remember when the White House was blown to smithereens in ''Independence Day''? Well, in ''DAT,'' all of Manhattan is flooded, then frozen. Neat!
Anyway, a decent disaster pic comes down to the handful of colorful individuals who will live (or, depending on the prominence of their billing, die), as it has since the days of chewy disaster meatballs like ''The Towering Inferno'' and ''Earthquake.'' And the heaviest lifting in Emmerich's production falls to Dennis Quaid, who plays noble paleoclimatologist Jack Hall, and Jake Gyllenhaal, as Jack's 17-year-old son, Sam. (Sela Ward plays the nurturing estranged wife and mother, and, for good measure, a caring hospital doctor; she gets to stay indoors and care for a bald kid with cancer -- womanly Florence Nightingale work.)
Jack, who was, coincidentally, standing on an Antarctic ice shelf (''the size of Rhode Island'') when the crazy thing cracked off, returns to Washington, D.C., like a thundering prophet, and, in the days before the day after tomorrow, tries in vain to convince the White House of the dangers of impending climate shifts. Sam, in those same balmy days, flies to New York City to enter a high school academic competition with some classmates (including Emmy Rossum as the pretty brainiac he fancies).
Then hell -- and Manhattan, and the whole top half of the U.S. -- freezes over. Sam and his stranded friends take refuge in the New York Public Library, burning books to keep warm; they're joined by a wise and crazy homeless man (Glenn Plummer) and his smart dog. And Jack decides to make his way up to NYC to find his son. The good news -- there's no one else on the roads. Quaid grimaces and stares with angry eyes to convey Jack's righteousness. (The actor knows the limits of disaster theatrics and conserves his energy.) Gyllenhaal, adept in films like ''The Good Girl'' and ''Donnie Darko'' at filling out characters of delicate complexity but new to the genre of big, dumb fun, tries to give Sam substance, then settles for adequate action logistics.
Ice envelops much of the northern hemisphere, and many, many people die. In the way of such hot air, the homeless guy survives and so, all will be relieved to know, does his dog.