A doomsday thriller pegged to global warming, The Day After Tomorrow delivers enough action and cataclysmic spectacle to compensate for its message-laden script. Clumsy in its domestic scenes, the film is visually overwhelming when depicting the destruction of Western civilization. While its politics aren't likely to win many converts, its ambitious scope and very satisfying special effects should make The Day After Tomorrow the first breakout live-action hit of the summer.

The script alternates between widespread environmental catastrophes, shown in riveting detail, and the sort of awkward personal drama that gives sci-fi a bad name. Climate experts Jack Hall (Dennis Quaid) and Terry Rapson (Ian Holm) represent voices of reason, summoning arcane data from around the world to prove that mankind has pushed Mother Nature too far. Jack even goes up against the hardheaded Vice President (Kenneth Welsh), but it takes several superstorms to persuade our leaders that global warming is for real. They may be too late.

After killer hail wreaks havoc in Tokyo, Los Angeles is ravaged by supercell tornadoes in a ferocious and expertly constructed montage. Jack's son Sam (Jake Gyllenhaal), on a class trip to New York, is among those trapped when a tidal wave floods Manhattan. (Emmerich and his special-effects teams pull out all the stops in this sequence, combining close-up hysteria with aerial shots that attain an eerie beauty.)

Heeding his father's advice, Sam and his friends Laura (Emmy Rossum), Brian (Arjay Smith) and J.D. (Austin Nichols) hole up in the Public Library, where books serve as fuel against temperatures so cold that death comes in seconds. Unfortunately, their rescue takes a lot longer to arrive. Too much time is spent on a maudlin subplot involving Jack's estranged wife Lucy (Sela Ward), a saintly doctor who is caring for a cancer-ridden child. The film's often striking imagery--flooded subways, an abandoned freighter floating up Fifth Avenue, snowdrifts engulfing the Statue of Liberty--can't compete against such soggy storytelling.

Quaid turns in a solid performance, fully aware that he is being upstaged by special effects. Gyllenhaal seems a bit sheepish at times, but steps up smartly to his heroic bits. He also works well with Rossum, who brings some depth to her purely decorative role.

Emmerich's direction is earnest and at times stodgy, while his script (co-written with Jeffrey Nachmanoff) has structural problems. Like his films Godzilla and Independence Day, The Day After Tomorrow boils down to a struggle for survival in the midst of horrendous destruction. But without a monster or aliens to defeat, the film's second half feels a little hollow. Still, brisk pacing and an upbeat tone keep viewers engaged even as the thrills subside. On top of that, the faint whiff of political controversy could broaden the audience for The Day After Tomorrow, making its box-office prospects a lot sunnier than its plot.

--Daniel Eagan