By MIKE HUGHES

Barack Obama's press-conference today set off some quick shuffling by the networks, including "American Idol," which moved to Wednesday and Thursday, a day later than usual.

TONIGHT'S ALTERNATIVE: "Nova: Extreme Ice," 8 p.m., PBS.

Stunning beauty and stark doom coincide, in this remarkable documentary.

Backed by National Geographic and "Nova," James Balag has been doing time-lapse photography for years, showing the ice receding much quicker than expected. That is entwined with interviews and visits to key locations, including a newly formed waterfall.

The pictures are gorgeous; the predictions are grim. By the end of the century, the film says, the oceans could be three feet higher; more than 100 million people could be displaced.