Tomas Alex Tizon

And it's not good what happens: FOR three days in March I camped on a drifting slab of ice, 200 miles north of Alaska, as close as I'd ever get to the top of the world and to knowing what it would be like to live on an ice cube.

The cold crept through my boots and socks, into my toes and up my legs. It numbed my fingers and face and froze the moisture in my eyes. It swept into my lungs.

My shelter was a plywood shack, which I shared with five men whom I seldom saw. Beneath us, under the ice, the ocean plunged 12,000 feet deep. One of my shackmates, as a way of warning, described what happened to a snowmobile that had broken through the ice. It sank, like a toy whirling through space, all the way to the sea bottom, where it presumably will rest in frigid darkness for eternity.

The message: Watch your step.