MY FATHER AND I FOUND OURSELVES abandoned on an ice floe off Greenland shortly thereafter. It was about the size of a football field and blocked the path of the motorboat we'd booked to carry us to the mainland. Confronted with the obstruction, the boat's operators, a pair of Inuit cousins named William and Kunuck Abelson, had ordered us onto the ice—and looked to be ditching us. We stood there shivering, watching their craft move away, in reverse.

"This is a rather upsetting development," said Dad.

Dan had headed back to the States two days earlier, at the end of our Iceland tour. (In Reykjavík, by the way, he'd at last had breakfast: coffee, doughnuts, and a horrific shrimp pastry. But only after getting hauled downtown by Iceland's finest for egregiously breaching the speed limit.)

My father and I had then made for Greenland, which dwarfs Iceland but is far less inhabited. The world's largest island is almost one-fourth the size of the U.S. but home to only about 57,000 people. Its massive ice sheet, estimated at 650,000 cubic miles, covers some 85 percent of the island. Findings vary, but it appears to be sloughing around 55 cubic miles into the sea every year.

We'd decided our first stop would be the island settlement of Kulusuk, an Inuit village (pop. 300) off the southeast coast. Do not believe the old chestnut that Iceland is green and Greenland is white. Kulusuk (or "Coal Suck," as my father would not stop calling it) in late May was mostly brown. A decade and a half ago, the hotel manager told us, you could still run a dogsled this time of year, but the air was already warmer than Easter on Cape Cod, and rivulets of thaw cut deep channels in the roads. The surrounding mountains had shed their winter mantle, revealing dark structures that looked like corroded Hershey's Kisses. The village's hundreds of sled dogs, each staked in its own diameter of mud, howled ceaselessly, seeming to mourn the premature onset of the summer sabbatical. We asked a few locals whether the early thaw was part of a noticeable long-term warming trend, and they looked at us the way I imagine a Texas rancher would if asked whether he had ever heard of cows.

For two days, we ventured out a little but mostly just holed up in our room in Hotel Kulusuk, where climate change evolved in my understanding from a vague and distant crisis to a calamity of a more personal scale. I was saddened to discover that ambient temperature in Greenland in May is no longer cold enough to (a) chill a six-pack of beer dangled out a hotel window on a bootlace or (b) prevent my father from swanking around in the nude.

After 48 hours, Dad had tired of watching the island erode. "Well, son, I believe I've enjoyed about all the Coal Suck I can stand," he said. I was in bed drinking warm beer and wearing my sleep mask as a shield against the unsetting sun and the pink vista of my father's flesh.

"I'm with you there," I said. So it was decided that we'd catch a boat to the vastest metropolis on Greenland's east coast, the village of Tasiilaq (pop. 1,883).

Out at sea, the ice was plentiful. The crossing was choked with pack ice and bergs calved from the Christian IV and Steenstrup glaciers, waning north of us. As we watched the Abelson cousins' boat retreat from our floe, huge, slumping meringues of ice towered over us, their hearts glowing the otherworldly glacial blue that is somehow the equal and opposite corollary of the orange cores of live embers. The cold coming off the icebergs was a pulsing, vital thing. The wind had big teeth.

"If you fell in," my father intoned, "I don't imagine you'd have much time to reflect on the experience."

"It'd be like falling into a vat of hydrochloric acid," I said. "Glug, glug, gone."

But the cousins didn't leave us. Just as I began to really worry, William opened up the throttle and came hell-bent for leather straight at us. The boat hit the floe, leapt like a breaching whale, and slammed down hard. My father and I clutched each other, waiting for our perch to crack like a saltine.

But the ice held. The Abelsons hopped out, giggled at us, and motioned for us to start heaving on the hull.

"My God," said Dad, "we're going to man-haul the damn thing."

A hundred yards of crusty ice, full of disconcerting voids, stretched between us and open water. With each push, we'd stumble. Every fourth step, you'd sink to your thigh, praying you hadn't found the trapdoor to the blue hereafter. The work drove Dad to painful coughing jags, but he wouldn't hear of sitting on the sidelines. An hour later, we were again puttering for Tasiilaq.