Nearly 400 billion tons of ice break away from the world’s glaciers every year, one symptom of the earth warming due to humanity pouring pollutants into the atmosphere.

Or so scientists say. I can’t vouch for the entire figure. But I can attest to 1,000 tons or so of glacier loss, the ice mass that broke off the Asia Glacier in Southern Chile on April 6.

I am certain of that because I was standing uncomfortably close when it happened and saw it: a wide swath of the blue ice face, maybe 150 feet top to bottom and 50 feet across, explode away in a cloud of ice crystals.

“Up! Up! Quickly!” cried a scientist off the Resolute, the Royal Canadian Geographical Society vessel that had brought us to the Southern Patagonian Ice Field.

I turned and, as suggested by informed scientific opinion, ran for my life, scrambling back up the slick, steep rocky outcropping.

It’s surprising how even the most cynical fellow can instantly follow the advice of climate science under certain circumstances. It helped that I also saw the big swell of gelid water, studded with chunks of ice the size of refrigerators, push away from the collapsed mass of glacier, rolling directly toward us, fast.

We had all been observing the glacier from the relative safety of a promontory. Arriving an hour earlier from the ship by Zodiac boat, a sturdy black inflatable craft, as part of a two-week expedition up the Chilean coast, we gingerly worked our way up the stone face and found comfortable vantage points.

I had been talking with Ian Goodwin, a climatologist from Australia, who explained that symptoms of climate change in the more temperate regions of the world can be less pronounced than at the pole.

“Down here in Patagonia, and the Antarctic peninsula, Southern Australia, South Africa, these are the areas where climate change is being amplified, at the Southern ends of the Tropics,” he said. “We might be seeing something less than a degree in the equatorial regions, but down here we’re seeing 2 1/2, 3 degrees of warming and major shifts…the changes we’re seeing here, these are massive retreats.”

Despite the bad news, it was still joy a joy to stand there, watching the occasional small departure of ice—”calving” is the technical term. You’d hear a percussive clap, some sharp, like rifle shots, some booming, like thunder. A chunk of the face would peel off dramatically. We didn’t realize it was merely foreshadowing the big event.

You never get tired of looking at glaciers, and it was with reluctance that we allowed ourselves to be coaxed back toward the boats, away from the point of maximum peril, right at the waterline, at the moment the glacier really put on a show.

The folks who organized the trip, One Ocean Expeditions, were understandably alarmed at the close call their passengers experienced before Asia Glacier. Endangering the customers is bad in the cruise business, though they also insisted that this was not a “cruise” at all, but “an expedition.” That must mean more than shipboard entertainment consisting of lectures on birds and climatology instead of bingo, but also implies a certain amount of confronting nature in all its raw power and unpredictability.

I found the moment more thrilling than scary—no one was hurt—then again, I wasn’t a paying customer, but a guest, invited by former Sun-Times editor Michael Cooke, now a fellow of the Royal Canadian Geographic Society, under whose aegis the Resolute sails. To check whether my freeloader status made me unusually blasé, I asked the only fellow former Chicagoan on the cruise, Len Miller, originally of Rogers Park, about our close brush with Asia Glacier.

“I thought it was ill-advised on the part of the expedition, but I don’t think they’ll do it again,” he said, noting he is planning to go on another adventure with them. “I haven’t withdrawn my deposit.”

The earth is warming, glaciers melting, water rising. Those who cover their ears and hum do so because they either have a financial interest in ignoring the risk, or sold themselves to political factions based on ignorance and an idiot skepticism of the already-proven. People are so strange. When scientists say “Run!”—some peril, a tidal surge, or a big tornado, is coming—most people comply. When that peril is years away, however, and those same scientists are trying to tell you how to diminish it, many refuse to listen.