When I first saw the news of the sinking of the M/S Explorer after it struck an ice floe last month, I nodded grimly, then went back to what I was doing. Few people familiar with Antarctica were surprised by the news. We’d been waiting for this.

For well over a decade, Antarctica has been the heart of my work and life. I worked out of McMurdo Station for the United States Antarctic Program, and became deeply attached to the empty horizons of East and West Antarctica, and to the marginal life that clings to the icebound coast. There is no place on Earth so colossal, so ephemeral. In my most recent jobs, I ran small tent camps that shook in gales and shivered in the cold. Perhaps the most fundamental lesson I learned—aside from how little we matter to nature’s great forces—is that Antarctica forces you to always prepare for worst-case scenarios. This is the land of no-options, where I have known multi-day storms to cancel flights, bury trucks and pin down icebreakers.

Visitors travel south to see a cold world of ice, and that is what they find. Navigation is difficult, maps are insufficient, weather is atrocious and floating ice is often undetectable.

Yet these days, more than 40,000 visitors—if you include the multiple visits by crew members—take leisurely spins through the ice-choked waters off the Antarctic Peninsula. Fifteen years ago, a mere 7,000 thousand took the cold trip south. This explosion in growth has been driven by profits, not, as we might hope, by improvements in nautical design or navigation. Despite the dangers of the Southern Ocean, larger and less ice-ready vessels carry more and more passengers into the uncharted waters of Antarctic “what ifs.”

They put their clients at risk, as well as the region’s other inhabitants. About 99.6 percent of Antarctica is covered by snow or ice. The marine mammals and birds that tourists covet, as well as a few hardy plants, thrive only in the .4 percent of delicate fertility left over. The fuel now leaking out of the Explorer (it carried an estimated 50,000 gallons) can only be bad news for Antarctica’s marine life.

As for the people aboard the Explorer, they were fortunate that time and weather worked in their favor. The ship’s compartmentalized hull design, which slowed the leak and allowed them a somewhat unhurried retreat to the lifeboats, is rare in the industry. The ship was small, the passengers adventurous, the crew experienced, the ice and ocean quiet. In other words, aside from the unhappy meeting with undetected ice, the people aboard the Explorer could not have had better luck.

This sinking of one of the industry’s more reliable ships should give pause to anyone thinking of cruising the dangerous waters off Antarctica. Picture the rapid sinking of an upscale behemoth populated by rhinestone cowboys, small dogs and seniors. (Last year Princess Cruises sent a thin-hulled vessel south with 3,500 passengers and crew, with another scheduled for this January.) The assurances of the cruise industry should no longer lull clients into complacency.

Government or maritime regulation may never bare enough teeth to stem the cruise ship tide in Antarctica. The continent, like the oceans, exists in an international legal limbo. The nations that are party to the Antarctic Treaty cannot mandate that ships be prepared for worst-case scenarios. The International Association of Antarctic Tour Operators provides polite oversight to its members (though some operators are not members), but makes little effort to limit ship traffic.

In the case of the Explorer, I was happy that the ship was small, that all personnel and passengers escaped unharmed. But what if there were 1,000 passengers rather than 91, and no other cruise ships were on hand to quickly pick them up? What if this incident happened during a three-day blizzard, with gale-force winds trapping lifeboats in churning growlers and sea ice? Hope for the best, but don’t be surprised if grim news comes.

Jason Anthony’s last Antarctica story for World Hum, A Brief and Awkward Tour of the End of the Earth, was selected for The Best American Travel Writing 2007. His Antarctic essays and photographs are available at www.albedoimages.com. He teaches at the Deck House School in Edgecomb, Maine.

Related on World Hum:
* Q&A with Susan Fox Rogers: Antarctica for ‘Dreamers and Readers’
* Environmentalist on Antarctica: ‘Do We Want This to Become Disneyland?’
* Scientists Unveil High-Def Map of Antarctica

Photo: AP.