PALMER STATION, ANTARCTICA
Andy Young is drilling holes into the melting snow on top of the Marr
Glacier when it happens.
There's a sharp crack followed by a rumbling thunder as garage-size chunks of blue ice calve off a nearby glacial cliff and tumble into the frozen sea 400 feet below, throwing waves across the harbor.
"That's a good one," Mr. Young says as he sticks a flag marker into the newly drilled hole. "You can see why we mark the route up the glacier - you just don't want to get too near the edges."
Like many glaciers in this part of the Antarctic, the Marr has been retreating at a surprising rate over the past quarter century. Every year, more rock emerges from beneath the melting wall of ice behind Palmer Station, a 40-man United States research station run by the National Science Foundation. Scientists arriving after a year's absence are surprised to find new beaches, outcroppings, even islands that had been hidden for thousands of years under the ice.
"When I was a student, I remember that climate change was envisioned as a slow process that could not be observed in a human lifetime. But indeed, that's very wrong," says William Fraser of Montana State University who, has been coming here since 1974. "Climate change can be a very rapid event, with abrupt and dramatic consequences for the landscape and ecology."
The Antarctic Peninsula region - a thousand-mile arm of glaciated land and islands reaching northward toward the tip of South America - has seen average temperatures increase by almost 5 degrees F. in the last 50 years.
As the region warms, glaciers have retreated, and floating ice shelves that may have formed many thousands of years ago have collapsed. Glaciologists ponder the possible future ramifications for even larger ice formations to the south. Collapse would raise world sea levels by as much as 18 feet.
Rodolfo del Valle, director of geoscience at the Argentine Antarctic Institute in Buenos Aires, knows just how dramatic climate change can be. In 1995, he and his colleagues were at their base camp on a rocky outcropping in the midst of the Larsen-A Ice Shelf, a floating ice sheet the size of Rhode Island and 500 feet thick. They used the shelf as a sort of highway, driving snow machines between geological sites on the peninsula.