Deep Bore Into Antarctica Finds Freezing Ice, Not Melting As Expected
Image Credit: National Geographic
Original Article | Author: Douglas Fox
Scientists have peered into one of the least-explored swaths of ocean on Earth, a vast region located off the coast of West Antarctica. It is locked beneath a crust of ice larger than Spain and more than 1,000 feet thick, making its waters perpetually dark—and extremely difficult for humans to access. Now, a team of researchers has bored a hole through the ice and sampled the ocean beneath it. Their work could shed light on a poorly understood, but ominous episode in Antarctica’s recent past.
A team of scientists from New Zealand began this two-month expedition in November. A ski-mounted Twin Otter aircraft ferried them 220 miles from the nearest base, landing near the middle of the Ross Ice Shelf—the massive slab of ice and snow, as flat and empty as a prairie, that hangs off the coastline of West Antarctica and floats on the ocean. Amid the glow of 24-hour summer sunlight filtering down through fog, they assembled an automobile-sized contraption of pipes, hoses, and boilers.
This machine generated a powerful jet of hot water, which they used to melt two narrow holes, each a few inches across, more than 1,100 feet down to the bottom of the ice. They then lowered cameras and other instruments through the holes, into the waters below. In doing so, they hoped to answer a question of worldwide importance: just how secure is the ice of West Antarctica?
The West Antarctic Ice Sheet is up to 10,000 feet thick in some places. It sits in a broad, low bowl that dips thousands of feet below sea level—making it vulnerable to deep, warm ocean currents that are already nipping at its outer edges. It is stabilized, at least for the time being, by a phalanx of floating ice shelves, that hang off its outer edges—of which the Ross Ice Shelf is by far the largest. Those floating shelves provide a buttress; they “are holding back a very big amount of ice,” says Craig Stevens, an oceanographer from the National Institute of Water and Atmospheric Research in New Zealand, who participated in the expedition.
Global sea levels would rise by 10 feet if West Antarctica lost these crucial stabilizers and spilled its ice into the ocean. Scientists fear that some of these ice shelves are already weakening. Stevens and his colleagues hoped to assess the health of the Ross Ice Shelf by measuring water temperatures and ocean currents beneath it—thereby determining how quickly ice is melting off its underside.
