Since the days of the 20th century polar explorers, scientists have been fascinated by the bright blue ponds and streams that form on the glaciers and ice shelves of Antarctica. But beyond their beauty is an imminent threat—one that just contributed to the recent collapse of an ice shelf.
Most research into the Antarctic ice melt has focused in on the impacts of warming ocean temperatures, which are slowly eating away at the ice from below. But a new survey reveals that surface meltwater drainage systems are more prevalent throughout the continent that was originally believed, ranging from ponds to a rapid seasonal river. And they could play a vital role in the future stability of Antarctica’s ice shelves.
The findings are a call to action to develop “more sophisticated views of the plumbing on our planet,” co-author Robin Bell, a polar researcher at Columbia University’s Lamont-Doherty Earth Observatory.
Researchers predict that the continent’s ice sheets contain enough ice to raise global sea levels by nearly 200 feet if it were all to melt. Though meltwater is thought to have contributed to the collapse of the Larsen B ice shelf in 2002, most research has focused in on the temperature of ocean water. In fact, no comprehensive view of Antarctica’s surface melt features existed before this recent study.
Bell and his partner Jonathan Kingslake found nearly 700 drainage systems that formed during the summer melt season. The largest body of water was located on the Amery Ice Shelf and reached 50 miles long. Amazingly, we didn’t even know it existed.
The different types of meltwater drainage systems introduce various scenarios for ice sheet stability. While a group of melt ponds contributed to the Larsen B ice shelf, a river system could actually protect an ice shelf. But meltwater streams could also transport meltwater to more vulnerable parts of the ice.
“We have these two different scenarios and we don’t know which one is more likely,” Kingslake notes. “So we can’t tell what the future holds for any one particular ice shelf.”
Kingslake and Bell hope to dive deeper into the existing data to determine why ice shelves exhibit different drainage systems and to pinpoint where the meltwater is going. This could help scientists better predict how different ice shelves will response to increasing temperatures.
“Looking at the presence of meltwater and its fate is critical,” Eric Rignot, a NASA glaciologist, commented.
Source: Weather, Popular Science