By Lise Alves, Contributing Reporter
MIAMI BEACH, FLORIDA – Large, thick, floating ice shelves in Antarctica are melting due to the warm air above – as well as the warmer ocean water running below, say findings published last week. The melting of these ice shelves help create conditions which could lead to accelerating sea level rise further, say scientists and researchers.
“Warm water circulation is attacking the undersides of these ice shelves at their most vulnerable points,” said glaciologist Karen Alley, visiting assistant professor of Earth Sciences at The College of Wooster in Ohio.
Although researchers have known about these so-called ‘upside-down rivers’ of warm ocean water for some time, current forecasts for sea level rise do not account for the phenomenon.
Now, researchers say, these rivers are likely to be included as one of the factors which are important to the future of Antarctica’s ice shelves and an important cause contributing to rising seas. “These effects matter,” she said. “But exactly how much, we don’t yet know. We need to.”
Researchers say that about three-quarters of the Antarctic continent is surrounded by ice shelves. These ice shelves are barriers which can slow down the flow of ice from the interior of the continent toward the ocean. But if an ice shelf shrinks or falls apart, ice on land flows much more quickly into the ocean, increasing the rate of sea level rise.
According to Alley and her colleagues this warm water has a tendency to infiltrate into the floating ice, forming a type of ‘river’ which runs through the shelves, eroding and weakening the margins of the ice.
These ‘rivers’ can grow miles wide and tens of miles long, according to Alley, making ice shelves more vulnerable and more likely to collapse into the ocean. This phenomenon seems to be occurring on ice shelves in both Antarctica and Greenland.
Alley and other researchers are planning to head back to Antarctica this fall to continue their work and perhaps understand better the continent’s ice dynamics and factors which can contribute to sea level rise.