June 22, 2012
Elephant Seals Assist In Ice Shelf Research
Brett Smith for redOrbit.com
In the Bizarro world of climate change crusaders, what is good is bad, what is up is down, and what is hot is cold.New research published this week in the American Geophysical Union journal Geophysical Research Letters asserts that an Antarctic ice shelf melting slower than expected is good news for those of us who dislike massive flooding – but bad news for those sounding the alarm against global warming.
During the two-year study, researchers led by Tore Hatterman of the Norwegian Polar Institute drilled holes through the Fimbul Ice Shelf in eastern Antarctica to gather the first direct measurements of the shelf´s melting underside. They also used data culled from a crack team of nine elephant seals equipped with sensors that measured salinity, temperature, and depth.
Hatterman´s team concluded that sections of eastern Antarctica are melting at significantly lower rates than current models have predicted.
“It has been unclear, until now, how much warm deep water rises below the Fimbul Ice shelf, and previous ocean models, focusing on the circulation below the Fimbul Ice Shelf, have predicted temperatures and melt rates that are too high, suggesting a significant mass loss in this region that is actually not taking place as fast as previously thought,” he said.
Earlier studies based on computer models without any direct data overestimate the water temperatures and amount of melting beneath the Fimbul Ice Shelf, the scientists discovered. This has led to the misconception that the ice shelf is degrading at a faster rate than it is gaining mass.
The newest study shows that water temperatures under the shelf are far lower than computer models have predicted, which means that the Fimbul Ice Shelf is melting at a slower rate. Hatterman said that the shelf could be in a state of equilibrium at the moment because ice buildup on top of from snowfall has kept up with the melting underneath.
The results also confirm a 20-year-old theory about how ice shelves melt that, until now, was too complex to be further investigated without a more comprehensive data set. Researchers said they hope to apply their study to other areas of Antarctica, primarily the eastern half because of its similar water and wind circulation patterns.
“Our data shows what needs to be included in the next generation models, in order to be able to do a good job in predicting future melt rates,” he added.
The Fimbul Ice Shelf is the sixth-largest of the 43 ice shelves that encircle the frozen continent. These massive floating fingers of ice act as a guard for the glaciers that flow into them. The concern is–if an ice shelf is melting rapidly, the glacier behind it may flow faster into the sea and contribute to rising sea levels.
“Ice shelves act as a mechanical barrier for the grounded inland ice that continuously moves from higher elevation towards the coast,” Hattermann said. “Once an ice shelf is removed, this ice flow may speed up, which then increases the loss of grounded ice, causing the sea level rise.”