KU prof: Global warming not sole culprit

Hot spots could be causing ice sheets to melt from below

A Kansas University researcher in a presentation to the American Geophysical Union today will show evidence that global warming may not be the only – and perhaps not even be the largest – cause of declining ice sheets on Greenland.

In a presentation at the AGU meeting in San Francisco, researchers from KU’s Center for the Remote Sensing of Ice Sheets will show evidence that a weakness in the earth’s crust could be causing underground magma to melt the ice above. If that is in fact happening, the water could be melting and carrying away more ice as it flows away from the “hot spot.”

“We think it may be a part of greater geothermal activity beneath the entire ice sheet,” said Kees van der Veen, a KU researcher and professor in the department of geography.

The CReSIS researchers found the weakness in the crust using data gathered with the center’s airborne radar, which has been flying over Greenland, combined with Navy data on the gravitational pull over the ice sheet. Van der Veen and Tim Leftwich, of KU, worked with Ralph von Freese of Ohio State University to analyze the data.

“For the most part, up until recently, the glaciologists ignored the geophysical activity beneath the ice sheets,” van der Veen said.

The initial studies revealed the one known hot spot in an area of northeast Greenland that is home to a recently discovered ice flow. The researchers theorize that the ice flow could have been started by the magma – and not human activity. These streams have become more powerful and more prevalent in recent years. They can be responsible for taking ice from the center of the ice sheet more than 400 miles out to sea, where it eventually melts.

“Where the crust is thicker, things are cooler, and where it’s thinner, things are warmer,” von Freese explained in a press release from Ohio State. “And under a big place like Greenland or Antarctica, natural variations in the crust will make some parts of the ice sheet warmer than others,” he said.

Melting ice sheets pose great dangers for humankind. If the ice sheet were to melt completely, entire portions of the American seaboard could wind up under water.

The researchers intend to search the rest of Greenland for more crust variation – and more ice flows – before examining Antarctica for the same conditions.