NASA Data Peers into Greenland’s Ice Sheet

NASA's Goddard Space Flight Center, Greenbelt, Maryland ^ | January 23, 2015, updated August 7, 2017 | George Hale, ed by Holly Zell

[SunkenCiv]

This new map allows scientists to determine the age of large swaths of Greenland’s ice, extending ice core data for a better picture of the ice sheet’s history. “This new, huge data volume records how the ice sheet evolved and how it’s flowing today,” said Joe MacGregor, a glaciologist at The University of Texas at Austin’s Institute for Geophysics and the study’s lead author.

Greenland’s ice sheet is the second largest mass of ice on Earth, containing enough water to raise ocean levels by about 20 feet. The ice sheet has been losing mass over the past two decades and warming temperatures will mean more losses for Greenland. Scientists are studying ice from different climate periods in the past to better understand how the ice sheet might respond in the future.

One way of studying this distant past is with ice cores. These cylinders of ice drilled from the ice sheet hold evidence of past snow accumulation and temperature and contain impurities like dust and volcanic ash that were carried by snow that accumulated and compacted over hundreds of thousands of years. These layers are visible in ice cores and can be detected with ice-penetrating radar.

Ice-penetrating radar works by sending radar signals into the ice and recording the strength and return time of reflected signals. From those signals, scientists can detect the ice surface, sub-ice bedrock and layers within the ice.

New techniques used in this study allowed scientists to efficiently pick out these layers in radar data. Prior studies had mapped internal layers, but not at the scale made possible by these newer, faster methods. Another major factor in this study was the amount of Greenland IceBridge has measured.

[GingisK]

I ran the calculation a few years ago. I worked with the current area of the oceans with the new volume of ice melt on top. I got a nine meter rise, which is in the vicinity of 27 feet. I didn't figure the volume of the space surrounding the oceans; however, a 27 foot rise does not go very far inland in most places.

Florida would be completely submerged, and New Orleans wouldn't need to worry about hurricanes any longer.

Seacoast cites the world over would be gone.

Now, those alarmist folks need to consider a few things. Greenland is a really big place where most of the ice mass is way north. Temperatures have not ever risen anywhere near the melting point. The higher temperatures experienced in the southern regions really are not so unusual. Remember, the Vikings called the place "Greenland" because it surely was when compared to Norway.

That ice sheet isn't going anywhere for a very long time. I read somewhere that the southern portion of the sheet is getting thinner while the northern region is getting thicker.

[Mr. Lucky]

Except, much of that land mass is significantly below sea level; as much as 3,500 meters.

[GingisK]

That is a major chunk of the ice. It is more like an iceberg that got grounded on an underwater mountain range.

[GingisK]

The drawing seems to show it is in a large bowl with a rim that extends above the water level. The ice below has already been accounted for in current sea levels, hasn't it?

There is plenty of ice that would cause trouble if melted, but no where near as bad as they tell.