Earth’s Internal Heat Drives Subglacial Melting in Greenland

This is pretty amazing.

earthsinternGreenland’s lithosphere has hot depths which originate in its distant geological past and cause Greenland’s ice to rapidly flow and melt from below.

To understand Greenland’s of today researchers have to go far back into Earth’s history. The island’s lithosphere has hot depths which originate in its distant geological past and cause Greenland’s ice to rapidly flow and melt from below. An anomaly zone crosses Greenland from west to east where present-day flow of heat from the Earth’s interior is elevated. With this anomaly, an international team of geoscientists led by Irina Rogozhina and Alexey Petrunin from the GFZ German Research Centre for Geosciences could explain observations from radar and ice core drilling data that indicate a widespread melting beneath the ice sheet and increased sliding at the base of the ice that drives the rapid ice flow over a distance of 750 kilometres from the summit area of the Greenland ice sheet to the North Atlantic Ocean.

The North Atlantic Ocean is an area of active plate tectonics. Between 80 and 35 million years ago tectonic processes moved Greenland over an area of abnormally hot mantle material that still today is responsible for the volcanic activity of Iceland. The mantle material heated and thinned Greenland at depth producing a strong geothermal anomaly that spans a quarter of the land area of Greenland. This ancient and long-lived source of heat has created a region where subglacial meltwater is abundant, lubricating the base of the ice and making it flow rapidly. The study indicates that about a half of the ice in north-central Greenland is resting on a thawed bed and that the meltwater is routed to the ocean through a dense hydrological network beneath the ice.

The team of geoscientists has now, for the first time, been able to prove strong coupling between processes deep in the Earth’s interior with the flow dynamics and subglacial hydrology of large ice sheets: “The geothermal anomaly which resulted from the Icelandic mantle-plume tens of millions of years ago is an important motor for today’s hydrology under the ice sheet and for the high flow-rate of the ice” explains Irina Rogozhina. “This, in turn, broadly influences the dynamic behaviour of ice masses and must be included in studies of the future response to climate change.”

Read more at: Physorg


Greenland remained stable for 2.7 million years “even during the warmest periods”

2.7-Million-Year-Old Forested Landscape Discovered under Greenland Ice Sheet

“We found organic soil that has been frozen to the bottom of the ice sheet for 2.7 million years,” said Dr Paul Bierman, a geologist with the University of Vermont and the lead author of the paper appearing online in the journalScience.

“The ancient soil under the Greenland Ice Sheet helps to unravel an important mystery surrounding climate change – how did big ice sheets melt and grow in response to changes in temperature?” said co-author Dr Dylan Rood from the Scottish Universities Environmental Research Center and the University of California, Santa Barbara.

The discovery indicates that even during the warmest periods since the ice sheet formed, the center of Greenland remained stable.

“Greenland really was green! However, it was millions of years ago. Greenland looked like the green Alaskan tundra, before it was covered by the second largest body of ice on Earth,” Dr Rood said.

Embed from Getty Images

(h/t IceCap)

Greenland Temperatures from stations with data from the 1800s.

Greenland Temperatures from stations with data from the 1800s. Updated link here.

It was warmer in the past.

These are the warmest years for each month and season.

Station SEP OCT NOV Autumn DEC JAN FEB Winter MAR APR MAY Spring JUN JUL AUG Summer
Upernavik 1928 1960 1878 2010 1873 1929 1947 1947 1916 1905 1932 1932 2008 2011 1960 2011
Ilulissat 1915 1960 1878 2010 1978 1929 1986 1929 1916 1905 1933 1932 1997 1960 1960 1960
Nuuk 2010 1960 1878 2010 2010 1917 1901 2010 1916 1953 2010 1932 1947 2008 2010 2010
Quaqortoq 2010 1960 2010 2010 1978 2010 1901 2010 1932 1881 1935 1932 1929 2003 1960 1929
Tasiilaq 1939 1915 2002 1941 1933 1987 1932 1929 1929 1926 1933 1929 1932 1939 2010 2003