Greenland ice sheets are beginning to melt at a dangerous rate, with great concern expressed amongst the scientific community over human-induced, climatic temperature changes. A band of global researchers claim their new study, written in Nature Geoscience, is the first to identify evidence that links the disappearance of Greenland’s ice sheets and heat generated from the Earth’s mantle.
The multinational research team have developed the IceGeoHeat project, headed by the GFZ German Research Centre for Geosciences. According to the GFZ website, this initiative aims to measure the patterns of geothermal heat, in areas that are predominantly enveloped by broad stretches of ice. The distribution and flow of heat within the subglacial areas, such as the Earth’s mantle, is thought to have a consequential impact upon the internal thermal configuration of these ice sheets.
The authors point to a complete absence of analogous research studies, a problem which has resulted in the scientific community’s lack of comprehensive understanding:
“… lack of direct heat flow measurements and a complete absence of reliable estimates of heat flow beneath the Greenland and Antarctic ice sheets have complicated physical modelling of ice sheets and lithosphere, deep ice coring, and climate reconstruction from ice core isotope records.”
According to the Daily Mail, the team have also cited contemporary climate models as far too basic, when taking into consideration the participation of the Earth’s lithosphere, which comprises of the crust and mantle.
Two of the GFZ team members, Alexey Petrunin and Irina Rogozhina, state that they have drawn a relationship between the pre-existing ice/climate model and a new thermo-mechanical model, specific to the Greenland lithosphere. Collating scientific research data from simulation models (covering a 3 million year period), and factoring ice core measurements and magnetic and seismic datasets, Petrunin tentatively conclude their determined model to be sound:
“Both the thickness of the ice sheet as well as the temperature at its base are depicted very accurately.”
Ultimately, the study revealed significant differences in “geothermal heat flux” across the central region of Greenland. The study suggests the thickest section of the Greenland ice sheet has been impacted significantly by heat from the deep within the Earth’s mantle. Since the lithosphere begins to thin, moving from west to east, there appears an associated change in the afore-mentioned heat flux. This claim could help scientists to, more accurately, understand the disappearance of Greenland’s ice sheet, on a region-specific basis.
These regional variations in heat flux may play a huge part in sea rise. It is estimated, Greenland’s ice sheet sheds in excess of 220 gigatonnes of ice, annually. This leads to a 0.7 millimeter difference in mean sea level, which is part of a total 3 millimeters worth of yearly change. This clearly demonstrates the huge global impact that Greenland’s melting ice sheets will have upon global climate change. However, according to the research team, the current model relies upon consideration of the ice cap, and an overly simplified effect of the lithosphere.
If the entirety of Greenland’s ice sheet were to melt, it is predicted that the sea level would increase by approximately seven meters. According to climate scientist, Jonathan Gregory, working on a separate study, at the University of Reading (England), a sea level increase of as little as one meter could submerge vast areas of Bangladesh. A number of eminent scientific figures continue to vigorously assert a relationship between climatic temperature rise and mankind’s global activity. The question now remains, to what extent does the Earth’s lithosphere influence the rate of melting of Greenland’s ice sheets, relative to climatic temperature change?
Putting this to one side, however, it seems the Earth’s mantle does indeed have a regional impression upon the heat flow amongst the different icy masses of Greenland. Following this exciting discovery, the research team are yet to study the reason behind the incredible thinness of Greenland’s lithosphere, details of which may also help to explain the disappearance of the region’s ice sheets.
By: James Fenner