While the faster melting of the Greenland ice sheet has largely been attributed to climate change, a team that includes a Trinity College Dublin (TCD) researcher claims there’s evidence it could be caused by activity beneath the Earth, too.
While even the very existence of climate change has been debated by an increasingly small minority, the majority of climatologists who do believe would also agree that an unnatural rise in temperatures is causing the polar ice caps to melt faster than they should.
Particularly evident has been the melting of the ice sheet of the Arctic nation of Greenland, which will eventually contribute to rising sea levels globally.
However, according to a new scientific paper, co-authored by TCD’s Dr Alan Vaughan, a research fellow in geology at the university, any future modelling must now also take into account significant geothermal activity beneath the Earth’s surface.
According to the team’s findings, it has, for the first time, proven that processes deep in Earth’s mantle are coupled with the flow dynamics and subglacial hydrology of the large ice sheet.
The North Atlantic Ocean is a ‘hotbed’ of tectonic activity, but the area around Greenland, in particular, is an area of ancient activity as between 80m and 35m years ago this activity moved Greenland over an area of abnormally hot mantle material, which is now responsible for the volcanic activity of Iceland.
‘An unexpected link’
This mantle material heated and thinned Greenland at depth, creating a zone 1,200km long and 400km wide where the present-day flow of heat from the Earth’s interior is elevated.
Due to the sheer size of such heating of the Earth’s mantle beneath the Greenland ice sheet, using radar and ice core drilling data the study shows that 50pc of the ice-covered area in central-northern Greenland is melting from below and that the meltwater is routed to the ocean through a dense hydrological network beneath the ice.
The resulting data should play a major part in determining any future climate change models in the same way carbon emissions are considered integral now.
Speaking of the paper, Vaughan said: “This study demonstrates an unexpected link between hotspot history and ice sheet behaviour.
“It shows that the influences on ice sheets span a huge range of timescales from the month-by-month changes of the ice cover to the multi-million-year epochs over which the Earth’s mantle and tectonic plates evolve.”
Cavern underneath an ice sheet image via Shutterstock