Greenland ice sheet IS melting but much of the heating is coming from INSIDE the earth
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| In total, the Greeland ice sheet contains an
amount of ice that would lead to a rise of global sea level by more than
seven metres, if completely melted |
Study suggests melting in an area is due to composition of Earth's mantle
The
IceGeoHeat team claims they produced more accurate forecasts by adding
their new findings to earlier models on climate change
Ice in Greenland is melting partly because of heat from the Earth's mantle, according to a team of international researchers.The
group claims that they are the first to find a connection between
melting of the Greenland ice sheet and the high heat flow from the
Earth’s mantle.The
findings, they suggest, could have implications for future predictions
on climate change and the reasons behind ice melt in the region.
The Greenland ice sheet is often considered an important contributor to
future global sea-level rise over the next century or longer.
In total, it contains an amount of ice that would lead to a rise of
global sea level by more than seven metres, if completely melted.
The ice loss from the ice sheet has been increasing over the last
decade, with half of it attributed to changes in surface conditions with
the remainder due to increased iceberg calving - the process by which
ice detaches from the glacier to become an iceberg.
The international research initiative IceGeoHeat, led by the GFZ German
Research Centre for Geosciences, said that the effect of the Earth's
crust and upper mantle in current climate modelling are too simplistic.
They modelled the Earth's mantle against the ice sheet and found that
melting occurs in a given area due to the composition of the mantle
underneath it.
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| The team modelled the Earth's mantle against the
ice sheet and found that melting occurs in a given area due to the
composition of the mantle underneath it |
Writing in the current online issue
of Nature Geoscience, the group argues that this effect cannot be
neglected when putting together data on climate change.
The
Greenland ice sheet loses about 227 gigatonnes of ice per year and
contributes about 0.7 millimeters to the currently observed mean sea
level change of about 3 mm per year.
The team point out, however, that existing model calculations were based on a consideration of the ice cap.
GFZ
scientists Alexey Petrunin and Irina Rogozhina have now combined
earlier ice and climate models with their new thermo-mechanical model
for the Greenland lithosphere.
‘We
have run the model over a simulated period of three million years, and
taken into account measurements from ice cores and independent magnetic
and seismic data’, said Petrunin.
 |
| The researchers believe that the coupling of
models of ice dynamics with thermo-mechanical models of the solid earth
allows a more accurate view of the processes that are melting the
Greenland ice |
‘The temperature at the base of the
ice, and therefore the current dynamics of the Greenland ice sheet is
the result of the interaction between the heat flow from the earth's
interior and the temperature changes associated with glacial cycles,’
said Irina Rogozhina who initiated IceGeoHeat.
‘We found areas where the ice melts at the base next to other areas where the base is extremely cold.’
The
current climate is influenced by processes that go far back into the
history of Earth: the Greenland lithosphere is 2.8 to 1.7 billion years
old and is only about 70 to 80 km thick under Central Greenland.
The
researchers believe that the coupling of models of ice dynamics with
thermo-mechanical models of the solid earth allows a more accurate view
of the processes that are melting the Greenland ice.
