The iceberg of the cities size float near the United Kingdom: what awaits Antarctica?
The signs just discovered in the bottom of the sea reveal it Huge icebergs sailed drift In front of the coasts of the United Kingdom. According to scientists from the British Antarctic Survey (Bas), the scraped brands show the place where the lower part of these icebergs dragged through the North Sea bottom between 18,000 and 20,000 years ago.
This is the First proof Chiara that monstrous blocks of ice They wandered in this area – less than 145 kilometers from the British coast – offers precious data on how I could change The frozen landscape of Antarctica While the continent is heated.
“We are talking about huge peaks or “tabular” iceberg peaks“The geophysicist Marino James Kirkham explains, Di Bas, referring to the icebergs that caused the deep furrows.” Conservatively, they measured between five and perhaps a few tens of kilometers in width – compared to the surface of a medium -sized British city such as Cambridge or Norwich – and could have a thickness of a couple of hundred meters. “
When were Iceberg in the North Sea?
Preserved in the sediments buried under the current marine foundation, these brands of Arasto date back to the last glaciationA period in which a layer of ice that covered most of the British and Irish islands withdrew due to the heating of the climate.
Were detected for the first time in the seismic data used to identify the platforms of Petroleum and gas perforation In the pelvis of the witch ground, located between Scotland and Norway. In this area, single furrows formed by small icebergs had already been detected, but the widths of large meters the soil of the witches show that there were also gigantic tabular icebergs.
Tabular icebergs come out of ice platforms, floating fronts of glaciers who They detached from the earth to lead to the ocean. Therefore, researchers can deduce that the British and Irish ice layer also had these structures.
Kelly Hogan, Geophysics Marina della Bas and Co -Author of the new study published in the magazine “Nature Communications”, explains how this provides historical clues. “With our data we can document The catastrophic collapse of these platforms Of ice at the end of the last era glacial “, he says”, because about 18,000 years we have detected a change in the type of lobster brands of the icebergs recorded in the sediments of the sea background, of gigantic tabular icebergs – produced by the normal life cycle of ice platforms – to much more numerous and small ice as iceberg like Iceberg like Iceberg as iceberg as small as little Disintegrated ice platforms“.
What does this suggest about the antarctic ice layer?
The ice platforms are important for the stability of the ice layerBas explains. They break through and maintain glacial ice, which otherwise would dry up much faster towards the ocean. The regular detachment of tabular iceberg on the edge of the platform attack – which sometimes only occurs every few decades – helps to keep the glaciers behind them in a stable state.
75% of Antarctica is surrounded by these floating platforms. But it is not clear how the frozen continent will move Climate change caused by man. Perhaps the most significant example of breaking an ice platform to date is what has happened with the Larsen B ice platform in 2002, the increase in air temperature has merged part of the surface of the ice platform, sending defrosting water through the platform and breaking the ice in countless small icebergs in just a week.
After the disintegration of the ICE platform, the glaciers who had been maintained Behind it increased its speed several times, accelerating its contribution to Increase in sea level. The old brands of the north -sea plow suggest that this phenomenon occurred on a much wider scale, when the British and Irish ice layer was quickly reduced by 200 and 300 meters per year at the edges.
A mystery that still persists is if this rapid retreat Was caused by the collapse of its ice platforms or if fragmentation was a symptom of the mass losses of the ice layer that were already underway. But the better appointments sediments could provide the answer.
“It’s an interesting problem that brings us to the heart of the influence of ice platforms In the modern layer of antarctic ice. If we observe a similar transition from large tabular icebergs to smaller icebergs, it could indicate that the continent is about to experience a significant and rapid loss of mass “, says Rob Larter, author of Bas.
