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South Pole's hot underbelly revealed: map shows how heat from deep within Earth creates 'hot spots' that speed up melting of the Antarctic ice sheet

last modified Dec 05, 2017 06:33 PM
A study led by British Antarctic Survey (BAS), mapped the amount of heat being released beneath the continent, using data primarily collected from magnetic measurements by aircraft. The resulting heat map is 30 to 50 per cent more accurate than previous studies. 'Hot spots' could add to drastic alterations already underway to the ice sheet.

The clearest map ever produced of the amount of heat being released from deep within the Earth below the Antarctic has been released.

Experts created the most up to date, accurate and high-resolution graphic of the ‘geothermal heat flux’ reaching the base of the region's massive ice sheet.

The data used comes primarily from magnetic measurements collected by aircraft flying over the continent and shows ‘hot spots’ in the area.

Scientists believe global warming is already causing drastic alterations to the ice, and higher levels of geothermal energy could worsen matters.

The study, led by British Antarctic Survey (BAS), reveals key areas under West Antarctica and on the Antarctic Peninsula, the most rapidly changing areas of the Antarctic Ice Sheet.

Of the various forces which shape and controls the flow of ice in the area, geothermal heat is the most poorly studied, the international team of scientists says.

The Antarctic Ice Sheet contains the largest reservoirs of fresh water on our planet, around 70 per cent of the world’s fresh water, and is currently losing ice, which contributes to rising sea levels. 

Heat at the bed of rock that sits under the ice sheet makes it easier for the ice to move. 

However, it is incredibly difficult to take direct measurements of heat from the Earth’s interior beneath 1.8 to 2.4 miles (three to four km) of ice in extremely cold and hostile conditions.

Instead, the researchers have used magnetic data to infer the heat levels, producing a heat map they say is 30 to 50 per cent more accurate than previous studies.

In a written statement, BAS glaciologist Professor David Vaughan said: 'If we are to predict with any certainty the future response of Antarctica in a warming world, scientists need to understand the role that heat from the Earth plays. 

'What we know is that over time, the heat flow into the ice is quite constant and so the ice sheet adjusts to it. 

'The ice loss we’ve seen in recent decades is actually the result of changes in air and ocean temperatures. 

'How the ice sheet will respond to these recent changes is influenced by the pattern of geothermal heat, and that’s why this new map is so important.' 

 The full findings of the study were published in the journal Geophysical Research Letters.

Just last week, scientists uncovered new evidence for an ancient heat source beneath the West Antarctic ice sheet.

The underground mantle plume is thought to be driving some of the melting seen beneath the ice, giving rise to lakes and rivers.

It’s thought to have formed 50 to 110 million years ago, long before the ice sheet itself. 

It has likely played a role in rapid collapses that took place during past periods of climate change and it could help explain some of the instability seen today.

The suspected geothermal heat source is situated deep beneath Antarctica’s Marie Byrd Land.

While it’s not a new phenomenon, it could help scientists better estimate the rate of future ice loss in the area, as the meltwater helps to lubricate the glaciers.

A scientist at the University of Colorado Denver first suggested the presence of a mantle plume beneath Marie Byrd 30 years ago.

This could explain volcanic activity and the dome feature.

In a new study, researchers used numerical modelling with the Ice Sheet System Model to study the plume, revealing natural sources of heating and heat transport from a number of processes.

They scientists also used observations of changes in the altitude of the ice sheet surface, captured by Nasa’s IceSat satellite and airborne Operation IceBridge campaign.

The study found that the energy flux from the mantle plume must not exceed 150 milliwatts per square meter – compared, for example, to a heat flux of 490 to 60 milliwatts in regions with no volcanic activity, and an average 200 milliwatts per square meter beneath Yellowstone. 

 

For further details, please see the source article here.

 

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