Daar is ‘n verskil tussen see en landys, as en wanneer dit vorm of smelt. Varswater vries ook vinniger as soutwater (see). ‘n Ysland wat groter word of kleiner word. Riviere was ook eens magtige riviere, tog is riviere se kontoere van miljoene jare steeds met ons.
While the interior of East Antarctica is gaining land ice, overall Antarctica has been losing land ice at an accelerating rate. Antarctic sea ice is growing despite a strongly warming Southern Ocean. ICE is expanding in much of Antarctica, contrary to the widespread public belief that global warming is melting the continental ice cap. The results of ice-core drilling and sea ice monitoring indicate there is no large-scale melting of ice over most of Antarctica, although experts are concerned at ice losses on the continent’s western coast.
Antarctica is a continent with 98% of the land covered by ice, and is surrounded by ocean that has much of its surface covered by seasonal sea ice. Reporting on Antarctic ice often fails to recognise the fundamental difference between sea ice and land ice. Antarctic land ice is the ice which has accumulated over thousands of years on the Antarctica landmass through snowfall. This land ice therefore is actually stored ocean water that once evaporated and then fell as precipitation on the land. Antarctic sea ice is entirely differentas it is ice which forms in salt water during the winter and almost entirely melts again in the summer.
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Robert Way explains how Antarctic sea ice has been changing in recent years and introduces the modern mystery of how Antarctic land ice is changing
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“Climate change” and “global warming” are phrases that are often used interchangeably, but they do mean different things. Peter Jacobs explains the history of the two phrases.
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Antarctica has 90 per cent of the Earth’s ice and 80 per cent of its fresh water. Extensive melting of Antarctic ice sheets would be required to raise sea levels substantially, and ice is melting in parts of west Antarctica. The destabilisation of the Wilkins ice shelf generated international headlines this month.
East Antarctica is four times the size of west Antarctica and parts of it are cooling. The Scientific Committee on Antarctic Research report prepared for last week’s meeting of Antarctic Treaty nations in Washington noted the South Pole had shown “significant cooling in recent decades”.
Australian Antarctic Division glaciology program head Ian Allison said sea ice losses in west Antarctica over the past 30 years had been more than offset by increases in the Ross Sea region, just one sector of east Antarctica.
“Sea ice conditions have remained stable in Antarctica generally,” Dr Allison said.
The melting of sea ice — fast ice and pack ice — does not cause sea levels to rise because the ice is in the water. Sea levels may rise with losses from freshwater ice sheets on the polar caps. In Antarctica, these losses are in the form of icebergs calved from ice shelves formed by glacial movements on the mainland.
Last week, federal Environment Minister Peter Garrett said experts predicted sea level rises of up to 6m from Antarctic melting by 2100, but the worst case scenario foreshadowed by the SCAR report was a 1.25m rise.
Mr Garrett insisted global warming was causing ice losses throughout Antarctica. “I don’t think there’s any doubt it is contributing to what we’ve seen both on the Wilkins shelf and more generally in Antarctica,” he said.
Dr Allison said there was not any evidence of significant change in the mass of ice shelves in east Antarctica nor any indication that its ice cap was melting. “The only significant calvings in Antarctica have been in the west,” he said. And he cautioned that calvings of the magnitude seen recently in west Antarctica might not be unusual.
“Ice shelves in general have episodic carvings and there can be large icebergs breaking off — I’m talking 100km or 200km long — every 10 or 20 or 50 years.”
Ice core drilling in the fast ice off Australia’s Davis Station in East Antarctica by the Antarctic Climate and Ecosystems Co-Operative Research Centre shows that last year, the ice had a maximum thickness of 1.89m, its densest in 10 years. The average thickness of the ice at Davis since the 1950s is 1.67m.
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This is the Ross Ice Shelf – the biggest floating ice shelf in Antarctica
At the Ross Ice Shelf in Antarctica, scientists used a hot-water drill hose to create a hole through the thick ice until they reached the perpetually dark water
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Sal ons ooit die diepgewortelde geheime van die ysberge, oseane van ysberge en gletsers wat smelt, die oseane van water begryp – dink nie ons weet regtig hoe diep is die see of ys wat ons beskerm nie. ‘n Asemhaling van die aarde? Tog glo heelwat ons ys smelt nou skielik alles – is dit werklik so?
Voor geboorte was ons almal omring met water tot ons die lig aanskou het, toe het ons na asem gesnak en lewe – dis lewe en wegbeweeg van die natuurlike beskerming. Ons het bly lewe – dis nie ‘n natuurfrats nie.
‘n Godgegewe lewe en doel op aarde – ook waar ons as volk kan voortleef en uitleef – nie die moorde verkragtigings en korrupsie van ‘n vals geskepte flaggie wat “reënboognasie” genoem word. Ons is dit aan ons nageslagte verskuldig. Ons is dit aan onsself verskuldig. As ander volke die reg het tot lewe, het ons ook.
ONAFHANKLIK 
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