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Greenhouse sea levels exaggerated

The frozen continent

The frozen continent

Antarctic scientists said yesterday that sea level rise caused by greenhouse warming may have been vastly overestimated. There is a popular belief that warming of 2-3 degrees will cause sea levels to rise by 120 metres, as happened in the last ice age.

But scientists from the Antarctic Cooperative Research Centre are predicting instead that oceans around the world will only rise about 90 centimetres a century.

They found melting ice in both Antarctica and Greenland will cause some increase in sea levels, but most of the rise will come from melting non-polar glaciers, and thermal expansion of the oceans.

However, they predicted that Antarctica was unlikely to melt with an increase of 2-3 degrees, because temperatures in most of Antarctica are well below the melting point of ice. However, if Antarctica were to melt, it contains enough frozen water to raise sea level by 55 metres.

Indeed, it is predicted that there will be more Antarctic ice in the short term, as warmer oceans cause greater evaporation and more snow falling.

Antarctic climatologist Professor Garth Paltridge says for catastrophic events to occur, the ice in both Greenland and the Antarctic would have to completely melt, an event they believe is unlikely.