Antarctica 'melting faster than first thought'

Scientists say Antarctica is melting, and much more than initially thought — spelling big trouble for Australia as sea levels rise.

Scientists used to think Antarctica was bucking the trend on global warming by getting cooler.

Now it seems they got it wrong.

US researchers have pored over data from satellites and weather stations in the biggest ever study of the frozen continent's climate and found it's warming after all.

University of Adelaide Research Institute for Climate Change and Sustainability director Barry Brook says the finding is alarming.

"That's bad news if you live near the Australian coast," Prof Brook was quoted by Nature magazine as saying.

"In some areas where you've currently got housing, you'd probably have to abandon those areas."

He said the sea would penetrate up to 1km inland in flat areas like South Australia's lower lakes.

Scientists now estimate the melting of Antarctica's massive ice sheets will cause the world's sea levels to rise by 1 to 2 metres by the end of the century.

The news comes as a Sydney University proposal to produce a plankton bloom in the Tasman Sea as part of a trial to combat global warming has drawn criticism from environmental groups.

Under the proposal, nitrate fertiliser would be sprinkled over a 1,600 square kilometre area of the sea to stimulate the bloom that researchers hope will sequester carbon at the bottom of the ocean for up to a century.

The UN's International Panel for Climate Change has described such a method of carbon sequestration as "speculative and unproven and with the risk of unknown side effects".

"If this experiment proceeds, the Australian Government's credibility as a protector of the oceans is on the line," conservation organisation WWF Australia's Rob Nicoll said in a statement.

"This action is little more than an attempt to find a shortcut for carbon polluting industries to gain carbon credits on the cheap, rather than through reducing their emissions."

Mr Nicoll said the proposal may breach global conventions and be harmful to marine ecosystems.

"There are no clear international guidelines for large-scale trials of ocean fertilisation and other forms of so-called geo-engineering," Mr Nicoll said.

He added that the experiment "is likely" to contravene the London Protocol for the Prevention of Marine Pollution by Dumping Waste and Other Matter, which will this year establish rules for such activity.

"Until these rules have been enacted we should refrain from attempting ocean fertilisation experiments," Mr Nicoll said.

A similar experiment in the Southern Ocean, which dropped 20 tonnes of iron sulphate, has been put on hold by the German government amid fears over its environmental impact.