CANBERRA: A government pledge to slash Australia's greenhouse gas emissions by 60 per cent by mid-century would not stop dangerous global warming and should be extended to an 80 per cent target, a report recommended on Friday.

Prime Minister Kevin Rudd was elected to power last year on a promise to aim for 60 per cent cuts in emissions by 2050, a more ambitious goal than the 50 per cent agreed on by leaders at the Group of Eight industrial countries in July.

But Ross Garnaut, an economist commissioned by the government to investigate how Australia should respond to climate change, released a report Friday recommending the 80 per cent target for 2050 and a 10 per cent interim target by 2020.

Such cuts are needed if Australia were to carry its fair share of the burden of holding the global carbon dioxide concentration in the atmosphere to 550 parts per million, he said.

That level of atmospheric pollution still posed “large risks to the Australian economy,” but developing countries would not agree to a safer target of 450 ppm, he said.

“Australia should now indicate its willingness to play its proportionate part in future, and if possible early movement toward a more ambitious global goal than 550 ppm,” Garnaut said in the report.

The government has vowed to introduce a so-called carbon trading scheme by 2010 designed to give companies a financial incentive to reduce greenhouse gases such as carbon dioxide, believed to contribute to global climate change.

But the government has yet to decide on what price to charge polluters.

Garnaut said a permit for creating 1.1 U.S. ton (one metric ton) of carbon dioxide should cost 20 Australian dollars (US$16). That price should be increased by 4 percent a year.

Garnaut predicted that would be close to the international price for polluting if a global free market in carbon-trading emerges from United Nation's agreement on the 550 ppm target.

He said he hoped the agreement would be reached at a U.N. climate conference in Copenhagen, Denmark in December next year.

The government has yet to respond to Garnaut's report. Rudd hopes to unveil his government's final blueprint for an Australian carbon trading scheme in December and introduce legislation to Parliament next March.

Australia is one of the world's worst carbon dioxide polluters per capita because of its heavy reliance on abundant coal reserves. As the driest continent after Antarctica, it is also considered one of the most vulnerable countries to climate change.