The government's scientific research agency CSIRO estimated that 18.7 billion tonnes of carbon dioxide, the greenhouse gas blamed for global warming, were released into the atmosphere in 2002 and 17.1 billion tonnes last year.

The figures compared to a 10-year average growth of atmospheric carbon dioxide of 13.3 billion tonnes and showed the biggest increase of the decade after a 23 billion tonne jump in 1998 -- much of that attributed to massive wildfires in Indonesia, CSIRO said.

The chief researcher at the CSIRO's atmospheric division, Paul Fraser, expressed alarm that the new jump in atmospheric CO2 came "despite global attempts to reduce these emissions".

"The results are concerning because carbon dioxide is the main driver of climate change," he said in a statement.

"I am a little bit surprised that the level is so high without input from forest wildfires," he said.

CSIRO based its estimates on measurements taken in eastern Australia, the southern island state of Tasmania, Macquarie Island in the sub-Antarctic, an Australian station in Antarctica and at the South Pole.

"The persistent increases (in CO2) measured over such a large region of the Southern Hemisphere ensure that they closely reflect the total global emissions," Fraser said.

The CSIRO data supports a similar finding by the US National Oceanic and Atmospheric Administration, which announced last week that data from Hawaii showed peak seasonal carbon dioxide levels last year.

Unlike in 1998, Fraser said, the recent jump in greenhouse gases appeared to be due solely to the burning of fossile fuels like oil, gas and coal.

"The difference between 2002-2003 increases and the last large increase in 1998 is that information from other trace gases in the atmosphere ... show that the source of the increase is most likely from the burning of fossil fuels rather than emissions from oceans, which are the world's biggest reservoir of carbon dioxide, or fires from burning forests," he said.

Environmentalists have been highly critical of the Australian government for joining the United States in refusing to sign the Kyoto Protocol on global warming, a still-unratified UN pact which ties industrial signatory countries to reducing emissions of carbon pollution.

Greenhouse gases have been blamed for a steady warming of the earth's atmosphere since the Industrial Revolution.

If left unchecked, global warming is projected to cause a significant rise in sea levels over the next century through the melting of polar ice caps and thermal expansion.

It is also blamed for an increase in extreme weather events like floods, droughts and storms and damage to coral reefs and other sensitive ecosystems.

TERRA.WIRE