Holmen said measurements at a Norwegian station high in the Arctic showed levels of carbon dioxide, the main greenhouse gas, were around 394 parts per million, up about 1.5 parts per million from the previous records early in 2007.

The levels have risen by about a third since the start of the Industrial Revolution in the 18th century, in tandem with more use of fossil fuels in power plants and factories, and defying recent international efforts to cut back.

The carbon levels usually peak just before the arrival of spring in the northern hemisphere, where most of the world's industries, land masses and plants are found. Levels then dip because plants soak up carbon dioxide as they grow.

Holmen said that the 2008 levels might still rise fractionally higher in coming weeks.

He said growing economies in Asia such as China and India were a reason for the rise in emissions, in line with a linked fall of industrial efficiency in the past two years or so -- more carbon is being emitted per dollar of economic output in a reverse of a long improving trend.

INEFFICIENT

"The affluent world wants to buy cheap stuff and we buy it...from the inefficient old-fashioned technology that we have got rid of," he said. He added that there were also signs the oceans had become less efficient at soaking up carbon dioxide.

The UN Climate Panel, which shared the 2007 Nobel Peace Prize with former US Vice President Al Gore, says that world emissions of greenhouse gases will have to peak by 2015 to avert the worst effects of global warming ranging from more droughts and floods to rising sea levels.

It says that carbon dioxide levels in the atmosphere are higher than for the past 650,000 years and says that it is more than 90 percent probable that humans are to blame for a related global warming.

Separately, Norwegian researchers said there were new signs that polluting mercury was being blown to the Antarctic even though the icy continent is far from most industrial centres. Mercury has long been a pollutant in the Arctic.

"A preliminary analysis indicates a mercury level approximately 40 percent lower than in the Arctic," Chris Lunder of the Norwegian Institute for Air Research told Stoltenberg during his trip.

"This is a rather high number considering the fact that only a quarter of the emissions occur in the southern hemisphere," he said.

China releases 28 percent of global emissions while South Africa, the nearest nation to Troll, which is about 250 km inland in Antarctica, accounts for 10 percent, he said.