The concentration of carbon dioxide (CO2), which accounts for 62 percent of greenhouse gases found in the earth's atmosphere, rose by 0.47 percent compared with 2003, the WMO said in its first annual update on greenhouse gases.

Levels of carbon dioxide were 35 percent higher than in 1750, before the Industrial Revolution, said the UN agency, which based its observations on a worldwide monitoring network.

"Levels of carbon dioxide continue to increase steadily and show no sign of levelling off," it said.

"Given that the lifetime of carbon dioxide in the atmosphere is 50 to 200 years, depending on how you calculate it, ... it doesn't take a nuclear scientist to state that we're going to have this problem for a long time," Len Barrie, head of the WMO's environment division, told the media.

"If we stop CO2 emissions to the atmosphere now, it would take 50 to 100 years before we start to see approaches to pre-industrial levels."

In contrast, the concentration of methane, which accounts for 20 percent of greenhouse gases, stabilised in 2004 after increasing by 155 percent over the previous 250 years.

The concentration of nitrous oxide, which represents six percent of greenhouse gases, went up 0.22 percent in 2004 and by 18 percent since 1750.

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CO2 Emissions In The Atmosphere Damaging Seabeds
Oslo (AFP) Mar 15 - Carbon dioxide emissions in the atmosphere are harming the world's seabeds, stunting the growth of coral reefs because of rising acidity levels in the water, according to a study due out in Norway this week.

"Marine life may experience great changes this century because of man-made CO2 waste. Climate change and the resulting acidification of the oceans will have an impact on the ocean environment," the Norwegian Directorate for Nature Management said in a summary of the study published on Tuesday.

According to the report, which summarizes existing knowledge in the field, the world's oceans, which absorb about one-third of CO2 emissions into the atmosphere, may see their acidification process speed up 100 times faster over the next 100 years than they have over the past 100,000 years.

The rapid acidification threatens the existence of corals, plankton and other marine life essential to the maritime food chain.

"The ecological consequences ... are unknown but the scenarios based among other things on research indicate a very negative impact," the Directorate for Nature Management said.

"This knowledge, in addition to what we know about the consequences of greenhouse gas emissions, show that it is more urgent than ever to find strategies to reduce the level of greenhouse gases present in the atmosphere," the summary said.

The full report will be presented this week in Trondheim, in western Norway, during a meeting of Ospar, an organisation for the protection of marine life which groups 12 countries bordering the Northeast Atlantic.

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