OSLO (Reuters) - Atmospheric levels of the main
"The rise is in line with the long-term trend," Kim Holmen, research director at the Norwegian Polar Institute, said of the measurements taken by a Stockholm University project on the Arctic archipelago of Svalbard off north Norway.
Levels of , the main greenhouse gas from human activities, rose to 392 parts per million (ppm) in the atmosphere in Svalbard in December, a rise of 2-3 ppm from the same time a year earlier, he told Reuters.
Carbon dioxide concentrations are likely to have risen further in 2009, he said. They usually peak just before the start of spring in the northern hemisphere, where most of the world's industry, cities and vegetation are concentrated.
Plants suck carbon dioxide, which is released by burning fossil fuels, out of the atmosphere as they grow. Levels fall toward the northern summer and rise again in autumn when trees lose their leaves and other plants die back.
"It's too early to make that call," he said when asked if there were signs that economic slowdown was curbing the rise in emissions. And he said any such change would be hard to detect.
"That's a tricky one to do," he said. "If we had, for example, a year with an unusually warm Siberian winter, that could cancel the human variation."
A warm Russian winter would allow more bacteria to break down organic material in the soil, releasing carbon dioxide.
Levels of carbon dioxide are around the highest in at least 800,000 years, and up by about a third since the Industrial Revolution.
The increase is caused by "mainly fossil fuel burning and to some extent land use change, where you have forests being replaced by agricultural land," Holmen said.
The U.N. Climate Panel says rising greenhouse gas concentrations are stoking warming likely to cause floods, droughts, heatwaves, rising seas and extinctions.
Latest data is from December because measuring equipment on Svalbard is being replaced.
"We can see the trend from these winter numbers," Holmen said. The numbers are higher than annual average year-round figures reported by groups such as the U.S. National Oceanic and Atmospheric Administration.
More than 190 nations have agreed to negotiate a new international deal by the end of 2009 to fight climate change. It would succeed the U.N.'s Kyoto Protocol, which sets carbon dioxide limits for 37 industrialized nations.
(Editing by Andrew Roche)
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