The latest information about carbon dioxide fertilization by which plants soak up carbon from the atmosphere "really paints a different picture of the way the world works," said panelist Chris Field of the Carnegie Institution of Washington.

In a book edited by Field and scheduled for publication in late February, researchers concluded that the land contains many large pools of carbon that are likely to shrink in the coming century.

A key reason for the differing conclusions, Field and his colleagues found, is that the predictions of the Intergovernmental Panel on Climate Change and other studies have relied on models that don't reflect some of the major processes by which carbon circulates through the environment.

Field and his colleagues also have discovered in a previous study that there may not be enough biologically available nitrogen to support certain optimistic estimates of the land's capacity for carbon fertilization.

"If you put together these two lines of evidence, we're looking at a future in which we may see less carbon being removed from the atmosphere," Field said.

"The fact that carbon dioxide fertilization is likely to be more modest does not imply that carbon management through planting trees is a bad idea," Field explained. "Planting trees is a great idea. It's just that the trees will grow at their 'normal' rates or slightly faster, rather than at supercharged rates."

Field co-organized the symposium with Stephen Schneider of Stanford University, pulling together speakers studying a variety of different landscapes, who met at the Annual Meeting of the Amer
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Contact: Monica Amarelo
mamarelo@aaas.org
206-774-6330
American Association for the Advancement of Science
15-Feb-2004