Swiss study suggests no relief from greenhouse gas effects

A theory that the greenhouse gas effects of raised carbon dioxide levels in the atmosphere could be offset by increased vegetation growth has been largely discredited by researchers in Switzerland.
As reported by Scientific American magazine, a team of researchers led by Christian Korner of the University of Basel conducted an experiment on a 500-square metre patch of deciduous forest over four years. They sprayed mature trees with two tons of extra carbon dioxide per day over the growing season. It turned out that not all species reacted in the same way to the heightened level of CO2, but overall the research showed no increase in stem growth or leaf production. If there were increased plant growth, then the plants would be able to store more carbon dioxide, thus offsetting the production of greenhouse gases.
There are still questions revolving around the issue however. The time scale of the experiment may have been too short to be reliable, and some carbon dioxide may have been sequestered in the tree root systems. Future studies are planned to be done on conifers and tropical trees.
See www.sciam.com