Higher CO2 levels may be good for plants: German scientists

Yahoo News 8 Jul 08;

The dangerous rise in greenhouse gases in the atmosphere may be troubling scientists and world leaders but it could prove to be a boon for plants, German researchers said Tuesday.

Increasing exposure to carbon dioxide appears to boost crop yields, Hans-Joachim Weigel of the Johann Heinrich von Thuenen Institute for rural areas, forestry and fisheries in the central city of Brunswick told AFP.

"Output increased by about 10 percent for barley, beets and wheat" when the plants were subjected to higher levels of carbon dioxide, Weigel said.

The Thuenen Institute, which has been monitoring the phenomenon in fields since 1999, trains CO2 jets on the plants so the gas reaches 550 parts per million in the air around them -- the level expected in the atmosphere by 2050.

Weigel said the studies have indicated that while greater CO2 exposure appears to spur growth, it can also undermine the quality of the produce.

He said the next step in the study would be to evaluate the effect of higher temperatures on plant growth -- which scientists cite as another consequence of higher CO2 emissions in the atmosphere.

Weigel said that while the institute's findings may prove surprising to some, they are not intended to undermine the drive to slash CO2 emissions.

"This research is not intended as an argument for doing nothing to curb the rise of CO2 levels," he said. "It is to find out what the effects would be."

Other studies have presented a more mixed picture about the impact of higher CO2 levels on plants, and there is uncertainty about its effects on soil fertility and which plants benefit most from more CO2.