From LA Times:
[quote]Some biologists had theorized earlier that rising greenhouse gas levels would encourage plant growth over the long term because of the increased amount of carbon dioxide in the atmosphere. But plant physiologists from UC Davis may have dashed those hopes.
They've shown that too much carbon dioxide, which plants need for energy, actually can inhibit a plant's ability to assimilate nitrates — nitrogen-based nutrients pulled from the soil that plants use to make enzymes and other essential proteins.
Without those essential proteins, plant health — and food quality — may suffer, the researchers say in a study published online Thursday in the journal Science.[/quote]