This actually makes me question the entire premise of global warming and agriculture. Would global warming necessarily be bad for agriculture? For example, the midwest is a fertile agricultural region, but that area has severe winters, and a relatively short growing season. Isn’t it possible that the midwest would be incredibly more productive, if the weather were warmer there over the course of the whole year? Couldn’t a little global warming thus be good for agriculture??? Carbon Dioxide is plant food, so ask the question this way. Does it help plants to give them more highly concentrated plant food?
Here are a few references:
Another benefit of climate change and increased CO2 – trees continue to grow at a faster rate
Newsbytes: World food production at record levels