http://www.construction-physics.com/p/we-need-more-research-on-how-co2?utm_campaign=post&utm_medium=web
I recommend this article from the newsletter “construction physics”.  It’s a good summary of the state of research on CO2 effects, we talk a lot about the effects of much lower concentrations but it’s unclear whether those effects are real, or caused by an associated condition, or just not as big as some studies indicate.

Zak