General chat.& Random stuff

My question here, is that if - as he states, that plant life starts to die at 0.2%, and we're currently at 0.4%, wouldn't it stand to reason that a small raise could also cause problems ?

What is normal range for CO2 in plants?
A plant can perfectly tolerate levels between 1500 and 2500 ppm, in practice levels do not usually even reach 900 or 1000 ppm. In all the biological machinery involved in the exploitation of the air's carbon, one of the most important enzymes is rubisco which is combined with CO2 to activate sugar formation.

Are higher CO2 levels good for plants?
Green plants grow faster with more CO2. Many also become more drought- resistant because higher CO2 levels allow plants to use water more efficiently. More abundant vegetation from increased CO2 is already apparent.