"2. We have seen vastly higher CO2 levels in planetary history and right now we are seeing what is actually all time lows. We should expect CO2 increases and, in fact, hope for them as going much below 300 ppm would see the beginning of a massive plant die off - there's a reason commercial greenhouses pump CO2 into their facilities."
We have seen vastly higher?
When? Some time before 400,000 years ago?