Fact: Plant life required carbon dioxide to exist.
Fact: Plants emit oxygen, required for humans to live.
So, we do away with as much carbon dioxide as possible, killing (or at least weakening) plant life which return the favour by giving off less oxygen.
Hey, presto! We all die and Earth goes on as it always has.
Fact: Animals exhale CO2
Fact: Plants have survived from the CO2 obtained from animals and humans way before humans even existed or started using fossil fuels.
So there's almost no chance of all plants dying from global warming regulations.
Fact: At CO2 concentrations of 200 ppm or less very little grows.
Fact: At high levels of CO2 plants grow like the dickens. All evidence we have shows that when the CO2 levels have been elevated the world was a much nicer place.
Fact: According to the geologic record in those rare times that the atmosphere has not been able to deal with elevated levels of CO2 the excess has gone into the oceans and precipitated limestone, thus sequestering the CO2 for later era's.