It might be useful to ask the scientic question, form the hypothetical:

  What effect does CO2 have on life, on our earthy environment?
  What effects do different levels of CO2 have on life on earth at the present, and in the past?

  The scientic answer to both these questions is that CO2 is the foundation of life and has
  only positive effects on life in our earthly environment

  Scientic observation proves CO2 fertilization has increased plant growth by some 30%
  and increased drought resistance in arid areas further greening our lands

  This means about 30% more food to eat, 30% faster tree growth, 30% increase in pasture grasses
  Naturally caused famine, hunger, and malnutrition have been conspicuously absent over the last 3 decades

  There is no corelation between CO2 levels and Earth's atmospheric surface temperatures

  CO2 does not cause the air to warm, it does not affect weather patterns

  Ideally, for Earth's environment and life to thrive best
  CO2 levels should be 600ppm to 1000ppm, which will not appreciably affect air warming

  Besides ... Global Warming has had nothing but benefits for life as well