tim flannery's triple backflip., page-20

3.Yes CO2 is essential, however an over abundance (from what ever source) has effects on Climate ie pollutant.

well no

go to a large tomato cropper and have a look at the amounts of co2 pumped into the system. very high amounts of the gas and the plants grow significantly.

then we eat them - no harmful effects that i can see

btw - it is a certainty and a scientific fact that enough gas of any kind including o2 will kill you. that doesnt make them pollutants that must be taxed