CO2 is the physical fuel in chloroplast based photosynthesis that allows plants to use solar energy to break off the carbon atom and create long chain carbon molecules (sugars) with it. The waste product being O2-oxygen. The very basis of all life on earth. Oxygen is actually the waste product of photosynthesis, but I don't see anyone calling that a "pollutant" either.
When this period of collective asshattery is over these people will be looked at as being every bit as ignorant and narrowminded as some illiterate, dark-ages, dirt farmer who thinks the earth is flat.
The Pleistocene era, the coldest the earth has ever been since there was oxygen and surface water, with ice caps going from the poles to the middle of the USA, lasted for almost two million years, and we only mark it as being over 11,000 years ago. That is the coldest our planet has even been. We ARE in a warming period. The evidence is pretty conclusive. But, we just (like 1/10 of a second ago in geologic time) got out of a very bad ice age. The world is going to get much, much warmer, and there is NOTHING we can do about it, nor should we try.
Before the ridiculous theory of Anthropogenic Global Warming, based on the concentrations of a trace gas, this was widely known and accepted even by students. It is only through the widespread dissemination of this ridiculous junk science for political purposes that such idiocy persists. It is nearly identical to the church of the middle ages promoting a flat earth to scare people into not exploring any further.