There is a caveat. They only consider CO2 from specific sources to be pollution, so we can't just blanket call it pollution. For example, the CO2 I exhale would not be considered pollution, but if it's coming from fossil fuels or even burning trees, then it is. I'm not sure how they handle the natural burning of tree, like wildfires though.
However we are releasing an excess amount that had been trapped and removed from that cyclical process, adding more energy into the system than its natural equilibrium usually takes.
This actually isn't true. They say they burning of trees requires such a long cycle time that the release of CO2 does contribute to global warming.
My main point was that this distinction isn't something that people commonly think about. Usually think mercury, sulfur, etc, which are not things we naturally emit.