Quote from dcraig:
Have you heard of light pollution or noise pollution? Neither noise nor light are necessarily bad, but in excess and in the wrong place they are not desirable. Same for CO2.
Human emitted CO2 is causing acidification of the oceans. This is pollution by any definition of the word.
And incidentally, CO2 is not harmless to humans in higher concentrations. I think it starts to set it at something like 5 -10 times current atmospheric levels (can't remember the exact level). Nobody is suggesting that we will reach these levels in the next 100 years, but should we burn all the fossil fuels - coal, oil gas, oil shale, sands etc, then levels could become directly harmful. Anyway, by that stage climate change would have become apocalyptic in extent.
The nasty thing about CO2 is that is only slowly scrubbed from the atmosphere by natural processes. The excess emitted by humans is there for decades and centuries. Just turning of the tap sometime in the future leaves a broken planet for a long time to come - and that is the best scenario.
for god's sake shut up ....