Marye wrote: I rather think we are arrogant and stupid enough to continue to polute. It is May and Toronto Canada has had it's second SMOG alert in as many days. I don't remember SMOG alerts when I was a child... I can hardly breathe outside. Who is the cause of this then, if it isn't man?
I don't think anyone here said the man doesn't pollute, just not to confuse pollution with carbon dioxide levels. When it is a component of the naturally occurring systems, variations in that system can be man-made or natural. So far the proof eludes science.
CO2 is not a atmospheric component measured for a smog alert.
Here's a good question for people who like to do their homework, what is the #1 source of freshly minted carbon dioxide in the atmosphere? Completely overwhelming all other sources. Warning, this is a tricky question.