Actually, it does exist. And as the article pointed out, it has been happening for millions (billions) of years. The argument is whether mans activities influences it anymore than the natural cycles that have existed since time began, and will exist long after we've turned to dust, and released the CO2 in our bodies back into the atmo.
I'm of the opinion that the universe is a very large, and very complex place, and we're pretty damn arrogant to think we know it all. We don't.
That, and the global warming "crisis" is in itself a man made phenomenon designed to redistribute the wealth of nations, and hobble continued grown and advancement of the west in general, and the USA in particular.
I guess I sould have done a better job of communicating my point. What I meant to say is that global warming as a consequence of man’s existence does not exist. This earth has been going through climactic changes since it’s beginning.