Lede is (deliberately?) misleading 

Global Warming has only been occurring since the 20th Century?  Hell, that's not only mislead, but it's an outright lie, apparently inserted for the ulterior purposes (advancing left-wing political agendas).

Global Warming is NOT a new phenomenon.  In fact, it has been steadily progressing for the last 12,000 years since the last ice age.  Warming itself is a loaded term, implying that there is a "pristine"/"correct" temperature.  A more accurate term would be "global thawing" as that's precisely what happens when the planet comes out of an ice age.