Your two comments are right on, and there is a third: You could hardly call it "global warming" when we've merely caught up to where we were three hundred years ago.
Quite simply, anybody who points to the current heat waves in various places as "proof" of Global Marming doesn't even understand their own hyposthesis and may be dimsissed with a wave of the hand.
The hypothesis is that the globe is warming up very slowly -- a small percentage of a degree per year and that it is a slow trend. So you don't even have to deal with the preposterous notion of whether it is human-accellerated (I think they are finally coming around to agreeing it is part of the planetary cycle).