Grape Volcano

It is very simple to prove that man-made CO2 does not deserve most of the blame ( or credit ) for whatever warming we have seen in this century- such warming trends have been equaled or surpassed by warming trends of the pre-industrial age. Therefore, it is logical to accept that the primary cause of all these warming trends, pre- and post-industrial, is a cause that existed during *all* these warming trends.

The sun was present for all recorded warming trends.

Man-made CO2 was only present for one warming trend ( this century's ).

If a volcano erupted twenty times in history but, before the twentieth eruption, someone planted grapes on the side of the volcano, would you insist that the grapes were the cause of the twentieth volcanic eruption?

That would make no sense. Obviously, the cause of the first nineteen eruptions is most likely to blame for the twentieth.

Similarly- if the earth has warmed in the same manner nineteen times in the past, would it make sense to argue that something which only appeared during the twentieth warming trend ( man-made CO2 ) was behind the most recent warming?