clipped from: wattsupwiththat.com   
As we move towards solving the climate crisis, we need to remember the consequences to civilizations that refused to take environmental concerns seriously.

It means that Gore is advocating the abandonment of the IPCC doctrine and barracking for the study and understanding of climate dynamics that ignores totally the IPCC/AWG doctrine and focuses on all the other variables, especially how climate dynamics are driven by atmospheric/oceanic oscillations, the natural internal dynamics of the climate system and the role of the Sun in climate dynamics.

Brian Fagan in Floods, Famines and Emperors  El Nino and the fate of civilisations 

Here are some quotes from his book:

“The “Classic Maya collapse” is one of the great controversies of
archaeology, but there is little doubt that droughts, fuelled in part
by El Nino, played an important role.”

“The droughts that afflicted the Maya in the eighth and ninth
centuries resulted from complex, still little understood atmosphere-
ocean interactions,