Re the temperature timeline posted above. There is about a 40 degree celsius difference in the average temperature between Helsinki and Singapore. Both cities provide a very high standard of living to their inhabitants. So humans can do quite nicely in a wide range of temperatures. Ask any Inuit.
As far as I know the mechanism that lead to the ice sheets is still unclear, neither temperature or CO2 explains it. It was the flooding behind the retreat of the ice sheet, The Laurentian Sea, that formed the geomorphology of New England and Eastern Canada. Interpreting that geomorphology provided my job. Al Gore highlighted in one of his original slides that the flooding was a warning of what would/could/might happen if we did not check climate change. After reviewing the other slides I came to the conclusion the man is the PT Barnum of our age and began to be very skeptical of the rest of the AGW movement. Everything else I have researched tells me that there is a gross oversimplification being sold of a very complex system we do not understand or control.
Most people are convinced that the relationship between climate and CO2 is analogous to the burner on your stove and the control knob. Simply not true and no evidence anywhere.
This article , referenced above,
https://www.sciencedirect.com/scienc...77379118307261, is really fascinating. Back when I tool up being an environmentalist the big concern was the next ice age! There was a lot of research, for the time, showing land use change in Canada and Australia, was behind climate change. How does land use affect water vapor? Any takers?
20driver