Often in the context of Anthropogenic Global Warming (AGW), comparisons are made to the changes of CO2 during the glacial cycles. Running the CRM models as in the last post, I compared runs for the Last Glacial Maximum and with variations holding a single component fixed in order to compare relative significance of glacial ice ( using 2010 instead of LGM ), CO2 ( using PreIndustrial instead of LGM ), Land Mask ( using 2010 land instead of the 5% increased land surface area from the LGM sea level fall ), and Orbit ( using the LGM orbit instead of LGM ).
The resulting annual mean radiance does not indicate a great deal of variance:
But as in the last post, the mean annual radiance obscures the dynamic seasonal variation of radiance:
This is seen in the depiction of the ranges of net radiance:
And the more significant term is the maximum net radiance, specifically at the latitudes of ice accumulation:
As to the glacial state, the most important factor appears to be the glacial state itself. This is consistent with stochastic resonance determining glacials, because there are two quasi stable solutions: non-glacial which tends to gravitate toward a non-glacial state, and glacial which feeds back to a continued glacial state. When snow and ice persisted for some period, feedback tended toward further accumulation. The effect of CO2 on maximum net radiance change is relatively small.