Comment on A biologist’s perspective on ice ages and climate sensitivity: Part I by Coldish

Herman: the primary evidence is the correspondence between summer insolation in the northern hemisphere (as calculated from the Milankovich cycles) and the oxygen isotope record from deep-sea sediment (which is thought to reflect ice volume). There is also a reasonably good correspondence between the Vostok isotope data and the deep sea record, at least back to 125 ka or so.