Oxygen isotopic ratios in the dating of ice cores
It was preceded and followed by warm interglacials which lasted on the order of about 10,000 years.
The glacial period shows significant shorter-period oscillations in climate.
If these processes occurred in such short periods, the entire chronology of the ice age is brought into question.
For example, the average global ocean temperature is typically estimated by the oxygen isotope ratios measured in ice cores.
Variations in oxygen isotope ratios from sea-floor sediment cores have extended climate studies to greater ages in the past, and have been interpreted to support multiple ice ages with intervening interglacials over at least the past one million years.
An underlying assumption of the Astronomical Theory is uniformitarianism.
The Younger Dryas Event is a climate reversal preceded and followed by abrupt warming during the deglaciation period about 11,000 years BP, according to the conventional chronology.
The event is documented in the δ have reported that portions of the Younger Dryas Event appear to have occurred in periods of less than four years.
This feedback mechanism, thought to be triggered by orbital variations, is a primary basis for current environmental extremism.
It is believed that a minor perturbation in solar heating caused by orbital changes could lead to another ice age or warming period.