The problem with inferring ancient temperature is you have to rely on sparse proximal data (ie tree rings, ice cores, etc) that is only accurate within 1 or 2 d

The problem with inferring ancient temperature is you have to rely on sparse proximal data (ie tree rings, ice cores, etc) that is only accurate within 1 or 2 degrees C for estimation and then you have to fill in whatever's missing, geographically and temporally. Still sometimes the data does indicate sharp, dramatic changes, such as the Younger Dryas, about 12K years ago. After the recent glacial period ended, roughly 14K YA, there was a plunge back to glacial temps over a couple centuries which lasted about 1200 years, then very suddenly the temperature rose almost 20C. https://en.wikipedia.org/wiki/Younger_Dryas#/media/File:Younger_Dryas_and_Air_Temperature_Changes.jpg https://en.wikipedia.org/wiki/Younger_Dryas#/media/File:Youn...