Origin of Ice Ages: Pollen Evidence from Arctic Alaska.

Pollen analysis of radiocarbon-dated samples from the arctic coastal plain of Alaska shows that vegetation of 14,000 years ago reflected a climate colder than the present, and that there has been a progressive warming, culminating in the present cold arctic climate. The record indicates that the Arctic Ocean has been covered with ice since the time of the Wisconsin glacial maximum, suggesting that the essential condition of the Ewing and Donn hypothesis for the origin of ice ages, that the Arctic Ocean be ice-free up to 11,000 years ago, cannot be met.