Abstract
Greenland ice cores provide us with insights that climate during the last 11,600 years, the Holocene, was relatively stable as it is compared with those in glacial periods. During this period, human societies changed from hunter-gatherer societies to agricultural ones, causing rapid cultural developments toward present. However, even in this relatively stable period a few abrupt climate changes have been known. In this paper, by closely looking at abrupt climate changes 8,200 years ago and 11,270 years ago, we will examine a range of natural climate variability that can not be inferred from short observational records.
