Paleoclimatological and paleoenvironmental records since 4000 a BP in sediments of alpine lakes in Taiwan

The 3 310-m-high Chia-min Lake records the climatic history since 4 ka B.P. in Taiwan. The warm/wet period before 2.2 ka B.P. seemed to correspond to the later part of the Holocene Megathermal, and the cold/dry period during 0-2.2 ka B.P. corresponded to the Katathermal. Before the termination of the Megathermal, an especially warm and humid segment (2.2-2.4 ka B.P.) emerged. The paleoclimatic records from Yuen-yang and Chi-tsai Lakes support the notion that the Megathermal in Taiwan terminated during 2-2.3 ka B.P. A warm segment (820-1 320 AD) in the Katathermal could be considered the Medieval warm Period. The climate turned cold and dry after 1 320 AD and this indicated the onset of the Little Ice Age. These paleoclimatic variations are also in good agreement with those recorded in Great Ghost Lake.