Abrupt climate changes of Holocene

This paper is a review of studies of abrupt climate changes (ACCs) during the Holocene published during the past ten years. North Atlantic cold events are indicators of ACCs. As indicated by North Atlantic ice-rafted debris (IRD), there were nine confirmed cold events during the Holocene, occurring at 11.1 kyr, 10.3 kyr, 9.4 kyr, 8.1 kyr, 5.9 kyr, 4.2 kyr, 2.8 kyr, 1.4 kyr, and 0.4 kyr respectively according to most representative results from Bond et al. (1997). However, the identification of chronology has been made with some uncertainties. Considerable climatic proxy data have shown that, during the cold events, substantial climate abnormalities have occurred widely across the globe, particularly in the areas surrounding the North Atlantic. These abnormalities were in the form of high-latitude cold in the both hemispheres, expansion of the Westerlies to low latitudes, drought in the monsoon regions, recession of summer monsoons, and intensification of the winter monsoons. Studies have indicated that the four ACCs occurring in the early Holocene may be related to freshwater pulses from ice melting in the northern part of the North Atlantic, and the other five ACCs that occurred during the middle and late Holocene may be related to the decreased solar activity.