TY - JOUR
T1 - The 8k event
T2 - Cause and consequences of a major Holocene abrupt climate change
AU - Alley, Richard B.
AU - Ágústsdóttir, Anna Maria
N1 - Funding Information:
Data provided by the National Snow and Ice Data Center, University of Colorado at Boulder, and the WDC-A for Paleoclimatology, National Geophysical Data Center, Boulder, Colorado, and by Minze Stuiver, Quaternary Isotope Laboratory, University of Washington, Seattle. Funding was provided primarily by the US National Science Foundation Office of Polar Programs, through several grants including 0126187 and 0229629. We thank numerous colleagues in the NOAA Abrupt Climate Change Panel, the NRC Abrupt Climate Change Committee, the Gary Comer Foundation Fellows, and the GISP2 and Siple Dome ice coring projects for data, insights and discussions. We thank David Pollard, Bill Peterson and Peter Fawcett for assistance in the modeling, Bill Curry for discussions and help with Fig. 1 , and Lloyd Keigwin for insightful comments. We thank many students at Penn State for insights to the event, and especially Glenn Spinelli and Michael Osterhout. We thank Trond Dokken and an anonymous reviewer for helpful suggestions.
PY - 2005/5
Y1 - 2005/5
N2 - A prominent, abrupt climate event about 8200 years ago brought generally cold and dry conditions to broad northern-hemisphere regions especially in wintertime, in response to a very large outburst flood that freshened the North Atlantic. Changes were much larger than typical climate variability before and after the event, with anomalies up to many degrees contributing to major displacement of vegetative patterns. This "8k" event provides a clear case of cause and effect in the paleoclimatic realm, and so offers an excellent opportunity for model testing. The response to North Atlantic freshening has the same general anomaly pattern as observed for older events associated with abrupt climate changes following North Atlantic freshening, and so greatly strengthens the case that those older events also reflect North Atlantic changes. The North Atlantic involvement in the 8k event helps in estimating limits on climate anomalies that might result in the future if warming-caused ice-melt and hydrologic-cycle intensification at high latitudes lead to major changes in North Atlantic circulation. Few model experiments have directly addressed the 8k event, and most studies of proxy records across this event lack the time resolution to fully characterize the anomalies, so much work remains to be done.
AB - A prominent, abrupt climate event about 8200 years ago brought generally cold and dry conditions to broad northern-hemisphere regions especially in wintertime, in response to a very large outburst flood that freshened the North Atlantic. Changes were much larger than typical climate variability before and after the event, with anomalies up to many degrees contributing to major displacement of vegetative patterns. This "8k" event provides a clear case of cause and effect in the paleoclimatic realm, and so offers an excellent opportunity for model testing. The response to North Atlantic freshening has the same general anomaly pattern as observed for older events associated with abrupt climate changes following North Atlantic freshening, and so greatly strengthens the case that those older events also reflect North Atlantic changes. The North Atlantic involvement in the 8k event helps in estimating limits on climate anomalies that might result in the future if warming-caused ice-melt and hydrologic-cycle intensification at high latitudes lead to major changes in North Atlantic circulation. Few model experiments have directly addressed the 8k event, and most studies of proxy records across this event lack the time resolution to fully characterize the anomalies, so much work remains to be done.
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U2 - 10.1016/j.quascirev.2004.12.004
DO - 10.1016/j.quascirev.2004.12.004
M3 - Article
AN - SCOPUS:14944357365
SN - 0277-3791
VL - 24
SP - 1123
EP - 1149
JO - Quaternary Science Reviews
JF - Quaternary Science Reviews
IS - 10-11
ER -