The abrupt climate warming events that occurred in Greenland during the last glacial period occurred very close in time to other rapid climate change events seen in paleoclimate records from lower latitudes, according to a new study, which reveals a near-synchronous teleconnection of climate events spanning Earth's hemispheres. The new high-resolution paleoclimate chronology, which was derived from thin layers of sedimentary cave rocks from around the world, provides a framework to improve climate change models and constrain ice-core chronologies. This is important in the context of considering future abrupt climate change around the globe. Climate records from Greenland ice cores spanning the last glacial cycle (115,000 to 11,700 years ago) reveal a series of abrupt climate fluctuations between warm and cold conditions. These oscillations, also known as Dansgaard-Oeschger (DO) events, are characterized by an abrupt transition to a period of rapid warming, which is followed by a more gradual, and then abrupt, return to a cooler climate state. The oscillations occur quasi-periodically on a centennial- to millennial-scale. Outside of the Arctic, similar abrupt climate change events during the last glacial have also been identified in a host of other paleoclimate records from far-away regions across the globe. While the processes responsible for the abrupt transitions aren't well understood, they are thought to be linked. However, due to the lack of precise paleoclimate chronologies with comparable resolutions, determining if Greenland's DO events occurred at the same time as other abrupt climate changes elsewhere remains difficult. Ellen Corrick and colleagues compiled data from 63 published, high-resolution and precisely dated speleothem records, which describe the last glacial period in regions across the Northern Hemisphere mid-latitudes to the Southern Hemisphere sub-tropics. Using the dataset, Corrick et al. investigated the timing of 53 major and minor abrupt warming events and found that those recorded in Greenland's ice were synchronous with abrupt climate changes across the Asian Monsoon, South American Monsoon and European-Mediterranean regions. The findings suggest that abrupt Arctic warming events triggered rapid climate change on a global scale.
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Science