The 8.2 Ka Abrupt Climate Event: Causes, Impacts and Future Implications

ABSTRACT The 8.2 ka abrupt event is now recognized as an ideal analogue to test model sensitivity to future North Atlantic freshwater forcing, due to its short, century‐long duration that happened in the current interglacial period under boundary conditions that were close to pre‐industrial conditions. Previously described anomaly patterns that emerge in this review are cooling around the North Atlantic and drier conditions in the Northern Hemisphere tropics. With newer reconstructions from the Southern Hemisphere, a clear picture of drying and the popular interhemispheric bipolar seesaw is confirmed. Most anomalies around the North Atlantic spanned ~100–200 years, whereas the impact on the hydrological cycle in monsoon tropics lasted for up to 400 years. Longer monsoon anomalies and a lag in response to North Atlantic cooling are possibly due to the role of atmosphere‐surface ocean teleconnection underlining its crucial importance in high‐to‐low latitude teleconnections. Unresolved questions remain about the seasonality of the climate response to freshwater forcing and the lag observed in the onset of anomalies in the monsoon tropics. The 8.2 ka event has been proposed as an analogue for future ocean circulation changes due to the future Greenland ice sheet melting; it is therefore crucial to refine the Atlantic Meridional Overturning Circulation response to the 8.2 ka freshwater forcing and estimates of changes due to topography and albedo changes over Greenland, which is still debated in the scientific community. This article is categorized under: Climate, History, Society, Culture > Disciplinary Perspectives Climate, History, Society, Culture > Ideas and Knowledge