What caused widespread cooling 8,200 years ago?

This drainage is thought to have freshened waters in the northern Atlantic Ocean, slowing down the density-driven oceanic circulation that helps to distribute heat. Noting that an actual chronology of events must be established before scientists can speculate on causes of this cooling, Hillaire-Marcel et al. study oceanic records downstream from Lake Agassiz's flood discharge route. They find that the lake's drainage occurred between 8,500 and 8,350 years ago but that sea-surface and deep-current conditions, derived from oceanic sediment cores, lack significant concurrent changes in the northern Atlantic. Instead, the data shows that the 8,200-year-old cooling event was generated by several factors, including melting of North American continental glaciers and subsequent rapid sea level rise which induced a large-scale reorganization of broad oceanic circulation patterns.-American Geophysical Union