Tudy Examines Climate Variability

A University of Miami (UM) Rosenstiel School of Marine and Atmospheric -led study challenges the prevailing wisdom by identifying the atmosphere as the driver of a decades-long climate variation known as the Atlantic Multi-decadal Oscillation (AMO). The findings offer new insight on the causes and predictability of natural climate variations, which are known to cause wide-ranging global weather impacts, including increased rainfall, drought, and greater hurricane frequency in many parts of the Atlantic basin. For decades, research on climate variations in the Atlantic has focused almost exclusively on the role of ocean circulation as the main driver, specifically the Atlantic Meridional Overturning Circulation, which carries warm water north in the upper layers of the ocean and cold water south in lower layers like a large conveyor belt. "The idea of the ocean as the driver has been a powerful one.” said UM Rosenstiel School Professor Amy Clement, the lead author on the study. We used computer models in a new way to test this idea, and find that in fact there is a lot that can be explained without the ocean circulation. While the overall rise in average temperature of the Atlantic is caused by greenhouse gases, this study examines the fluctuations occurring within this human-related trend. Identifying the main driver of the AMO is critical to help predict the overall warming of the North Atlantic Ocean in coming decades from both natural and man-made climate change.