North Atlantic Deep Water North Atlantic Deep Water formation has been dramatically reduced at times during the past (such as during the Younger Dryas or during Heinrich events), and that this might correlate with a decrease in the strength of the Gulf Stream and the North Atlantic drift, in turn cooling the climate of northwestern Europe. There is concern that global warming might cause this to happen again. It is also hypothesized that during the Last Glacial Maximum (LGM), NADW was replaced with an analogous watermass that occupied a shallower depth known as Glacial North Atlantic Intermediate Water (GNAIW). North Atlantic Deep Water North
Agulhas Current but sometimes meanders on the Agulhas Return Current merge to contribute to the shedding of an Agulhas ring. In the southeast Atlantic Ocean the current retroflects (turns back on itself) in the Agulhas Retroflection due to shear interactions with the strong Antarctic Circumpolar Current, also known as the "West Wind Drift" despite referring to the ocean current rather than to the surface winds. This water becomes the Agulhas Return Current, rejoining the Indian Ocean Gyre. It is estimated that up to 85 Sv (Sv) of the net transport is returned to the Indian Ocean through the retroflection. The remaining water