Final answer:
In our current understanding of the Atlantic MOC, the salinity has decreased due to climate change and the melting of ice in the Arctic, which is affecting ocean circulation patterns and climate.
Step-by-step explanation:
In our current understanding of the Atlantic MOC (Meridional Overturning Circulation), the salinity has decreased. The Atlantic MOC is a large-scale ocean circulation that transports heat from the tropics to the North Atlantic. It is driven by differences in density, which are influenced by temperature and salinity.
Due to climate change and the melting of ice in the Arctic, freshwater is entering the North Atlantic, diluting the salinity and affecting the Atlantic MOC. This decrease in salinity can have significant impacts on ocean circulation patterns and climate.