CHANG­ING CUR­RENTS

Asian Diver (English) - - Ocean Ambassador Adex 2017–2018 -

Melt­wa­ter from glaciers and ice sheets will im­pact the sys­tem of ocean cur­rents that move heat around the world, and drive the cli­mate. Sci­en­tists are now ob­serv­ing fluc­tu­a­tions in these cur­rents.

About a quar­ter of our planet’s heat flux (the heat that is moved around the world) is driven by a cur­rent called the At­lantic Merid­ional Over­turn­ing Cir­cu­la­tion (AMOC).

The cur­rent is pow­ered by vari­a­tions in water den­sity: Water that is cold or salty sinks; water that is warm and less saline rises. To­day, cold water sinks in the North At­lantic and flows south­wards, while warm wa­ters at the sur­face flow north­wards in a cur­rent called the Gulf Stream, which keeps the cli­mate in north­ern Europe un­usu­ally mild for its lat­i­tude.

If water in the north­ern hemi­sphere gets too warm, or too fresh, then it will not be dense enough to sink, and will create a “traf­fic jam”, pre­vent­ing the cur­rent from flow­ing as it should.

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