Permanence of Ocean Currents
Date: Winter 2011-2012
Are ocean currents permanent?
Although many ocean currents have been around for many thousands or
years, they can and do change over time. One of the problems some
scientists see with global warming is that some currents may shift
or stop all together.
For example, some folks, are worried that much fresh water may flow
into the sea from melting ice in Greenland This would, they say,
stop the Gulf Stream in the Atlantic ocean which keeps Europe
warm That would plunge Europe into another ice age.
But, on the whole, ocean currents do not change over the life of a
Since ocean currents are controlled by several factors: wind - which is the main cause of the different rotations in the northern and southern hemisphere, salinity - which, for example is the main factor in the southward diffusion from the north pole in the Atlantic ocean and the gulf stream, temperature, general ocean floor topography, etc. - changes (on a geological time scale) will cause changes in the ocean currents.
For example, if we imagine that most of the ice in the north pole were to melt, then then, after all that fresh water has mixed in, there would no longer be a salinity gradient between the northernmost regions of the Atlantic, versus those closer to the center, the Atlantic conveyor belt may slow down or stop. ... but, again, this is on a geological time scale, so be aware that changes in ocean current do take a long time to develop and change.
Greg (Roberto Gregorius)
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Update: June 2012