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Unlikely…But Possible

The Gulf Stream is a powerful, warm, and fast moving current that transports warm water from the southern tropical regions near the equator to the colder regions near Greenland and Northern Europe. This helps keep Northern Europe’s climate mild and comfortable.  This “conveyor belt” is a very important mover of heat.  At the same time it allows cooler water to circulate south to allow the equatorial regions to keep from overheating. 

                                            

 But how does this complicated conveyor belt (called the Thermohaline circulation/ Thermo meaning heat and haline meaning salt) of warm and cold water work?  It works based off of the idea that things that are more dense (salt water) sinks below things that are less dense (fresh water). 

As the salt water sinks it does so with so much energy that it pulls the warm water on the surface in the opposite direction, much like a conveyor belt, thus allowing the different waters to move (cold water along the bottom of the ocean south and warmer water along the surface northward). 

What happens when this circulation is interupted? 

“Just over 8000 years ago, a huge glacial lake in Canada burst, and an estimated 100,000 cubic kilometres of fresh water rushed into the North Atlantic. Researchers now say they know for sure that this catastrophic event shut down the Gulf Stream and cooled parts of the northern hemisphere by several degrees for more than a hundred years. The findings show modelling studies are right to suggest that something similar could happen with equal abruptness as the planet warms under human influence. The film The Day After Tomorrow (imdb, wikipedia), which portrays such a scenario, may have exaggerated – but not by much.” Read more here or here.

What is important to remember however, is that when the lake in Canada burst 8000 years ago and during the recent Little Ice Age the temperatures were much colder than they were today.  These colder conditions made it so parts of Europe froze more readily.  Some climatologists now feel that by the time this conveyor belt were to shut down again (this is obviously not a good thing and some say the signs of it beginning are here read about it), enough ice will already be melted and the temperatures will be high enough that the lack of warm water moving north may be a welcome vacation from the extreme heat becoming characteristic in Western Europe (read more here and here) . 

Even if it isn’t as dangerous for Western and Northern Europe, we must not forget our neighbors to the south.  The thermohaline current not only brings warm water north; it brings cool water south.  Is it possible that if the conveyor belt shuts down, the equatorial regions may get even hotter than it already is because of a lack of cool water circulating their way?  Time will tell.

The ice sitting on top of Greenland is of great concern because it is melting extremely rapidly and is dumping more fresh water into the North Atlantic Ocean interupting the delicate balance of fresh and salt water.  Some scientists are worried that this could trigger the same situation as happened in the past triggering small ice ages (read about it).  Other scientists aren’t as concerned about another ice age being triggered (check it out).  They are more worried about the rise in sea level that is likely to occur from the masses of land based ice constantly calving (breaking off) into the oceans. 

Below you will find two videos explaning the thermohaline circulation:

Either situation is not one to be happy about!


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