The Gulf Stream, also known as the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that originates in the Gulf of Mexico, exits through the Straight of Florida, and follows the eastern coastlines of the United States and Newfoundland. Its extension toward Europe, called the North Atlantic drift, makes West-European countries considerably warmer than they would be otherwise.
A river of sea water, called the North Equatorial Current, flows westward off the coast of northern Africa. When this current interacts with the northwestern coast of South America, the current forks into two branches. One passes into the Caribbean, while a second flows north and east of the West Indies. These two branches rejoin to pour through the Straits of Florida.
Consequently, the resulting Gulf Stream is one of the strongest ocean currents known, transporting 1.4 Petawatts of power. It moves at an incredible rate of 30 million cubic meters per second. After it passes Cape Hatteras, this rate only increases to 80 million cubic meters per second. The volume of the Gulf Stream easily dwarfs all rivers that empty into the Atlantic combined, which barely total .6 million cubic meters per second.
As it travels north, some of the warm water transported by the Gulf Stream evaporates. This increases the salinity of the water in the stream, and in the North Atlantic Ocean the water is so cold and dense with salt that it begins to sink. It then becomes a part of the North Atlantic Deep Water, a southgoing stream.
The effect of the Gulf Stream is sufficient to cause certain parts of the west of Britain and Ireland to be an average of several degrees warmer than most other parts of those countries. Indeed, in Cornwall, and particularly the Isles of Scilly, its effects are such that plants associated with much warmer climes, such as palm trees are able to survive the rigours of northern winters. Logan Botanic Garden in Scotland benefits strongly from the Gulf Stream, allowing their specimens of Gunnera Manicata to grow to over 3 metres tall.
With the recent phenomenon of global warming, some scientists have expressed concern about the sink mechanism outlined above. Specifically, fresh water resulting from the melting of the Arctic polar cap could dilute the Gulf Stream and make it light enough not to sink. The result would be a huge climate change in northern Europe, with unknown consequences. Some fossil remnants hint at the possibility that a similar event has already happened several times in the past, but fossil evidence is questioned. After an initial rejection, the scientific community is evaluating this theory more seriously, as data about historic climate show sudden changes between cold and warm periods.
References
Further reading
Hycom Consortium