Where Is the Gulf Stream?
The Gulf Stream is in the Atlantic. It is a warm ocean current which flows steadily from the Gulf of Mexico north-eastwards. One branch reaches the Canary Islands, turns southwards and moves back across the South Atlantic, The other branch flows past the western coasts of northern Europe.
This current, which is like a river in the sea, is 50 miles wide at its narrowest and nearly 2,000 feet deep. It sweeps along with it many forms of warm water life from the tropics, but these die before they reach the European coasts where the warm water mixes with cold water moving down from the Arctic.
The Gulf Stream has a great effect on the weather of Britain and Norway. The prevailing south-westerly winds are warmed by it and collect moisture which turns into rain. In winter the warm water keeps open the cold northern ports, such as Hammerfest, in Norway, and Murmansk, in Russia, while harbors in the Baltic, many miles farther south, are blocked with ice. In summer it causes bright flowers to bloom on the west coast of Spitzbergen 500 miles north of Norway. In contrast, the east coast, cooled by Arctic water, is bleak and colorless.
In 1912 the United States Congress was asked for money to build a jetty which, it was thought, would divert the Gulf Stream and make it flow up the east coast of the United States. Although this scheme was unlikely to be successful, it was just as well for Britain and Norway that it was never tried. Without the Gulf Stream, Britain’s winters would be very much longer and colder, and Norway’s harbors, which are vital to the country, would be frozen over for many months.
The Gulf Stream proper is a western-intensified current, driven largely by wind stress. The North Atlantic Drift, in contrast, is largely thermohaline circulation–driven. In 1958 the oceanographer Henry Stommel noted that “very little water from the Gulf of Mexico is actually in the Stream”. By carrying warm water northeast across the Atlantic, it makes Western and especially Northern Europe warmer than it otherwise would be.
However, the extent of its contribution to the actual temperature differential between North America and Europe is a matter of dispute, as there is a recent minority opinion within the science community that this temperature difference (beyond that caused by contrasting maritime and continental climates) is mainly due to atmospheric waves created by the Rocky Mountains.
European discovery of the Gulf Stream dates to the 1512 expedition of Juan Ponce de León, after which it became widely used by Spanish ships sailing from the Caribbean to Spain. A summary of Ponce de León’s voyage log, on April 22, 1513, noted, “A current such that, although they had great wind, they could not proceed forward, but backward and it seems that they were proceeding well; at the end it was known that the current was more powerful than the wind.” Its existence was also known to Peter Martyr d’Anghiera.
Benjamin Franklin became interested in the North Atlantic Ocean circulation patterns. In 1768, while in England, Franklin heard a curious complaint from the Colonial Board of Customs: Why did it take British packets several weeks longer to reach New York from England than it took an average American merchant ship to reach Newport, Rhode Island, despite the merchant ships leaving from London and having to sail down the River Thames and then the length of the English Channel before they sailed across the Atlantic, while the packets left from Falmouth in Cornwall?
Franklin asked Timothy Folger, his cousin twice removed (Nantucket Historical Society), a Nantucket Island whaling captain, for an answer. Folger explained that merchant ships routinely crossed the then-unnamed Gulf Stream—identifying it by whale behavior, measurement of the water’s temperature, and changes in the water’s color—while the mail packet captains ran against it.
Franklin had Folger sketch the path of the Gulf Stream on an old chart of the Atlantic and adds written notes on how to avoid the Stream when sailing from England to America. Franklin then forwarded the chart to Anthony Todd, secretary of the British Post Office. Franklin’s Gulf Stream chart was printed in 1769 in London, but it was mostly ignored by British sea captains. A copy of the chart was printed in Paris circa 1770-1773, and a third version was published by Franklin in Philadelphia in 1786.