The Artemis Transat

In recent years, the question of the Gulf Stream’s hypothetical disappearance has been raised with the melting of Arctic glaciers due to global warming taking the blame. The rise of rain levels over the Atlantic, caused by the greenhouse effect, could also play a part in the Gulf Stream’s demise since these two combined factors bring a considerable volume of freshwater to the northern part of this ocean. The differential in density between Arctic and Norwegian Sea waters would then be reduced and it is estimated that the area where cold, salty and dense water descends would slide south all the way to the Azores, where the Gulf Stream would quickly die.




The consequences of this disappearance are widely debated within the scientific community, but the brutal dawn of a new Ice Age in Europe (as depicted in Roland Emmerich’s “The Day After Tomorrow”) is not regarded as a credible hypothesis. Numerous simulations tend to show that a decrease in winter temperature would be observed if the Gulf Stream was to cease existing, but this scenario would not be enough to counteract the warming – Martin Visbeck (Leibniz Sea Science Institute, Kiel, Germany) is one of many scientists to endorse this idea and Visbeck predicts that the Atlantic currents may weaken by 30% at the most by 2100. A major beneficial effect of the North Atlantic Drift’s dive is the burial of approximately a billion tones of carbon-dioxide each year: given this fact, it is simple to understand why the reduction of this dynamic is a source for concern.

It is also necessary to emphasize the role of the Labrador Current: a flow of water originating in the Arctic Ocean and generated by an encounter between the Occidental Greenland Current and the Baffin Island Current. It travels south along the eastern coast of Newfoundland, then towards the southwest and Nova Scotia. The Labrador Current induces a cooling of eastern Canada and New England, its waters being 8 to 10° C colder than those encountered at the same latitude in Europe or western USA. This current is responsible for the drifting of Greenland icebergs towards the North Atlantic during spring and summer. The thick fog over the Grand Banks is caused by the arrival of warm and humid air over this area of cold water.

What are the implications for the Artemis Transat fleet?
The Atlantic currents are determined by the Gulf Stream and the North Atlantic Drift up to 50 – 55° W. Further west, the skippers will benefit from the Labrador Current, except for those who choose a southerly route. Exiting the English Channel, the fleet will sail against 0.5 to 0.6 knots of current all the way to 45° to 50° W at whichever latitude they choose to sail. West of 50° W and until the latitude of South Nova Scotia, currents shift around. The Labrador Current then kicks-in, flowing towards the WSW at roughly 0.5 knots. Below 42° N and off the coast of the United States, the Gulf Stream travels to the NE at an average of 0.5 to 0.7 knots: its speed being reduced by contact with the Labrador Current (in terms of instant speed, the Gulf Stream can reach 5 knots at the most, mainly below 40° N). The tidal currents can reach several knots, but this phenomenon is independent from oceanic currents.


Focus... Icebergs
They can be encountered starting from 40° W, and go – in extreme cases - as low as 38° N (latitude of Lisbon, Portugal), with a maximum concentration in the area located East – South –East of Newfoundland. Thanks to the presence of the warm Gulf Stream, it is rare to spot icebergs lower than 48° N, but some years there have been reports of large chunks of ice “cruising” off New York! It is important to stress the fact that May is the month of the year during which iceberg concentration reaches its peak in that part of the Atlantic. Between 1990 and 2007, the average number of reported icebergs in May is 147, for an annual average of 471 in the zone covered by the International Ice Patrol (Canada and USA), spanning from 48° N to 52° N.


Thanks to Patrice Klein (Ifremer Brest) and Pascal Landuré (MeteoStrategy) for their precious collaboration.