There are two currents responsible.
The first ocean Current is called the 'North Atlantic Drift'
(not the Gulf Stream - the North Atlantic Drift is a continuation
of it). It flows from 300 miles west from New York to Europe
at less than 5 miles an hour (measured by boats and satellites).
It is a warm current as it raises temperatures.
There are various causes
of ocean currents. The North Atlantic Drift is caused by
strong South-West winds in the Gulf of Mexico. A Mediterranean
current is caused by differences in salinity.
But why should a flow of
water so cold in winter it would kill anyone in it for more
than a few minutes responsible for high temperatures in
Europe. The reason is that water is a super reservoir of
heat. It can be heated to a deeper depth than land has a
high specific heat capacity (takes a lot of heat to raise
its temperature). On the coasts of Europe this heat is released
and carried towards land by the South Westerly prevailing
winds. These warm the winds raise the temperatures of Western
Europe. If you happen to swim in the sea (at Bournemouth)
and swallow some sea water (not recommended) you will notice
how remarkably salty the water is. Although all sea water
is salty it is especially so as it was transported from
the Gulf of Mexico by the North Atlantic Drift.
Newfoundland is made even
colder by a cold current. It is called the Labrador current
Cold water travels down from the arctic.
At one point the two currents
actually meet. The different densities means that just like
air masses the two do not mix well! Instead of depressions
being formed this ocean current junction is famous for its