Riding on the Gulf Stream
On the way from Cuba to the Bahamas, Statsraad Lehmkuhl sails through seawater that holds 33 degrees C. In a few months, the same water will heat the coast of Norway.
It is here, between Cuba and Florida, that the warm water that makes the climate in Norway mild and nice, flows into the Atlantic ocean.
In the image below, you can see the Gulf Stream meandering forward. It flows like a river from the Gulf of Mexico and north towards Europe, moving more water than all the rivers on the planet, combined.
The speed is not impressive, only 6 kilometers per hour, fast enough to help Statsraad Lehmkuhl onwards.
– We arrive in the Bahamas tomorrow morning after some nice days at sea, less motoring than expected and upwind sailing all the time, being ‘pushed’ in the right direction by a very helpful Gulf Stream, writes captain Jens Joachim Hiorth in his log on the first of December.
Without the heat from the Gulf Stream, Norway would have the same cold climate as Greenland, Alaska and northern Canada.
The hot water is not pushed to the north, it is sucked. The engine is cold and salty water in the North Atlantic. When the seawater freezes to ice here, the remaining water becomes saltier. Salty and cold water are heavy, and sink just like the piston in a pump. Hot water is sucked northwards on the surface, and pushes cold water southwards down in the depths.
Wind and tides also create currents, but all the deep ocean currents are created like the Gulf Stream, due to differences in salinity and temperature.
The engine that drives the Gulf Stream does one more important job. The sinking water removes CO2 from the atmosphere. In the last 100 years, the ocean has taken up a quarter of all the CO2 that we humans have emitted.
The water in the surface absorbs CO2 all over the globe, but it is only in two areas that this CO2-rich water sinks into the depths: around Antarctica, and in the North Atlantic. It can take hundreds of years before this water reappears on the surface.