«The Gulf Stream, together with its northern extension towards Europe – the North Atlantic Drift – is a powerful, warm, and swift current that originates in the Gulf of Mexico, exits through the Strait of Florida, and follows the eastern coastlines of the USA and Canada before crossing the Atlantic. At about 30ºW-40ºN, it splits in two, with the northern stream crossing to northern Europe and the southern stream recirculating off West Africa.
It influences the climate of the east coast of North America from Florida to Newfoundland, and the west coast of Europe. It is a western-intensified current, largely driven by wind stress. The North Atlantic Drift, in contrast, is largely thermohaline (temperature and salinity) circulation driven. By carrying warm water northeast across the Atlantic, it makes Western 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.
The Gulf Stream transports about 1.4 petawatts of heat – equivalent to 100 times the world energy demand. It carries water at a rate of 30 million cubic meters/second (30 sverdrups) through the Strait of Florida. After it passes Cape Hatteras (North Carolina), this rate increases to 80 million cubic meters/second.
As it travels north, the warm water undergoes evaporative cooling and brine exclusion. The cooling is wind driven and causes evaporation, leaving a saltier brine. In this process, the water increases in salinity and density, and decreases in temperature. The second process involves the formation of sea ice, which likewise increases the salinity of the brine solution, thereby decreasing its freezing point. These two processes produce water that freezes at a lower temperature than 0ºC.
In the North Atlantic, the water becomes so cold and dense that it begins to sink down through warmer, less salty and less dense water. This downdraft of heavy, cold and dense water becomes a part of the North Atlantic Deep Water Current, a south going stream.
There is some speculation that global warming could decrease or (even) shutdown thermohaline circulation and therefore reduce the North Atlantic Drift. This could trigger localised cooling in the North Atlantic and lead to cooling (or lesser warming) in that region, particularly affecting areas such as Scandinavia and Great Britain. The chances of this occurring are unclear.
At present, most available data show that Gulf Stream flow was stable over the past 40 years. One report, based on a snapshot survey, suggested that the deep return flow has weakened by 30% since 1957, which would imply a weakening in the North Atlantic Deep Water production. However, this should have caused a temperature drop of several degrees in northwest Europe, which has not been observed. It was later discovered, using the first cross-Atlantic array of moored current meters, that variations within one year were just as large.
At least part of the apparent weakening of the Gulf Stream, if real, may be cyclical and connected to recent positive values of North Atlantic Oscillation. Recent research shows that Gulf Stream volume transport during the Little Ice Age was 10% weaker than today’s, implying that diminished oceanic heat transport may have contributed to the 16.th- to the mid-19.th-century cooling in the North Atlantic.»
"Gulf Stream", Wikipedia - edited & abridged
Man had no significant intervention in the Little Ice Age.
But what about now?
The Industrial Revolution only started by the end of the 18.th century, and up till now gazillions of tons of Carbon Dioxide (CO2) have been already thrown into the atmosphere, being the first cause of the greenhouse effect and of global warming.
For the very first time in the history of our planet – ± 4,500 million years – mankind may be altering life support conditions forever. From now on, environment and eco-worries will always be inseparable.
But what kind of signals do we get from economy and politics?
You think about that, dear blogger friend, and find it out…
Think meanwhile about Seychelles Islands, which are about to be submerged by the Indian Ocean… Or some of Solomon and Vanuatu islands threatened by the Pacific… Can this be sheer speculation?