The current is driven by wind, not melt water. The day the artic becomes just as warm as the tropics is the day the cycle ends...what are the odds of that?

Partyguy, you are very strange, that comment is really odd. Being a disruptive norty boy again?! Northern England and the Eastern Seaboard of the US are warmer than Russia and internal Canada because the north atlantic drift sucks warm water from the Caribean. It shuts down if too much fresh water from melting glaciers stops the process, this has happened before, and both places could see temperatures plunging maybe 5 degrees. When the cycle ends, the poles get a bit warmer from higher absorbtion of sun from more sea water, the bit inbetween the poles and the tropics gets a bit colder when less heat flows up from the tropics, and the tropics heat up to the point where coral reefs and rainforests cannot survive, because the mechanism for transfering heat from the tropics to the sub-tropics and temperate areas shuts down. Read "Heat" by George Monbiot.

The weather in Europe this year has been what one would expect from a weaker north atlantic drift, the artic jet streams that are usually over the nordic countries has strayed far south and covered the UK. Story is, that a few hurricanes should shift it north, but, if a weak north atlantic drift is stopping hurricanes from transferring heat north, then that won't happen. Scary stuff if I'm right, but I'm not a metreologist, so, I may be totally wrong!!

"Nobody needs to go anywhere else. We are all, if we only knew it, already there." (Aldous Huxley "Island" 1962, p38)

The Thermohaline Circulation (THC) is not primarily wind driven. You are wrong, again. The temperature differential coupled with the salinity differential (and the resulting differences in density) are the major driving factor in the Thermohaline Circulation. So how does it work? Northern latitude cooling of highly saline ocean water is the main driver. As that water cools and achieves significant density differences, it sinks which pulls more southerly water north to be cooled yet again.

The arctic ice melt is of interest because while it is not lowering the salinity, it is in an area of the world that contains large amounts of non-oceanic ice (Greenland, Canada, and Siberia) which if melted would inject a large volume of fresh water into the arctic region. Exactly what effect this would have on the THC is not well understood at this time but it is believed that certain northern regions which have experienced balmy weather might not continue to do so.

Finally, no one has suggested that the arctic will become as warm as the tropics. That comment was a deliberate strawman, which is common from you. In fact, I cannot recall a single comment from you that ever contained anything other than smartass remarks intended to incite flame wars. You might eventually try contributing something useful to the discussion instead of trying to be a troll.

"The greatest shortcoming of the human race is our inability to understand the exponential function." -- Dr. Albert Bartlett
Into the Grey Zone

GZ -- there's a conflation of terms here, in large part (though not exclusively) by Partyguy. The "Arctic drift current" in the parent poster's context appears to refer to the Gulf Stream, which is indeed wind driven. The THC, as you point out, is density driven.

The Gulf stream is not wind drive, it is to do with the interaction between fresh and saline water around Greenland, as mentioned by the previous post. The gulf stream sucks warm water from the west indies towards greenland. Weather systems feed from that energy in the same way that hurricanes feed from the warm water of the gulf of mexico. This gives tropical jet streams power to push arctic jet streams northwards away from western europe and parts of the US eastern seaboard, explaining why london does not have a similar climate to somewhere like moscow, which on the same lattitude. Take away the gulf stream and, apparently, England would have the climate of Spitzburgen (I think that's the name, an arctic island somewhere north of norway).

By the way, I've seen many people like Party Guy in other blogs that aim to deal with issues where there are strong vested interests. I have no doubt that there are people out there paid by vested interests to disrupt blogs and put doubt into people's minds, just as these corporations do with the media, spreading lies and commissioning "scientific" reports, like was done by Esso and the like to give the illusion that there is no consensus in the scientific community about global warming, and the same applied to the tobacco industry. They exhibit a similar technique, repeating commonly held myths with no backing and having a dismissive argumentative tone in their comments. Can spot em from a mile off. The thing is, that nobody in their right mind would spend so much time on a blog that was so anti their point of view, especially if they knew nothing about the subject and got slagged off all the time, unless they actually had a vested interest to do so.

"Nobody needs to go anywhere else. We are all, if we only knew it, already there." (Aldous Huxley "Island" 1962, p38)

This thread is now moribund, but this comment still merits a correction. The Gulf Stream today is part of the surface component of the Meridional Overturning Circulation, which is the North Atlantic part of the THC. If the extreme scenarios pan out and the THC weakens or shuts down because of icesheet melt, then the Gulf Stream will continue, it just won't be carrying heat to N. Europe. That heat will remain in low latitudes.

If you look at the flow over N. America you will note that just past the Rockies the flow drifts to lower latitude over the Great Plains, then swings back up to higher lats over the Eastern Seaboard. That swing is driven by a need to conserve angular momentum; it helps that the flow would otherwise be blocked by the N. Atlantic subtropical high (aka Bermuda or Azores High, depending on season). That swing is also what drives the Gulf Stream.

Weather systems feed from that energy in the same way that hurricanes feed from the warm water of the gulf of mexico.

Weather systems over the US and Europe are extratropical cyclones, which are completely different from tropical cyclones (though one can morph into the other, usually tropical to extratropical). The former is driven by thermal and humidity differences between airmasses and is controlled by the polar jet (which of course is a boundary itself), the latter is a heat engine converting warm ocean surfaces to high wind and heavy rain and form within an airmass.

Hi davet,

I just wanted to say "thanks" for your addition here.