Rasmus said:
Well, as far as I know, global warming will lead to local cooling. Since the gulf-current might be diverted, if the ice continues to melt at the north pole. If the gulf-current suddenly end off the coast of spain, we would have a BIG problem. (snip)
First, the Gulfstream ends way off the coast of Norway. South bound currents off the Spanish Atlantic coast are cold. The same situation holds true on the west coast of North America. In our case the California Current (As the Japanese Current is known after it turns south from Alaska) is a cold water current. The warm air Europe gets comes from the Middle Atlantic, the Gulfstream as it passes by North America, and North America itself.
Second, the sudden 'cut-offs' of the Gulfstream those many millennia ago came about thanks to the sudden introduction of a lot of fresh water in a comparatively short time. The Arctic ice cap isn't that big in terms of volume. It's thing, all things considered, rarely averaging over 30' thick. In addition, it isn't all fresh water ice. Most of it is salt water ice. It takes a while for the salt to leach out of the ice. Then you have the barriers to water going from the Arctic to the Atlantic.
The largest connection between the Atlantic and Arctic Oceans, the Denmark Straits, is a shallow body of water. Were it twice as deep as it is, then you would see a substantial exchange of (relatively) warm water from the Atlantic with cold water from the Arctic, and a very different world. As it is, there is very little transfer of water between the two oceans through the Denmark Strait, and even if the Arctic ice cap melted I doubt that would change.
Why? Because that fresh water suddenly introduced to the Arctic Ocean would most likely be thoroughly 'diluted' by the ocean water well before it even got near the Atlantic
It's Greenland you need to worry about. With her western mountains it's more likely all that water from a sudden, catastrophic melting of the ice would flood into the waters between Greenland and Norway, cooling them and interrupting the winds that carry the last little bit of Gulfstream warmth to Scandinavia. With the diluted sea water heading south along Europe's Atlantic coast and causing all sorts of havoc to the coastal marine life. So all you Skands might want to stock up on cold weather gear, just in case.