North Atlantic Weather

1 Apr 2011

At scientists have been finding out why it is cold in NE America but not in NW Europe at the same latitude (a paper in Nature, March 31st 2001). It is 10 degrees Fahrenheit warmer in NW Europe than it is on the opposite side of the Atlantic. It seems the same thing occurs in the Pacific where winters in the Vancouver and Seattle region are mild in comparison with the same latitude on the eastern side of the ocean. The culprit, it is alleged, and it is really an allegation, is that warm currents of water in the east make it colder. That sounds like a paradox but there is logic to the tale. Warm water heats up the air in the sky above the ocean current but draws in cold air from the Arctic which forms a plume just to the west of the warmth - the eastern continent from Quebec and Labrador south to Maine, Massachusetts and New York State etc. The conventional explanation has always been that it is the Gulf Stream that delivers warm water to NW Europe - but apparently, the latest research is that ocean currents are not actually capable of transporting a lot of heat. Here, I'm fairly bemused as Ice Age Theory is all about the transportation of warm ocean water from the tropics into the polar regions - in order to bring such cold phases of climate to an end. The Gulf Stream runs up the west of the Atlantic, hugging Ireland and northern Scotland and warming Norway before swinging around and running down the eastern side of the Atlantic. In the Ocean Circulation model this takes place at a deeper level in the east than it does in the west - hence the current has little effect. The big question I suppose is how does the air warm up if the current has sunk to depth? This paper seems to upset the applecart - we shall have to wait and see how it pans out. A computer simulation was used and more computer research is planned.

Another paper, this time in Nature Geoscience, March 30th, claims the  transportation of warm water brings heat to the Greenland ice shelf and is eroding the edges of the glaciers. This paper is heavily focussed on global warming, and seems to be the work of environmentalists and produced under the funding of a pro-AGW body, and says Greenland glaciers have been melting at an alarming rate - and the melting is accelerating (a reference it seems to a recent calving incident) and so on. See where it says that warm water meets cold water from the Arctic around the coast of Greenland. This causes the warm Gulf Stream to sink as it is salty and as a result of this the ocean surface, or topmost layer, becomes cold. However, the deeper warm water current erodes the glaciers underneath but from the surface they appear as large as ever as a result of the cold water at the top - and eventually break up to produce ice bergs. None of this is particularly new - apart from the evidence of erosion below the water line that is confirmed, and presumably has been taking place for eons. Quite why this represents irrefutable proof of global warming is unclear. It may just be a caveat.