This passionate posting over at Daily Kos caught my attention. So I’m trying to understand the fundamentals a bit more and ignore the passion. The first image shows a warm current of ocean water sweeping up the west coast of Greenland. The posting suggests this is tied up in the recent snows in England and makes the usual suggestive tie to global warming. All in all it made me curious.
This first map shows the major currents of the North Atlantic. If you look at the eastern sea board of the US you’ll see the gulf stream, in warm red, flowing up the coast. Below that a cold blue stream of water flows south. The Gulf stream begins life in the Gulf of Mexico, while the cold current begins along the coast of Labrador.
You’ll notice that the Gulf stream pumps a lot of warmth into the ocean around England, Iceland, Norway. The trade wind plays a key role in that. (Read about the North Atlantic Oscillation to get a feel for the drivers of those trade winds.) The winds sweep west to east across the seas south of Iceland drawing warmth from the Gulf stream depositing it into British Isles, and Europe.
The second map shows the currents in more detail. You can see that some of of the gulf splits off and is drawn up around the tip of Greenland and then along up the west coast of Greenland.
These days we have satellites that can report on the temperature of the sea’s surface, so called SST. And that can then be plotted either by temperature SST, or by how much the temp has varied from the usual SSTA. In the alphabet of worry A is for anomaly. The third map shows how much the surface temp. is anomalous compared to the seasonal average. Uou can see the current that wraps the bottom of Greenland is about one degree warmer than usual. That map is for Jan 6th. You can keep an eye on it if you want, there are some cool animations there, but not of the anomalies.
But I suspect that this happens when ever they get a serious round of cold weather in Europe. It does presumably increase the ongoing of glacier retreat along west coast of Greenland.
The nightmare scenario is that the Gulf stream stops warming Europe. But the story above starts with a cold spell in Europe; not the other way around. I can build scenarios with positive feedback loops in them using only the above; but they seem pretty tenuous and uninformed to me.