After years of telling us that global warming would make us warmer:
According to Dr David Viner, a senior research scientist at the climatic research unit (CRU) of the University of East Anglia,within a few years winter snowfall will become “a very rare and exciting event”. “Children just aren’t going to know what snow is,” he said (Independent)
After the run of mild winters we got a run of colder seasons: the “BBQ summer” that wasn’t and a few severe winters and as sure as the return of midges out came the “of course the it’s all the slowing gulf stream” nonsense.
So when WUWT posted today with Atlantic ‘conveyor belt’ current – still going strong I thought “finally proof positive to show to alarmists and stuff where no photovoltaic will work”. Instead, its a much more confusing picture:
the authors note that although some studies have suggested that the AMOC is slowing down due to global warming, the NBC shows multidecadal variability but no significant slowing trend over the past 50 years. (Source: Journal of Geophysical Research-Oceans – no link!)
But, of course the big lie, is that 0the (global warming affectable bit of the so called) Gulf stream is the reason the UK is warmer than a similar
latitude on the American coast. In fact the East-West coasts of the Pacific have the same temperature difference due to the same reason: trade winds pusing oceans currents that warm the Eastern shores of the sea. And, unless anyone is suggesting global warming is going to stop the sun shining and the earth rotating, there will always be Northerly trade winds diverted to the East which will warm those eastern shores.
You don’t believe the UK’s Winter climate is moderated by the gulf stream? Please explain.
The gulf stream is the current squeezed out of the gulf of Mexico between Florida and Cuba. It is driven by Westernly equatorial winds. This current is visible via infra-red as a wiggly line (like toothpaste) up until around Newfoundland, where it becomes part of the North Atlantic drift. The North Atlantic drift is a current pushed along by the SW trade winds and the Coriolis force moves this current to the East coast. This warm current keeps the UK warmer than comparable latitude on the West of the Atlantic (Note: all this is driven by trade winds which are part of the normal pattern of air movement of the planet – air movements that no one is suggesting will change as a result of CO2).
Now there is a very small current (I call it the Arctic current but others call it the North Atlantic conveyor) from memory this is something like 1/50 or 1/2000 … anyway it is absolutely minuscule compared to the massive North Atlantic drift which keeps the UK warm (a similar current keeps the East coast of the pacific warm).
So, far this is just schoolboy geography available in most good textbooks on the subject.
Now for the bit which is all the fuss. The Arctic current is a current from the Atlantic which takes warm water past the Shetland-Iceland gap into the Arctic ocean. As I said, this is a very small current: it can’t affect the overall flow of the North Atlantic drift, but it can “kink” the current so that more of it reaches the Northern areas of the UK. Importantly (for you) it appears to be driven by evaporation and salinification of the water which causes the warm water to cool and sink. This is what drives the so called “Conveyor” current. The theory is that melting ice will cause this conveyor to stop.
So what would be the impact? The affect of the Arctic current is to create a “kink” in the much greater north Atlantic drift which circulates warm water past the UK. This kink brings causes warm from the Atlantic drift (aka Gulf stream) to head up past the top of Scotland into the North Sea around Norway and Shetland. So, the greatest impact would be to Shetland & Norway because they would no longer have the “kink” that brings the North Atlantic drift (aka “Gulf stream”) into this area.
As for the rest of the UK, the best estimate is based on the Pacific East-West temperature difference. As far as I can recall, this is almost the same as the East-West temperature difference in the Atlantic. So, realistically the effect would be pretty small. I’d guess it could be around 1C – which just about cancels out the realistic estimates of CO2 induced warming.
To summarise – there could be significant effects of a few degrees the closer you get to the shetland-Norway gap. Any suggestion that the UK will be as cold as a similar latitude on the West coast of the Atlantic (Newfoundland) is at best totally gullible at worst fraudulent. You don’t make such an easy and obvious mistake by accident – people who study ocean currents know this notion of parity between East-West is bollocks!
But all this is academic, as there is not any reliable evidence the Arctic current has diminished.
From that article and a cople fo others on the NASA site it seems that the old ‘conveyor belt model may no longer hold water – if you’ll pardon the pun. That’s a relief – I don’t want the boat to get frozen into the bay, handy though it would be to be able to walk out to the mooring 🙂
Do you doubt that the conveyor has historically operated at some times and not at others, or that such changes made a significant climate impact on Europe? I’m not sure if you are saying such things never happened and that a shutdown or diminishment would have no substantial effect, or are just making a more minor point about terminology.
This is all theoretical in present day human terms, if there’s no change in the conveyor anyway, I’m just trying to sort out which point you are making.
Zeph, the main factor bringing warmer water (and air) to the NE shores of the Atlantic are the same that bring warmer water and air to the NE shores of the Pacific. These factors are caused by the general circulation pattern (google Hadley cell) and the rotation of the earth. There is no way on earth these will turn off unless or until the trade winds that drive them disappear.
Apparently, the much smaller “conveyor” current has turned off in the past. This is because this current is driven by particular circumstances in the Arctic ocean which can be affected by changes in the environment there, but whilst this current is susceptible to climate variation it is a much smaller current.
But, whilst it is a smaller current, it will put a “kink” in the main Atlantic current and without the conveyor the warming current is likely to move offshore bypassing the North of Scotland, Iceland and not getting round to Norway and the North Sea. This is because this area is a bit of a “cul-de-sac” which is only fed by warmer currents due to the Arctic ocean current (i.e. the conveyor).