Gulf Stream Myths (2)

Another March, another collection of scientific half-truths about the Gulf Stream. I do not believe it is a coincidence that I wrote about gulf stream myths a year ago, quoting also Richard Seager, Senior Research Scientist at Columbia University’s Lamont-Doherty Earth Observatory:

“That the Gulf Stream is responsible for Europe’s mild winters is […] nothing more than the earth-science equivalent of an urban legend. […]

All Battisti and I did was put these pieces of evidence together and add in a few more illustrative numerical experiments. Why hadn’t anyone done that before? […]

The blame lies with modern-day climate scientists who either continue to promulgate the Gulf Stream-climate myth or who decline to clarify the relative roles of atmosphere and ocean in determining European climate. This abdication of responsibility leaves decades of folk wisdom unchallenged, still dominating the front pages, airwaves and Internet, ensuring that a well-worn piece of climatological nonsense will be passed down to yet another generation.”

Nothing has changed since. And so yesterday we have learned that the “Atlantic’s Gulf Stream has huge influence on atmosphere“. But is it really so?

(1) Not to mention Prof. Carl Wunsch, let’s have a look at what NASA has to say about oceanic currents:

“The major surface currents are wind generated (as most other oceanic currents are)”

Therefore, rather than discovering that “a band of rain […] tracks the warm surface water” it may very well be the other way around.

(2) In terms of European warming by the Gulf Stream, let’s also compare like-for-like following Seager’s line of thought: and so the cities to choose around latitude 50N are Vancouver (V) and London (L), not Quebec City or the island of Newfoundland.

Vancouver and London, in fact, have an Ocean to their West: while Quebec City, Newfoundland, or the Avachinsky volcano in Kamchatka, all places much cooler on average than London, are just east of a continent.

And so: weather conditions as from the BBC weather site show very little difference between the two cities. Values in the following list are VancouverLondon: for example “Avg Min: -1.3C” means Vancouver is 1.3C cooler in average minimum temperature, than London.

Average Sunlight (hours): 1.2
Temperature (C):
Avg Min: -1.3
Avg Max: 0.2
Rec Min: -3.2
Rec Max: -0.4
Relative humidity am: 11.4
Relative humidity pm: 6.4
Average Precipitation (mm): 72.1
Wet Days (+0.25 mm): 1.6

As it happens, there are warm Oceanic currents that reach Vancouver. But how likely is it that they are as powerful there as the Gulf Stream is in London? What a remarkable coincidence that would be.

Rather, the best explanation in the Occam’s Razor sense is that the warming of Vancouver and London compared to other places around latitude 50N, is due to a metereological (atmospheric) effect, not an Oceanic one.