I get this flag goes up when someone talks about properties but leaves out numbers. “How much?” “Is it enough to matter?” “How big compared to counter forces?”.
It’s very easy to speak of a true technical property, but have it gnat’s knees compared to a Boeing 757… and not notice.
There was this article about how “Glacial Melt” was swamping the salinity of the north Atlantic ocean. Yet at the same time, there’s a giant and variable flow of salinity enhanced Gulf Stream water into the north Atlantic. What are these comparative sizes? What is the comparative size of the changes in the two? Silence…
So I figured I’d make a bit of noise about it and see if anything started to jell.
First off, what started me on this was an article at Tallblokes:
Research finds link between rainfall and ocean circulation in past and present
The data showed that, in comparison to today, the Atlantic Ocean surface circulation was much weaker during the Little Ice Age, a cool period thought to be triggered by volcanic activity that lasted from 1450-1850. Since these set of ocean currents are known to influence global climate, the researchers were interested to see if it correlated with rainfall in the Western Hemisphere, and how such a correlation could change over time.
Now my first flag goes up when they say the circulation was weaker during the little ice age, when things were more frozen, yet that is NOT when glaciers are melting. Consistency Alert Captain!… So the current slows down when it is cold and frozen but supposedly also slows down when it is hot and glaciers are melting? When, then, does it speed up? (Crickets!)
In a comment, I linked to another article that also makes claims about the currents and precipitation:
Researchers at The University of Texas at Austin have found that a well-known period of abrupt climate change 12,000 years ago occurred rapidly in northern latitudes but much more gradually in equatorial regions, a discovery that could prove important for understanding and responding to future climate change.
The research, published Sept. 2 in Nature Communications, focuses on the Younger Dryas, a cooling period that started when the North Atlantic Current, an ocean current, stopped circulating. The event caused Earth’s northern hemisphere to enter into a deep chill, with temperatures in Greenland dropping by approximately 18 degrees Fahrenheit in less than a decade.
The event also caused rainfall to decrease in places as far away as the Philippines. However, whereas temperatures in Greenland responded quickly to the ocean current shutdown and subsequent reboot 1,000 years later, it took hundreds of years for rainfall in the Philippines to be affected and to recover.
“We found that the temperature in Greenland is like a small ship that you can stop and turn quickly because of the influence of sea ice in the region, while rainfall in the tropics is like a big ship that takes a long time to course correct,” said Jud Partin, a research associate at the University of Texas Institute for Geophysics (UTIG) who led the study.
So again we have a cold spell with slowed / halted Gulf Stream and north Atlantic current. Does the cold stop the circulation or does the circulation stop cause the cold? In either case, how can it be that “melting glaciers” causes a halt when the glaciers are growing like crazy in the Younger Dryas?
I smell a simplification-rat in folks thinking about melting glaciers…
In this article:
I looked at this paper:
What I said about it was:
What I find particularly interesting about this one is that it shows that even Florida is anti-phase to Greenland. Mostly it is based on water, rather than directly on cold, but that’s fine. It finds that during the glacial (when Florida was about twice as wide as it is today), the way rains were controlled by warm / cold was about the same. When it is cold, not much rain. When it’s warm, lots of rain. Now that happens between winter and summer, then it shows up as a climate shift.
So every Heinrich Event shows up as cold in Europe, but wet in Florida (so the pine trees grow and the pine pollen spikes up) as Florida gets wetter and warmer. When it’s warm in Europe, Florida is more cool, so dry, and you get oaks. There’s a lot more in the article. Grasses and some other plants too. GISP Ice cores.
The key takeaways for me were simple. That 1500 year cycle keeps on happening. Though sometimes with a partial skip (weak cycle). It is water mediated with the Gulf Stream taking a break for a while and both Arctic and Antarctic deep water formation being involved. Something outside natural ocean oscillations drives it as it stays on the same periodicity despite a variety of ocean changes and ice changes and even strength of event changes. The metronome doesn’t shift much (though the effects sometimes skip a beat).
Now if it is warm melting glaciers causing the Gulf Stream / North Atlantic Drift to slow or halt, how can that be happening when Europe is getting more frozen and the heat is backing up in Florida and the Gulf of Mexico?
How can it happen on a regular 1500 year cycle without outside drivers?
To me, it looks far more like solar inputs to the ocean drive the overturning (compare the MW of solar heat in the global tropical and temperate oceans vs the pittance of MW-thermal in a glacial outflow) and those thermal driving changes reflect in the speed of the current.
How big is the Gulf Stream? Are glacier flows at all near it in size?
The Gulf Stream is typically 100 kilometres (62 mi) wide and 800 metres (2,600 ft) to 1,200 metres (3,900 ft) deep. The current velocity is fastest near the surface, with the maximum speed typically about 2.5 metres per second (5.6 mph).
Where is the 100 km wide river of glacial meltwater into the North Atlantic?
Where is the kilometer deep river flowing into the north Atlantic?
100 km x 1 km = 100 sq.km of cross section. Or 100 million meters^2. Moving at 2.5 metres/sec gives 250 Million cubic meters per second. (Provided I’ve got the math and units right). Further down in the Gulf Stream wiki they state that near Florida it is:
As a consequence, the resulting Gulf Stream is a strong ocean current. It transports water at a rate of 30 million cubic meters per second (30 sverdrups) through the Florida Straits. As it passes south of Newfoundland, this rate increases to 150 million cubic metres per second. The volume of the Gulf Stream dwarfs all rivers that empty into the Atlantic combined, which barely total 0.6 million cubic metres per second.
So there’s a range of about 1/8 to 2/3 of the simple cross section math result.
At an average discharge of about 209,000 cubic metres per second (7,400,000 cu ft/s; 209,000,000 L/s; 55,000,000 USgal/s)—approximately 6,591 cubic kilometres per annum (1,581 cu mi/a), greater than the next seven largest independent rivers combined—the Amazon represents 20% of the global riverine discharge to the ocean.[
The entire Amazon River is less than 1/1000 that size.
209,000 / 250,000,000 = 209/250,000 = 0.000836
Now uplift that for the other possible volumes, it’s
209,000 / 30,000,000 = 209 / 30,000 = 0.0069666
or it’s possibly more like
209,000 / 150,000,000 = 209 / 150,000 = 0.0019904
None of them is big enough to be found even in the rounding errors of Gulf Stream Flow and variation.
There is no Amazon of Glacial Melt. Not even 1/10 of an Amazon…
So just how much can “Glacial Melt” stand up to variation of Gulf Stream flow? Can that flea on the mouse’s tail really steer and halt the elephant?
IMHO this little “rough estimate” sanity check shows the whole “Glacial melt slowing ocean currents” to be a canard of the worst kind.
Yes, it needs much more detailed numbers to be run. Yes, it is only a ballpark sanity check. But also yes, when you have a control input that’s at least 1/10,000 the size of the thing it is reputed to control, AND the physical history has the results opposite to that reputed control, your control input is not a control input.
I would assert that far far more important are variation of solar input to the tropical oceans (in particular where the solar energy is deposited – on the surface as IR and reds, or deep as UV and blues) and variations in the global winds and tides (likely heavily influenced by the lunar tidal changes of ocean depths and tides).
How else can you get a regular 1500 year cycle but by external drivers?
The 1,800-year oceanic tidal cycle: A possible cause of rapid climate change
Charles D. Keeling* and Timothy P. Whorf
Variations in solar irradiance are widely believed to explain climatic change on 20,000- to 100,000-year time-scales in accordance with the Milankovitch theory of the ice ages, but there is no conclusive evidence that variable irradiance can be the cause of abrupt fluctuations in climate on time-scales as short as 1,000 years. We propose that such abrupt millennial changes, seen in ice and sedimentary core records, were produced in part by well characterized, almost periodic variations in the strength of the global oceanic tide-raising forces caused by resonances in the periodic motions of the earth and moon. A well defined 1,800-year tidal cycle is associated with gradually shifting lunar declination from one episode of maximum tidal forcing on the centennial time-scale to the next. An amplitude modulation of this cycle occurs with an average period of about 5,000 years, associated with gradually shifting separation-intervals between perihelion and syzygy at maxima of the 1,800-year cycle. We propose that strong tidal forcing causes cooling at the sea surface by increasing vertical mixing in the oceans. On the millennial time-scale, this tidal hypothesis is supported by findings, from sedimentary records of ice-rafting debris, that ocean waters cooled close to the times predicted for strong tidal forcing.
When you have gigantic massive flows of hot water caused by solar heating the entire tropical ocean even into the temperate ranges; when you have gigantic massive winds caused by the same that account for large wind driven tidal forces and currents, when you have gigantic cyclical lunar tidal driven flow changes:
How then can you claim a minuscule VARIATION in a trivial amount of fresh water is doing anything significant at all?
From the Gulf Stream Wiki:
As it travels north, the warm water transported by the Gulf Stream undergoes evaporative cooling. The cooling is wind-driven: Wind moving over the water causes evaporation, cooling the water and increasing its salinity and density. When sea ice forms, salts are left out of the ice, a process known as brine exclusion. These two processes produce water that is denser and colder (or, more precisely, water that is still liquid at a lower temperature). In the North Atlantic Ocean, the water becomes so dense that it begins to sink down through less salty and less dense water. (The convective action is not unlike that of a lava lamp.) This downdraft of cold, dense water becomes a part of the North Atlantic Deep Water, a southgoing stream.
Now what are the odds that salinity increases in wind driven flows of 1000 times to 10,000 times larger ocean current can overwhelm salinity decreases from glacial melt?