The Gulf Stream is weakening - says science.
Is the North Atlantic understood?
Has the North Atlantic become the newest playground for climate science? Support has now come from the New York Times, (March 03, 2021), citing some scholars fear that “The warming atmosphere is causing an arm of the powerful Gulf Stream to weaken”. The title of the article written by Moises Velasquez-Manoff and Jeremy White is: “In the Atlantic Ocean, Subtle Shifts Hint at Dramatic Dangers”. It immediately met with great approval from the readers: Fantastic article! Fantastic visualization! Amazing graphics!
It is undoubtedly of high journalistic quality. Pretty much everything said in science is addressed in an understandable way, from the melting of the ice on Greenland to global warming by humans. The article ends by quoting Dr. Lozier as follows: “There’s no consensus on whether it has slowed to date, or if it’s currently slowing. But there is a consensus that if we continue to warm the atmosphere, it will slow.” A recent paper by L. Caesar et al (Fn.1) spurred the NYT to pick up the issue, which is discussed as it follows.
From time to time cold spots emerge in the North Atlantic (NA). New research paints a ‘consistent picture’ of change to the Atlantic’s ‘conveyer belt’, which plays a major role in world’s weather. Its finding says that a region of Newfoundland defies global warming. Is a cold blob in the North Atlantic a matter to be concerned of? That may depend on whether the authors took the following three aspects into consideration:
a. The average depth is about 3’300 meters, and colder than + 4°C. A cold spot showing up at the sea surface is presumably a very small fraction from entire water volume of the North Atlantic, presumably less than 0,1%.
b. Are considerations mainly based on air temperatures from 1900 to 2013 (see Fig. at top), of any help in the climate change debate.
c. Do the most pronounced climatic shifts since 1850, the strong warming from 1919 to 1939 and the lasting cooling from 1940 to mid-1970, played any role with regard to the topic? (Details HERE)
On none of these elementary points the research paper by L. Caesar in NATURE titled: “Current Atlantic Meridional Overturning Circulation weakest in last millennium”, pays attention that puts the paper in the category of speculation. Here after at first the paper’s Abstract, followed by a few comments.
The AMOC is popularly known as the Gulf Stream System. The Gulf
Stream is typically 100 kilometres wide and 800 metres to 1,200 metres deep. That
is certainly a lot of water, but how much compared with the entire NA water
volume. Is it 0,5%, or more, or less, and is this flow of water and its
surrounding observed, and data available in reasonable numbers?
How can one take seriously a study that ignores the subject of investigation, namely the North Atlantic? Using proxy data instead is misguided and irresponsible. At most proxy-data may tell that air sea temperatures have been warmer or colder for some time, but nothing at all about the status and movement within the water-body at any time in the past. To claim that one can make statements about the future behavior of the water masses is speculative, arrogant and naive.
None of the above-mentioned points (a-c) is discussed by the authors. At least they should have mentioned the huge dimensions involved, and the huge supremacy of ocean temperature over air temperature, which is a too big story to be raised here.
Even if science is unwilling to consider whether the two most prominent changing trends in the climate during the last Century had been anthropogenic, their findings about the processes of the AMOC in recent decades, or during the last 1000 years”, are incomprehensible. None of the internal ocean processes are explained, the dimensions and parameters involved ignored, no detailed observation data discussed, but instead assessed by computer-modeling.
Meanwhile Wikipedia summaries the state of research as it follows:
A shutdown or slowdown of the thermohaline circulation is a hypothesized effect of global warming on a major ocean circulation. A 2015 study suggested that the Atlantic meridional overturning circulation (AMOC) has weakened by 15-20% in 200 years.
The only fact known is, there is sometimes a cold blob. No surprise if the waterbody is in permanent flow and has only a mean temperature of plus 4°C., and the Gulf Current as only a small part of the total. Discussing in abstracts about the AMOC is an easy task. On the other hand clarifying what has caused the AMOC to support the major climatic shifts in the last Century (see above, item. c.), seems to be a too difficult task for science.
Let’s finish this discussion
with Dr. Lozier statement (see above): “But there is a consensus that if we
continue to warm the atmosphere, (it) AMOC will slow.” Any consent does not
replace missing evidence, and neither logic consideration. In physics the
higher the heat the more fluid motion increase. The North Atlantic has become a
scientific playground, full of speculations. That seems to be enough for them.
No matter what happens to global weather, climate scientists have a pack of
excuses ready to roll, so they can “explain” how they knew this was going to
happen all along, including greenhouse-clobal-warming.
Fn. 2: More examples of proxy data: ice cores, fossil pollen, ocean sediments, ratios of oxygen isotopes in air bubbles trapped in ice masses, , lake levels; pollen sediments in lakes/ rivers/oceans/ and coastal areas; pack-rat middens; glacial termini, borehole temperature; coral bleaching; ; archeological information . https://meteor.geol.iastate.edu/gccourse/history/paleoclimate/examples2.html