From MasterResource

By Robert Bradley Jr.

Ed. note: A recent peer-reviewed article in Nature (discussed here) has, once again, knocked this speculative “fat tail” hypothesis down to size. “Based on the here identified relationship and observation-based estimates of the past air-sea heat flux in the North Atlantic from reanalysis products,” the authors concluded, “the decadal averaged AMOC at 26.5°N has not weakened from 1963 to 2017 although substantial variability exists at all latitudes.”

Climate alarm is the name of the game for the government-led Climate Industrial Complex to keep the taxpayer grants going to the wind, solar, and battery rent-seekers. Nature is optimal and fragile, and the game is to throw hypotheticals against the wall to see what might stick. The mainstream media is hungry for a scary scenario too.

One perennial fear is a potential collapse of a crucial system of ocean currents known as the Atlantic Meridional Overturning Circulation (AMOC). A few scientists are ‘out there’ predicting an increasing chance of a collapse, but the consensus leans the other way. [1]

Forty-four scientists, including Michael “Climategate” Mann, published an open letter with ominous implications. “Recent research since the last IPCC report does suggest that the IPCC has underestimated this risk and that the passing of this tipping point is a serious possibility already in the next few decades,” the letter states. The missive closes with a call to action:

Recognizing that adaptation to such a severe climate catastrophe is not a viable option, we urge the Council of Nordic Ministers to (a) initiate an assessment of this significant risk to the Nordic countries and (b) take steps to minimize this risk as much as possible. This could involve leveraging the strong international standing of the Nordic countries to increase pressure for greater urgency and priority in the global effort to reduce emissions as quickly as possible, in order to stay close to the 1.5 °C target set by the Paris Agreement.

The media loved it. “Key Atlantic current could collapse soon, ‘impacting the entire world for centuries to come,’ leading climate scientists warn,” wrote Sascha Pare in LiveScience. “How much should you worry about a collapse of the Atlantic conveyor belt?,” asked Bob Henson at Yale Climate Connections.

Carl Wunsch Rebuttal

Are the risks of a collapse of the dominant mechanism of northward heat transport in the North Atlantic, ushering in record cold, a real threat? Has it been “greatly underestimated” as the above letter states? In such instances, a good second opinion is needed, and Carl Wunsch of MIT is about as good as one can get.

I emailed Professor Wunsch with the query:

Many years ago, Dick Lindzen gave me your address to ask about the fear of a disruption of the conveyor belt in regard to the Atlantic Meridional Overturning Circulation. You expressed doubt back then.

This alarm is in the air today, and I wondered if you had some thoughts on this post (below) to share on LinkedIn where a debate is taking place. 

Among the many reasons why we ought to cut climate-warming greenhouse gas emissions as quickly and sharply as possible, the weakening of a system of ocean currents known as the Atlantic Meridional Overturning Circulation, or AMOC, ranks high indeed. Several key scientific papers over the last couple of years have put this long-percolating climate concern back on the front burner. It’s hard to overstate how widespread and calamitous the impacts could be if this conveyor belt were to collapse – and it’s a process that could begin in the next several decades, if the new work is on target.

He responded:

I’m aware of the fuss going on about the AMOC. Indeed I co-authored a paper about it not long ago (I’ve attached it). It’s somewhat technical.

To clarify however: I am *not* a climate skeptic, and I regard the threat of major climate change as very real and very worrisome.  In that context, one can argue that alarming the public about elements such as the behavior of the AMOC could lead to useful actual political and scientific/engineering progress and precautions.

Where I become conflicted is when the particular science is mis-interpreted and mis-understood. Turning the AMOC on and off as an explanation of major past and possible future change has become a go-to-story for people who want a simple explanation of a very complicated system. [Wallace] Broecker [here] did the world a great dis-service with his advocacy of the “conveyor belt” which leads people to think they understand a system which looks nothing like his picture (a memorable graphic however). 

There are lots of issues connected with the fuss over the AMOC. Amongst them, prominently, are the use of numerical models which produce ocean circulations that are far from what we actually observe. How seriously should one take their “predictions”? That the climate can change dramatically from what we have known for the last several hundred years is a fact, and a very worrisome fact at that. Does that mean the AMOC stories in the media are correct? 

Climate is a global phenomenon. Consider a hypothetical situation: turn the North Atlantic Ocean abruptly into all land. Zero AMOC; removal of a major current system. How does the climate system adjust? At the present time, the Earth is in near thermal balance (radiation incoming from the sun is almost equal to that radiated back to space—the small excess of incoming over outgoing is the global warming phenomenon). Physics suggests that the system would adjust to the removal of the North Atlantic by ultimately re-establishing global near-heat balance.

How does that happen? Change in clouds? Change in ocean circulation? Change in distribution of ice sheets? Change in atmospheric circulation? All global. How long does it take (years, decades, centuries)? What will the climate be like during the transition? We do not have numerical models with the demonstrated skill to answer such questions. Could be terrible, however. Suppression of the AMOC, should it happen, raises precisely the same global questions with the added complication that the North Atlantic circulation itself would also change.

Isn’t it worth taking some precautions? It’s an insurance problem in the same sense that I would rewire my house if an electrician told me that the existing wiring could cause a fire (not that a fire *will* happen; only that we know it could). 

Comment

We live at a time when climate scientists do not want to be labeled a skeptic or denier, yet honest scientists are still doing their duty to weigh in against undue alarmism. (Note the beginning and end of Wunsch’s replay above.)

Also note that how the Deep Ecology notion of an optimal, stable, fragile climate is the default thinking of so many natural scientists. The idea that the human influence on climate could be positive and even a ‘fat tail’ good (such as cancelling out a series of volcanoes or a natural global cooling) is not part of the analysis.

[1] Atlantic Meridional Overturning Circulation (AMOC) describes the movement of water from north to south and back from south to north in the Atlantic Ocean. This circulation is responsible for warmth in different parts of the world and carries essential nutrients for ocean life.

The question is whether this (very slow) process is slowing down because of anthropogenic warming of the water, which would cause droughts in South Africa and sea level rise in the eastern U.S.

Source: What is the Atlantic Meridional Overturning Circulation (AMOC)?

It could be that all the extra carbon dioxide in the atmosphere – the steady increase year on year, reported since 1958, despite all the airplanes grounded through covid it kept on increasing – is a consequence of the oceans breathing out a bit more, and nothing to do with you and me.

The amount of carbon sequestered in the oceans was meant to increase with the apparently significant increase in atmospheric levels because of industrialisation, except that observations, actual measurements, suggest that there has been no long-term increase.  The oceans might be breathing carbon dioxide in, and out, to their own rhythm that has nothing to do with you and me – or all the windfarms.

It could be that mankind is irrelevant to the cycles of ocean warming, that dictates atmospheric levels of carbon dioxide.

The Earth’s oceans contain somewhere in the vicinity of 50 times more carbon than the atmosphere.  The global carbon ocean reservoir is about 38,000 gigatons of carbon, while the atmosphere contains only 730 gigatons. In the atmosphere carbon is present as carbon dioxide, which is just 0.04% of the atmosphere by dry weight.

Carbon dioxide is a tiny fraction of the atmosphere, and there is constant exchange of carbon dioxide between the atmosphere and the ocean.  This exchange has been described as inhale and exhale, since forever.

The ocean takes up carbon dioxide through photosynthesis by phytoplankton, as well as by simple dissolution, that is carbon dioxide dissolves in water.  Carbon dioxide reacts with seawater, creating carbonic acid (H2CO3). Carbonic acid releases hydrogen ions, which combine with carbonate in seawater to form bicarbonate (HCO3-).

The amount of carbon dioxide absorbed by the oceans varies with latitude.  At high latitudes/towards the poles the ocean will absorb/store more carbon dioxide and more easily, because of the lower temperatures.

An overall increase in ocean temperatures, especially at the poles where they vary according to long cycles, could mean more exhaling relative to inhaling of carbon dioxide, over the year over the Earth.  That is not what the dominant paradigm has theorised.  But it is what the measurements show.

Ocean temperatures also vary seasonally.  Concentrations of bicarbonate peak in surface seawaters in April at the latitude of Hawaii, which is also the time of year when atmospheric carbon dioxide is highest as measured at Mauna Loa.  Atmospheric concentrations of carbon dioxide vary seasonally, as does the sea surface temperature, at the latitude of Hawaii, which is the main site for monitoring global change in atmospheric levels of carbon dioxide.

I will be discussing all of this with Sydney University Professor Ivan Kenney on 25^th February, by Zoom.   There will be just 100 places if you want to be a part of this discussion, so make sure you are registered for my Mail chimp specifically tick the box ‘New Theory of Climate’ here: https://jennifermarohasy.com/subscribe/

This zoom is part 2 of a discussion I began with Bill Kininmonth last year, more information about that here,

https://jennifermarohasy.com/2024/12/oceans-warm-atmosphere-with-meteorologist-william-kininmonth-audio-and-summaries/

Ivan Kennedy is an emeritus professor in the School of Life and Environmental Sciences at the University of Sydney.   His 2023 research paper – entitled ‘The Seasonal Keeling Oscillation in Atmospheric pC02 is Caused by Variation in Seawater Surface Temperature’ published in the journal Examines in Marine Biology and Oceanography – will be distributed to those who register for the zoom a few days before the discussion.

Seasonal variability in atmospheric levels of carbon dioxide and long term trends will be the focus of this discussion with Ivan planned for Tuesday 25^th February at noon Brisbane time (Australian Eastern Standard Time, AEST – an hour later in Sydney because of daylight saving and the day before in Texas because of datelines etc.).   The link will be in the Mailchimp, for those subscribed to ‘New Theory of Climate’, and I will send it out next Tuesday.  That is the plan.