The Oceanic Central Heating Effect

Guest essay by Philip Mulholland

In my previous essay We Must Get Rid of the Carboniferous Warm Period I discussed the role of the polar seas around Antarctica in generating the cold dense oxygenated marine water that dominates the abyssal ocean depths of our modern world. I now want to discuss the role of shallow tropical seas in generating warm dense oxygen-poor marine water and how this fundamental and often overlooked process explains the presence of abyssal ocean warm water and high atmospheric carbon dioxide concentration during previous geological times, in particular the Cretaceous period.

It is a mid-June day in 1991, West Caicos, a small uninhabited tropical island in the Turks and Caicos archipelago, bakes in the hot summer sun. I am on a field trip to the British West Indies organised by Dr Hal Wanless of the University of Miami, to study the modern geology and natural depositional environments of a marine carbonate platform. A visit that, even now, I consider to have been the best field study trip of my entire geoscience career. Located in the trade wind belt, the Turks and Caicos Islands lie at the south-eastern end of the Bahamian chain of Atlantic Ocean carbonate-platform islands. With the Tropic of Cancer passing to the north of the group, at midday the June sun is directly overhead and your shadow falls exactly beneath you. By evening, the summer thunderstorms arrive tracking west across the ocean, passing by on their way to the Caribbean.

For most of the year, the climate of West Caicos is dominated by dry trade winds. These are derived from the downwelling of the Hadley Cell, centred over the Atlantic Ocean to the north-east.


The low rainfall and high evaporation rate make the climate too dry for sugar cane production, an economic enterprise tried by past entrepreneurs at this remote island location. Salt production, the original economic activity of the Turks and Caicos, was also attempted at West Caicos, but that enterprise failed too. At West Caicos the salt pans were located on the site of a major wash-over fan in the northwest of the island. The bedrock here consists of permeable limestone rubble and not impermeable mudflats, the place of choice for salt production on the other islands in the group. This site, with its poor hydrogeology, probably accounts for the failure of the West Caicos salt pan enterprise.

Now West Caicos is a nature reserve and the native bromeliad flora are left to grow undisturbed. We are here to undertake a west to east traverse across the island to see how the individual elements of its geology have been created by the natural marine processes of active carbonate deposition occurring over the past few thousand years, since the sea level rise at the end of the last ice age flooded the Caicos platform.

We begin our journey in the sea, swimming with mask and flippers off the island’s west coast; here we observe the corals thriving in the shallow warm waters of the reef flat, everyone’s ideal coral island setting. Swimming is easy in the warm water with its slight swell, as we make our way out to the drop-off, and spot the barracuda fish below, patrolling the reef edge, marking its location. Then everything suddenly changes, the seabed disappears from sight as the water depth precipitously increases, the water colour becomes a deep blue and its temperature abruptly falls. With the sudden temperature drop I experience cramps in both legs and am grateful for the life jacket I’m wearing and the presence of my safety buddy, as swimming becomes difficult in the now cold water. So where has the warm water gone? Leaving this question unanswered, we swim to the support boat and head back to the island’s shore.

Our next stop is just off the beach, here the corals are no longer thriving, they are being buried by carbonate beach sand and the burrows of innumerable marine creatures pockmark the seabed. This change to carbonate sand is not evidence of environmental degradation, this sand zone is also a thriving pristine environment, it is simply no longer the coral’s home and a new force of nature, sediment derived from the inorganic carbonate beach factory, dominates the scene. Carbonate geologists estimate that approximately 50% of all the carbonate rock on Earth is generated by inorganic means and our next stop is the factory floor, the sand generating swash zone of the carbonate beach environment.

We arrive on the western beach of West Caicos, standing in the shallows where the seawater reaches its warmest temperature. We observe the continuous back and forth motion of the water as each wave arrives, rolling the grains of carbonate sand and creating a smooth beach profile with a distinctive sedimentary pattern or facies. Hal draws our attention to the beach rock in a small cliff adjacent to our landing point. Here we can see, preserved in the vertical rock face and deposited at a time of previously higher sea level, the sedimentary facies of the same near shore environments we have just observed offshore.

In the base of the cliff we find the fossil corals, above them surrounding and smothering them we see the lithified carbonate sand grains and the distinctive cone shaped burrows of long dead marine animals. Above this zone are the smooth layers of sand from the old swash zone forming a structured Z shaped pattern in the cliff face marking the exact tidal limit of the ancient beach. This is a classic geological example of the “Principle of Superposition and Original Horizontality”, where the younger sediments of the proximal shallow-water beach environment extend over the older distal deeper-water coral reef, as the sea bed shallows and the island grows seaward. The effects of this principle are regularly observed in marine carbonate deposits, with each upward episodic sea level change defining the next level in a repeated pattern of sedimentary growth.

We climb off the beach, up onto the rock outcrop and on its upper level we find gigantic boulders of beach rock with the same three facies as before, but tumbled out of their original setting. Hal observes that these boulders have been ripped out from the cliff and deposited up here by a storm surge from a former hurricane. My personal opinion is that this could be a tsunami deposit, given that we are due north of Hispaniola and at the western end of the active Puerto Rico submarine trench, this explanation of a powerful wave, generated by a submarine earthquake, also seems plausible. It is my view that in geoscience it is always good to consider more than one possible explanation for any set of field observations.

We are now standing at the top of the cliff on the highest and oldest part of the island. Turning to face east, the land falls away in a gentle slope and in the distance, on the horizon, a line of sand dunes rises behind a blue saline lake, Lake Catherine. Following a straight track, laid out by the former sugar plantation enterprise, we are soon back down at sea level, walking out on a causeway across the brine lake. Half way across there is a break in the track, the site of a former culvert, where the lake water flows though the causeway gap from north to south. Hal explains that on every visit to West Caicos he has always observed the same continuous direction of flow, so a tidal explanation for the movement of the water can be discounted.

Lake Catherine occupies the site of an old bay on the island’s former east coast, now separated from the lagoon by lines of barrier dunes, but its waters are still connected to the sea by an underground limestone aquifer. The wind driven marine current flowing west towards West Caicos island across the shallow Caicos lagoon creates a hydraulic gradient on the islands east coast that forces seawater underground, through the island’s limestone core to emerge in and flow through this central blue lake, before the water again makes its way back underground to regain the open sea on the island’s west coast.

Beyond Lake Catherine the track rises to a cut through heavily vegetated small hills, the maturity of the bromeliad flora demonstrates the significant age of these now inactive sand dunes. At the crest line, a new vista appears, in the distance a second line of modern sand dunes lies beyond a sabkha mudflat. We descend and cross the sabkha, its fragile algal crust breaking under the pressure of our footsteps, to reveal soft gypsum mud below. The presence of natural gypsum (hydrated calcium sulfate) in this ocean island setting is a surprise and is a testimony to the effectiveness of the high evaporation rate of the Caicos climate in concentrating the seawater brine.

Leaving the sabkha we climb the line of modern dunes, the loose carbonate sand and the sparse vegetation of grasses demonstrate the young age of this second barrier to be crossed before we reach the modern east coast of West Caicos. Beyond the crest, a rapid descent brings us down to a wide wind swept beach. A continuous drying wind, blowing in our face, moves the loose sand off the shore, adding to the dunes behind us and raising the island’s surface above sea level by means of aeolian sedimentation.

Here on the wide eastern beach, sitting below a small Casuarina tree and facing the shallow lagoon, we see the true extent of the carbonate sediment factory, a prolific producer of inorganic carbonate sand. Oolitic (egg shaped) grains roll in the beach swash zone growing layer on layer to produce an onion ringed sand grain wrapped around an original seed crystal of aragonite. Out beyond the beach the shallow warm sea, with water depths of less than 10 metres, extends eastward for 100 km, it is dotted with small patch reefs of coral rising clear of the sandy bottom. Parrot fish, with their strong beaks, bio-erode the coral and excrete crystals of indigestible aragonite, mineral seeds that form an endless supply of crystals around which new oolitic sand grains grow, in a symbiotic union of organic and inorganic sedimentation.

It is now 22 years since that summer day, yet the memories of my short visit to West Caicos remain vivid. Looking back, it is time to place all the elements of that day into an environmental synthesis and answer the question of what happened to the warm surface water when I swam beyond the reef edge into the cold water of the Atlantic Ocean.

There are two major types of marine carbonate environment: carbonate platforms and carbonate ramps. Carbonate platforms are found throughout the tropical oceans of the modern world and consist of isolated flat topped carbonate banks that are very sensitive to global seawater drawdown. During the ice ages, when the sea level lowers as ice builds up on land, carbonate platforms are easily exposed and then become incapable of further sedimentary growth; warm water production ceases, inorganic calcium carbonate formation stops and the associated process of carbon dioxide gas liberation fails.

Marine inorganic carbonate sedimentation is a geological process that occurs in shallow warm-water, tropical seas. The crystalline chemical solid calcium carbonate is unusual in that it becomes more insoluble as water warms. Carbon dioxide gas dissolved in cold water creates the weakly acidic carbonic acid which can dissolve solid calcium carbonate crystals creating water soluble calcium bicarbonate, by this mechanism the carbon dioxide becomes chemically associated with the calcium, and not just simply dissolved in the water. Calcium bicarbonate however, unlike calcium carbonate, does not exist in a solid chemical form, it occurs only in solution. In the warm surface waters and beach zones of shallow tropical seas calcium bicarbonate solution becomes thermally unstable, calcite precipitates naturally from the seawater as the water soluble calcium bicarbonate reverts to insoluble calcium carbonate crystals, liberating carbon dioxide molecules.

The geological record shows that half of all marine limestones were formed from seawater by the mechanism of direct chemical precipitation in a purely temperature and evaporation driven process. These non-biological limestone rocks include oolitic carbonate sandstones; even now egg-shaped grains of these carbonate sands form abundantly in the shallowest and warmest waters of the modern Bahamian platform lagoons.

The Caicos Islands are an example of a modern active carbonate platform that, during our current interglacial high sea level, forms an area of shallow lagoon surrounded by the deep waters of the Atlantic Ocean. The dimensions of the platform are large, in the south it extends from West Caicos to Seal Cays, a distance of about 100 km, while in the north it extends from Providenciales to East Caicos a distance of about 80 km. The platform covers an area of approximately 5,400 sq. km, of which only 430 sq. km is land and about 5,000 sq. km is covered by shallow sea. This shallow lagoon is a gigantic solar energy collector, each day the tropical sun warms the seawater and all day and night the dry north-east trade wind enhances the surface evaporation, increasing the seawater salinity and driving the water westward across the lagoon towards West Caicos and the open ocean beyond.

As the temperature and salinity of the seawater increases in the lagoon a process of evaporitic precipitation of salts from marine waters becomes possible. The deposition of these salts occurs in a distinct sequence. Calcium carbonate, the least soluble salt, precipitates first. The water soluble calcium bicarbonate is converted to calcium carbonate precipitate with the release of gaseous carbon dioxide. This process takes place in the warmth of the beach swash zone and accounts for the prolific carbonate sand sedimentation found here and throughout the Bahamas.

The next salt that precipitates from the seawater concentrate is gypsum (hydrated calcium sulfate). This process takes place on the West Caicos sabkha, behind the dunes, where the ponded seawater, driven onto the island by the wind, concentrates by further evaporation. The third salt to precipitate is halite (sodium chloride) this is the most soluble mineral of the three and therefore the least likely to precipitate. The waters of the brine lake demonstrate that there is the potential for this process to occur on West Caicos, and would do so if a suitable natural salt pan existed here, as happens on other islands within the group.

As a consequence of the process of evaporation the sun warmed seawaters leaving the Caicos lagoon, on its western margin, are more saline and therefore denser than the colder open ocean waters that have flowed around the archipelago. At the reef edge this density difference allows the warmer lagoon water to sink down below the colder less saline ocean water and accounts for the sudden thermal contrast I experienced while swimming in the sea off West Caicos. It is interesting to note that the world freediving record was set at Providenciales, where the warm dense water exits from the Caicos lagoon and descends into the Atlantic Ocean depths.

Carbonate ramps are found on continental shelves in shallow tropical seas and form extensive coastal fringes. Unlike flat topped carbonate platforms, carbonate ramps are tilted and therefore robust to global sea level drawdown. They can maintain warm water production, calcite precipitation and carbon dioxide emission to the atmosphere throughout the sea level fall of a glacial cycle. Carbonate ramps are rare in the modern world. The best example is the Emirates coast on the southern margin of the relatively small (in geological terms) Persian Gulf. Because it is not the continental shelf margin of an open ocean, this shallow gulf, with its maximum water depth of 80m and restricted size, is vulnerable to global sea level fall, during ice ages the ramp ceased to function as the seabed turned into exposed land.

Although the modern world lacks major continental shelf tropical seas capable of hosting carbonate ramps, they occurred extensively in the geological past. For example, during the Cretaceous period a region of shallow tropical seas associated with the margins of the Tethys Ocean existed in the Horse latitudes of the northern hemisphere. In these shallow seas major carbonate ramps developed and abundant carbonate sedimentation occurred. The shallow waters of the carbonate ramp, warmed by the tropical sun, generated dense saline marine brines that filled the abyssal depths of the Cretaceous world ocean with warm anoxia prone bottom water, while at the surface inorganic carbonate sedimentation released carbon dioxide gas into the Cretaceous atmosphere.

The climatic difference between our modern cold ocean world and the ancient warm ocean world of the Cretaceous is simply due to the presence in the Horse latitudes of shallow tropical seas containing the carbonate ramps that form the planet’s “oceanic central heating system”. The physical location, areal size, and water depth of the world’s shallow tropical seas throughout geological time dictates the quantity of solar energy that these seas can collect from the tropics. Our modern world, with its carbonate platforms and restricted ramps (such as the Persian Gulf) that are sensitive to global sea level fall, has a much less efficient and less robust planetary “oceanic central heating system”.

In the argument of which comes first: atmospheric carbon dioxide levels or warm ocean water, the geological evidence is unequivocal: The “oceanic central heating effect” dog wags the “atmospheric greenhouse gas” tail.


Personal Statement:

I am a professional geoscientist with a BA in Environmental Sciences from The University of Lancaster in 1974 and an MSc in Conservation from University College London in 1981, where I studied the natural regeneration of woodland in Epping Forest using a Markovian Matrix technique to determine the temporal balance between Birch, Oak and Beech trees in a successional replacement cycle.

I started my career in the Institute of Geological Sciences (now the British Geological Survey) where I worked for 10 years learning about geology from experts, before moving on to continue my career in industry. Geology is a field science and the best geologist is the person who has seen the most rocks. I am a generalist by aptitude and therefore rely on the field work of experts when attempting to understand the interlocking complexities of geoscience.


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I’ve enjoyed here the tagging along on your run
You’re a rock-science George L Mallory
The Cretaceous northern seas warmed in the sun…
That’s a Horse lat of whole different calorie!
===|==============/ Keith DeHavelle

Jim Hodgen

Wonderful essay. I learned a great deal. The Hadley illustration was also very illuminating… I’ve never seen that one before and it really opened my mind. Great job.


An excellent essay. Interesting and informative.


“Carbon dioxide gas dissolved in cold water creates the weakly acidic carbonic acid which can dissolve solid calcium carbonate crystals creating water soluble calcium bicarbonate, by this mechanism the carbon dioxide becomes chemically associated with the calcium,”
This may not be accurate as what you describe would happen in distilled water but not in the complex buffer that comprises seawater. Released protons from carbonic acid are going to be inconsequential in the face of this buffer.
Indeed, photosynthesis is an alkalizing process and the pH in bays and estuaries, and undoubtedly in lagoons, can reach pH 10+ on a sunny day. Carbonic acid would become carbonate directly and bicarbonate would be scarce. More carbonate means more calcium carbonate deposition from the extended equilibrium from carbonic acid to calcium carbonate. The protons from carbonic acid cannot alter their own equilibrium, as an outside source of protons could.

Timothy Sorenson

A very nice read, enjoyed it immensely.

Roger Dueck

Excellent and enjoyable dissertation, Philip. I always enjoy a well-founded geological discussion and this is one! How unfortunate the IPCC dismisses the Geological Profession as simply knowing, well…ROCKS!
Roger Dueck, P.Geol.


An outstanding read. Thank you. Has anyone ever suggested that you have the perfect job?

Doug Proctor

Excellent summary of the process in the Caicos, a complex and interrelated situation beyond the appreciation of those focused on solitary, unique or, at most, limited parameters.
I’m a sedimentary geologist, oil and gas, graduate of University of Western Ontario, 1978. I first worked in the field as a mineral geologist; since then I have spent a lot of time in the Rockies which is mostly (near Calgary) a Mississippian and Devonian carbonate area. Cambrian carbonates also, but sandstones (quartzites) and trilobite-rich shales, too. The Cretaceous here is dominated by shallow shelf sandstones with erosional and redepositional strand beaches and offshore bars. Shallow portions go to estuarine sandstones, conglomerates and coals, with associated oyster shells.
The temporary nature of climate and environment is evident whereever you go. When you study rock core or rock in the field, you see sudden shifts of environment and exposure surfaces that tell you that even in “stable” times, stability is a relative term. It has become clear that what we see in the rock record is rarely the mundane, as day-to-day processes tend to smear and disrupt sedimentary features. There are sudden events that allow things to be both deposited where they will be undisturbed and preserved where yesterday they were destroyed.
Geologists are not good warmists if your evidence is short-term, by which we mean even hundreds of years. That is why people like Suzuki hate us (possibly not an exaggeration) and claim we are all “shills of Big Oil”. We see through our careers that wide swings of environment – climate driven, in many cases, if carbonate deposition and cessation are evidence of shift of temperature, wind and water qualaity – are common throughout time. Rock cycles of less than a meter over hundreds of square kilometers provide clear signs that big changes happen suddenly over huge areas, and happen cyclically, if not in a predictable pattern over the longer term.
I spent some time on Bermuda. The island is, in essence, the remains of surface-cemented carbonate sand dunes. They rise up to 100m above current sea level, and are a smaller portion of their original size before the post-glacial seas rose to flood the exposed, surrounding platform (where the sand came from for the dunes). I was able to see the various shoreface and offshore sediments in the eroded bases of the seacliffs: obviously the seas used to be higher than present, as the sand dunes developed ON TOP OF the shallow water sands and slightly deeper waters (the beach portions are absent, as expected, from erosional effects before sand dune cover protected the nearshore sands).
I also spent some time in Abu Dhabi, where I collected (and subsequently carved) primary gypysum nodules from the sabkha. The sabhka is only about 3000 years old, having pushed the sea back some 7 to 10 kilometers. I found relict nearshore, planar sand “hills” over preserved sand dunes (tops clipped off) that stood about 1.5 m higher than the currrent sabkha, itself perhaps 0.8m higher than the currrent Arabian Gulf (it floods during big storms from the east). Even with this limited experience, it is clear that the “stable” climate and ocean level is not really stable. Big changes happen regardless of whether we own SUVs.
A few years ago I drove to the Arctic Ocean, or at least as far as you can get at Inuvik, near the Arctic Ocean. I say this because the Mackenie River has a delta that is about 150 kilometers long – although at the end of the ice age, the waters flowed directed into the Arctic Ocean, sealevel rise and sediment infill have taken the mouth of the river far, far north. And no wonder! I flew to Banks Island, one of the smaller Arctic Island where I was astounded to see in the beach cliffs (10 to 15 m high at Sachs Harbour) OFFSHORE mud deposits. A geological survey worker there told me they estimated post-glacial Arctic rise at Banks Island to be about 26m. The Arctic only 15,000 years ago was very, very different from today.
There is far more and far more signficant variation on the several thousand year time frame than we were taught in school or any of the Gore-ists understand. The variations are NOT just grand scale, like an ice age or a warm period. The variations bounce things around enough to bring forests to where the Saskatchewan glacier in Alberta is only now melting enough for us to find the stumps. We had a desert from Arizona up through the Canadian prairies, warmth enough to allow snakes to migrate to the extreme northeast of Alberta (Wood Buffalo National Park). They survive by moving underground in a karstic environment of dissolved limestone. They have to: in all directions the land is muskeg, permanently cold and deathly to snakes. They cannot leave just as they cannot arrive.
I could go on, and some say I cannot do otherwise. My point is that geologists who wander this world and look at what they see, discover that major climate changes far beyond what we have seen in since 1850 have happened over and overe again without any catastrophic reason. There is no need to invent a difficult CO2 change to account for what we have seen since the ’70s, since we have no clue (and I mean this in the sincerest way that respects all the work that has been done on this subject) as to why such important changes happen without cosmological-level reasons.
The warmists like simple answers. They like to think the world is a kind place full of natural order and slow movements – if Man is not involved. Big stuff just doesn’t happen, unless the virus called Homo sapiens is invoked. Skeptics exist because there is big evidence that what we are seeing has many precedents, none of which are CO2 caused. And many of which are an order worse than what we have seen in the last few decades – and yet the world has done very well through every one.
Calgary, in June, had a three-day rain that melted the late-winter snows in the mountains. We had a 1 in 200-year flood which shocked everyone – except the 3000 geologists in this city who understood what caused the “floodplain” on which we live, and that the drop from the Westin Hotel on 4th Avenue is not a 1m random drop but the edge of the last major period of flooding – when? Dunno. A thousand years? 500? Hard to tell. Bison bones are still getting washed out of hillside landslides of old, so this land isn’t all that old. Except perhaps in the minds of Suzuki and Gore.
Changes in the past due to non-CO2 does not, of course, invalidate current changes due to CO2. But if your primary evidence is “change”, and then you use CO2 because it is the only solution you and your UN department can think of, you have a lot of living, investigating and thinking to ignore to keep thinking that way.
Just make sure you don’t ask a geologist. Or any other shill for Big Oil, I gather.


After your admirable analysis of the Carboniferous, I’m glad you turned your attention to the Cretaceous.
The Jurassic also had shallow seas in the Horse Latitudes, notably the European archipelago whose lagoons left us the Lagerstätten in which Archaeopteryx & its marvelously preserved contemporaries were found. The Cretaceous however enjoyed more thermal expansion, thanks to heating by volcanism at the sea floor spreading ridges where Gondwanaland was splitting up.

“A vist that, even now, I consider to have been the best field study trip of my entire geoscience career.”
Am I one of only four people on this site who attended and completed high school? Could we please have a verb in this sentence?
And, seriously to all, “its” and “it’s” are two far different words, could maybe the moderator make these posts somewhat readable? How about Spell-Check, Bueller, anyone?
That being said, hot water, cold water, salty and not-so-salty, lots of oxygen and maybe a little less oxygen, NO ONE among the great unwashed voters could possibly CARE LESS, how is this helping to undo the savagery of Gore-Hansen-Schmidt-Nuccitelli? And that clown with the column at NYT?
This is POLITICS, kids, not science. Science left the building quite some time ago.

I have to chuckle, Michael Moon
You hit your own ‘submit’ too soon
For in your blast of snarky slices
You’ve written several comma splices
Since punctuation gives you grief
Use semicolons for relief
And of the first of sins you note
You’ve missed a verb in what you wrote:

“And that clown with the column at NYT?”

But here’s a larger point: Go light
When dishing a grammatic slight
This might be politics to you
But science must be kept in view
We’re not just ranting and vote-getting
And this you seem to be forgetting:
This is the world’s best science site
We show the skeptic side is right!
And if you think it’s crucial here
(Though education I hold dear)
An institution’s just one tool
I never did complete high school
I had two jobs and needed three
The time for school eluded me
So that diploma’s out of reach
My college time was just to teach
===|==============/ Keith DeHavelle


Doug Proctor, never have stayed that close to geology but I learned much from your comment. Not any specifics especially but especially the overview of what you were sharing. Nice.

TG McCoy

Very good and informative-real science, sir.


Keith DeHavelle says:
October 20, 2013 at 10:41 pm
Not to mention its was used correctly. Michael should look for a refund on his education; whether it’s high school or higher.

ferd berple

Michael Moon says:
October 20, 2013 at 9:48 pm
“A vist that, even now, I consider to have been the best field study trip of my entire geoscience career.”
Am I one of only four people on this site who attended and completed high school? Could we please have a verb in this sentence?
con·sid·er verb \kən-ˈsi-dər\
: to think about (something or someone) carefully especially in order to make a choice or decision
have verb \ˈhav, (h)əv, v; in “have to” meaning “must” usually ˈhaf\
transitive verb
a : to hold or maintain as a possession, privilege, or entitlement


Great stuff Philip. Most importantly, the process of ocean de-gassing of CO2 is explained nicely.
Doug Proctor: I could go on, and some say I cannot do otherwise. Ha ha – good line. I also figure that late snow until early May, and snowmelt concentrated into a shorter period than usual, with heavy rain had a lot to do with Calgary’s flood this June. More plausible than the “extreme” meme that was bandied about, especially when the last similar flood was in 1924.
Back in the UAE, I experience the Emirates Coast carbonate ramp whenever I go to the beach.
Michael Moon: the verb is “consider” in the sentence you don’t seem to like.

Interesting diagram. Hadn’t considered that there are actually two areas of convection on the planet. The convergence zone between the trades, and the convergence zone between the westerlies and the polar easterlies. well, three if you consider the second zone is both N and S.


muphry’s law strikes hard.


I’m wondering a bit where all the CO2 originates. If a great deal of quondam CO2 precipitates via bicarbonate as CaCO3 every year to the bottom of the ocean, is it replenished by the atmosphere? The bicarbonate comes from where? The atmosphere? Of course there would be exchange between the ocean and the atmosphere, and the ocean should be a much larger reservoir of dissolved CO2/bicarbonate than the atmosphere. It seems to me we are failing to recognize the importance of undersea volcanic sources of CO2. Then CO2 liberation from the ocean boosting atmospheric levels makes more sense. The discussion below [2] of C isotope ratios is worth considering. Biological factors are not insignificant; e.g. CO2 -> bicarbonate driven by nitrogen fixation.
2) (interesting, very speculative 3×10^6 underwater volcanoes??)
(the orthodox view)

Peter Miller

Doug Proctor, I agree with you about how geologists are a very sceptical group of individuals.
However, a caveat is needed; this only applies to those in the private sector. Geologists in the government sector are much less likely to be sceptic, for the very simple reason that there are obvious employment consequences if they express anything other than alarmist views.
And that is the nub of the problem, CAGW is the fantasy of government, or quasi-government ‘scientists’.


A fascinating read, well written and explained.


What was the global rate of accumulation of organic matter during the carboniferous period?
What was the level of CO2 in the atmosphere at the start of the carboniferous period? There must have been vast quantities available to be sequestered in the coal and oil deposits, as well as in carbonate rocks.
Did the level of atmospheric CO2 fall during the carboniferous period as the organic matter accumulated, or was it replenished by some mechanism, such as undersea volcanoes?

Keith DeHavelle says:
October 20, 2013 at 10:41 pm
Very nice! (That was quick, too!)

Berényi Péter

What happens to the warm dense brine descending at the western edge of the Caicos platform? Was the full process ever investigated?

Peter C

Loved Episode one and two! Correction: I loved both essay number one and essay number two.
I hope I have that correct now. I don’t think that I will criticise an author ever again, Keith DeHavelle might be lurking!


@ StephenP The accumulation of coal & oil deposits were likely due more to the lack of organic decomposition in deoxygenated swamp water rather than any humongous increase in deposition. Bacterial decay is much more rapid in the presence of oxygen and associated fauna that “plows” the organic soil horizons.
Peat Bogs can be found in similar environments today.


Wonderful contribution. Vivid description of a real place and clear explanation of the processes at work. I could practically feel that warm salt-rich water pouring off the western ledge of the platform. Thanks!


But doesn’t ‘back radiation’ accelerate the precipitation rate of calcite hence the recycling of CO2.
What about the feedback?
What about the children?
What about grants for ‘The Team’?
[‘Back radiation’ does not exist: it is a failure to understand the difference between a real energy flux set by the vector difference of Radiation Fields and an isolated Radiation Field, the potential energy flux to a sink at absolute zero.]

Bloke down the pub

When I was at school, I studied geology and one day we visited nearby Leckhampton Hill to see exposures of the oolitic limestone which make up much of the Cotswold escarpment. Happy days, even if it doesn’t quite compare to a field trip to the Turks and Caicos.


Exactly, the deposits do not decay because they are in anaerobic conditions. They keep on accumulating, so there must have either been a ‘humungous’ amount of CO2 present at the start of the carboniferous, or there must have been a source of fresh CO2 to keep the organic matter accumulating. By burning fossil fuels, are we now returning the CO2 in the atmosphere to the level it was at the start of the carboniferous period?


AlexM says: [‘Back radiation’ does not exist: it is a failure to understand the difference between a real energy flux set by the vector difference of Radiation Fields and an isolated Radiation Field, the potential energy flux to a sink at absolute zero.]
Please say it regularly and often.
(and mind if I borrow that great short and correct wording?)
And the energy flux set by the vector difference of Radiation Fields = photons. By definition.
Just love it when someone actually understands physics here!

“The climatic difference between our modern cold ocean world and the ancient warm ocean world of the Cretaceous is simply due to the presence in the Horse latitudes of shallow tropical seas containing the carbonate ramps that form the planet’s “oceanic central heating system”. “
No argument to substantiate this is given. Yes, the shallow water is warmer. But that doesn’t mean it is collecting more heat than a corresponding area of open ocean. In fact less, because it gets the same sun but radiates away more as IR. The deep ocean is cooler because in addition to the fluxes of heat from sun and upward IR, and evap etc, heat is transported by advection toward the poles. It is already warming the earth in that way. In shallow seas that mechanism is impeded, so heat accumulates. Some can go to global warming, but it is a small fraction.
If you put a blanket over a room heater to restrict air movement, then the heater gets hotter. But it doesn’t heat the room better.

Rob M.

Excellent Essay thank you. I am a layman and thoroughly enjoyed it and found it easy to understand and follow. I am sure that took effort, and it is appreciated. Doug Proctor, your comment was equally fascinating to me and has piqued my interest to do some follow-up. I find geology fascinating. Thank you too.

jam south london
Copy and paste this link Barbican Battle of Ideas yesterday mentioned it during the Ben Pile Mark Lynas debate
For the American and Aussie reader the political class tried to destroy Rupert Murdock .
The Sun the biggest selling UK newspaper Murdock Tabloid .Cant take down the Politians but take down what they stand for.

“The “oceanic central heating effect” dog wags the “atmospheric greenhouse gas” tail.”
Quite so:
June 25, 2008
“the atmosphere stores only a miniscule proportion of the heat stored by the oceans. The heat stored by the atmospheric greenhouse effect is far less in quantity and far less long lasting than the heat stored by the oceans.
Man made CO2 is but a tiny part of a tiny part of a tiny part of the whole”

Mike McMillan

Very good post. I followed the journey with Google Earth, though the image resolution wasn’t good enough to see the finer points. Learned much, thanks.

Don K

Excellent. I enjoyed the article very much. A couple of questions if I may:
1. Mud flats under the salt flats on other islands? I’m at best mediocre at geology and self-taught to boot. But doesn’t “mud” imply a source of silicate material? Where is it coming from on a carbonate platform? Windborne dust from Africa?
2. The cliff with a relict coral reef at the base? How high? How old? Such features are apparently found in the Bahamas, Barbadoes, Hawaii, and a few other places. But as far as I can tell from reading, most low coral islands are just that … low. e.g. The highest elevation in the Florida keys is only about 6 meters. Presumably a dune. Many Pacific/Indian Ocean islands apparently aren’t even that high. I’m thinking that it’s possible that current “sea level” (would that it were actually level) may be about as high as it gets in the current planetary landmass configuration and that the relatively infrequent exposures that suggest higher sea levels during prior interglacials are due to regional land uplifts (tectonics), not higher global sea levels.
An alternative explanation for the apparent lack of ancient beach fronts in equatorial reasons might be that islands made of carbonate and carbonate sand might be subject to slow erosion from rain water.
I’m thinking that maybe we aren’t all in danger of drowning from global warming although the social/economic/human problem remains that much too much human infrastructure is built much too close to the ocean to avoid damage from storms and local tectonic affects.

I really enjoyed reading this, following the links and educating myself by looking up unfamiliar terminology.

Nick Stokes says:
October 21, 2013 at 3:26 am
In fact less, because it gets the same sun but radiates away more as IR.
The article isn’t about radiation. It explains the release of CO2 from warm oceans. It shows that it isn’t just a matter of CO2 dissolved in water. The CO2 is bound up with calcium, and enhanced by calcite precipitation, which means the assumed mechanism of CO2 release from simple warming is incomplete.


Michael Moon says:
October 20, 2013 at 9:48 pm
“A vist that, even now, I consider to have been the best field study trip of my entire geoscience career.”
Could we please have a verb in this sentence?
The verb is implied. Just read it as “[This was] a visit that …..” or imagine a semicolon where you see a period and get over it. I didn’t have the trouble you claim to have with the second paragraph. I agree that the intricacies of carbonate chemistry in subsequent paragraphs is a little daunting, but it just goes to show that things are complicated. Hence, Secretary Moniz was not correct when he related at a recent hearing that models shouldn’t be considered the final word because there’s simple arithmetic that bolsters the global warming thesis.


Nick Stokes says:
October 21, 2013 at 3:26 am
“…If you put a blanket over a room heater to restrict air movement, then the heater gets hotter. But it doesn’t heat the room better.”
Nick always try to throw a wet blanket over any observation that is contrary to AGW. Hey Nick, here’s an analogy for you:
A “scientist” that only “sees” AGW gets on the elevator of a large skyscraper. He is on the 1st floor. So, he presses button “1”, cause that is what he “knows”. Does he go anywhere?


geran: “Does he go anywhere?”
The baseline is P3. So he always goes up.

Kip Hansen

Thank you — great piece. My wife and I have enjoyed our times in the Caicos, coming and going from the Caribbean. One highlight of the voyage is stopping on the other, East, side of the island group at Big Sand (or sometimes Great Sand) Cay the East side of which faces the Atlantic all the way to Africa — and collects an incredible amount of floating stuff for beach combing.

Alan the Brit

Yet gain more reason why I just love this website. I learn so much from it! If it was up to me, I would have it on every school curriculum!!!!!


Don K says:
October 21, 2013 at 4:57 am
The highest elevation in the Florida keys is only about 6 meters. Presumably a dune.
nope, fossil reef, Windley Key….~18 ft


Alan the Brit says:
October 21, 2013 at 6:55 am
… “I learn so much from it! If it was up to me, I would have it on every school curriculum!!!!!”
WUWT University?

I really liked this essay, especially the crossing of the island, studying as you went.
The internet may be great, allowing us to sample a variety of minds, but I feel some get stuck in a virtual reality, and forget the value of a “field study.” Step outside. View the wonder of Creation.
The complexity of our world is utterly amazing. We are all focused on CO2 these days, but a few years back the focus was the ozone layer, and that too turned out to involve stunning complexity. I can remember a wonderful description of the journey of Bromine from plankton in a storm to the stratosphere to interactions with Ozone.
I really like the sense of understanding I get from grasping an element of how Creation works, but I’d be a fool if I pretended I understood the entirety. There is no shame in being humbled by wonder.
One aspect of the peculiar psychology of some Alarmists is, I imagine, that when they become aware they cannot grasp the sheer magnitude of Creation they do not feel wonder, but instead feel panic.


verb \kən-ˈsi-dər\
: to think about (something or someone) carefully especially in order to make a choice or decision
: to think about (something that is important in understanding something or in making a decision or judgment)
: to think about (a person or a person’s feelings) before you do something in order to avoid making someone upset, angry, etc.
Michael Moon says:
October 20, 2013 at 9:48 pm
I think he did put a verb in the sentence.


Our next stop is just off the beach, here the corals are no longer thriving, they are being buried by carbonate beach sand..
Here the corals have and will never thrive, they are being buried by carbonate beach sand..sedimentation

Joe Crawford

“… It is my view that in geoscience it is always good to consider more than one possible explanation for any set of field observations.”
Ah, the old adage about two geologists, one outcrop and three theories.


More informative of overall carbonate geology/geochemistry mechanisms in one read (and more entertaining!) than several weeks of my dry Carbonate Geology college course. Excellent. I found some interesting maps and cross sections at that reinforce his word pictures.
I would also like more discussion on how warm deep seas (vs cold ones) would affect the overall climate – anyone?