Picture this: it’s a hot day, and you grab a soda can that’s been in the sun. You crack it open—psssht—and CO₂ fizzes out, tickling your nose, maybe spraying your shirt if you’re slow. It’s a tiny chaos, a burst you can’t control. Now imagine that fizz across the ocean’s sun-warmed surface, covering 71% of Earth, bubbling CO₂ into the air we breathe. Wild, right? A bit mad. I reckon it's a missing piece of the climate puzzle.
The IPCC pins it all on smokestacks—11 billion tonnes of carbon a year from fossil fuels. Even skeptics like the CO₂ Coalition echo this, leaning on guys like Ferdinand Engelbeen who do their maths by the consensus numbers on this issue of CO₂ origins.
But they might have it all back to front and be leaving out ocean chemistry and biology. In fact, I’m convinced they are.
The Keeling Curve—CO₂’s climb from 280 to 420 ppm—carries their blame. But what if the ocean’s fizzing more than they think? Their rock-solid evidence could be mostly myth.
I’ve been digging into this with Ivan Kennedy, my second guest for the webinar series ‘Towards a New Theory of Climate Resilience’. That was back in February and I’m still to process the audio from this discussion.
Instead, my focus has been on writing technical papers. Ivan and I are working through a hypothesis that could perhaps flip the climate script.
Engelbeen claims fossil fuels’ isotopic fingerprint—light ¹²C (isotope C12) dragging the air’s ¹³C-to-¹²C ratio from -6.5‰ (per mille)* to -8.5‰ since 1850—is proof of coal and oil’s guilt. Ocean CO₂, averaging 0‰ from deep waters, should nudge it up—not down. Case closed.
Except. That ¹²C/¹³C tale’s shakier than they admit. What if the ocean’s surface, warmed by the sun, fizzes CO₂ richer in ¹²C than the deep oceans 0‰?
Calcification—limestone forming in seawater—might churn out CO₂ at -10‰ or lower, diluting that delta 13 signal just like fossil fuels. It’s not the deep ocean I’m on about—it’s the top 65 meters, the mixed layer, where sunlight and warmth cause biological action. So much action that it has built the biosphere’s great carbonate deposits, even the White Cliffs of Dover.
Ivan and I talked some of this over—Great Barrier Reef, North Pacific—during our webinar (soon my first podcast—thanks for waiting!). Calcification’s no sleepy trick; it’s a biological buzzsaw—corals, algae, phytoplankton like coccolithophores churning limestone. In summer blooms, they might pump out tonnes of CO₂, light on ¹³C. Our Thermal Acid Calcification (TAC) hypothesis says nature’s pitching in more than you might think.
Ponder this next time you sip a soda: could the ocean be bubbling up a CO₂ twist?
TAC’s perhaps a second plank in my New Theory of Climate Resilience. Subscribe for irregular updates, and to know about next webinars.
In churn and current, me with that silver scuba air tank at the surface above the mixing layer at the Great Barrier Reef. And the top/feature image is of my scuba buddies diving off the edge from Myrmidon Reef that is already at the edge, photographed by underwater photographer, scuba buddy and boat skipper Jenn Mayes.
This is Part 2 of How Climate Works. Part 1 was with Bill Kininmonth. I never properly processed the audio from Part 1, and I accepted the AI summary of our meeting click here.
Postscript
From a paper by Werner Berner et al. 1980. In Radiocarbon, Vol 22, No.2. pgs. 227-235. Suggesting higher carbon dioxide levels just a few thousand years ago.
************
When we say deep ocean carbon is 0‰ (per mille), we're talking about its carbon isotope ratio, specifically the δ¹³C value. This is a measure of how much carbon-13 (¹³C) is present relative to carbon-12 (¹²C), compared to a standard reference.
In this case, 0‰ doesn’t mean there’s no carbon-13 in the deep ocean—it means the ratio of ¹³C to ¹²C in deep ocean dissolved inorganic carbon (DIC) is about the same as the standard reference, which is usually the Vienna Pee Dee Belemnite (VPDB). A δ¹³C of 0‰ indicates no enrichment or depletion of ¹³C relative to that standard.
Now, why is deep ocean carbon around 0‰? It’s because the deep ocean is a massive, well-mixed reservoir of carbon that’s been cycled through various processes over long timescales. Surface ocean carbon starts with a δ¹³C of about +1 to +2‰ due to photosynthesis, where phytoplankton preferentially take up ¹²C, leaving the surface water slightly enriched in ¹³C. But as organic matter sinks and decays, it releases carbon back into the deep ocean. This process, along with the mixing of water masses, balances out the isotopic signature. The deep ocean ends up with a δ¹³C close to 0‰ because it reflects a long-term average of all these inputs—biological, physical, and chemical—without much net fractionation.
In terms of carbon-13, this means the deep ocean has a pretty stable and "neutral" amount of ¹³C compared to the global carbon cycle. It’s not heavily skewed like surface waters or organic matter (which can be -20‰ or lower due to that photosynthetic preference for ¹²C). So, a δ¹³C of 0‰ tells us the deep ocean is kind of a baseline, a big pool where carbon isotopes have settled into equilibrium over thousands of years.
"Simply said, his calculation is based on a wrong model with all inflows and outflows of the atmosphere in one direction, while in reality almost all natural fluxes are bidirectional"
"bidirectional": and never balanced.
"Cohenite, did you read that one of your references:
https://www.sciencedirect.com/science/article/abs/pii/S0921818113000908"
Yes, I'm fair, I included a critique of the other papers.
"The other works are from Harde and Berry, who don’t understand the difference between a residence time (4 years), which moves lots of CO2 between the different reservoirs, but doesn’t net remove one gram of CO2 out of the atmosphere, and the adjustment time (50 years) which is the real net removal rate…"
Incorrect. The difference between the residence time of 1 CO2 molecule and the adjustment time or the time required for a bulk of CO2 to be altered is a favourite alarmist myth. Bob Cormack one of your old sparring partners, who did the above analysis of why ACO2 CANNOT be the cause of the increase in atmospheric CO2, also looks at the difference between the residence and the bulk rates of flux:
https://australianclimatesceptics.com/?p=1
[…] at Dr. Jennifer Marohasy’s always interesting blog, she makes an interesting claim about ocean outgassing of […]
Jennifer,
Some more critique at WUWT from Willis Eschenbach:
https://wattsupwiththat.com/2025/04/12/ocean-co2-outgassing-with-temperature/
Let me know if you have a figure?
https://breadonthewater.co.za/2024/07/28/the-mystery-of-the-missing-human-generated-carbon-dioxide/
I still think it is about 140 ppm per degree K as per Ennersbee's work.
The contribution of man is greatly overestimated.
[…] at Dr. Jennifer Marohasy’s always interesting blog, she makes an interesting claim about ocean outgassing of […]
Cohenite, do you have a direct link to that calculation?
Anyway, several wrong assumptions...
He assumes that the 14C spike decay is similar as for a 12/13C spike decay, while it is a factor 2.5 or so. That is because the deep ocean return has no 14C spike from 1,000 years ago and the supply of 14C-free CO2 from fossil fuels.
He assumes that I assume a constant supply, which it never was. A linear year by year increase is what fossil fuel emissions are, leading to a slightly quadratic CO2 increase in the atmosphere, resulting in a slightly quadratic increase in uptake and a near constant ratio between emissions and sinks (about a factor 2).
He assumes that the sum of the inputs gives the absolute pressure to push the outputs, so the human portion in the atmosphere and outputs never can be higher than the ratio in the inputs. The human ratio in the inputs was 1.5 to 5% (1960-2020), the ratio in the atmosphere is already over 10% and in the ocean surface over 6%...
Simply said, his calculation is based on a wrong model with all inflows and outflows of the atmosphere in one direction, while in reality almost all natural fluxes are bidirectional, largely independent of the CO2 pressure in the atmosphere and only the unbalance between ins and outs gives the increase in the atmosphere and that unbalance is directly proportional to the extra CO2 pressure above equilibrium with the ocean surface, not the absolute CO2 pressure...
https://www.ferdinand-engelbeen.be/klimaat/klim_img/mass_fluxes_real.jpg
Cohenite, did you read that one of your references:
https://www.sciencedirect.com/science/article/abs/pii/S0921818113000908
He shows that Humlum is wrong by assuming that the increase in the atmosphere is not man-made...
The other works are from Harde and Berry, who don't understand the difference between a residence time (4 years), which moves lots of CO2 between the different reservoirs, but doesn't net remove one gram of CO2 out of the atmosphere, and the adjustment time (50 years) which is the real net removal rate...
And thanks for the post on Judith's blog by Fred Haynie, didn't remember that one, good reactions of myself, héhé...
Peter Etherington-Smith is quick to refer to other scientists as "corrupt" and "willfully stupid", but when someone points out his drivel, he turns into a snowflake.
So much for a reasoned scientific discussion on this platform without being insulted and demeaned. If you decide to embrace bad science, that is your choice.
Finally a mate of mind did this proof that the increase in atmospheric CO2 is natural. Ferdinand gets another mention; he gets around!:
We know from empirical data (the bomb spike) that atmospheric concentrations decay back to equilibrium in an exponential curve, C(t) = C(t=0)exp(-t/a), where a is the time constant of the decay (and ~0.7a is the half-life).
The decay rate at any time, t, is dC/dt = -1/a * C(t=0)exp(-t/a) = -1/a * C.Hence, the concentration decay rate is proportional to the concentration (what makes the system linear, and is the generating definition of an exponential).
(I’m going to refer to all rates and quantities as positive, and identify which way they’re going by labeling “in” -to the atmosphere, and “out” -of the atmosphere.)
Let’s suppose we have an equilibrium with Rin = Rout, and C = constant. If we measure Rin = Rout = 100Gt/yr (carbon, not CO2), and C = 800Gt, we can immediately deduce the time constant, since R = 1/a * C, we get a = C/R = 8 years. (This is ~ 30% smaller than derived from the bomb spike data, so perhaps there is more than 800Gt C in the atmosphere, or we need to include some fraction of the biosphere, or the estimates of Rin, Rout are high.)
Now, let’s suppose we add an Anthropogenic component, “Ain”, to “Rin”, and continue doing so for an indefinite time. How much does C increase? There are two ways of doing this – both easy since the system has been measured to be (nearly) linear:
1) Increase at equilibrium (t -> infinity):Since Rin = 1/a*C_natural, then (Rin + Ain) = 1/a * (C_natural + C_anthro). These linear equations are easily solved for C_anthro = a * Ain.Hence, if Ain = 8Gt/year, C_anthro = 64Gt/year, or about 8% of total atmospheric concentrations. (Also, about 30 ppm).
Note that this is the maximum concentration increase that can be caused by an Anthropogenic input of 8 Gt/yr that continues forever. It does not continue to build up, as Ferdinand assumes – that assumption is equivalent to assuming that the time constant, “a”, is very large – 100’s of years. Making this (hidden) assumption then raises the problem of where is all the missing carbon in the atmosphere (or equivalently, why is the carbon cycle so very far out of balance?) Also, of course, such an assumption cannot explain the bomb spike data without ad hoc assumptions about the behaviour of C14 vs C12.
2) The same result can be gotten by considering the discrete yearly increases in C anthro:
Year 1 total C_anthro = AinYear 2 total C_anthro = Ain + (1-1/a)AinYear 3 total C_anthro = Ain + (1-1/a)Ain + (1-1/a)^2 * Ain…Year n total: C_anthro = Ain * Sum(r^n), where n goes from 0 -> n , (r=1-1/a)
This is a geometric series, whose partial sum (at year N) is:C_antho = Ain *(1-r^n)/(1-r),and the infinite sum (at forever) is:C_anthro = Ain *1/(1-r) = a*Ain (after substituting r = 1-1/a)
So to summarize:1) Measurements show that the atmosphere adjusts to an input of CO2 by an exponential decay. This implies that the sink rates are proportional to the concentrations.2) Both the measurements and estimates from total CO2 amounts give similar time constants for the decay.3) Points 1 and 2 put a limit on the increase in CO2 atmospheric concentration that can be caused by a continuous anthropogenic input to the yearly input times the time constant.4) The claim that a continuous anthropogenic input can cause a continuous, fixed increase in CO2 atmospheric concentration contradicts both the measurements in point 1 and the estimates in point 2, hence is false.