Dave Burton
April 22, 2022 2:13 pm
... There is no “natural increase” in the amount of CO2 in the atmosphere. Nature is removing CO2 from the atmosphere, each year, not adding it. Mankind has added about 180% of the measured increase in the amount of CO2 in the atmosphere since 1959.
We know from reliable measurements that every year since 1959 the amount of CO2 in the atmosphere has increased by less than the amount of CO2 which mankind has added to the atmosphere (with the arguable exception of 1973, a year in which the two numbers were very similar).
That means the only reason that the atmospheric CO2 level continues to rise is that mankind is adding CO2 faster than nature is removing it.
I sometimes say that all of the rise in atmospheric CO2 concentration since 1959 is due to mankind’s emissions, but that’s not quite precise. Actually, in those 63 years, mankind has added about 180 ppmv of CO2 to the atmosphere, nature has removed about 79 ppmv from the atmosphere, and the atmospheric CO2 concentration has risen by the difference between those two numbers: about 101 ppmv.
So mankind can take credit for about 180% of the (beneficial!) rise in atmospheric CO2 concentration since 1959.
The “effective” residence time (a/k/a the “adjustment time”) for CO2 added to the atmosphere is about fifty years, making the half-life about 35 years. That’s much longer than you would guess from the decay rate of the 14C “bomb spike.” This is a log scale plot of the decline of 14C levels in the atmosphere, following the atmospheric test ban treaty:
(Note: ¹⁴CO2 is 4.5% heavier than normal ¹²CO2, which affects biological uptake and diffusion rates slightly. But not much.)
16.6 years is obviously much shorter than the 50 year effective lifetime of atmospheric CO2 emissions. Can you guess why?
The answer is that some of the processes which remove ¹⁴CO2 from the atmosphere do so by exchanging it, one-for-one, for ¹²CO2.
Those processes cause the fraction of 14C in the atmosphere to decline without actually reducing the amount of CO2 in the atmosphere. That means the 11.5 year half-life and 16.6 year residence time are necessarily less than the effective lifetime / adjustment time of CO2 emissions.
That 50 years effective lifetime is deduced from measurements.
Dave Burton
April 22, 2022 3:21 pm
In the ice core records we can see that CO2 trend reversals generally lagged temperature trend reversals during glaciation / deglaciation cycles. That is strong evidence that global temperature affects the amount of CO2 in the atmosphere, but it does not mean nothing else affects the amount of CO2 in the atmosphere.
Glaciation / deglaciation cycles are generally estimated to correspond to about a 5-10°C variation in average global temperature. (More where there’re ice sheets, of course.) That drives about a 90 ppmv change in atmospheric CO2 level (though it takes thousands of years to be fully realized).
But we’ve measured a 101 ppmv increase in atmospheric CO2 level since 1958: For global warming to cause such a large increase in CO2 level would obviously require MORE than than the 5-10°C global temperature change that the Earth sees when going from glacial maximum to peak interglacial warmth. So, are you contending that the Earth has warmed by > 5-10°C since 1958?
Mark BLR
April 23, 2022 7:11 am
... Why is it so hard to understand that human emissions have been nearly double the increase in the amount of CO2 measured in the atmosphere? We certainly don’t know the exact quantity that was emitted, and even the exact CO2 concentration change is not known with absolute certainty, but when the amount we emit is about double the amount that CO2 increases, it should be obvious to any scientifically literate person that the extra human-emitted CO2 had to be absorbed by nature. If nature is a net sink, it can’t simultaneously be a net source.
Dave Burton
April 22, 2022 2:55 pm
Frans wrote, “The idea that human CO₂ is the all-determining cause of the increased concentration is based on the assumption that the natural inflows and outflows are always and exactly in equilibrium with each other.”
That’s nonsense. The fact that the increase in the amount of CO2 in the atmosphere is due to our emissions is determined from measurements, not any sort of assumptions:
1.We know how much CO2 there is in the atmosphere, since we measure it quite precisely (since 1958), so we know how much it is increasing.
2.We also know how much CO2 is emitted from burning fossil fuels and making cement, because the bean-counters keep track of such things.
If you subtract the former from the latter, the difference is the amount of CO2 which Nature removes each year.
Frans wrote, “the IPCC-models calculate with a small residence time of about 4 years for natural CO₂ and a large one for human CO₂: “The removal of all the human-emitted CO2 from the atmosphere by natural processes will take a few hundred thousand years (high confidence)”.
Very long residence times are calculated by integrating the hypothetical “long tail” of the CO2 decay curve. The practical “effective residence time” (a/k/a the “adjustment time”) for CO2 added to the atmosphere is about fifty years, making the half-life about 35 years.
Rich Davis
April 23, 2022 7:36 am
Nobody is saying that nature is “just a sink”. The reason why the net natural flux is a sink right now is that there is a driving force. There is more CO2 in the atmosphere than there “should be” based on Henry’s Law and the current average temperature of the ocean surface. The extra CO2 is the result of centuries of accumulation of our emissions.
The extra CO2 is transient but the rate of adjustment is slow enough that the gradual accumulation is possible. The extra CO2 is NOT A PROBLEM. The extra CO2 is BENEFICIAL. The extra CO2 is THANKS TO MAN.
Dave Burton
April 22, 2022 3:28 pm
migueldelrio wrote, “Warming oceans outgas CO2.”
Not when the atmospheric CO2 level has increased by 49%. The temperature dependence of Henry’s Law decreases effective CO2 solubility in water by about 3% per 1°C of surface water warming: A 49% increase in atmospheric CO2 partial pressure increases effective CO2 solubility in water by 49%. Which one has the greater effect, migueldelrio? +49% or -3%?
Rud Istvan
April 22, 2022 2:55 pm
This post’s finding is probably (and unfortunately) not correct. There is a simple yet very robust way to show that. And a second way to confirm the first.
Photosynthesis preferentially uses the lighter 12C isotope rather than the also stable but heavier 13C isotope. The result of sequestering hundreds of millions of years of photosynthetically produced fossil fuels is mainly 12C sequestered, thereby enhancing the ratio of 13C remaining in the atmosphere.
As fossil fuels began to be consumed in significant quantities circa WW2, it can easily be shown using mass spec that the proportion of 13C to 12C has since been declining. That cannot be because of the post’s contemporary carbon biosphere cycle affected by slight warming. It has to be because fossil fuel consumption frees lots of previously sequestered 12C.
And therefore the Keeling Curve rise in total atmospheric CO2 isn’t mostly from the slight warming, Henry’s law, and all that. It is mostly from fossil fuel consumption. The last few decades observationally declining trend in the atmospheric 13c/12C ratio is easy to verify online.
As a Lemma concerning Henry’s Law and the oceans, the ocean temperature (and salinity) is remarkably stable (at about 4C) below the thermocline. Recent posts here explained the underlying physics. This was known long before ARGO. The thermocline is ‘mostly’ (80%) at most 750 meters deep; it is a bit shallower (600 meters) over much of the vast tropical ocean.
There is literally zero temperature change below 2000 meters, deliberately the ARGO design max depth for OHC measurement. (I imaged these details by latitude in essay Missing Heat in ebook Blowing Smoke. I reposted that image in my post here on ‘ARGO-fit for purpose’ a few years back.)
There simply is not enough dissolved CO2 above the ‘main’ (80% of delta T) thermocline for Henry’s Law and about delta 1C at the surface to explain the Keeling CO2 Curve. The oceans average about 4000 meters depth. That entire column is CO2 saturated. Only at most about 750/4000 or 20% is even subject to any Henry’s law argument at all. Oceanography 101.
Ferdinand Engelbeen
April 22, 2022 4:29 pm
I don’t know where you have had any chemistry, but Henry’s law still works perfectly for CO2, but only for dissolved CO2, not for the equilibrium reactions that converts CO2 into (bi)carbonates once CO2 is dissolved.
That makes that both in fresh water and seawater a doubling of CO2 in the atmosphere will give a doubling of dissolved CO2 per Henry’s law.
As pure CO2 is 99% of all inorganic carbon species in fresh water, a doubling in the atmosphere gives near a doubling in water and then it stops.
In seawater, pure CO2 is only 1%, bicarbonates 90% and carbonates 9% of all inorganic carbon species.
If you double that in the atmosphere, CO2 doubles from 1% to 2%, again per Henry’s law, but the rest doesn’t double, as dissociation of CO2 into (bi)carbonates also sets H+ free, thus the solution gets less alkaline and that pushes the equilibrium back to pure CO2.
The net result is that a doubling of CO2 in the atmosphere doubles free CO2, but total DIC (CO2 + (bi)carbonates) increases with 10%. Still, seawater can absorb 10 times more CO2 for the same increase of CO2 in the atmosphere than fresh water. That is the Revelle/buffer factor…
If you heat a solution of bicarbonates (stomach salt), I am pretty sure that a lot of CO2 will get out of the solution, despite that the solution gets more alkaline…
Practically all inorganic carbon on this world: oceans, carbonate rock, volcanoes,… is much higher in 13C/12C ratio (around zero per mil) than everything organic (most below -20 per mil). There are only two main sources of low-13C on this earth: recent organics and fossil organics.
As recent organics are gaining mass (the earth is greening), thus removing more 12CO2 than 13CO2 in ratio, the only cause of the steep decline in 13C/12C ratio in the atmosphere is our use of fossil fuels.
Ferdinand Engelbeen
April 22, 2022 11:38 pm
The oceans release and absorb CO2 even when they are alkaline. All is a matter of concentrations, pH and temperature. These three factors give the partial CO2 pressure in equilibrium with the above atmosphere, no matter the pH level itself. Take a stomach salt solution and add a drop of vinegar: CO2 will be released, even when the pH still is largely alkaline…
It is impossible that the oceans would absorb CO2 indefinitely, as that would imply zero CO2 in the atmosphere. And again, a CO2 sink is not responsible for the CO2 increase in the atmosphere. Currently the ocean surface absorbs CO2 and DIC increases. That is measured at every point in the oceans where DIC is measured over longer periods.
CO2 and seawater DIC were in equilibrium with the atmosphere for millions of years, be it with (long) delays, as it takes a lot of time to move CO2 into and out of the deep oceans to get an equilibrium between atmosphere and oceans.
For the surface (mixed) layer that is far more rapid: a matter of years, but that contains only around 1,000 PgC, compared to the atmosphere at 830 PgC.
Ferdinand Engelbeen
April 22, 2022 5:13 pm
Sorry, but you are completely wrong about the cause of the CO2 increase in the atmosphere. That makes that the very good pages that you have made will suffer from that terrible mistake.
Indeed, Murry, Salby, Berry and several others have made the same fundamental mistake: The atmosphere is NOT a single reactor with one inlet and one outlet where the outlet flux is directly proportional to the height (pressure) in the reactor.
The bulk of the CO2 fluxes are seasonal and bidirectional. These are caused by the seasonal temperature changes and hardly influenced by the CO2 pressure in the atmosphere.
Even if the seasonal fluxes doubled over time, that has zero influence on the total amount of CO2, as long as the influxes and out fluxes are in equilibrium.
Over the past 60+ years, the out fluxes were always larger than the influxes, it simply is impossible that the natural fluxes were the cause of the CO2 increase, as the net result of all natural fluxes is more sink than source, already 60+ years…
Human emissions are one-way additions and larger than the measured increase in the atmosphere. Any book keeper will show you that this is what counts, not how much money is circulating in your business…
Then a few specific remarks:
“At 1 °C temperature increase, this results in an increase in emissions from the oceans of 19 PgC/yr.”
Which is impossible, as the CO2 in the atmosphere increases, thus the partial pressure difference (pCO2) between CO2 in the atmosphere and the ocean surface gets smaller again, and gets the old flux rate once the delta-pCO2 is the same as before at about 12-16 ppmv/K
If there is any increase in fluxes, again that is for both sides of the balance: the CO2 sinks in the oceans increased more than the sources…
Donald L. Klipstein
April 22, 2022 7:38 pm
Regarding: “The natural fluxes are much larger. To and from the sea this is about 80 PgC/yr, to and from land about 120 PgC/yr.”
Most of this is oscillatory source/sinks, such as vegetable mass including leaves of deciduous trees. Then there are the oceans outgassing CO2 where they’re especially warm, but that gets matched by sinking by the oceans that is in addition to the net sinking by the oceans.
The annual wiggle in the monthly CO2 measurements by the Mauna Loa observatory shows peak downturning month and peak upturning month have CO2 rate of change being on average about 8 times the annual rate of change.
Also, there are natural sources and natural sinks even happening at the same time and pace, such as extratropical forests having quickening decay of the lots of dead vegetable matter that many of them have in late spring and early summer while they are also going gangbusters with starting to use sunlight and CO2 for building new biomass.
Ferdinand Engelbeen
April 23, 2022 2:50 am
Your theory is already falsified, as the current amount of human CO2 in the atmosphere, based on the 13C/12C ratio, is already 10%, far beyond the 4% that can be reached for a one inlet – one outlet river example or the one reactor with one inlet and one outlet of Harde.
The atmosphere is not a one direction in/out scheme, as most of the fluxes are temperature controlled seasonal and bidirectional. That gives a very short residence time (about 4 years) because much CO2 is exchanged between the different reservoirs, but that doesn’t influence the total amount of CO2 in the atmosphere.
Any extra CO2 above equilibrium does influence the balance between inputs and outputs, but that is a pressure controlled process, near completely independent of temperature that controls the seasonal fluxes…
The base of the 13C/12C change as measured in ice cores, firn and atmosphere and coralline sponges in the ocean surface, which closely follows the changes in the atmosphere
Tom.1
April 23, 2022 5:14 am
If there has been a net increase in the natural flow of CO2 to the atmosphere, then it would be additive to the anthropogenic flow. However, the increase in CO2 in the atmosphere is less than the known anthropogenic flow, which must mean a net decrease in the natural flow. There is no other explanation."
Ferdinand Engelbeen
April 22, 2022 11:46 pm
Nature is absorbing more and more CO2, despite rising temperatures for the simple reason that the increase in the atmosphere is faster than dictated by Henry’s law (12-16 ppmv/K) for the decreased solubility of CO2 in warming ocean waters…
MGC
April 22, 2022 9:57 pm
It is childishly easy to prove that nature cannot possibly be causing the CO2 increase in the atmosphere. Here’s how:
1- human are emitting over 30 gigatons of CO2 into the air every year ( data from easily verified fossil fuel usage data)
2- CO2 levels in the air are increasing by only around 20 gigatons per year. (data from Mauna Loa CO2 measurments)
3- Where are those missing 10+ gigatons of CO2 going? CO2 can’t just magically disappear. There is only one possible explanation: nature is absorbing that CO2 out of the air. Nature is actually taking more CO2 OUT of the air than it is putting INTO the air.
Pretending that nature, which takes more CO2 OUT of the air than it puts into the air, could possibly make CO2 in the air increase, is just as utterly ridiculous as pretending that taking more money OUT of your bank account than you put into it somehow makes the account balance “increase”.
Even a grade school child would easily understand this. So why does WUWT publish such utterly ridiculous, totally lying anti-reality drivel?
...and Then There's Physics
(@wottsupwiththatblog)
April 23, 2022 1:23 pm
Atmospheric CO2 has increased from 280 ppm to about 419 ppm. That’s about 295 GtC. Total human emissions are about 650 GtC. So, the rise in atmospheric CO2 is equivalent to just under 50% of total human emissions. Typically the airborne fraction is estimate to be about 0.46.
Tom.1
April 23, 2022 7:47 am
The fact remains that on any time frame you want to look at, there is less of an increase in the amount of CO2 in the atmosphere than the amount of manmade CO2 that is going into the atmosphere. The only way that works is if all the other CO2 flows are net going from the atmosphere to the land and oceans. The natural fluxes are much larger than the manmade contribution, but for the increase in the air to be less than the manmade contribution, the natural fluxes must be net negative with respect to the air.
Ferdinand Engelbeen
April 24, 2022 12:14 am
All the CO2 in the oceans doesn’t count as long as it stays there. No matter how much CO2 is moving between the different reservoirs, as long as the inputs equal the outputs nothing happens with the amounts in the reservoirs. Only the difference between inputs and outputs matters and that is only half human emissions, no matter how small that is…