Guest Post by Willis Eschenbach (still banned from X aka Twitter, see here)
The most excellent reef and ocean scientist Jennifer Marohasy put up a Facebook post recently on the lack of much effect on the atmosphere CO2 levels from the 2020 emissions drop due to COVID. She says this shows human CO2 emissions have very little effect on atmospheric CO2 levels. However, I fear her graph is greatly misleading.
The problem is that she is showing the full range of two related but very different variables. Let me see if I can clear up the confusion.
To begin with, we need to change the CO2 emissions to parts per million by volume (ppmv) of CO2. To do that, we need to divide the gigatonnage (billions of tonnes) of CO2 by 7.81 gigatonnes of CO2 emissions per each 1 ppmv increase.
Next, we need to account for the fact that the earth is constantly absorbing and sequestering CO2. I find there’s an excellent fit to be had by using the following procedure. The underlying assumption is that every year, a certain small percentage of “excess” airborne CO2 is being sequestered by natural processes, with the rest of prior emissions remaining in the air. What is “excess CO2“? Well, it is the amount in excess of some undetermined baseline, which we expect to be on the order of the historical value of about 285 ppmv.
So I set up an Excel spreadsheet to use Solver to search for the value of the unknown percentage which remains after the ongoing sequestration, as well as the value of the unknown baseline, that give the best fit to the actual airborne CO2. You can download my spreadsheet here, it’s only 23 kbytes. I get the following values:
Unknown baseline: best fit = 286.8 ppmv
Given that the fitting process could have come up with a very wide range of values, that is a very good indication that atmospheric CO2 levels are indeed related to human emissions.
Unknown percentage remaining after each year’s sequestration: best fit = 98.1%
And here is what those values give as a result. Remember, I’m calculating the best fit of human emissions to the actual airborne CO2 values using just two fitted variables—the amount remaining after annual sequestration, and the pre-industrial baseline.
Now, on my planet at least, that’s a very good fit. At all points, it’s within 1.5 ppmv of observations, and the R2 of the estimate and the observations is 0.997
A couple of comments on that. First, for a two-parameter fit between emissions and CO2 level, with one of the fitted parameters coming out very near the expected value, that seems clear evidence that the rise in CO2 levels is MAINLY a result of human emissions.
I say “mainly” because as you note, the observed CO2 level goes both above and below the estimate. I assume this is because of changes in both emissions and sequestration rates.
Now, as you can see, Jennifer is right that the estimate for the time of the dip due to COVID is slightly below the actual values. How much? The largest difference is the year after COVID, when observations are a whopping 0.7 ppmv above the value estimated from the emissions … be still my beating heart.
However, the same is true during a number of periods in the record.
Why doesn’t the COVID drop make much difference? Four reasons.
First, the e-folding time “tau” for the slow decay of a pulse of CO2 is ~ 50 years, so any year is greatly affected by the previous years.
Second, the drop in the emissions was small, only about 5%. Such small changes occur throughout the emissions record, and are smoothed over by the natural process of sequestration.
Third, the emissions dip was short, only one year long, with the next year returning to normal amounts.
Fourth, there are other factors at play, changes in natural emissions and sequestrations.
In closing, folks may ask about “tau”, the time constant being only 50 years when the scientific solons say excess CO2 remains in the air for hundreds and hundreds of years. So are they correct? Well … yes …and no. Excess CO2 remains, just not very much. Given the annual decay rate calculated above, .981, here’s how that plays out for the excess carbon.
(Yes, I know that’s different from what the standard “Bern Model” of CO2 sez … see my post on that model, including the previous post linked therein.)
My best wishes to Jennifer Marohasy despite her claims in this one case—she’s a most valuable and insightful scientist.
==========
Me, I’m not only in the very remote Solomon Islands near the Equator, north of Australia, where I worked for eight most wonderful years. I’m in the even more remote Western Province of the Solos, chewing betel nut with lime and leaf, and having a great time. I also, for the first time in three weeks, have reasonable Internet. Why?
My friend with whom I’m staying has Starlink. So for all you Elon haters out there, he’s done a huge service for mankind.
Best of the South Pacific to all, going scuba diving tomorrow, back to the US next week.
w.
AS IS MY CUSTOM, I ask that when you comment you quote the EXACT WORDS you are discussing. It avoids endless misunderstandings.
Willis mutters about defending his often stupid waffling, in this case offering to defend more “Steel Greenhouse” nonsense disguised as a reference to a carefully crafted experiment by R W Wood, in 1910 or so.
Here’s Willis, refusing to accept reality and the laws of thermodynamics because someone pointed out that you can’t use the radiation from a cooler body to raise the temperature of a hotter one –
He decides that he can at least make the objects the same temperature, because one is only a little colder than the other. But even this doesn’t work, because Willis prefers fantasy to fact.
Two objects at the same temperature are in temperature equilibrium. One will not magically become hotter, just because Willis insists it must. So Willis has a sphere of a certain temperature, surrounded by a steel shell, all in deepest darkest space – no external heat source to be found.
Willis decrees the shell to be at the same temperature as the enclosed sphere, (physically impossible), but fact is not allowed to get in the way of the Eschenbach fantasy. Willis fondly imagines that the enclosed sphere will heat up, and become hotter than its surrounding steel shell – due to the magic of the GHE!
Willis is both ignorant of physics, and a fool for believing that natural laws can be dismissed at will. So, an ignorant fool, as well as a liar about defending his bizarre assertions!
The Willis “defence”? He talks about pig wrestling – as if the average swine would lower himself to giving a dud like Willis a good thrashing.
He’s good for a laugh anyway, is Willis.
Pass. First rule of pig wrestling applies. Plus I’m sure sane people see right through your claims.
w.
Really? One of the characteristics of insanity is a refusal to accept reality. For example a person who believes that the radiation from a colder body can raise the temperature of a hotter one, plainly refuses to accept reality.
Another example might be a person who bizarrely believes that adding CO2 to air makes it hotter!
No sane and knowledgeable person would entertain such strange ideas. Maybe you are just ignorant and foolish, having religious faith in the existence of a mythical effect which doesn’t even have a consistent and unambiguous description.
Maybe you should “pass” on reality, and stick with fantasy.
“One of the characteristics of insanity is a refusal to accept reality.”
As you have done in your continual spouting of an incorrect understanding of Wien’s Law!
Which of course you can’t quote me doing.
Why is that, do you think?
I’ve quoted you doing this on multiple occasions, here’s one:
“You said:
Here’s AI for you –
“According to Wien’s Law, a source emitting 15 micron photons would be a relatively cool object with a temperature around 193 Kelvin (-80°C”. So you are going to heat CO2 at say 20C with IR from a -80 C source, are you?”
Phil,
So? According to every Wien’s Law calculator (eg WolframAlpha), I’m right – which means you are somewhat ignorant.
i suppose you are now going to start burbling about “black bodies” and similar diversions.
So maybe you can show your foolishness by pointing out where I have erred – you may indulge in silly semantic games if you wish. It won’t help you, I’m afraid.
You’re just not very bright.
” According to every Wien’s Law calculator (eg WolframAlpha), I’m right – which means you are somewhat ignorant.”
Actually that source agrees with me, they use the same equation which I have quoted to you before!
λmax = b / T where b is Wien’s constant (2898 µm⋅K)
So the maximum wavelength of a blackbody emitter is inversely proportional to the absolute temperature which is not what you said so you clearly misunderstand what the calculator is telling you (despite my having explained it to you before)!
If you do the calculation for an emitter at -80ºC you’ll find the wavelength of the peak is ~15μm with a spectral radiance of 1.10107 W/m2/sr/µm.
Repeat the calculation for an emitter at 25ºC you’ll find the wavelength of the peak is ~9.7μm but that it still emits at 15μm but at a lower radiance than the peak: 6.54732 W/m2/sr/µm at 15µm.
So a source at 25ºC emits about 6.5 times as much 15µm radiation as a source at -80ºC! Thus completely refuting your assertion that:
“According to Wien’s Law, a source emitting (radiation with a maximum intensity at a wavelength of) 15 micron photons would be a relatively cool object with a temperature around 193 Kelvin (-80°C)”
My correction to your statement added in parenthesis.
“i suppose you are now going to start burbling about “black bodies” and similar diversions.”
Hard not to since Wien’s Law specifically refers to Blackbodies!
“Wien’s Law, sometimes called Wien’s Displacement Law, is a law that determines at what wavelength the intensity of radiation emitted from a blackbody reaches its maximum point.”
No answer I see!