On Twitter, people will say most anything if it aligns with their beliefs and their cause. In this case, climate scientist Ken Caldeira gets called out over some claims about coal and CO2 by our own Willis Eschenbach. It looks like a clear-cut case of confirmation bias.
Willis replies:
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Wilis, I am a bit confused, which at 92 is to be expected. But this effect of
CO2, I understood that it was logerthermic, that it became less and less of
an effect as the pip in the atmosphere increased.
MJE VK5ELL
“On Twitter, people will say most anything…”
Well, as the tweet says, it’s actually said in a paper in JGR. In fact, WUWT wrote about it here. He actually goes through a calculation process similar to here, with similar results, as shown in the graph featured in the WUWT post (which on my page is shown just above the “Related Posts” part here). The difference seems to be that he, as he expresses, “integrates to infinity”. IOW he allows for a lifetime of many millennia, even with decay. I don’t know how meaningful that is, but it seems to be what he does.
Great contribution. I was just about to check-out the local bridges to see if I could find a troll, but now I don’t have to.
Nick was just offering a rational observation. That’s not trolling. If he’s wrong, explain why so we can all benefit.
There was nothing of substance in his post to address. His “rational observation” was clearly taking digs at the post author and possibly other WUWT participants.
For integration to infinity to be meaningful the amount of CO2 in the atmosphere can ever only increase, never decrease. You know very well that is not true, Nick.
“can ever only increase, never decrease”
Not at all. In fact, their Fig 1 shows the decay curve of a pulse. The issue is that they assume the decay is, after a while, very slow, and so has a large integral over all time. But it is decreasing.
People have missed the most important “fact” about heating the Earth.
The Earth is in a daily chaotic temperature equilibrium. Every day it warms by about 10 degrees Celsius over land, and every night it cools by about 10 degrees Celsius over land.
The Stefan–Boltzmann law states that the total energy radiated per unit surface area of a black body across all wavelengths per unit time is directly proportional to the fourth power of the black body’s thermodynamic temperature T.
If the Earth warms to more than the equilibrium temperature at any time, the Stefan-Boltzmann law ensures that the Earth will radiate more energy, and move the Earth nearer to the equilibrium temperature. For example, after summer (which has a lot more energy than a lump of coal), a hemisphere returns to winter (often 20 to 30 degrees Celsius colder than summer).
The CO2 liberated by a lump of coal may affect the equilibrium temperature of the Earth by a tiny amount. But it doesn’t keep warming the Earth forever. What effect would a forest fire have on the Earths long-term temperature? That would generate millions of times more CO2 than a lump of coal. Does the Earth get permanently warmer after every forest fire?
Alarmists should learn to keep their mouths shut, until after they put their brain into gear. Because loose mouths generate heat.
Instead of the “lump of coal” I’d like to see the calculations for “winning WWII” as a much more useful example.
Calculate how much coal, diesel, gasoline, food, ammunition etc. that was consumed by the Allies from Sept. 1 1939 to Sept. 2 1945. Then express how many billions and billions of years this amounts to in the climate scientists mind.
Answer can be in “hiroshimas” if needed…
Frankly, I don’t get this idea that CO2 resides in the atmosphere for any fixed period of time, whether it’s years, decades or centuries. When I went to school, I remember being told that CO2 bonds with water on contact, and I remember performing a simple experiment in the chemistry lab that proved it. The same fact came up in biology too, I distinctly remember being told that rainwater is always a mild solution of carbonic acid, an important part of the carbon cycle. Therefore, if it’s raining out, I can easily imagine a molecule of CO2 emerging from the factory chimney and being absorbed by a raindrop within seconds of being released. Where does this idea of “residence” come from?
Shark,
Good point. I hope someone can offer an explanation.
You are assuming that CO2 + H2O only goes to making carbonic acid. As anyone who has spilled a soda bottle will tell you, the reaction can go in the other direction, too. In real life, we have CO2 being released (okay, being “restored”) to the atmosphere, then dissolved in cold ocean water (cold, liquid water hangs on to CO2, except when it doesn’t).
Cold sea water can take up a lot of of C02. Warming sea water can release all that CO2. Residence time is an odd amalgam of CO2 absorption, release, and dissolution in the atmosphere. All those add up to sequestering or releasing CO2 that has taken up residence in our atmosphere
Okay, but in the soda bottle the CO2 is around 3-4 times atmospheric pressure, and when that pressure is released the excess CO2 escapes. Not so with the raindrop. The rainwater runs off into the river and on to the sea where the CO2 can be absorbed by algae, and on into the carbon cycle. Or that same molecule may indeed be released into the atmosphere, where it may meet another raindrop. But I still cannot accept that CO2 can remain in the atmosphere unchanged for decades, centuries, or as Mickey Mann claimed recently in a BBC interview, millenia.
I would like to see the error terms associated with some of these “calculations.”
The heat produced by burning some coal will go in the end upward by convection and then will be lost into space by radiative transfer (thanks to active gases in the infrared spectrum, as CO2 or WV is …) so that the net energy accumulated in the atmosphere will be ZERO point ZERO.
You can multiply ZERO point ZERO by any dummy number you want Mr Caldeira, the result will be always ZERO point ZERO.
Try to think about thousands of volcanoes emitting heat during billions of years … and despite that, we are in a glaciation epoch, so : where did all this heat went ? In the bottom of the Oceans ?
Seems that the Climate Clownery is knocking down new bounds every each day.
Negative feedbacks reduce heating effects, Petit_Barde, but not to “zero point zero.”
The direct heating effect on the whole Earth of burning coal is, indeed, small. But it’s not “zero point zero.”
The indirect warming effect from elevated CO2 levels is larger than that, but still modest. It’s not “zero point zero,” either.
The Precious Air Fertilizer (CO2) acts as a dye in the atmosphere, which “colors” the atmosphere in the far infrared, esp. around 15 µm, which, significantly, happens to be close to the peak of the Earth’s emission spectrum. In graph of the Earth’s emission spectrum (measured from orbit above the tropical western Pacific), the big green notch is the effect of CO2:
Since nearly all of the emissions from the Earth are in the far infrared, but over half of the incoming energy (from the Sun) is at shorter wavelengths, tinting the atmosphere in the far infrared has a differential effect. Since there’s more outgoing than incoming far infrared, GHGs absorb mostly outgoing radiation, preventing it from escaping into space. That causes warming. (It’s not how actual greenhouses work, but it’s still a real effect.)”
That big green notch in the graph is the effect of CO2 in the atmosphere, on the Earth’s emission spectrum. At the bottom of the notch, the emissions which make it to space (to be measured by the satellite) are only about 1/3 the intensity of the emissions at those same wavelengths which left the surface.
That’s why CO2 warms the Earth.
BTW, look at the very center of that green notch. Do you see the narrow spike?
That’s CO2 radiating, from the upper stratosphere.
Of course, there’s not much of it, way up there, where the pressure is only a few millibars. And, of course, there’s very little pressure broadening, so the spike is very narrow. But it is clearly visible.
Ken Caldeira and I argued about this on Twitter, here:
https://twitter.com/ncdave4life/status/1144026113108336641
He thinks the average residence time for added CO2 is nearly 10,000 years. It’s actually about fifty years.
This is a log scale plot of the decline of 14C levels in the atmosphere, following the 14C “bomb spike.”
http://2.bp.blogspot.com/-G79oXdgIZC4/UnteTCVaGGI/AAAAAAAAAA0/AbSzY3s5ZP0/s1600/logc14.jpg
When atmospheric tests of A-bombs and H-bombs suddenly ceased (following the atmospheric test ban treaty), the 14C concentration dropped on a near-perfect exponential decay curve, with a half-life of 11.5 years, implying a residence time of 16.6 years.
(Note: 14CO2 is 4.5% heavier than normal 12CO2, which affects biological uptake and diffusion rates slightly. But not much.)
However, some of the processes which remove 14CO2 from the atmosphere do so by exchanging it 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 of CO2 emissions.
The effective lifetime of anthropogenic additions to CO2 in the atmosphere, variously defined as the time it would take for 2/3 or 63% (1-(1/e)) is roughly fifty years, making the half-life about 35 years.
That’s the result that Prof. Richard Lindzen reported during the Q&A (3rd video) of this (excellent!!!) lecture:
● Part 1: https://www.youtube.com/watch?v=hRAzbfqydoY
● Part 2: https://www.youtube.com/watch?v=V-vIhTNqKCw
● The Q&A which followed: https://www.youtube.com/watch?v=69kmPGDh1Gs (including his discussion of CO2 atmospheric lifetime)
That’s also the approximate result that Dr. Roy Spencer found:
http://www.drroyspencer.com/2019/04/a-simple-model-of-the-atmospheric-co2-budget/
That’s also the approximate result that I got, first with a little program to simulate declining CO2 levels, based on the historical CO2 removal rate as a function of CO2 level, and then with a modified version of the program based on Dr. Spencer’s model; source code here:
http://sealevel.info/CO2_Residence_Times/
Ferdinand Engelbeen reported roughly the same result, here:
https://edberry.com/blog/climate-physics/agw-hypothesis/contradictions-to-ipccs-climate-change-theory/#comment-50170
That last one is a link to Ferdinand’s comment on a blog article by Ed Berry, in which Ed claims that the residence time of anthropogenic CO2 is very short, mankind’s CO2 emissions have little effect on the CO2 level, and the rise in atmospheric CO2 level is due to a warming climate. (Ferdinand is right, and Ed is wrong.)
What this means is that if anthropogenic CO2 emissions suddenly ceased, it would take about 30-40 years before half of the cumulative anthropogenic CO2 increase was gone from the atmosphere.
The essential insight to perform these calculations is that the rate at which various chemical and biological processes remove CO2 from the atmosphere is, very closely, a function of the atmospheric CO2 level. The question is, what is that function?
We needn’t wonder, because:
We know, very precisely, what the annually averaged atmospheric CO2 level has been for the last sixty years, and how it has changed from year to year.
We also know, with pretty good precision, from economic data for the production and use of coal, oil, natural gas, and cement, how much CO2 mankind releases each year. (There are other factors, like land use changes, which are less precisely known, but they’re small relative to fossil fuel emissions, so they can’t affect the calculation very much.)
The difference between the amount of anthropogenic CO2 emitted, and the amount by which CO2 level increases year-to-year, is the “removal rate.” That’s the rate at which negative feedback mechanisms, like terrestrial “greening” and dissolution into the oceans, remove CO2 from the atmosphere.
Another figure sometimes mentioned is the “airborne fraction.” It is just the amount by which CO2 level increases year-to-year divided by the anthropogenic emission rate. It doesn’t represent anything meaningful. (It is sometimes inaccurately described as the portion of CO2 emissions which go into the atmosphere; that’s wrong, because ALL the CO2 emissions go into the atmosphere, and hardly any of the CO2 that is removed actually comes from that year’s emissions.)
The key point is that we have excellent records from which we can calculate, quite precisely, what the CO2 removal rate has been every year, and we can tabulate that as a function of the same years’ annual average CO2 levels, from 315 ppmv (in 1958) to 410 ppmv (now). Then, since we know removal rate as a function of atmospheric CO2 level, we can easily calculate the residence time.
Caldeira would doubtless object that the CO2 removed from the atmosphere has not been returned to coal beds. Rather, it’s moved from the atmospheric carbon reservoir to the ocean’s carbon reservoir and the biosphere / soil reservoir, and it won’t stay there forever.
That’s true, but irrelevant, for practical purposes.
In the case of the oceans, it’s a distinction without a practical difference, because the oceans’ carbon storage is so vast, compared to the atmosphere, and calcifying coccolithophores transport carbonates from surface water, where the CO2 dissolves, to the ocean depths.
In the case of the biosphere / soil, the objection is less obviously unreasonable. But there’s no good reason to expect the carbon sequestered by “greening” (enlarging the biosphere) to return to the atmosphere, until CO2 levels are someday again very low.
The hypothetical “long tail,” which so drastically exaggerates Caldeira’s “residence time” figure is not based on measurements. It represents modeled predictions of carbon theoretically released into the atmosphere from oceans and biosphere / soil in the distant future, when atmospheric CO2 levels are very low (well below 350 ppmv).
But when CO2 levels are very low, the climate threat will be cooling rather than warming, and browning from CO2 starvation rather than greening from CO2 fertilization. So, even if you accept the IPCC’s foolish claim that the next 0.5° or 1.0° of warming will be bad, there’s no denying the proven fact that the last 1°C of warming, and the ≈20% agricultural production boost from higher CO2 levels, were good. So when CO2 levels are very low, the release of CO2 from the biosphere / soils and oceans into the atmosphere will indisputably be a very good thing.
Yet Caldeira wants you to think it’s a bad thing. That’s just crazy talk.