A commenter brings news of an obviously wrong paper that has just appeared in Global and Planetary Change. The paper purports to be a radical revision of our understanding of the carbon cycle by Hermann Harde. The key conclusions are (and reality in green):
- The average residence time of CO2 in the atmosphere is found to be 4 years.
[The residence time for an individual molecule is not the same as the perturbation response time of the carbon cycle which has timescales of decades to thousands of years.]
- The anthropogenic fraction of CO2 in the atmosphere is only 4.3%.
[Actually, it’s 30%.]
- Human emissions only contribute 15% to the CO2 increase over the Industrial Era.
[It’s all of it.]
Since these points contradict multiple independent sources of evidence, I can, without hesitation, predict that there are fundament flaws in this paper that will raise serious questions about the quality of the peer-review that this paper went through. Oddly, this paper is labeled as an “Invited Research Article” and so maybe some questions might be asked of the editor responsible too.
Notwithstanding our last post on the difficulty in getting comments published, this paper is crying out for one.
But this kind of thing has been done before, does not require any great sophistication or computer modeling to rebut, and has come up so many times before (Salby (also here), Beck, Segalstad, Jaworowski etc.), that perhaps a crowd-sourced rebuttal would be useful.
So, we’ll set up an overleaf.com page for this (a site for collaborative LaTeX projects), and anyone who wants to contribute should put the gist of their point in the comments and we’ll send the link so you can add it to the draft. Maybe the citizen scientists among you can pull together a rebuttal faster than the professionals?
Update: The crowd-sourced comment has appeared Köhler et al (2018).
References
- H. Harde, "Scrutinizing the carbon cycle and CO2 residence time in the atmosphere", Global and Planetary Change, vol. 152, pp. 19-26, 2017. http://dx.doi.org/10.1016/j.gloplacha.2017.02.009
- P. Köhler, J. Hauck, C. Völker, D.A. Wolf-Gladrow, M. Butzin, J.B. Halpern, K. Rice, and R.E. Zeebe, "Comment on “ Scrutinizing the carbon cycle and CO 2 residence time in the atmosphere ” by H. Harde", Global and Planetary Change, vol. 164, pp. 67-71, 2018. http://dx.doi.org/10.1016/j.gloplacha.2017.09.015
wili says
This seems very far off the mark. Can anyone figure out how he got these numbers and where exactly he goes wrong?
“Scrutinizing the carbon cycle and CO2 residence time in the atmosphere”
http://www.sciencedirect.com/science/article/pii/S0921818116304787
Abstract:
“Climate scientists presume that the carbon cycle has come out of balance due to the increasing anthropogenic emissions from fossil fuel combustion and land use change. This is made responsible for the rapidly increasing atmospheric CO2 concentrations over recent years, and it is estimated that the removal of the additional emissions from the atmosphere will take a few hundred thousand years. Since this goes along with an increasing greenhouse effect and a further global warming, a better understanding of the carbon cycle is of great importance for all future climate change predictions. We have critically scrutinized this cycle and present an alternative concept, for which the uptake of CO2 by natural sinks scales proportional with the CO2 concentration. In addition, we consider temperature dependent natural emission and absorption rates, by which the paleoclimatic CO2 variations and the actual CO2 growth rate can well be explained.
The anthropogenic contribution to the actual CO2 concentration is found to be 4.3%, its fraction to the CO2 increase over the Industrial Era is 15% and the average residence time 4 years.”
[Response: Oh dear me. Yes, it’s nonsense. But apparently it’s an “Invited” paper? (I’ve never heard of that either). Some questions are going to be raised about the peer review and editorial process here… – gavin]
Scott Strough says
@Gavin in his response to @228,
The most immediate flaw that jumps up immediately, no matter what the number they use are interpreted to mean, is the failure to acknowledge that an anthropogenic degeneration of the natural uptake side of the carbon cycle has occurred simultaneously with increased fossil fuel emissions. So while it may be true that “uptake of CO2 by natural sinks scales proportional with the CO2 concentration”, this feedback effect is not large enough to offset emissions. It is still AGW regardless of whether caused by increased source emissions or decreased sink function! We have done BOTH.
wili says
Thanks for the fast response, GS. I was surprised to see this kind of thing in what seems to be a pretty solid publication.
If you could provide any pointers on what exactly he left out that skewed the numbers so wildly, that would be helpful. I’m sure the denialosphere is about to grab this and run with it, so it would be nice to have factual ammunition on hand. Thanks again–wili
Marco says
@232-234, Global and Planetary Change also published the Humlum et al (2013) paper discussed some years ago by Rasmus (https://www.realclimate.org/index.php/archives/2012/09/el-ninos-effect-onco2-causes-confusion/) which had three(!) comments, all downgrading that paper to “not even wrong”. The same journal also has published some pretty bad papers from Mörner.
Hank Roberts says
“alternative concept”
That’s like an alternative fact. but less well supported?
Hank Roberts says
P.S., prior discussion of Harde’s climate model:
https://skepticalscience.com/denier-dinner-disaster-dessert.html#107243
...and Then There's Physics says
I think Gavin Cawley’s paper is already almost a rebuttal (it was a response to the Essenhigh 09 paper that Harde cites while ignoring Gavin Cawley’s response). For example, I think the reason Harde gets 4 years for the residence time is because he’s computing how long it would take to turn over all the CO2 in the atmosphere, rather than how long it would take for an enhancement in atmospheric CO2 to decay.
icarus62 says
Crikey, it’s not hard, is it? We’ve emitted ~545 GtC since 1750, atmospheric CO2 has only risen by ~120ppm (230 GtC), hence 100% of the rise is anthropogenic. QED. None but the breathtakingly obtuse or willfully ignorant would dispute this.
Gavin Cawley says
I wrote a comment paper on the residence time argument of Essenhigh,
Gavin C. Cawley, On the atmospheric residence time of anthropogenically sourced carbon dioxide, Energy & Fuels, volume 25, number 11, pages 5503–5513, September 2011. (http://theoval.cmp.uea.ac.uk/publications/pdf/ef2011a.pdf)
Which may have some useful material, as does my SkS article on Salby’s theory
https://www.skepticalscience.com/salby_correlation_conundrum.html
Pretty poor the paper cites at least two papers that have been the subjects of peer reviewed comments, but fails to cite the comments.
Be happy to help out if I can.
BTW the 4.3% figure is about right if it refers to the fraction of CO2 molecules of directly anthropogenic origin (i.e. not counting those swapped with “natural” CO2 by the vast exchange fluxes’ in which case it is accurate, but irrelevant/misleading)
Victor Venema (@VariabilityBlog) says
“Invited research article” does not mean much. Authors are encouraged to write to the editor before submitting an article. If they do so, their article is labelled as “invited research article”.
Really hard to understand how this paper passed peer review. Could someone try to submit a get-me-off-your-fringe-email-list manuscript to Global and Planetary Change to check if they read the manuscript.
John C Mruzik says
It may make the deniers happy for while, but reality will bite them on the butt. Already, (OT) plants approved for certain zones are dying because of the polar vortex.
Eli Rabett says
It’s late and have not read this beyond the abstract but
http://www.earth-syst-dynam-discuss.net/esd-2015-63/
looks essentially the same. Eli’s friends can let lose.
Eli Rabett says
Should have noted different authors but the same circle
Gavin Cawley says
I would start with the mass balance equation, as Harde says it is a “fundamental law that must be obeyed by any legitimate model of CO2”, with which I would agree,
dCO2/dt = En + Ea – An
where En and Ea are natural and anthropogenic emissions respectively and An = Ap + deltaA is absorption by natural sinks. Rearranging
dCO2 – Ea = En – An
We know the LHS is negative (atmospheric CO2 is rising more slowly than the rate of anthropogenic emissions), so the RHS must be negative as well, so we know natural uptake is greater than natural emissions, so nature is a net carbon sink and is opposing the rise, not causing it.
Harde makes an obvious error here
“Nevertheless, > 98% of the total actual emission per year can be characterized by a residence time [4.1 years] … For the remaining 1.9%, which are not re-absorbed, the IPCC assumes that they cumulate in the atmosphere…”
This implies that most CO2 is removed from the atmosphere within about 4 years, but it isn’t, it is mostly just replaced by CO2 from natural sources, which doesn’t change atmospheric concentrations. The difference between residence (turnover) time and adjustment time is a bit counterintuitive (and IMHO made more difficult to understand in the terminology used in AR5), but if you are going to write a paper suggesting that the carbon cycle scientists are wrong, then the onus is on you to make sure you really understand it first. There is a very small chance you are Galileo, but a rather larger probability that it is you that is wrong. I somehow doubt Harde discussed this with any of the AR5 authors (just Prof. Salby).
I suspect one of the reasons the paper made it through peer review is:
“‘Referees
Please submit, with the manuscript, the names, addresses and e-mail addresses of five potential referees. Note that the editor retains the sole right to decide whether or not the suggested reviewers are used.”
I really think journals shouldn’t do this. If the action editors are suitably qualified, they ought to be able to identify suitable reviewers for themselves, and suggesting reviewers is likely to lead to friendly review of weak papers by reviewers that also suffer from the same misunderstandings.
Ed Davies says
Isn’t it plausible that 4.3% of the carbon atoms in the atmosphere are literally anthropogenic (e.g., what we’d measure if we could tell them apart by isotope or having a dot of red paint on them or whatever) yet humans are still responsible for a more-than 30% increase in the overall amount, the other more-than 25.7% coming from carbon atoms displaced from flora and fauna and solution in seas, etc, by other anthropogenic carbon emissions? I.e., an approximately 4.3% increase in the overall available pool resulting in a 30% increase in the amount in the atmosphere.
So their statement might not be actually false as such – just wildly, and one would guess wilfully, misleading.
MA Rodger says
The “renowned professor of physics and expert on spectroscopy Dr. Hermann Harde,” as he is described on the planet Wattsupia, has quite a history of modelling the GHG effect on climate. He evidently suffers from a particularly high level of wanton ingnorance to persist in such arrant stupidity.
Hermann Harde (2014) [PDF] ‘‘Advanced Two-Layer Climate Model for the Assessment of Global Warming by CO2’ OPEN JOURNAL OF ATMOSPHERIC AND CLIMATE CHANGE, Volume1,Number3.
Hermann Harde (2013) [PDF] ‘Radiation and Heat Transfer in the Atmosphere: A Comprehensive Approach on a Molecular Basis’ International Journal of Atmospheric Sciences, Volume 2013.
Hermann Harde (2011) ABSTRACT ‘How much CO2 really contributes to global warming? Spectroscopic studies and modelling of the influence of H2O, CO2 and CH4 on our climate’, Geophysical Research Abstracts Vol. 13.
Bob Loblaw says
An analogy (limited to the strength of analogies…)
I am a poor student, working a part-time job that barely covers my expenses. I get paid each week, directly into my bank account, and I withdraw funds during the week to pay for everything. The average residence time of my paycheck is about 4 days – from the time it goes in, until the time I take it out. Life is tough.
Fortunately, I have a generous Grandma. She sets up a trust fund, and that fund sends an extra $100/month into my account. I continue a frugal life, but I spend half of it each month on a few luxuries. The other half stays in my account. The $100/mo is quite small compared to my regular paycheck and expenses.
After four years of school, I find that I have accumulated $2400 in savings, which works out to an average of $50/mo.
Where did the money come from? By Harde’s argument (and Essenhigh’s, and Salby’s), money only stays in my account for an average of 4 days, so virtually all of my Grandma’s gift to me is gone. Grandma’s trust fund is not a factor in the growth of my bank account.
Those of us that are sane think “If it weren’t for my Grandma’s generosity, I would not have that extra $2400 in the bank today”.
Also have a friend, who gets paid the same wage as me, but she only gets paid once per month. As for me, she lives from hand to mouth and spends every penny she earns. The average residence time of money in her bank account is about 15 days. She also has a generous Grandpa that sends her $100/mo, and she also spends half of it to treat herself. After four years, she also finds that she has $2400 more in savings than she would otherwise.
Following Harde et al‘s logic, the quadrupled residence time of money in her bank account alters the extent to which a generous grandparent has helped us save. She, like me, however knows that the $2400 availble after four years would not be there if it weren’t for Grandpa.
William Connolley says
Harde is on Lindzen’s list of 300 self-certified nutters: https://cloudup.com/iHcBpTDmCNu
Alastair McDonald says
I have been looking at the carbon cycle recently from the POV of a citizen scientist. I too have been puzzled by the short residence time of CO2 in the atmosphere and the much longer times that have been estimated for the recovery from anthropogic forcing, i.e. the time it will take to recover from burning fossil fuels. The estimates are in the order of thousands of years, compared with only five years for the lifetime of CO2 molecules in the atmosphere.
The answer is that the atmosphere is not a closed system. It is connected to the oceans, and what should be considered is the atmosphere-ocean system, not the atmosphere alone. Just as Bob Loblaw has a generous Grandma, so too the atmophere has a generous ocean, always willing to share its CO2 with the atmosphere. And like Bob’s Grandma, the ocean has much greater reserves than its client. The residence time of CO2 in the oceans is of the order of 3,800 years.
See https://www.e-education.psu.edu/earth103/node/1019
The atmosphere will not recover until the ocean recovers which will take in the order of 4,000 years.
Hank Roberts says
Thank you. That’s a most useful reference, worth bookmarking and checking as the news rolls in.
wili says
Thanks all for the discussion and links. RC at it’s best!
...and Then There's Physics says
Alistair (#19),
I think there is another aspect that the site you included in your comment does not cover, which is the long-term removal of CO2 via weathering. The timescale over which our emissions will have fully dissolved in the oceans is certainly hundreds, if not a few thousand, years. However, once ocean invasion is complete we would expect something like 15-30% of our emissions to still be in the atmosphere. This will be removed, very slowly, via silicate weather and will take >100 kyr.
Mal Adapted says
William, ditto Hank. Lindzen’s list is fascinating, and dense with data. The short CVs listed with the names may contain clues to individual signer qualifications as well as motivation.
MR-SH says
I can hardly believe such a paper is an “academic invited” one. If the CO2 life time is only four years, where did the CO2 source of the recent increasing concentration come from? Since the fossil fuel based carbon emission is known, others must be compensated by the natural sources.
MA Rodger says
William Connolley @18,
To be clear, that is a list of three-hundred-plus folk calling for Trumppp to pull the US out of the UNFCCC because apparently CO2 “is plant food, not poison.” We are told the “300 eminemt scientists and other qualified individuals from around the world” collected by Dicky Lindzen are his “fellow scientists” who have “the training needed to evaluate climate facts, and offer sound advice.” It is far from clear why Lindzen chose these particular 309 “fellow scientists.” It may be that they are not “self-certified” nutters as suggested @18 but chosen especially.
Yet however the 309 were collected, it is a rather strange list. Dicky seems to be saying that he agrees with the garbage presented as “climate facts” in, for instance, this latest Hermann Harde paper being discussed in this thread. Yet that cannot be true as Lindzen has refuted such nonsense in the past, branding it a gift for those who disagree with his assessment of AGW. Surely it would be correct to say that the “300 eminemt scientists and other qualified individuals from around the world” are actually in total disagreement when it comes to evaluating “climate facts”? To “hear from such people” is not going to be very helpful to someone developing policy decisions based on “climate facts.”
But this is a new world of non-truth we have entered with the likes of dear old Aunt Beeb and other trusted media outlets are now branded an “enemy of the people.” Within such a new world, we should be prepared to be utterly gobsmacked by the new reality that we are going to encounter.
Christopher Hogan says
I read the the Lindzen letter referenced above. Golly.
I know Lindzen has a theory that a change in tropical cloud cover will offset greenhouse-gas-caused warming, the unproven “iris effect”. But in that letter, he comes across as a complete global warming denialist. The Paris Accord ” … targets minor greenhouse gasses, primarily Carbon Dioxide, C02 for harsh regulation.” And atmospheric C02 buildup is environmentally beneficial because it is ” … plant food, not poison.”
First, I find it odd that the letter to the President contains eccentric punctuation. I’d have said “… primarily carbon dioxide (C02), for … ” instead of “… primarily Carbon Dioxide, C02 for …” as in the letter.
Second, if C02 didn’t matter (“minor greenhouse gas”), there would never have been any reason to care about the “iris effect”. It is only relevant in that it was supposed to offset warming that would otherwise occur. So, to say that C02 doesn’t matter appears completely inconsistent with what he has written in the past.
Finally, I think the most revealing aspect of this letter is the preponderance of words and dates that imply “elderly”. The signature pages are full of words such as “emeritus”, “retired”, “former” and so on. By eye, I’d say at least half are retired, counting all signatories (including those for whom there are no clues as to age or working status.)
That looks like a validation of what Planck about scientific revoluations. New scientific truths triumph largely because their opponents eventually die.
Ray Ladbury says
Alastair, it goes even beyond that. It is not just the atmosphere and the oceans, but:
1) the atmosphere (which can also be subdivided into northern and southern hemispheres, and even into Hadley Cells) all with fairly short time constants
2) the upper ocean–time constant on the order of years to decades
2a) the biosphere–time scale from 1 year to decades and even centuries and millennia for some processes
3) abyssal ocean (timescale of many decades to ~a century or more)
5) the geosphere–timescale of millennia to eons. These were the processes that sequestered the carbon deep in the Earth as coal, oil, natural gas…
The key is that all of these processes interact. Different ones are important on different timescales, and if you ignore processes that are important on different timescales, it becomes a harde problem. ;-)
S.B. Ripman says
This newspaper article about a new study about to be published in ‘Nature’ gives an idea of the complexity of the processes related to CO2 in the atmosphere, and how the oceans fit in:
http://www.independent.com/news/2017/feb/26/ocean-air-carbon-dioxide-chemistry-experiment/
The conclusion that carbon uptake by the seas is likely to be lessening is cause for concern.
Scott Nudds says
9. “We’ve emitted ~545 GtC since 1750, atmospheric CO2 has only risen by ~120ppm (230 GtC), hence 100% of the rise is anthropogenic.”
LOL. No, it’s all been absorbed many times. With a residency of 4 years, it’s been absorbed about 30 times, so really man is responsible for reducing the CO2 level by 30 times his emission rate. If we hadn’t been burning all that carbon, the CO2 levels would be 15 times higher than pre-industrial levels.
This elementary science will soon be leaving the lips of Koch funded denialists and Lemar Smith.
LOL!
outspokenskeptic says
There is one extra piece of evidence that proves Hermann Harde is wrong (together with his mentor Salby) , and that is the isotopic signatures of the atmospheric carbon. Even if we assume that the convoluted and incomplete carbon cycle that he is proposing would be right (which in itself is a huge leap of faith), that carbon cycle would only explain to some extent this type of graph
https://static.skepticalscience.com/pics/CO2_Emissions_vs_Concentration.png
but would never be able to explain two other very important lines of evidence that we have:
https://static.skepticalscience.com/pics/cg_d13C.png
https://static.skepticalscience.com/pics/14Cratio.png
(and at least one of them would have to look the complete opposite of what we see for this new mathturbation to be accurate).
Scott Strough says
@15 Ed Davies
“Isn’t it plausible that 4.3% of the carbon atoms in the atmosphere are literally anthropogenic … yet humans are still responsible for a more-than 30% increase in the overall amount”
That was actually partially my point I made earlier. Disruptions in the carbon cycle are also anthropogenic in origin. Whether a specific molecule came specifically from a fossil fuel isn’t really the point at all. It’s the net effect of our impact to CO2 levels that ultimately matter regarding AGW.
Eli Rabett says
Alastair, the atmosphere equilibrates with the upper ocean whose CO2/HCO3-/CO32- content is about the same size. This occurs in the 5-10 year range. OTOH equilibration of the upper ocean, the atmosphere and the biosphere with the deep abyss takes a few thousand years.
David Griffiths says
NASA provides a very clear pictorial explanation of the Carbon Cycle at http://earthobservatory.nasa.gov/Features/CarbonCycle/.
With a little thought you can quickly see where Harde’s errors come from.
Barton Paul Levenson says
CH 26, Lindzen’s iris theory is not just unproven, it has been repeatedly disproven since he first introduced it in 1982. He has offered essentially the same paper once every ten years or so, and each time, it gets shot down by observations. Eventually the journals are going to stop printing him, the way the astronomy journals did with Halton Arp.
Phil says
CH @26 – Your first point about punctuation etc. Fred Singer’s (long) biography actually cuts off mid-sentence. Presumably Lindzen didn’t expect Trump to read that far :-)
Hank Roberts says
Did the auto industry ever argue that photochemical smog (from burning nitrogen in internal combustion engines) is plant food?
Tony Weddle says
Does Harde offer an explanation of how the CO2 concentration has increased by over 40% in the industrial age? Does he also suggest how it could be reduced?
Brian Dodge says
“We have critically scrutinized this cycle and present an alternative concept, for which the uptake of CO2 by natural sinks scales proportional with the CO2 concentration.”
http://www.sciencedirect.com/science/article/pii/S0921818116304787
“Unfortunately, a new study by Reich and Hobbie(2) in Nature Climate Change indicates that nitrogen availability does indeed constrain the CO2 fertilization effect over the long term, at least for grassland plants.” http://cedarcreek.umn.edu/biblio/fulltext/Templer_NatureClimateChange_2013.pdf
If the authors were so ignorant of the extant literature to have chosen a linear model known to be grossly inaccurate, I don’t think I’ll waste $39.95 for more complicated handwaving. Any bets as to whether the authors are remotely familiar with Liebig’s Law of the minimum, or what the California drought did to agriculture? “The biggest chunk of that cost will come from the fallowing of 542,000 acres that lack water for irrigation, the study said. That’s about one-fifth more land than drought forced out of production last year, researchers noted.” http://www.capitalpress.com/California/20150818/drought-fallows-half-million-acres-in-california (NB, there was a decline of 9 million acre feet of surface water partially balanced by an increase of 6 million acre feet of well water, for a net decrease of only 3 million acre feet)
What about non agriculture land? (73% of California, 55% of the USA, 62.5% world
“. Although WUE was positively correlated with CUE, NPP, and LAI, average baseline WUE was highest in grassland systems, which also had lower rates of mean annual NPP, precipitation, and LAI. Under baseline conditions, WUE was negatively correlated with precipitation across all ecosystem classes and ecoregions.”
https://www.fs.fed.us/rm/pubs_journals/2016/rmrs_2016_malone_s001.pdf
What about the oceans, 70% of the earth’s surface?
“Addition of carbon dioxide to the ocean reduces the carbonate ion concentration and thereby reduces the solubility of carbon dioxide in seawater. This is a large effect for increasing the atmospheric carbon dioxide concentration by 100 ppm. (from 370 to 470 ppm) would decrease carbonate ion concentration by 40% more than would have been the case if carbon dioxide concentrations were raised from the pre-industrial 280 to 380 ppm. Thus the oceans ability to take up carbon dioxide is reduced as atmospheric concentrations rise.[OOOPS; this nonlinear effect puts their “alternative concept” into the realm of Trump administration “alternative facts” – BD]
Although the deep ocean could dissolve 70 to 80% of the expected anthropogenic carbon dioxide emissions and the sediments could neutralize another 15% it takes some 400years for the deep ocean to exchange with the surface and thousands more for changes in sedimentary calcium carbonate to equilibrate with the atmosphere. Consequently atmospheric concentrations of carbon dioxide could become substantially elevated before the ocean is able to remove this added carbon dioxide.
Because the deep-ocean has a fixed rate of mixing the higher the rate of emissions the lower the proportion of those emissions that will be taken up by the ocean.” Is their model, er, “alternative concept” steady state, or transient? Does that make it more,or less, than “not even wrong”? (“…es ist nicht einmal falsch!” – Wolfgang Pauli)
...and Then There's Physics says
Tony,
I think using the Salby argument that it’s simply a temperature dependence. The immediate response to that is that if a 1K warming can increase atmospheric CO2 from 280ppm to 400ppm, then it should have decreased to zero during a glacial period, which is clearly nonsense.
Hank Roberts says
Patrick Bohlen says
How could this paper ever had made it through peer review. The conclusions are so far off established science that any qualified editor or editorial board would never had allowed it to be accepted for publication. My question is how can we hold this journal accountable for publishing rubbish?
Russell says
41:
“My question is how can we hold this journal accountable for publishing rubbish?”
In the 21 years since , the well-qualified Editors of Social Text published
Transgressing the Boundaries: Towards a Transformative Hermeneutics of Quantum Gravity,
a larger number of better qualified editorial boards have launched newer journals and volumes publishing sillier papers touching on how CO2 impacts matters Anthropocene, Capitalocene, Necrocene and Chthulucene.
https://vvattsupwiththat.blogspot.com/2017/02/dead-but-dreaming-at-cthulhucene-epa.html
It is surprising that Lindzen’s cohort , or the press release writers employed on their behalf, have not graphed the anti-Plancktonic correlation between the number and circulation growth of these organs of postmodernism, and the average age of their authors and readers.
Ann K says
Did he refer in that article to the CO2 residence time at earth’s surface? It was my understanding that CO2 in the upper atmosphere (and thus neither readily available to plants nor to ocean absorption) was responsible for the “greenhouse”. Am I misunderstanding the significance between surface CO2 and that several miles up? (Forgive my naïveté, but this is not my field. Thanks.)
gavin says
There is a draft comment now ready to be worked on. Email me if you want to take part.