From BINGHAMTON UNIVERSITY and the “worse than we thought, doubling down on CO2 for Paris” department, comes this claim that we are well on our way to a hothouse Earth. Except, the study isn’t confirmed yet, by the researcher’s own admission (see end of PR). he needs more data, but that won’t stop the headlines leading up to Paris. Meanwhile, present day climate sensitivity seems to be far less than 3°C, if fact there’s quite a number of papers suggesting that sensitivity to CO2 is lower than IPCC model predictions.
Study: Earth’s climate more sensitive to CO2 than previously thought
Return to hothouse climate may take less carbon dioxide than expected
A team of Binghamton University researchers including geology PhD student Elliot A. Jagniecki and professors Tim Lowenstein, David Jenkins and Robert Demicco examined nahcolite crystals found in Colorado’s Green River Formation, formed 50 million years old during a hothouse climate. They found that CO2 levels during this time may have been as low as 680 parts per million (ppm), nearly half the 1,125 ppm predicted by previous experiments. The new data suggests that past predictions significantly underestimate the impact of greenhouse warming and that Earth’s climate may be more sensitive to increased carbon dioxide than was once thought, said Lowenstein.
“The significance of this is that CO2 50 million years ago may not have been as high as we once thought it was, but the climate back then was significantly warmer than it is today,” said Lowenstein.”
CO2 levels in the atmosphere today have reached 400 ppm. According to current projections, doubling the CO2 will result in a rise in the global average temperature of 3 degrees Centigrade. This new research suggests that the effects of CO2 on global warming may be underestimated.
“Take notice that carbon dioxide 50 million years ago may not have been as high as we once thought it was. We may reach that level in the next century, and so the climate change from that increase could be pretty severe, pretty dramatic. CO2 and other climate forcings may be more important for global warming than we realized.”
The only direct measurement of carbon dioxide is from ice cores, which only go back less than 1 million years. Lowenstein and his team are trying to develop ways to estimate ancient carbon dioxide in the atmosphere using indirect proxies. He said that their approach is different than any ever undertaken.
“These are direct chemical measurements that are based on equilibrium thermodynamics,” he said. “These are direct laboratory experiments, so I think they’re really reliable.
Lowenstein wants to look at nahcolite deposits in China to confirm the results found in Colorado.
###
The study, “Eocene atmospheric CO2 from the nahcolite proxy,” was published Oct. 23 inGeology.
Amazing that they really believe they can determine CO2 concentrations from 50 million years ago.
It can be done, but whether THEY can do it is debatable.
They used precipitation rates of two lacustrine evaporite salts from a single location to determine global aCO2?! AMAZING! Evaporite precipitation rates are completely dependent on the salts dissolved in the water and the rate of water input vs evaporation. Where aCO2 fits into this and how they normalized the proxy^2 data to water input vs evaporation, I do not know, I’m not versed in pseudoscience.
So why don’t you do it ??
So, why do you suppose they call proxies “proxies?” Could it be because they can only approximate what might be the truth, not tell the truth? Have scientists forgotten that they don’t know the truth, only seek it? After all, no one know for sure when there might be a piece of evidence that will disprove the proven – by proxy, that is. So which “proxy” do you intend to use to determine CO2 from 50,000,000 years ago? Or do you have a time machine to take modern equipment back to test for it?
I suspect the word derives from the same source that “voting by proxy” does. Something about indirect.
“…CO2 levels during this time may have been as low as 680 parts per million (ppm), nearly half the 1,125 ppm predicted by previous experiments. The new data suggests that past predictions significantly underestimate the impact of greenhouse warming and that Earth’s climate may be more sensitive to increased carbon dioxide….”
OR, maybe CO2 doesn’t drive catastrophic warming the way some think it does… Wow, what an epiphany!
Why is it modern so-called scientists can’t build a simple logic tree to explore all the possibilities?
They have names to make and grants to reap.
Robert of Ottawa,
I would move one letter of the last word to the end and I think it would be more accurate, but it would probably get me moderated and banned. 🙂
Hard to understand they can get a grant when they can’t do math. We usually say nearly when we are on the underside of the number as in 480 is nearly 500. but their number of 680 ppm is “nearly half” the 1,125 ppm predicted? My calculator says that’s 60%, which really isn’t “nearly” half. Yeah, it’s nit-picking, I suppose, but it feels more like nitwit picking.
If you look at this…..it’s a 100 % error. Between the two value of previous and new measurement. So how accurate can this be? Not very in my estimation…yet the scientists are trying to estimate climate sensitivity based on this error….and another for temperature. Geesh…. Probably the best they can say is that if appears that co2 levels were higher in the far past and warmer than today…..but certainly not enough information to perform a climate analysis
go look at the first estimates of the speed of light
Mosher again. Stupid is as stupid does. The first measurements of the speed of light were actually pretty good. Technology wasn’t really up to much in those days
That’s what I don’t get. This headline presumes all warming is due to CO2, which is clearly unprovable at best and obviously false with scant glance at the 20th century. How do these people get their degrees without knowing basic logic?
…they majored in theology?
I presume they retrieved samples from within the time period of the Ice Cores and then calibrated their techniques by comparing the results to reality?
Never mind. What wasI thinking?
Sarc, but
There is no ice from Eocene left.
Hey, geology students have to eat too.
…it’s a rocky road. 🙂
Just don’t take it all for granite.
Well so long as we can keep to the unreproducible past we can speculate all we want school of paleontology has always been right about every hypothesis they have ever come up with.
Amongst their many failings, these “researchers” never seem to understand that correlation does not mean causation.
Nobody expects the sloppy attribution.
Our chief weapon is surprise. Surprise and fear. Two weapons…surprise and fear and a desire to interpret a weak correlation to fit with a predetermined agenda.
The chairs they want their opponents in are not comfy.
Yes, and what makes them think that CO2 is the only thing that effects temperature? What causes the ice ages to come and go? Why was it warmer in the MWP than now when Vikngs were farming for many years Greenland? This paper is like kid’s school stuff.
Correlation is mathematics. Causation is physics.
QED.
g
This is simply a confusion about whether CO2 is the earth’s thermostat or its thermometer. Do CO2 levels determine climate or do they reflect climate? For the last 3 million years CO2 levels were mostly due to the latter. However this balance can be perturbed by orbital changes, volcanism and also by human activity but these all also eventually re-balance
On these time scales, Henry’s Law guarantees that CO2 is a reflection of climate and not its cause. The best Ice core data for the last 400,000 years show that CO2 lags temperature by about 800 years. That is not coincidentally about the estimated round trip time for the thermohaline circulation, under the reasonable expectation that ocean absorption/outgassing is from its surface.
ristvan,
Recently confirmed by the data from Dome C over the past 800,000 years (resolution ~560 years), which overlap with the Vostok data over 420,000 years (resolution ~600 years)…
Henry’s Law is an equilibrium conditional concept.
Earth is never in thermal equilibrium.
g
ristvan writes: “CO2 is a reflection of climate and not its cause.”
Which is in conflict with the authors, who claim:
“These data support a causal connection between elevated [CO2]atm and early Eocene global warmth”
This seems to be an ongoing disagreement, is there any way to resolve it or will it remain unsettled science?
George, you are being foolish. At sufficient timescales, even a dynamic system’s effects can be estimated based on Henry’s law. Estimations of basic effects are easy. Precise calculations are impossible. Any undergraduate Chemical Engineer knows this.
Here are some articles which question our ability to correctly calculate the sensitivity of proxy records:
http://www.upi.com/Science_News/2015/11/11/Idea-of-slow-climate-change-in-the-past-is-flawed-researchers-say/5681447257780/
http://www.nature.com/ncomms/2015/151110/ncomms9890/full/ncomms9890.html
Exactly! How about that maybe CO2 was being sucked up by a healthy biosphere at an unexpectedly high rate? Or Is it possible that stellar local growing conditions sucked out lots of CO2 from the atmosphere locally, and these particular deposits are NOT representative of the whole Earth? How do they know that the Earth wasn’t cooling and the cooler ocean water absorbed a bunch of CO2? We shouldn’t be the ones asking these questions.
I count 8 “may”s in the PR. Wow. The authors really don’t care how little substance there is below the headline.
Which is why I’m not sure we should even re-post crap like this, extending its life in daylight. The best thing that could happen to such dreck is no one reading it and a swift trip to irrelevancy.
” may ” does not equate to ” might “.
May grants permission; might grants speculation.
g
They never had ANY permission 50 million years ago.
IPCC AR5 Figure 8.15 shows RF of 2.3 W/m^2 (W is power not energy) for the 115 ppm increase in anthropogenic GHGs between 1750 to 2011 with an error bar from 1.1 to 3.3. ToA is 340 W/m^2 while various absorptions, reflections, etc. are on the order of scores w/ +/- 10s of uncertainties. The 2.3 W/m^2 is lost in the magnitude and uncertainties of the overall balance.
Nobody can place a reliable number on the connection & sensitivity between GHGs and RFs.
“W is power not energy” Why do you suppose so many apparently don’t get this?
W/m2 is power areal density.
When many graphics are labeled as “heat” or “energy” balances and the units are in W/m^2 several high powered experts apparently don’t understand it. And that m^2? ToA? Surface? Over 1 hour or 24? Lit side of the earth or dark side, too?
Not that dark side.
It may have something to do with density.
“The significance of this is that CO2 50 million years ago may not have been as high as we once thought it was, but the climate back then was significantly warmer than it is today,”
I may only play a climatologist on television, but surely the average temperature of the earth depends on far more than just CO2 concentration. As just one example, the shifting positions of the continents shape the ocean currents, thus affecting the transportation of heat around the globe.
You would make a very unsuccessful government-bought climate shill, sir.
No! It’s all the CO2’s fault! Global warming! Hurricanes! ISIS! Hemorrhoids! Justin Beiber! CO2 is really Satan in disguise! Unless we all stop driving our cars tomorrow, we’re all doomed! Doomed! The Day After Tomorrow! Waterworld! Mad Max! Ghostbusters 3! Dooooomed!
Wait! You’re on to something!
CO2 has been increasing- so has the number of failed Hollywood movies!!!
CO2 causes bad Hollywood movies!!!
Can I have another grant, please?
Thread winner! I knew there was a reason.
/Mr Lynn
And then there is that variable star that comes up every day…
I swear that I am living in the Aristotelian times when the sun was perfection itself. Nothing like a little paganism in your escathological cargo cult religion.
They have a lower bound of 680 ppm and an upper bound of 1260 ppm. The previous estimate was >1125 ppm, WHICH IS WITHIN THEIR BOUNDS. Honest researchers would say “we have developed a new method of estimating past CO2 which delivers results CONSISTENT WITH previous methods”. Where is the evidence that the previous (higher) lower bound was actually wrong? For that they need an upper bound that is higher than the old lower bound.
“Where is the evidence that the previous (higher) lower bound was actually wrong?”
“For that they need an upper bound that is higher than the old lower bound.”
Or a press release.
Ching!
Reality check: we know that atmospheric CO2 has nearly doubled since the late 1800s. If this hypothesis is correct, we should have seen temperature increases of about 3°. But we haven’t, therefore the hypothesis is falsified.
And I’m not even a scientist!
CO2 has not nearly doubled, but has increased by about 50% since the 1800s.
IF the effect of CO2 is logarithmic then the first 50% will drive temperatures higher more than the second 50% will do so.
IF temperatures have increased by about 0.9degC since the 1800s (which may not be the case due to problems and errors with the underlying data and adjustments, homogenisation, station drop outs and corruption via UHI etc) and IF all of this increase is due solely to CO2 driving temperatures upwards (which may not be the case since all or some part of the temperature rise may be due to natural variation – after all the planet was rebounding from the depths of the LIA), it is difficult to see how Climate Sensitivity to a doubling of CO2 could be more than 1.7 degC Ie., 0.9deg C for the first 50% rise in CO2 + 0.8degC for the second 50% rise in CO2.
It seems to me that we can be fairly sure that currently (with the present topography of the Continents and present level of CO2 in the atmosphere), Climate Sensitivity (if any at all) cannot be higher than 1.7degC.
Of course, recent papers suggest that Climate Sensitivity is lower than that figure. And, of course, as the ‘pause’ continues and extends, Climate Sensitivity must (and I mean must) come down to even lower figures.
Unless there is a step change in temperatures coincident with this current ongoing strong El Nino, as there was a step change in temperature coincident with the 1997/8 Super El Nino, I would expect to see the ‘pause’ continue and extend into 2019 resulting in many more papers being published putting Climate Sensitivity below 1.5degC in the run up to AR6, with some papers putting Climate Sensitivity at about the no feedback level of about 1.2degC
Sorry, had my numbers wrong, my apologies, I thought we had nearly doubled already. Still, the point is the same…current observations don’t support the “even greater than thought” hypothesis.
One thing I will say: state your assumption Richard. That calculation assumes that CO2 is responsible for all warming in the 20th century and otherwise that the climate would have had a stable temperature.
To assume a greater than ~2C per doubling sensitivity requires that the Earth sans-CO2 increase would have been strongly cooling. For this, there is no evidence. There is circumstantial evidence from the historical record that we are due for a warm period and some warming might be natural.
benofhouston
I agree with the points you raise in both your paragraphs.
But I thought that I had made it clear that my simple calculation, which should be seen as a back of an envelope calculation, was an assumption based calculation being based upon the assumption that CO2 being entirely responsible for the observed warming, and that I was raising doubts both as to the amount of warming observed AND as to whether CO2 was really responsible for entirety of the observed warming.
Personally, I am extremely dubious that there is much as 0.9degC warming; I do not consider that we know within half a degree as to how much real warming has taken place since the 1800s. Further, I consider that it is almost certainly the case that natural variation is responsible for a good proportion of the real and true warming, and possibly even for the entire warming. Personally, apart for the impact of land usage change, I would not rule out natural variation being the sole cause of any and all real warming that has taken place since coming out of the LIA.
But as you say, to get a Climate Sensitivity of more than 2degC one has to assume that natural variation was and continues to be negative.
Of course, natural variation was negative from the 1940s to the early/mid 1970s (when cooling was observed), and maybe this continues to be the case through to the current day, but CO2 as from the mid 1960s was beginning to cancel out the negative natural variation, and as from the mid 1970s had completely offset the natural cooling and between the 1980s to late 1990s the warming of CO2 was so much stronger than the negative natural variation that it was effective to result in rising temperatures, AND now from the late 1990s natural variation has turned even more strongly negative (than it was through the 1980s and 1990s) such that now natural variation is capable of cancelling out the warming effect of rising CO2.
That scenario does not sound likely to me, but since we know so little and understand even less about natural variation and the extent of its upper and low bounds and why it fluctuates etc, I guess that the above scenario cannot be ruled out.
Katherine
Good to see your further comment. I agree with the thrust of the point that you were making, although personally I think that we can only say that high Climate Sensitivity (and this is the sensitivity upon which cAGW is based) has been disconfirmed. Given the measurement errors that we have and the lack of knowledge and understanding of natural variation which appears to be noisy and (highly) variable we cannot say for certain that there is no, or even only small, Climate Sensitivity to CO2.
Personally, I consider that we can say from observational data (bearing in mind its limitations) that Climate Sensitivity can’t be higher than about 1.3degC, and that is not a scary figure and will only lead to modest warming, which warming will be a net benefit for the globe as a whole, albeit it may bring negative consequences to small areas which can easily be adapted to cope.
Personally, I suspect that Climate Sensitivity, at today’s level of CO2 in the atmosphere, is considerably less than 1.3 degC, and I do not rule out the possibility that it is zero, or so damn near zero that we cannot and will not be able to measure its signal. In fact I would go as far as saying that the balance of evidence does not support the proposition that CO2 at above 200ppm drives temperature at all (but proxy evidence must always be viewed with caution, and our temperature measurements and there resultant data sets are thwart with errors, uncertainties and limitations).
400 ppmm is not even close to double 280 ppmm.
Don’t need to be a scientist to be able to do 4-H club maths.
g
IPCC AR5 Figure 6.1
The typical global carbon balance (not CO2!) shows 45,000 Gt of stores and a couple hundred Gt/y of sourcing and sinking fluxes. Anthropogenic’s contribution – 4. That’s correct, 4. And that number was fabricated with a 57/43 partition to make the anthro contribution and 1750 to 2011 numbers match. And a new sink was created out of the void.
Actually Katherine, you are wrong on two counts; but at least as good a guess as these grant endowed nut jobs.
Not only is 400 not twice 280, but there is no basis for believing that a doubling would result in a 3 deg. C or F Temperature increase. They have, and often do go(ne) in completely opposite directions at the same time, so they clearly are not functionally related.
g
George, I think you are being a bit too strong here. You are ignoring that there are clearly other factors at play in temperature that are as great or greater than CO2. Something can be functionally related but overridden by other circumstances.
George
I would not ordinarily get involved in this debate, but I too consider that you are being a little too strong on Katherine (in your comment of November 16, 2015 at 2:57 pm), and I am only commenting since this is not typical of your style; there are a number of commentators who I always look out for, and you are one of them, so I am fairly familiar with your style, and I have never perceived this to be edging on rude.
In my opinion there is never an excuse to be gratuitously rude (and I consider your comment of November 16, 2015 at 2:57 pm to over step the mark as the second paragraph was simply not called for; your first paragraph was enough for the real point that you wanted to make), and one has to bear in mind that people do not take the same care when they make a comment as they do when they work since most people are commenting in their spare time and this is not in endless supply. Further, people often to not check every fact, before making a comment, and often make comments based upon recollection (which recollection inevitably is not always 100% accurate). This is unfortunate, but is not the result of being stupid.
But the general thrust of Katherine’s comment was sound. in that she was making the point that observational evidence on temperatures does not support the wild claims made for Climate Sensitivity. I do not consider that any impartial observer could strongly contest that.
I do not like to see people barked at, even trolls should, in my opinion, be treated with a reasonable degree of respect. Maybe it is just my old fashion attitudes in that I consider that good manners are never out of fashion. Anyway, I do not mean any disrespect George, since I always welcome your insight. So sorry for my two pennies worth if you consider it unjustified (and it certainly is not my job to police what people comment or how they express themselves so I may well be over stepping the mark butting into this debate).
Anyway, I just wish to make it clear that I agree with the general thrust of Katherine’s argument, but I agree that there was an error in suggesting that CO2 has already doubled, but that error does not detract from the general thrust of her argument.
SUNY Binghamton, kewl.
Little known fact, the SUNY B campus was designed and built all at once as a replacement for the old Harpur College. This gave the architects some poetic licence, not a good idea.
The whole campus, with it’s buildings and roadways is laid out in the image of a *Human Brain*.
Unfortunately, the administration building is in the position of the all-important brain stem. *sigh*
The campus access road forms the spinal column.
You pick up a campus map, look it over, and “where have I seen this before?”
“Co-precipitation of nahcolite and halite (NaCl) now establishes a well-constrained lower [CO2]atm limit of 680 ppm for the EECO. Paleotemperature estimates from leaf fossils and fluid inclusions in halite suggest an upper limit for [CO2]atm in the EECO from the nahcolite proxy of ∼1260 ppm.”
So CO2 varied between 680 and 1260 ppm?
I noticed the usual I need more grant money key phrases:
“a causal connection” “which suggests” “may have been”
I’ll see your “more sensitive to CO2 than previously thought” and raise you a “sea levels rising by 8 meters”.
…or just simply that’s all the CO2 the higher temps could release
“The early Eocene (Ypresian) is thought to have had the highest mean annual temperatures of the entire Cenozoic Era, with temperatures about 30° C; relatively low temperature gradients from pole to pole; and high precipitation in a world that was essentially ice-free. Land connections existed between Antarctica and Australia, between North America and Europe through Greenland, and probably between North America and Asia through the Bering Strait. It was an important time of plate boundary rearrangement, in which the patterns of spreading centers and transform faults were changed, causing significant effects on oceanic and atmospheric circulation and temperature.”
http://www.ucmp.berkeley.edu/tertiary/eocene.php
CO2, CO2 wherefore art thou CO2?
Tom in Florida,
If we may assume that the ~30°C is right for the overall ocean temperature of that time, and the current average ocean temperature is ~15°C, that means that with ~16 ppmv/°C (per Henry’s law), the CO2 levels should have been 240 ppmv higher than pre-industrial (290 ppmv), or about 530 ppmv. The 680 ppmv thus may be possible.
Of course, not directly comparable, as ocean currents were different and still lots of carbonate deposits were not yet formed.
Anyway they have things upside down: CO2 changes were driven by temperature changes and the opposite influence is minimal…
And just who is going to grant you permission to ” ass-u-me ” that the ocean temperature was 30 deg. C
A 15 deg. C increase in 70+ % of the earth surface, would according to Frank Wentz et al, result in a 105% increase in atmospheric water vapor (7% per deg. C rise).
The resulting increase in cloud cover, would shut down the surface insolation big time.
I think you ” may ” not ” ass-u-me ” a 30 deg. C ocean Temperature.
g
The positions of the Earth’s land masses have changed significantly in the last 40 million years.
One of my university professor’s favorite expressions was Ceteris paribus. It means “all other things being equal”. ANY geologist should be aware of the theories that link the Earth’s climate to the positions of the continents. The continents have moved. All other things are, therefore, not equal. We can make no relationship between CO2 and the planet’s climate during the Eocene.
This is really sad and pathetic.
g is being rude with no reason.
These back of an envelope calculations have little more worth than be a starter for more thorough thinking.
How did they get non ice at the then prevailing earth axis poles, unless the tropics of Capricorn and Cancer were at – and + zero deg. latitude ??
This is beyond my knowledge without checking underlying facts/data (which I have not done), but is it not the case that there is only extremely substantial Antarctic ice because Antarctica is now at the South Pole? Back during this epoch, Antarctica was not in the same position, ie, was not over the South Pole, and the same is so of the Arctic Continental shelf.
Even today, Arctic ice is minimal, and that is with our today’s temperatures. If the globe was 30degC then almost certainly ocean levels were higher and there may have been no Arctic land mass over the North Pole so it is easy to see that the Arctic would also be ice free.
What I am saying is that without land masses situated over the poles, the oceans never get cold enough to freeze.
Of course what high temperatures say about cloud formation and the then water cycle is a matter of conjecture. With higher temperatures one would expect more evaporation and hence more cloudiness globally.
But then again we already today have the equatorial and tropical ocean bordering on 30degC, and if higher latitudes were considerably warmer resulting in extra cloud formation and IF the extra cloudiness remains at high latitudes then whilst the albedo changes, given that solar irradiance is weak at high latitudes it may not have as severe an impact as you suggest.
Unfortunately all of this is very difficult to pontificate upon since the land distribution and its general topography (where are the mountain ranges, how high are the mountain ranges, what were the prevailing wind directions, how did warm and cool air interact etc) is not known with sufficient certainty. This is just wild speculation, and that is why the study is couched in such conditional language with maybes and ifs.
Shouldn’t the conclusion be that CO2 is less correlated with temperature than was previously thought?
Or that CO2 at higher levels isn’t well-mixed.
Wasn’t there a lot of volcanism in the area of the Rockies 50 million years ago?
Just more Crap On Parade 21…..if they try hard enough , they may even convince themselves….bless their little hearts .
“needs more data” = “investigator needs more funding”
—
One of the peculiarities of compulsive gambling is the ‘double down’: the belief that the more his ‘luck’ seems to be going bad, the more the gambler is willing to invest in the game, convinced that luck is about to turn his way.
This seems to be an occupational disorder among climate researchers, along with innumeracy.
Lowenstein and his team are trying to develop ways to estimate ancient carbon dioxide in the atmosphere using indirect proxies.
Kind of like Mann and the tree ring data, using indirect proxies that could never be validated because there are no direct observations to corroborate the proxies. Of course it needs more funding, er… data, yes it needs more data.
Do they not teach null hypothesis and identity theorem in Kindergarten anymore?
So what is null hypothesis. Nobody ever mentioned those words to me in any science class ??
g
Hi george,
You must know that the Null Hypothesis (paraphrasing here) is the generic hypothesis that current observations are within normal parameters, with or without the extraneous variable that is being claimed.
The Null Hypothesis must be falsified if any alternative hypothesis is true (man-made global warming, for example). If the alternate hypothesis makes no observable difference, then it can be completely disregarded. Anything that makes no difference doesn’t matter.
Maybe they didn’t teach the Null Hypothesis in your science or maths classes, because it started out as something that was applied to biology, drugs, and pharmaceuticals.
Or maybe they didn’t teach it until after the Civil War. ☺
yep george.
a whole lot of skeptics mistake a TOOL of statistics USED by scientists as science itself.
Well heck, Steven, you misteak natural warming cycles for alarming man-made threats.
positive climate science feedback: Since we think co2 governs temperature, and temperature is high even when co2 is only moderately elevated, we think co2 governs temperature even stronger than we first thought!
More sensitive now. Less sensitive in the past. Hotter now. Cooler in the past. All models hotter in the future and cooler now. Real data falsifies this inane BS. All wrong. Propaganda.
It surely means that co2 is much stronger per molecule today than it was in the past. co2 is evolving. /s
Did a count and found only ten uses of “may” in the article.