Clyde Spencer
2023
ABSTRACT
The role of anthropogenic methane (CH4) in global warming is exaggerated. The atmospheric concentration of carbon dioxide (CO2), as measured at Mauna Loa Observatory (MLO), is above 420 ±0.7 ppmv (parts per million-volume) and is increasing about 2.8 ppmv annually. CH4 has a concentration of about 1.9 ppmv and is increasing about 0.014 ppmv annually. The anthropogenic contribution to the annual CH4 increase is a fraction of the total, probably about one-third, albeit the official estimate was increased in recent years. CH4 has more potential for warming than CO2, but it is effectively gone in about a decade, having a commonly cited long-term impact that is only about 32X that of an equal weight of CO2. Accounting for the CO2 warming equivalence on a mole-fraction basis reduces the equivalence factor to less than 12X. It is the long-term impact we need to be concerned about because of an arbitrary temperature threshold claimed to be threatening our survival after 2050. With CO2 being more than 200X as abundant, even with the greater potential impact of CH4, the Global Methane Pledge will, at most, achieve a 0.58% annual decrease in CO2-equivalent CH4.
INTRODUCTION
More than 100 member nations, represented at the 26th Conference of the Parties (COP26) to the UN’s Framework Convention on Climate Change, committed to the Global Methane Pledge (GMP). The GMP was created using information provided by Krane (2022) and others; it is a commitment to reduce the estimated 33% of total annual methane (CH4) emissions derived from fossil fuels, by at least 30%, compared to 2020. The intent is to reduce methane emissions because of the claimed greater warming potential of CH4 than CO2.
From the International Energy Agency (IEA):
“…, the most common [metric] is the global warming potential (GWP). This can be used to express a tonne of a greenhouse-gas emitted in CO2 equivalent terms, in order to provide a single measure of total greenhouse-gas emissions (in CO2-eq).
The Intergovernmental Panel on Climate Change (IPCC) has indicated a GWP for methane between 84-87 when considering its impact over a 20-year timeframe (GWP20) and between 28-36 when considering its impact over a 100-year timeframe (GWP100). This means that one tonne of methane can considered to be equivalent to 28 to 36 tonnes of CO2 if looking at its impact over 100 years.”
Paraphrased from Chapter 8 (Physical Science Basis) of the IPCC Fifth Assessment Report, the GWP of a greenhouse gas is defined as the integrated radiative forcing, over some time interval, resulting from a pulse emission of that greenhouse gas, as compared to an equal mass of CO2. After some caveats about the definitions and utility of the metric, it says, “Thus, the name ‘Global Warming Potential’ may be somewhat misleading, and ‘relative cumulative forcing index’ would be more appropriate.” They continue with, “The GWP has become the default metric for transferring emissions of different gases to a common scale; often called ‘CO2 equivalent emissions’ … The GWP for a time horizon of 100 years was later adopted as a metric to implement the multi-gas approach embedded in the United Nations Framework Convention on Climate Change (UNFCCC) and made operational in the 1997 Kyoto protocol.” This provides precedence for using a 32X multiplier rather than the commonly quoted 85X.
From Figure 1, below, the average annual CH4 emissions-increase over the period January 2018 – January 2022 was 0.014 ppmv. Therefore, the pledged annual reduction in fugitive CH4 would be less than 10% (30% of 33%) of 0.014 parts per million-volume, or 0.0014 ppmv annually. That is, the annual increase in CH4 emissions would decline from 0.014 to 0.013 ppmv. One should probably consider that an upper-bound, considering the history of compliance with IPCC goals.
Assuming that the equivalent long-term global warming potential of CH4 is about 32X that of CO2, the reduction goal would be equivalent to 0.044 ppmv of CO2 (32 x 0.0014). The net annual increase in atmospheric CO2 is about 2.8 ppmv recently, having ranged from about 2.0 to 3.6 ppmv over the last 20 years. [See Fig. 4 in Spencer (2021)]. Thus, the first-order estimate of the reduced warming impact of reducing anthropogenic CH4 would be less than 1.6% of the temperature increase attributed to the net annual CO2 increase. This approximation will be refined further, below. We can use this initial estimate as a sanity check on the refined estimate.
(https://gml.noaa.gov/ccgg/trends_ch4/)
(https://gml.noaa.gov/ccgg/trends_ch4/)
Unlike CO2, atmospheric CH4 does not always increase. As can be seen in Figure 1, above, CH4 concentrations plateaued during the decade from 1999 through 2009. It isn’t certain why that happened. It does suggest that we need to learn more about the CH4 cycle.
As recently as 2017, NOAA dismissed the claim that fugitive emissions resulting from fossil fuels were driving the increase in atmospheric CH4. However, that is inconvenient for the political activity at COP26 and 27. From Figure 1, above, the seasonal range (≈0.023 ppmv), which probably represents the natural emissions, is about twice the annual net increase (0.014 ppmv), which probably represents mostly anthropogenic emissions.
PROBLEMS
A problem is that the atmospheric concentration of CO2 is reported invariably as parts per million by volume (ppmv). Most commonly, one sees graphs of the increase in CH4 in units of parts per billion by volume (ppbv), as shown in Figure 1. Many people find it difficult to make direct comparisons because the scale used for CH4 inflates the amount subjectively by three orders of magnitude. For clarity and objectivity, CH4 should be reported in the same units as CO2 when comparing the relative warming potential.
Krane (2022) cites a source that claims “Over 20 years, methane causes 85 times more warming than the same amount of carbon dioxide.” There is a problem with this also. Chen and Zou (2022) state that “Based on the assessment in IPCC AR6, the methane perturbation lifetime is about 12 years. Others, such as NASA, claim that the methane is gone in 10 years. While opinions vary on the details, experts agree that CH4 only has a lifetime of about 10-12 years in the atmosphere. CH4 is converted to CO2 and is then counted in the monthly CO2 measurements as part of the CO2 flux. To simplify things, we could assume that most of the impact occurs in the first decade after release; however, our concern should be with the long-term impact. As noted above, the UNFCCC settled on the 100-year time-frame GWP for the 1997 Kyoto protocol.
There is yet another more important problem: Infrared radiation is absorbed by individual molecules of CO2 and CH4. Therefore, the proper measure of the potential warming is the relative number of molecules, or the mole fraction, not the bulk mass (molecular weight).
The claim for the mid-range, long-term warming potential of CH4 is 32 times that of CO2. However, that equivalence is for equal weights of the two gases! The multiplier is a poor choice for comparison because CO2 is more than two orders of magnitude more abundant than CH4 in the atmosphere. As pointed out previously, CH4 and CO2 atmospheric concentrations are reported typically as a volume fraction, not a weight fraction. Because they have different molecular weights, equal molecular concentrations of the two gases do not weigh the same. CH4 has a molecular weight (16.0 g/mole) about 36.4% of CO2 (44.0 g/mole). That is to say, when the equivalent warming potential of CH4 is calculated for the same volumetric concentration of CO2, or molecules in a given volume, the warming potential is significantly less than 32X. Specifically, 1.0 ppmv of CH4 has less than 12 times (11.6X) the long-term warming potential of 1.0 ppmv of CO2, not 32X. Rarely does the news media, or even the climatology community, make this distinction, quoting instead, the equal-mass (weight) equivalences. That makes the problem seem more threatening.
Not surprisingly then, there are some contradictions in a SciTechDaily article about methane ‘super-emitters.’ It quotes NASA Administrator Bill Nelson egregiously saying, “Reining in CH4 emissions is key to limiting global warming.” The concentration of CO2 in the atmosphere is currently above 420 ±0.7 ppmv. CH4 concentration is currently about 1.9 ppmv, which is equivalent to 22 ppmv of CO2, or about 5.2% of the CO2 concentration.
The recent annual increases in CH4, resulting from all emissions (0.014 ppmv/yr) is equivalent to about 0.16 ppmv/yr of CO2, which is about 5.8% of the annual CO2 increase, and only about a quarter of the average monthly uncertainty in the Mauna Loa Observatory CO2 measurements. Thus, assuming fossil fuels account for about 33% of the total annual CH4 emissions, fossil fuel emissions only account for about 0.054 ppmv CO2-equivalence, or about 1.9% of the annual CO2 increase. Reducing that 1.9% by 30% (1.9% x 0.30% = 0.58%) is not going to limit global warming! It is naive to think so. The expected CO2 -equivalence reduction resulting from the Global Methane Pledge is less than the uncertainty of the measured monthly CO2 concentrations.
SUMMARY
It is disingenuous for climate-change alarmists to focus on the large Absolute Global Warming Potential (AGWP) of CH4 on a weight-equivalence, because CO2 is more than two orders of magnitude more abundant than CH4 on a molecular basis, which is how the concentration and annual flux are reported usually. Furthermore, CO2 and CH4 have not been equally abundant since at least the early-Proterozoic Eon, meaning the last two billion years. Using a molecular basis (parts per million-volume mole-fraction) to account for the lighter CH4 reveals that the annual contribution to warming is a fraction of that claimed for CO2 and, therefore, attempts to reduce warming will have insignificant effects.
The global rate of increase of CH4 was about 0.014 ppmv/yr in 2020. The estimated fossil fuel contribution to that (33%) is 0.0046 ppmv and a 30% reduction of that is (0.30 x 0.0046) 0.0014 ppmv/yr. Converting that fractional flux to its long-term CO2-equivalence (11.6 x 0.0014) gives an annual reduction of 0.016 ppmv/yr. That is, if all nations on Earth were to achieve the pledge made by the 100+ COP26 nation-members, there might be about 0.016 ppmv less CO2-equivalence of CH4 emitted into the atmosphere annually. That is 0.58% of recent annual CO2 increases.
There was a 10% (by weight) average annual decline (monthly maximum decline > 18%) in anthropogenic CO2 emissions during the COVID-19 pandemic shutdowns of 2020, with no observable decline in the atmospheric CO2 rate of seasonal increase, seasonal maximum, or net annual increase. [See Spencer (2022)] We have no empirical evidence that a 0.58% decrease in CO2-equivalent CH4 will have a measurable impact. I consider the claim that focusing on reducing CH4 is the “cheapest, quickest way to reduce climate change without roiling the economy,” to be wishful thinking unsupported by the facts.
Approximately one-half to two-thirds of the annual emissions of CH4 are natural and not amenable to reduction by humans. (In fact, the recent movement to re-introduce beaver in locations where they have become extinct may increase CH4 emissions.) Historically, Conference of the Parties (COP) nation-members do not have a good record of achieving their pledges. We would be doing extremely well to decrease all anthropogenic CH4 emissions by half. Perhaps that is why the pledge goal is only 30% of the 33% (≈10%) attributed to fossil fuels. Thus, an expensive, concerted effort to reduce annual anthropogenic CH4 emissions might reduce the CO2-equivalence from 1.9% to about 1.3%. I would not consider that “key to limiting global warming.” The impact is truly lost in the noise.
REFERENCES
Lan, X., K.W. Thoning, and E.J. Dlugokencky: Trends in globally-averaged CH4, N2O, and SF6 determined from NOAA Global Monitoring Laboratory measurements. Version 2023-02, https://doi.org/10.15138/P8XG-AA10
Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
https://www.iea.org/reports/methane-tracker-2021/methane-and-climate-change
https://scitechdaily.com/nasas-emit-mission-detects-more-than-50-methane-super-emitters-from-space/
https://gml.noaa.gov/ccgg/trends_ch4/
Much more proof that all politicians are corrupt than that methane has an effect on anything since the most common way people discover methane is because it tends to combust on mixture with atmosphere… and yet they don’t automatically imprison politicians for running for office or for the lies they say to do so.
CH4 does not combust in the atmosphere. It is clear you have no engineering experience.
Well, it doesn’t and it does burn naturally.
Will O The Wisp
Science proposes that will-o’-the-wisp phenomena (ignis fatuus) are caused by the oxidation of phosphine (PH3), diphosphane (P2H4), and methane (CH4). These compounds, produced by organic decay, can cause photon emissions. Since phosphine and diphosphane mixtures spontaneously ignite on contact with the oxygen in air, only small quantities of it would be needed to ignite the much more abundant methane to create ephemeral fires.[39] Furthermore, phosphine produces phosphorus pentoxide as a by-product, which forms phosphoric acid upon contact with water vapor, which can explain “viscous moisture” sometimes described as accompanying ignis fatuus.
Did you mean “spontaneously combust?”
Other than combustion, methane (unlike CO2) can escape from the top of the atmosphere. In a gas, at a given temperature, the average molecular speed is inversely proportional to the square root of molecular weight.
This means that the average molecular speed of a methane molecule (MW = 16) is about 32% faster than that of a nitrogen molecule (the most plentiful molecule in air, MW = 28). Methane emitted at the surface tends to rise through the atmosphere (unlike CO2 which is heavier than air), and some methane molecules can escape the earth’s gravity into space.
This is illustrated by the large outer planets of the solar system, which are colder than Earth (lower molecular speeds) and have stronger gravity, which have atmospheres that are predominantly methane. The gravity on Mars is much weaker than that of Earth, so it can only hold a thin atmosphere of mostly CO2. Since Earth is much warmer than Jupiter, but has weaker gravity, it cannot hold methane in its atmosphere, but can hold heavier nitrogen and oxygen.
I wish to thank Clyde Spencer for pointing out the difference between “equivalent CO2 of methane” on a mass or mole basis, since this can be confusing for people who have not studied chemistry (or have forgotten what they learned). Anthropogenic emission rates are usually expressed in tons (mass) per year, but concentrations in the air are usually expressed in ppm (volume of gas per volume of air), which is proportional to moles of gas.
This confusion also applies to emissions, which are sometimes expressed in tons of “carbon”, and in other sources as tons of CO2. Due to the molecular weights, burning 12 tons of carbon atoms yields 44 tons of CO2, or a ratio of 3.67 tons CO2 per ton carbon burned.
Also, burning 16 tons of methane also yields 44 tons of CO2, or 2.75 tons CO2 per ton of methane. But since a ton of methane absorbs as much IR radiation as 32 tons of CO2, the best way of reducing “warming” due to methane is to burn it to 2.75 tons of CO2, which only has 2.75 / 32 = 8.6% of the IR-absorption rate of the original methane.
This means that a misguided effort to ban gas stoves would not only deprive people of an inexpensive way to cook food, but would also increase “global warming”.
The minor little problem is that the absorption spectrum of methane overlaps water vapor and CO2, and both are on a log scale of effects. Testing methane alone in dry air is deceptive.
That means the 0.58% reduction that the Global Methane Pledge might accomplish is ‘optimistic.’
Actually it means it’s bullshit. Just like all the other “human induced climate” nonsense.
How true
Exactly. Since both absorption bands, CO2 and CH4, are saturated. The only warming comes from expanding the width of the bands. CO2 has energy available in the atmospheric window. CH4 on the other hand only absorbs small amounts in its absorption band. When the width expands the band is still completely saturated by water vapor. No additional absorption occurs.
For the areas of overlap, the width of the wings of the narrow bands become effectively the width of the water vapor.
Please look carefully at the spectrum:
According to Lillesand and Kiefer, 1994, earth’s emission only starts at 9 um
There is no absorption by CH4 in the spectrum of earth. So, the net effect of more CH4 in the air is cooling, rather than warming.
Dear friend. It seems we agree. But be careful with the red-blue diagram, as it is also misleading. First of all, it is obviously not on scale, as it depicts the earthshine to be just as big as the sunshine….Truth is: earth shine is smaller than sunshine, at all wavelengths, as shown above (Lillesand and Kiefer)
Furthermore, it seems as if in that presentation earthshine starts at between 7 and 8 microns, but even that is not true. As I said, I am going with Lillesand and Kiefer on that. You can calculate this with Wien’s law. The maximum temperature on earth is about 50C and that would only occur during the day in the lower atmosphere. According to Wien’s Law, that corresponds with a source of 9 um. But even that radiation does not make it to TOA. Because if I board a plane and flying at the height of 10km, I find that everywhere around me the temperature is ca. -50C which corresponds to a source of ca. 13 um.
Anyway, I did some comprehensive calculations on the spectrum of CO2 and I find that here the amount of energy (SW) being deflected towards space by the CO2 is just as much as the amount of energy being trapped on earth:
An evaluation of the greenhouse effect by carbon dioxide | Bread on the water
If I apply same method as shown above to methane, it is obvious that I will only find a cooling effect, no warming effect: There is no absorption by CH4 in the emission spectrum of earth.
By far the most common, most prolific and effective greenhouse gas is water vapour and clouds. At 95% of the total this swamps all others, Why is this rarely mentioned. Surely the reason can’t be because we have no control over it! Can it ?
Related to that, I have to wonder why those who should know better have supported the recent movement to reduce anthropogenic CH4 emissions. Three explanations immediately come to mind: 1) they are innumerate, or, 2) they realize that it is impractical to make any significant reductions in anthropogenic CO2 emissions, and they want to give the appearance of doing something, or, 3) they are willingly participating in a deception for hoped for personal gain. I’ll let the reader decide which option is more probable.
4) all of the above
Water vapor is not a direct cause of global warming.
It is a positive feedback, amplifying OTHER causes of troposphere
While water vapor is from 60% to 750% of the entire greenhouse effect, which includes clouds, water vapor does not directly increase the greenhouse effect.
According to the Clausius-Clapeyron relationship, atmospheric water content increases by between 6 and 7% per 1 °C. Therefore, even just an increase of 1.5°C could result in ~9% more water in the atmosphere, which could have a major impact on storm systems and subsequent rainfall.
If they can’t blame it on human prosperity, it’s a non-factor to “climate.” /sarc
Reducing methane emissions or any other emissions is not the goal. Eliminating fossil fuels are an interm
Reducing methane emissions or any other emissions is not the goal any more than reducing anthropogenic climate change is the goal.
“committed to the Global Methane Pledge (GMP)”
You are writing a lot about the pledge. It is always a good idea to say what it actually is. It has its own home-page here where I found this:
“Participants joining the Pledge agree to take voluntary actions to contribute to a collective effort to reduce global methane emissions at least 30 percent from 2020 levels by 2030, which could eliminate over 0.2˚C warming by 2050. This is a global, not a national reduction target. Participants also commit to moving towards using the highest tier IPCC good practice inventory methodologies, as well as working to continuously improve the accuracy, transparency, consistency, comparability, and completeness of national greenhouse gas inventory reporting under the UNFCCC and Paris Agreement, and to provide greater transparency in key sectors.“
The important word is “could”. Since it will have no effect, they have an out when questioned in the future.
Except that it is not voluntary for the citizens, residents, tax payers, and customers who make up the countries whose political masters make the pledge.
Except that compliance is dictated to those people by the corporatist, Western, polities that are falsely called democratic.
Except that it is a pledge, and not a treaty so as to deliberately avoid democratic challenge and debate while imbuing it with the force of law.
Except that the 30% figure is absolutely meaningless even to the most exaggerated claim of global warming caused by greenhouse gases.
Except that there is no proof that any greenhouse gas managment scheme, but especially energy deprivation, is either practical or effective in climate control.
Except that the concept of a national greenhouse gas inventory is ludicrous.
Except that 0.2° C warming is neither harmfull nor significant in terms of natural variation on human health and well being, but the demonstrable political and economic harms of these counter measures are obvious.
Except that the text of the pledge has little or nothing to do with the article above.
Except for all that, and more, you almost had a point there.
My little brain is reporting an overflow error. note I do not fall into the AGW camp by any means before I get down votes!
Let me try and figure out the logic of the “pledge”.
1) reduce methane emissions by 30% by 2030
2) may reduce temperature by 0.2 K by 2050
3) methane oxidises to carbon dioxide and I presume water over 20 years (shouldn’t that be given as a half life?)
4) therefore one molecule of methane becomes one molecule of carbon dioxide & two molecules of water
5) methane concentration is three orders of magnitude smaller than carbon dioxide
6) doesn’t this imply that any temperature increase attributed to carbon dioxide over the same period is three orders of magnitude greater than 0.2K? That we are actually living on the planet Venus?
It seems reasonable to me that the concentration of methane should have a half-life. However, in reading various publications on the issue, I have not seen any ‘authority’ speak about a half-life. It is always cited as a “life time” or “gone after.”
Is that the best you can do? It was already over 2,000 words and pushing the limit of the attention span of most. Some compromises had to be made.
The section — “which could eliminate over 0.2˚C warming by 2050“ — is an assertion that is not only unsupported, but cannot be supported without an agreement on the climate sensitivity. However, assuming for the sake of the argument that preventing over 0.2˚C warming is an achievable goal, we can do a sanity check. Obviously, if only a few of the signers of The Pledge make a conscientious effort, there is little hope that they can make up, with reductions, for what the others don’t do. It would have to be a concerted effort. Even then, considering that the last century has seen a temperature increase of about 0.10-0.17˚C per decade, with ~94% of it supposedly coming from CO2, it is improbable that reductions in CH4 would save >0.1˚C per decade over 2 or 3 decades, particularly in the light of having demonstrated that the upper-bound of CO2-equivalence methane is about 0.6% of the annual increase of CO2.
Yes, tiresome non sequitur is the best that “he” cando.
> It was already over 2,000 words
You could have saved at least 3,000 by making sure you did not attack a strawman, Clyde.
How about adding a few more words to your comment to give it some substance and thus allowing me and others to understand what you mean?
It’s obvious. If you criticise something without clearly saying what it is, then you are very likely attacking a straw man.
You are something else, Stokes!
My very first sentence was, “The role of anthropogenic methane (CH4) in global warming is exaggerated.” Is that not clear to you? I then went on for over 2,000 words to defend that assertion in detail.
“using the highest tier IPCC good practice inventory methodologies,”
Shame the IPCC doesn’t use the highest tiers of good scientific methodologies !!
One methane reduction would be to shorten your comments
Thank you for this article. “The impact is truly lost in the noise.”
Agreed, even though in my view it is for reasons more fundamental than the math used here, from which I conclude that the climate response of CO2 and CH4 emissions cannot be reliably distinguished from zero in any case.
I am highly concerned about the farmers being increasingly targeted because of the obsession with methane and nitrogen (N2O) emissions. Not to mention the regulatory-driven problems with restricted supply and higher cost of diesel fuel.
Instead, we must LEAVE THE FARMERS ALONE.
As livestock is one of the major contributors of methane and the global population appears to be plateauing, the consumption of livestock and products associated would surely be plateauing as well. Bottom line from that, methane from livestock has already reached its peak and has become a non issue.
I’ve always found this argument curious. Cows do pass gas; they also eat grass. If you look at the carbon cycle of a cow, the net gain in CO2/CH4 to the atmosphere is zero.
That’s true of all humans and animals
Human beings do exhale almost three billion tons of carbon dioxide annually, but the carbon we exhale is the same carbon that was “inhaled” from the atmosphere by the plants we consume.
And we pass gas too, but we blame the dog and that cheap food we feed him.
I’ve not dug into the numbers on this issue, but I suspect the lunatic CAGW cargo cultists are counting GHG emissions from the full production cycle, ranch to table, not just direct ruminant emissions.
The fools who want to eat worms and insects don’t seem to realize that even these invertebrates emit methane and CO2. Massive scale “farming” of these, sufficient to feed world population, if it were even remotely feasible or acceptable, would require a gargantuan industrial enterprise that would easily approach or exceed the impacts of the agricultural food, feed and fiber industry. Plus, I haven’t yet seen anyone produce a nice Angora sweater from crickets and earthworms.
rather fiction than exaggeration.
No where in all of that gobelty gook, was there an estimate of how much warming, business as usual, methane is projected to cause. Policy makers need to be told how many degrees of global warming they can expect, due to methane, by 2100. That has never happened!
Methane is increasing about 7 ppb annually or about 0.5 ppm by 2100. If anyone can show that to cause more than 0.05 deg Celsius of warming, they should show their work.
The problem is that without a reliable estimate of the climate sensitivity — the amount the Earth can be expected to warm with a doubling of CO2 — there can be no prediction of the impact of CH4. The accepted climate sensitivity estimate for CO2 has been about 3 deg C for more than 40 years. However, recent estimates have been 1 deg or less. What I attempted to show is that whatever the climate sensitivity actually is, the contribution of methane cannot be the “cheapest, quickest way to reduce climate change without roiling the economy.”
The basic climate sensitivity of CO2 is about 1.2K. See James Hansen chapter 8 IPCC AR4. All the values you gave included feedback speculations.
Methane is on track ti increase about 0.5 ppm by 2100. How much global warming will that cause?
Thanks for your response (-:
Too small to measure
Just like CO2, since ALL of these alleged “sensitivities” are based on the assumption “all other things held equal.”
Which they have never been, are not, and will never be.
Observations show NO effect.
ECS has to have three decimal places, or it is baloney.
Knowledge gained with my BS degree.
I disagree. Sometimes calculations with just orders of magnitude can give one an insight on a problem.
I’m just an eng-in-eer and a computer guy — that did a bit of computer modeling back in the day. And I say that if you think that CO2 at 0.04 percent in the atmosphere is a problem then I gotta bridge to sell you. And if you think that NH4 at 0.00019 percent in the atmosphere is a problem then you must think I’m dumb or something.
But nitrogen N2 at 78 percent in the atmosphere… OMG!
That 0.04 percent of the atmosphere is still about 10^21 molecules /m3.
And that 95% H2O in the atmosphere is still about er..erm.. much, much more
Water vapor is individual molecules of H2O that are part of the collection of gases in the atmosphere. Varies greatly from place to place, and from time to time. It averages only about 0.4% of the atmosphere, but varies from as much as 4% in the humid tropics to near 0% in cold polar regions.
Water vapor is also 60% to 70% of the total greenhouse effect including clouds.
CO2 at 0.04% is a problem.
C3 plants (85%) would grow better at 0.075% to 0.15% CO2, which would support more human and animal life on our planet.
I already own 25% of the Brooklyn Bridge but am interested in diversifying. What bridge are you selling?
At a recent US Senate Judiciary Committee hearing Senator Whitehouse (D-RI) stated ‘methane is probably one of the most dangerous greenhouse gases, we see plumes of it miles long floating across the United States’.
As far as I am aware methane is invisible: ‘methane: a colourless, odourless flammable gas which is the main constituent of natural gas. It is the simplest member of the alkane series of hydrocarbons. Chemical formula: CH4’ (Oxford).
Senator Whitehouse joins Greta in seeing the invisible
I wonder if he knows those plumes of “methane” is water vapour?
At the Heartland Climate Conference a speaker was asked a question about atmospheric methane and warming. The speaker deferred to Will Happer who was in the audience at that particular session: Dr. Happer jumped up (despite his advancing age, he is quite spry), took a microphone at the front of the room, and answered the question, in few sentences, ending with
“It [methane] is trivial. There is no reason to regulate methane.”
Dr. Happer is the Cyrus Fogg Brackett Professor of Physics, Emeritus, at Princeton University, and a long-term member of the JASON advisory group, where he pioneered the development of adaptive optics. One of his specialties is the transmission of light and energy through atmospheres.
On a personal note, he is a very amiable man, very approachable, and interested in the opinions and personal understandings of everyone he meets. And a terrific dinner table conversationalist. His wife is equally charming, and when asked, admitted that she actually enjoys these scientific conferences and the people she meets, admitting that she does not understand everything in the presentations, but enough not to feel lost. (I assured her that it was the same for myself.)
I see that I am in good company. 🙂
Methane absorption is mostly in the same bands as other IR absorbing gases (mainly H2O), so its entire removal would make almost no difference in the real atmosphere, and 30% removal would be 30% of almost nothing….graphic courtesy of Wikipedia in keeping with their terms of usage.
CO2 and/or Methane DO NOT WARM ANYTHING … They insulate and slow the loss of heat (like all “greenhouse” gasses) … stop saying they warm anything …
If you slow the loss of heat you warm the planet.
Very good.
Clyde,
Thank you for this persuasive article. I am following the vilification of methane closely because New York State’s Climate Act is obsessed with making methane evil. They have gone so far as to calculate their emissions with a global warming potential of 20 years because of it!
Do you have any thoughts on the van Wijngaarden & Happer paper that used many measurements of the observed greenhouse effect to develop a general relationship that can be used to predict the effect of increasing concentrations of greenhouse gases. The paper shows that show that increased CO2 will have a modest and decreasing effect on the greenhouse effect if concentrations are doubled. The primary driver of this observation is the saturation effect. Global warming potentials are based on a molecule-by-molecule relationship that does not account for the situation in the atmosphere. van Wijngaarden & Happer’s relationship proves that increased atmospheric concentrations of methane and nitrous oxides will have an imperceptible effect on the overall greenhouse effect. For methane the reality of the infrared absorption curve is that the wavelengths where it enhances the greenhouse effect are much smaller than the peak of the curve where CO2 affects it.
My impression is that your work is consistent with that work making New York’s obsession with methane totally irrational.
Thank you
I’m not nearly as bright, experienced, or competent as Happer, and will gladly bow to his authority.
Thank you for considering my article persuasive. It was difficult to write, trying to make all the details comprehensible. My rating is currently at a whole 2.5, with 4 votes! 🙂
I have never voted on any article or comment, But I would be willing to vote for the first time, if I only knew how to give you 5 stars. I read up to 48 short “one-page” articles each morning, speed reading the for about five minutes each. I recommend the best articles on my CLIMATE SCIENCE AND ENERGY blog.
This article is included even though it took 10 minutes to read.
I like articles filled with data, that add information to prior methane articles I’ve read, even if that makes them harder to read, and not as popular.
Honest Climate Science and Energy Blog
Thank you, Richard.
Thank you for the link to the paper by Wijngaarden and Happer. I have not read it previously and I am trying to read it quickly now.
“… only about 32X that of an equal weight of CO2.”
Really? not per molecule ? (then 31.1X)
(Wijngaarden & Happer – Relative Potency of Greenhouse Molecules, Table 4)
I have been trying to understand the point of your comment and am still at a loss. Table 4 is basically “forcing powers per additional molecule in units of 10−22 W at the altitude of the tropopause.”
I was speaking about the Global Warming Potential (GWP) and spent some time with it, even quoting the IPCC. The essence of my article was that I too think that the GWP should not be by weight, although that is the common way it is presented. My calculations lead me to believe that the GWP100 should be 11.6X CH4 when calculated on a molecule-by-molecule basis of equivalence.
However, even if I am wrong, I demonstrated that for the assumption of 32X, the reduction in heating would be less than 1.6% of the annual increase of CO2. Thus, CH4 is not a significant contributor compared to CO2.
Agree, CH4 is not a significant contributor compared to CO2.
David Coe & al. calculates the climate sensitivity for methane to be 0.06 degC in a realistic atmosphere with water vapor. https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijaos.20210502.12.pdf
Relative to climate, the participating amount of methane is 5400 Mt build-up in the atmosphere and 600 Mt emittet to the atmosphere in one year. If the emission was suddenly stopped, still 580 megatonnes would be converted to CO2 the first year, leaving approx 90 per cent intact. Next year 10 per cent down again and so on, thus half af the methane would be gone in 6 – 7 years.
Those facts are taken into consideration in the definition of the Global Warming Potential.
There is no real evidence that adding any of the greenhouse gases to the atmosphere causes surface warming. AGW is a false hypothesis.
That is an assertion without facts in evidence. You might start out by explaining why the moon is so much colder than Earth.
Umm, it’s farther away?
NASA says the daily highs hit around a toasty +240°F. But that’s at the equator. I’m sure it’s colder at the North Pole.
I do wonder if the moon had a pure nitrogen atmosphere, would it be any warmer? And if we had a pure nitrogen atmosphere, would we cool to the black body temperature of 254K?
Only sometimes, like the Full Moon phase.
From memory:
The lit side of the moon reaches about +130ºC, the dark side about -170ºC. Our atmosphere keeps us cool during the day, warm at night.
If adding CO2 to the atmosphere caused surface warming, one would expect that the increase in CO2 over the past 30 years would have caused at least a measurable increase in the dry lapse rate in the troposphere but that has not happened. A good measure of the thermal insulating characteristics of the atmosphere would be the temperature profile as exemplified by the lapse rate. As derived from first principals, the dry lapse rate in the troposphere is equal to -g/cp where g is the acceleration of gravity and cp it the heat capacity of the atmosphere at constant pressure. The lapse rate is not at all a function of the LWIR absorption properties of any component gasses so the AGW hypothesis cannot be true. All gases in the Earth’s atmosphere contribute to its thermal insulating properties, not just the gasses with LWIR absorption bands. Actually it is the so called greenhouse gases that act as coolants in the upper atmosphere radiating LWIR energy out to space.
… . .
As is the assertion that CO2 or methane does anything, other than hypothetically (i.e., all other things held equal).
No empirical evidence supports “CO2 drives temperature,” and a good deal says it does nothing.
Only if one chooses to greatly exaggerate the effects of methane on global warming would one cite the effect of the first molecule added to a water-free atmosphere laboratory setting as you have done Mr. Spencer. In our real atmosphere which contains up to 4% water vapor the effect of added methane is immeasurably small since the IR bands where it can operate are nearly saturated already. Double it, triple it or increase it by any amount you chose, it will have no measurable effect. See Happer for details.
Please quote where I said anything about the “first molecule added to a water-free atmosphere in a laboratory setting.” You are making assumptions and claiming things I did not say.
Just to be clear, the whole point of the analysis was to show that the effect of methane is only about 1/3 of what is usually claimed, and that the Global Methane Pledge will be ineffective in slowing the rate of measurable warming.
I have no issues with Happer. I’m using the claims of the IPCC to demonstrate that their political actions are not capable of achieving their promises.
Talk’s cheap for the climate changers until it dawns on them their necks are on the chopping block if the lights go out.
Polls looking like Labor will take office with NSW now in election mode-
NSW election: Labor’s Chris Minns backflips on energy policy with plans to buy Eraring power station (msn.com)
and Federally Albo must know the NEM grid is in trouble and that’s a lot of electorates-
‘Gas has a crucial role’: Prime Minister stares down Greens call to ban new fossil fuels (msn.com)
Now they’re left straddling the barbed wire fence trying to play the middle.
Fig 1 in the above post tells us all you need to know about Methane atmospheric levels .
Between 1999 and 2009 methane levels were static so where was the problem?
THERE WAS NO PROBLEM.
There was no problem as world livestock numbers were also static and coal mining was level at 4.7 billion tonnes over those 10 years .
Methane breaks down in the upper atmosphere into CO2 and H2O ( water vapour ) within 10 years
Methane levels only started to rise when China and other Asian countries increased their use of coal which increased from a steady 4.7 billion tonnes to exceed 8 billion tonnes .
There is a massive amount of methane in coal seams and it is released during mining transport and combustion.
As I have written here before all fodder that livestock consume has absorbed CO2 from the atmosphere so over a ten year period not one atom or molecule of carbon is added to the atmosphere.
Enteric methane is a closed cycle ,not one additional atom of carbon or molecule containing carbon is added to the atmosphere over any ten year time frame .
Why should any country reduce their food exports when they are neutral and the problem is the massive increase in coal production in Asia.
China now uses 5.3 billion tonnes of coal per year .
There was no problem with methane levels when the world was using 4.7 billion tonnes .
Western countries have to wake up to where their policies are taking them as Asian countries are determined to become the worlds power house fueled by coal .
Well, there’s still no “problem” with methane levels, the alleged “problem” is imaginary, just like the alleged “problem” of CO2 levels.
If methane is really a problem how do the environmental apostles expect to improve things by putting us all on a vegetarian diet? Have they tried it? The average vegan can burn a hole through an electric bus seat in seconds.
Not even mentioned is the fact that the “absorption bands” for methane are overlapped by WATER VAPOR.
The mythical “global warming potential” of methane is in reality non-existent.
What’s up with the headline photo being of a stovetop fire / flame being one where the fuel is not natural gas? This appears to me as having the gas fuel being much richer in carbon than natural gas is, and at least as carbon-rich as propane is.
Address your question to Charles.
“The atmospheric concentration of carbon dioxide (CO2), as measured at Mauna Loa Observatory (MLO), is above 420 ±0.7 ppmv (parts per million-volume) and is increasing about 2.8 ppmv annually.”
No it isn´t.: (Mauna Loa web page)
“Data are reported as a dry air mole fraction defined as the number of molecules of carbon dioxide divided by the number of all molecules in air, including CO2 itself, after water vapor has been removed. The mole fraction is expressed as parts per million (ppm).“
There is no volume. What does ppmv even mean for a gas?
The mole fraction is at 420ppm, the unit is mol/mol (molecule/molecule).
Concentrations are expressed as mol/v or in g/v.
This 420ppm thing is a mixing ratio not a concentration.
I believe the correct answer to be a), for a fixed volume at standard temperature and pressure, such as 1 liter, the mole fraction will vary with the number of molecules of CO2, which is the concentration.
https://en.wikipedia.org/wiki/Air_pollutant_concentrations