Methane: Much Ado About Nothing

David Archibald

Thanks to Modtran, an online program maintained by the University of Chicago, we know that carbon dioxide’s heating effect is logarithmic.  The first 20 ppm of carbon dioxide heats the atmosphere by 1.5°C. At the current concentration of 412 ppm each extra 100 ppm is only good for 0.1°C. Carbon dioxide is tuckered out as a greenhouse gas.

But what of methane which is the excuse du jour for wrecking livelihoods, towns, industries and whole economies? Methane, with a half life of nine years in the atmopshere, is carbon dioxide’s little brother in the pantheon of the satanic gasses.

Witness this headline about antics in New Zealand:

We return to Modtran to see what that oracle will tell us about methane’s heating effect. This is the model output converted to degrees C:

While not as pronounced as carbon dioxide’s drop off in heating effect with concentration, the effect is still there such that at the current concentration of 1.9 ppm, each extra 0.1 ppm heats the atmosphere by 0.05°C. With the methane concentration currently rising by 0.1 ppm every 20 years, the atmosphere will get an extra 0.2°C of heating by 2100. The reader can decide whether or not he/she/it need be worried by this projection.

But methane has only been going up at that rate for a few years. The atmospheric concentration of carbon dioxide has measured since 1958. Methane measurements only started in the mid-1980s and this is what the data looks like:

There is a steep rise at the beginning but then from the early 1990s to 2010 the concentration went sideways for nigh on 20 years. The Cape Grim concentration is particularly flat. NASA has helpfully provided a graph of rate-of-change:

There are three years – 2000, 2001 and 2004 – in which the methane level went down. Let’s disregard the noise and look at the bigger picture evident. And that is the rate of increase declined for 20 years and then went up for 20 years. A few more decades of observations might show whether or not this is cyclic.

But farms that have been going for generations might be wiped out by unnecessary concern about methane while we are waiting for that data.  So we will make a stab at the underlying science. Two factors are likely involved.

Firstly plant productivity has been going up with the increase in the atmospheric carbon dioxide concentration. Parts of the West Australian desert now have 30% more plant matter than a scant 30 years ago. The same is true of the vast stretch of forest and tundra across northern Russia. Unless this vegetation is consumed by fire, its fate is to be the source of methane via termites or rotting. So the hand of Man is not necessarily involved in a rising methane level.

Secondly, the Sun was more active in the second half of the 20th century than it had been in the previous eleven thousand years. That stopped in 2006 with the end of the Modern Warm Period. The Sun has become less active as shown by this graph of solar extreme ultra violet produced by the University of Bremen:

Our current solar cycle, 25, is tracking lower than any of the previous four. The natural enemy of methane is ozone, the most reactive gas in nature. Ozone is produced in the upper atmosphere by radiation with wavelengths less than or equal to 242 nano metres acting on oxygen. So less ozone has been produced since 2006 and this is when the atmospheric methane level stopped falling and started rising again.

Case closed. Nothing to see here. Move along. Only idiots would get hung up on such a minuscule effect that we can’t change anyway. There are real problems coming at humanity that will take all our attention. Destroying the production base in the interim will only make our situation worse.

David Archibald is the author of The Anticancer Garden in Australia

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DMacKenzie
November 19, 2022 10:22 am

The world has greened and methane is a byproduct of of the composting of the additional growth especially of boreal forests….plus a bit from more natural gas production that is displacing coal fired generation, and more from rice paddies that are feeding a larger population, and termites. Don’t panic there politicians and gretageddonists! It converts to CO2 when it bumps into ozone and it should reach an equilibrium level or even start declining in a decade or so.

AGW is Not Science
November 19, 2022 10:33 am

Lest we forget, all the Modtran numbers show is the amount of warming that would HYPOTHETICALLY occur, ALL OTHER THINGS HELD EQUAL.

In reality, the hypothetical effects of adding more of either CO2 OR methane is meaningless, since negative, offsetting feedbacks will render them indistinguishable from ZERO.

That is what observations support. At the end of the day, the Earth is a WATER planet. We have never been, are not, and will never be in control of the hypothetical “greenhouse effect,” because over 70% of the Earth’s surface is WATER.

Richard Greene
Reply to  AGW is Not Science
November 19, 2022 12:02 pm

The greenhouse gas water vapor is linked to the temperature of the troposphere. It is a positive feedback to any warming of the troposphere caused by manmade greenhouse gas emissions.

michael hart
Reply to  Richard Greene
November 19, 2022 12:15 pm

Unless, of course, you wish to take the formation and action of clouds into consideration.

AndyHce
Reply to  michael hart
November 19, 2022 12:45 pm

And the cooling effect of increased surface evaporation taking more heat energy high into the atmosphere to radiate away — which is part of the action of clouds but not their direct, blocking sunlight part.

Rud Istvan
Reply to  michael hart
November 19, 2022 3:00 pm

We know for sure two things. The water vapor feedback sign must be positive because we have net positive humidity (water vapor is a GHG), and the cloud feedback sign per CERES must be negative . But by how much each, we can only approximate. Per ARGO ocean rainfall, WVF is about half modeled. Per WE Ceres analysis, CF is mildly negative rather than significantly positive as modeled. Both observations combined explain why EBM ECS is about half of models. And those three observations by themselves cancel ALL climate model future alarms. Game over, except politically.

Richard Greene
Reply to  michael hart
November 20, 2022 3:12 am

Increased cloudiness is a negative feedback to the positive feedback of increasing water vapor with a warming troposphere. It may be clouds that prevent runaway global warming that Climate Howlers imagine. There is still a positive water vapor feedback, but not without limits.

This is the official NASA-GISS position. Please refute it if you think you know better:

Since the late 1800s, global average surface temperatures have increased by about 2 degrees Fahrenheit (1.1 degrees Celsius). Data from satellites, weather balloons, and ground measurements confirm the amount of atmospheric water vapor is increasing as the climate warms. (The United Nations’ Intergovernmental Panel on Climate Change Sixth Assessment Report states total atmospheric water vapor is increasing 1 to 2% per decade.) For every degree Celsius that Earth’s atmospheric temperature rises, the amount of water vapor in the atmosphere can increase by about 7%, according to the laws of thermodynamics.”

Richard M
Reply to  Richard Greene
November 19, 2022 12:37 pm

Except the warming never takes place due to boundary layer feedbacks, so no water vapor feedback.

Richard Greene
Reply to  Richard M
November 20, 2022 3:13 am

Please read the official NASA-GISS position on this subject, in my earlier comment, and refute it if you believe you know better.

DMacKenzie
Reply to  Richard Greene
November 20, 2022 2:12 pm

So say 1 degree increase…assuming 7% more cloud cover per degree, then Earth’s Albedo of 0.3 due to its 65% cloud cover and cloud Albedo of .5 to .7, we should expect about 10 watts more Sunlight reflected into outer space due to planet Albedo change. That’s enough heat to cause the planet to cool by 1/2 a degree again…
Or assume 3.5% cloud cover increase as half of the water saturated air is falling and half is rising…..then about 5 watts worth of cloud reflected sunlight, which is a wash with upwelling IR from Stephan Boltzmann due to 1 degree temp. increase. Thats equilibrium….assuming some other factor has caused a 1 degree increase in surface temp to start with. In the real world many things cause much more than a 1 degree change in surface temp. A blast of sunshine between the 65% cloud cover or a sprinkle of rain for example.

RobJM
Reply to  Richard Greene
November 20, 2022 8:19 pm

Richard Greene water vapour feedback is negative due to decreasing humidity in the upper troposphere combined with increasing humidity near the surface. That increases the lapse rate resulting in increased convective cooling that bypasses the GHG effect. Thats why the hotspot is missing.

E. Schaffer
November 19, 2022 10:33 am

Another case of the “critical side” involuntarilly supporting “consensus science”. The IPCC does not really like methane forcing for a simplistic reason. Methane decays relatively fast and is not a lasting issue. CO2 of course is neither, but it will circulate a lot longer.

As you can learn from modtran, which is very imprecise in terms of methane, it provided about 1/2 of CO2 forcing, given it went up from 0.7pbb to 1.8bpp. So it is a pretty important anthropogenic GHG, as far as GHGs are important at all.

According to AR6 however, methane only provided 1/4 of CO2 forcing. So relative to CO2 the IPCC downplays the role of methane.

old cocky
Reply to  E. Schaffer
November 19, 2022 11:49 am

given it went up from 0.7pbb to 1.8bpp.

Where did those numbers come from? The chart in the head post shows ~1600-1750 ppb in 1984, and ~1800-1950 ppb in 2020.

E. Schaffer
Reply to  old cocky
November 19, 2022 11:55 am

You could just google it..

comment image

old cocky
Reply to  E. Schaffer
November 19, 2022 12:30 pm

O-kay.

So, ~700 parts per billion in 1700 to 1800 parts per billion in 2000?

DMacKenzie
Reply to  E. Schaffer
November 21, 2022 8:00 am

It’s amazing how low and steady it was before people could measure it….

Reply to  old cocky
November 19, 2022 12:24 pm

Most methane values are given in PPB. He’s just mixed up PPM and PPB.

w.

old cocky
Reply to  Willis Eschenbach
November 19, 2022 1:18 pm

Mixing up ppm and ppb was easy enough to work out, but the 700 ppb didn’t bear any relationship to the graphs in David’s article.
That’s been resolved now, although it would take some little while to turn up that particular chart on duckduckgo.

E. Schaffer
Reply to  Willis Eschenbach
November 19, 2022 1:28 pm

Ja, sorry. That is because in modtran you have ppm figures, while the chart names ppb…

Editor
November 19, 2022 11:37 am

Thanks, David. You say you are using MODTRAN “model output converted to degrees C”. But you haven’t specified how you made the conversion.

Also, these results are quite different from the results of the formulas used by the IPCC (Ramaswamy et al., 2001), viz:

fMN=function(M,N) {
 0.47* log(1 + 2.01e-5 * (M * N) * 0.75 + 5.31e-15 * M * (M * N) * 1.52)
}

fch4=function(M, M0 = 697, N0=270) {
 .036 * (sqrt(M) - sqrt(M0)) - (fMN(M,N0) - fMN(M0,N0))
}

In these formulas, M0 is the methane concentration at time 0, N0 is the N2O concentration at time 0, and M is the methane concentration, all of them in parts per billion.

The formulas are discussed here.

Next, I was unable to duplicate your MODTRAN results. Here are the changes in W/m2 per .1 PPM increment in CH4.

comment image

Two issues. First, although they show the same dropoff, my MODTRAN results are cruder than your results. Where did you get the more accurate numbers?

Second, the changes in W/m2 shown above are ~ equal to your results in °C …

My best to you, I do love a man who does his own research and has the hair to put it out for public peer review.

w.

Last edited 2 months ago by Willis Eschenbach
Richard Greene
November 19, 2022 12:00 pm

At the current concentration of 412 ppm each extra 100 ppm is only good for 0.1°C.

There is a positive feedback because a warmer troposphere holds more water vapor, whose greenhouse effect is added to the effect of CO2. The +0.1 degree C. is wrong. The right answer is “We Don’t Know”.

That positive feedback has never caused runaway global warming, as Climate Howlers claim, even with CO2 10x higher than today.

OBSERVATIONS:
CO2 in 1975 = 331 ppm
CO2 in 2021 = 415 ppm
Change in CO2 = +84pp
Change in avg. temperature, 2021 versus 1975 = +0.7 degrees C.
Worst case for CO2: +84ppm plus feedback causes +0.7 degrees C.
Actual effect of CO2 plus feedback = unknown
The guess of +0.1 degrees C. is a lowball guess.

I believe the claim that +100ppm CO2 (plus feedback) will result in a warming of +0.1 degrees C., as the author claims with great certainty, is just his personal guess (aka BS). My personal guess, based on observations, is higher than that, but the right answer is still “No One Knows”.
Perhaps a better answer is “harmless global warming — good news if you live in a colder climate”.

Last edited 2 months ago by Richard Greene
Tom Abbott
Reply to  Richard Greene
November 19, 2022 2:34 pm

“The right answer is “We Don’t Know”.”

That’s correct.

mikelowe2013
November 19, 2022 12:01 pm

The big mistake is to presume that Ardern’s actions are based on science, which as an experienced fish-and-chip wrapper she knows nothing about. Her response is purely political, and is especially designed to keep happy her similarly-technically-ignorant chums in the Green party! No worries of it destroys our most successful industry!

Graham
Reply to  mikelowe2013
November 19, 2022 5:14 pm

Farmed animals are not a problem with global warming as their methanecan never be a problem .
The world methane levels shown above by Chloe Taylor all show a flat line from 1999 to 2008. Enteric methane from farmed animals were not raising the levels SO WHERE WAS THE PROBLEM with farmed animals .
There is no problem as all fodder that farmed animals consume has absorbed the gas of life CO2 from the atmosphere.
The very small amount of methane that is expelled during digestion breaks down in the upper atmosphere in 9 years into CO2 and water vapour .
Not one additional atom of carbon is added to the atmosphere .
I have already asked this socialist government here in New Zealand lead by our Communist Prime Nut Jacinda ,when I appeared before their select committee for their Zero Carbon Bill.
I showed the committee one of the graphs that is shown above and also a graph of world coal production .
Coal was steady at 4.7 billion tonnes till 2009 and then rising to over 8 billion tonnes and to 8.056 billion tonnes in 2021.
This government are trying to destroy our agriculture on which New Zealand relies on to earn overseas funds .That stupid woman JA tried to say that more customers will buy our food because of its low carbon footprint .
She is ignorant because New Zealand exported food already has the lowest carbon footprint even after shipping around the world .
The UN issued a directive that countries should not take action to lower emissions that would effect food production.
This ignorant attack on farming will destroy thriving country districts as the levies on methane and nitrous oxide will force farmers in outlying areas to sell to carbon farming companies .
Carbon farming is the biggest rort that a government could impose on New Zealand .
Foreign companies cannot buy farms but this government is allowing them to buy up farms to plant in pines to earn carbon credits which will all end up overseas,.a great way to stuff a country .
These carbon forests will become fire hazards as the pines age and fall over in storms .
I heard a forester trying to defend the plantings saying that there would be roads through the forests for fire protection .If these forests cauch on fire helicopters with monsoon buckets would be the only way to fight the fires and most areas do not have rivers or lakes close by .

Richard Greene
November 19, 2022 12:08 pm

Suddenly methane is trending?
That can’t be good news.
I read a William Happer article on methane at Real Clear Energy on November 16. Jumpin’ Joe Biden babbled something about methane the other day (I’m not sure what — I couldn’t find my Jumpin’ Joe Biden Gibberish Magic Decoder Ring). The Happer article is worth reading:

A Little Learning on Methane and Climate Change | RealClearEnergy

David Dibbell
Reply to  Richard Greene
November 19, 2022 12:27 pm

Thanks for that link.

michael hart
November 19, 2022 12:12 pm

Good points, well made.

Aspiring geoengineers really ought to be proposing putting more methane into the atmosphere. The extra warmth would not only be probably net beneficial for the biosphere but would allow them to better test their models. With a ~9 year half-life, any effects would be quickly reversible.

Richard Greene
November 19, 2022 12:16 pm

Somewhere in EGYPT
November 18, 2022
COP27 Press Release for immediate distribution:

The Official Announcement by COP27 Officials:
(aka Big Shot Officials)
The Official COP27 Statement on Methane — The Deadly Gas
“15 member nations have agreed to ban the sale and
consumption of baked beans to reduce methane emissions”

Last edited 2 months ago by Richard Greene
macromite
November 19, 2022 12:17 pm

Only idiots would get hung up on such a minuscule effect that we can’t change anyway.”

Good article David, but two points you might have elaborated on. First, those that worship in the Church of Climate Change are idiots.

Second, those behind the Methane Crusade are not idiots, but corporate conglomerates and their compliant government cronies that want to force the small farmers out of business. They can’t do it through fair competition, so they seek government mandates. In the Netherlands, for example, it seems pretty clear that methane, nitrates, etc are being used to eliminate small farms that are too productive and efficient to be outcompeted by conglomerates.

This is always the way, of course, rules and regulations are rarely imposed to protect the public, or if they do it is incidental to their primary purpose: to favour large corporations or guilds over small businesses. I was just looking over some plumbing supplies in Queensland, Australia, and the display had a prominent warning that it was illegal for an unlicensed person to do their own plumbing. Just who is that regulation protecting from me installing a new tap on my sink?

One wonders what industries are the primary beneficiaries of the Methane Crusade, but I suspect that it is the artificial meat industry and the promoters of powdered crickets as the solution to the evils of meat eating.

Petit-Barde
November 19, 2022 12:30 pm
CD in Wisconsin
Reply to  Petit-Barde
November 19, 2022 4:37 pm

I shall do my part for the climate by refraining from eating baked beans. /sarc

Richard Greene
Reply to  CD in Wisconsin
November 20, 2022 3:15 am

I’m nominating you for a Nobel Prize
If Al Gore can get one, anyone can.

Kit P
November 19, 2022 12:38 pm

All this science is nice but there is no interest in it. If you graph ghg emissions per kwh. Nuclear, solar, and wind are small but only nuclear can be used by a an industrial society.

Nature gets rid of waste biomass by producing ghg with bacteria or fire. Man applies this complex science to treat waste. If you would add an disputable energy recovery device to the natural processes it would 900 times better to reduce ghg.

It has been done too. Two problems. First way more complicated to explain than a solar panel that does not work. Second, for those who are good at science and primary job is producing something like milk or treating sewage, they are too busy to recover small amounts of energy.

mkelly
November 19, 2022 12:48 pm

Post says:” The first 20 ppm of carbon dioxide heats the atmosphere by 1.5°C.”

Will you please say exactly how it is that CO2 “heats” ( using your word) the atmosphere?

Richard Greene
Reply to  mkelly
November 20, 2022 3:17 am

CO2 inhibits Earth’s ability to cool itself
The +1.5 degrees C. does not include a water vapor positive feedback.

mkelly
Reply to  Richard Greene
November 20, 2022 6:57 am

Thanks but you are not the author and your explanation is not specific nor directly address how CO2 “heats” the atmosphere.

186no
Reply to  Richard Greene
November 21, 2022 11:12 am

CO2 inhibits Earth’s ability to cool itself”
Really, without any qualification? Given that it can only do, as you state, very partially, because as you very well know (or should) only part of the spectrum of radiation is reflected and very little at that, CO2 is a trace gas in the “atmosphere” and the undisputed giver of life to billions in tandem with sunlight and H2o – avail yourself of NASA satellite photographs of this greening effect. Your crusade, with “others”, to demonise this non polluting essential for humankind and animal life on this planet in the manner you do is utterly delusional; have you nothing better to do with your spare time?

BTW, if you are in the UK, ever munched on peppers grown in Holland….?

It doesnot add up
Reply to  mkelly
November 20, 2022 2:42 pm

The bonds of the molecules vibrate much like a boxer’s punchball on a spring. Some of those vibrations are like the punchball being knocked sideways on its stand, and others are like elongations and contractions of the spring. When a boxer throws a flurry of punches at the punchball at just the right frequency successive punches are timed to make the vibration more energetic: the same effect is well timed pushes of a child on a swing. When an infrared photon of the right frequency (or equivalently wavelength, with frequency ν =c/λ where c is the speed of light and λ is the wavelength) engages with a CO2 molecule, it makes it vibrate more energetically, with the energy of the photon (hν, where h is Planck’s constant 6.6 10^-34 Joule seconds) changed into energy of vibration.

Gas molecules are constantly moving, and indeed the temperature of a gas is a measure of the average (root mean square to be technical) speed of the molecules. They are constantly having close encounters with each other, bouncing off each other in collisions. If they were just a monatomic inert gas the behaviour is similar to billiard balls. However, with molecules with vibrating bonds the encounters are more like with a boxer throwing punches which can knock the next molecule much harder than the inert billiard ball would, transferring energy of vibration to kinetic motion the other molecule, like a boxer knocking his opponent across the ring. Faster motion equals higher temperature. Rinse and repeat very often, particularly in denser, lower levels of the atmosphere where there are more molecules to bump into.

At higher levels of the atmosphere and where it is much colder with molecules moving more slowly, the time between collisions lengthens. That allows time for the energy of vibration to be re-emitted as a photon before it gets a chance to kick another molecule. Those photons that are emitted downward will enter denser, mostly warmer layers of atmosphere and get a chance to engage with a CO2 molecule there. Those emitted upwards will pass through a less dense atmosphere, and have a chance to reach space, taking their hν of energy with them.

mkelly
Reply to  It doesnot add up
November 21, 2022 8:55 am

Thanks. I don’t know if that is the author’s thinking but at least it was specific and not some statement that says “and then magic happens”.

Do you assume that every encounter is additive? It is entirely possible the encounter could cause a slowing.

If energy is transferred then the CO2 must be reduced in energy. So isn’t it a wash?

Again thanks.

It doesnot add up
Reply to  mkelly
November 21, 2022 5:35 pm

Addition occurs whenever a molecule that has become more energetic due to absorbing a photon transfers some of that energy to another molecule. It is of course possible for a collision to be by a faster moving molecule that transfers some of its energy to the CO2 molecule, but that is relatively unlikely because of the addition of the photon energy and the constant punching back from vibration. It would mean that the CO2 molecule is speeded up and will soon collide with something else at least in the denser lower atmosphere, giving it more of a kick.

Gary Pearse
November 19, 2022 12:50 pm

Doesn’t CH dissolve in seawater? Probably. Between it’s short half life and increasing partial pressure, it will attenuate. What about methane eating microbes? Didnt take long to find it:

“Anaerobic methanotrophic Archaea (ANME) form syntrophic association with sulfate-reducing bacteria (SRB). Their symbiosis facilitates the anaerobic oxidation of methane (AOM) in marine sediments and thereby modulates its flux to the atmosphere.”

https://www.energy.gov/science/ber/articles/symbionts-methane-eating-microbes-fix-nitrogen.

Yep, as I and a billion others have known for generations, the overarching net feedback in nature is negative!! Le Châtelier’s Law. If you get too much of something, the system reacts to not only reduce it, but to exploit it! (That last bit is my axiom!).

Hmm … rice paddies emit a lot of methane and microbes exist that fix nitrogen using methane, yeah.

Gary Pearse
Reply to  Gary Pearse
November 19, 2022 12:51 pm

err CH4.

Steve Case
November 19, 2022 1:11 pm

Methane: Much Ado About Nothing
David Archibald
____________________________

Thanks for bringing up this favorite topic. We just came out of the mid-term election cycle and most of us are probably able to cite the gist of most of the never ending ads for our favorite and most disliked local candidates. The point of all the annoying repetition is that it works.

Some of the issues that constitute the world of Climate Change are more important equal than others. The truth about methane, nitrous oxide and the misleading Global Warming Potential (GWP) numbers can’t be stressed enough. A Google [news] search on Methane and N2O makes point.

The GWP numbers for Methane and nitrous oxide tell us they are many times more powerful at warming than CO2, but we are never never told how much global warming, in degrees, they will actually produce. By the end of the century it’s probably less than a tenth of a degree. People need to know that.

Christopher Chantrill
November 19, 2022 1:30 pm

I was wondering about the CH4 concentration. So now we know that;

CH4 concentration: 1.9 ppm
CO2 concentration: 412 ppm
O2 concentration: 210,000 ppm
N2 concentration: 780,000 ppm.

Yep. We animals are feasting on an O2 concentration that is over five hundred times the CO2 concentration on which plants are trying to survive.

John Kelly
November 19, 2022 2:08 pm

I suspect that methane (and nitrogen) has emerged as the next gas that will destroy the world because the settled scientists are understanding that CO2 is loosing its mojo. Got to keep the scare campaign going and who better to push is that that nutcase in NZ.

RelPerm
November 19, 2022 2:26 pm

I shake my head in disbelief when I see statements as Methane is a more potent greenhouse gas than CO2, it just doesn’t fit with spectral absorption curves and incoming/outgoing radiation potential. Is someone not tAking into account interference?

143A07D6-C724-4BFC-BBEA-9C7CCD46EC5D.jpeg
Mikehig
Reply to  RelPerm
November 19, 2022 2:51 pm

To these eyes methane’s absorption bands are almost covered by those of water vapour – which is at 10,000+ times the concentration.

lgl
Reply to  RelPerm
November 20, 2022 11:32 am

12 km to space is probably more relevant
https://twitter.com/RARohde/status/1197147289229385728/photo/1

Rud Istvan
November 19, 2022 2:51 pm

I went and looked up the basic MODTRAN standard atmospheres (there are six depending on season (summer, winter) and latitude (poles, mid latitudes, tropics)). They all include a ‘standard’ humidity based on altitude, which by itself fully explains the general result posted here—negligible significance. Methane IR absorption significantly overlaps water vapor IR absorption per Happer (much more than CO2), so it’s effect must be very little given Modtran standard humidity assumptions.

The climate alarmists trying to eliminate cows in favor of bugs refer to methane GHE potency measured in the lab, which is by purposeful definition a zero humidity atmosphere since H2O is the most potent GHG. But the reality is that Earth is a water planet with lots of humidity most places most times. So all their lab projection stuff is wildly unrealistic. IMO deliberately so. No way in the real world will I ever eat mealworms and crickets instead of steak and burgers ‘to save the planet’. I note in passing that no one at COP27 did, either.

Kevin Kilty
Reply to  Rud Istvan
November 19, 2022 5:54 pm

There is no winter tropics atmosphere, but a U.S. 1976 Standard atmosphere is included — making six. I wish we had full access to modtran, but the interactive wrapper at UofChicago limits a person to choice of atmosphere model, some scale adjustments for ghg’s, vertical path only, and a temperature offset that adjusts the entire atmosphere. That’s it.

old cocky
Reply to  Rud Istvan
November 19, 2022 7:07 pm

trying to eliminate cows in favor of bugs

That whole “get rid of farm animals” thing totally mystifies me. A very large proportion of domesticated ruminants are range grazed on country which isn’t economic for crop production. It’s possible that sheep and cattle produce more CH4 emissions than an equivalent stocking rate of macropods would, but if Australian rangeland wasn’t grazed it would just burn in massive wildfires.
The wool from sheep would also have to be replaced by n alternative fibre, which would increase petroleum use one way or another.

It’s also interesting that there isn’t an equivalent push to ban rice growing, since flood irrigated rice is a vary large source of methane emissions. Even sillier, there isn’t a push to replace flood irrigation of rice by drip irrigation.

Chemman
Reply to  old cocky
November 19, 2022 8:44 pm

What we do about the pesky termites which, IIRC, are the biggest contributors of CH4 to the atmosphere.

old cocky
Reply to  Chemman
November 19, 2022 10:06 pm

That’s alright. termites are insects, so we can eat them 🙂

Alastair Brickell
Reply to  old cocky
November 20, 2022 2:31 pm

Yes, but just don’t you dare burp or fart afterwards.

sherro01
November 20, 2022 3:39 am

Please extend your methane graph back towards the zero X-axis origin.
0.05 ppm creates a bar about 0.4 deg C high – or does it?
These doubling calculations have to start from a specified point on the X-axis.
The reason for the choice has to be stated.
What happens at 0 ppm? Obviously no heating is produced.
Please try the doubling exercise in molecules, like 1 to 2, 2 to 4, 4 to 8 ……
All of these seem to fail because the molecules would need to carry prodigious energy to make heat.
Where is the concentration where each methane molecule CAN carry enough energy to produce measurable heat?
Would not that concentration be a candidate to start the doubling exercise?
I do not know the answer. What am I missing?
Is the answer in quantum theory and calculated allowed molecular excitation states?
Geoff S

It doesnot add up
Reply to  sherro01
November 20, 2022 1:18 pm

From Wijngaarden and Happer – Methane and Climate

In the dilute “optically-thin” limit, WH[1]
show that the tropospheric forcing power per molecule is P{i} = 0.51×10−22 W for CH4
, and P{i} =
2.73×10−22 W for CO2

For the tropopause, WH [1] show that for current atmospheric concentrations of greenhouse gases,
the forcing power per molecule for CH4
and CO2 are
2.8 x 10-24 W for CH4
9.0 x 10-26 W for CO2

WH1 is their full detailed paper Influence of Greenhouse Gases on Thermal Radiation from the Earth

donklipstein
November 21, 2022 9:23 am

Pre-industrial methane is fairly well known as about .722 ppm or around 700 ppm in pre-industrial times. There was a slowdown of manmade increase of atmospheric methane around 1990 (1988 was 1.7 ppm), but there is concern that this slowdown may get reversed.

Meanwhile, I added up the increments in the twice-shown graph from .8 to 1.9 PPM, and that’s about .75 degree of warming.

old cocky
Reply to  donklipstein
November 21, 2022 11:35 am

Pre-industrial methane is fairly well known as about .722 ppm or around 700 ppm in pre-industrial times.

As a popular TV science show presenter used to say – “Why is it so?”

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