From what I can gather, the cited paper argues that O2 is effectively a weak anti-greenhouse gas since it scatters incoming solar radiation back to space. That’s not the direction I expected an answer to come from, but interesting.
Since that seems to be viewed as the most significant effect of increasing O2, would it then be safe to assume that increasing density of the non-GH gases has little or no effect on the rate of outward energy transfer?
For example, if there were no N2 or O2 in the atmosphere, but the same amount of CO2, would the rate of outward energy transfer be essentially unchanged?
To perhaps refine the question, if I tracked the energy of a single outgoing longwave photon, would it have the same probability under both high and low O2 levels of escaping to space as opposed to returning to earth, in spite of a difference in the number of molecule-to-molecule collisional transfers in the atmosphere en route to a final disposition?
Not trying to be dense, just trying to get a crisper understanding of the relevant mechanisms…
zebrasays
Ravenpaw #91,
The problem with analogies…and I use them sometimes, reluctantly… is that they often are not necessary, and rarely precisely correct.
So, we would have to go into further detail.
The conveyor belt is not variable in speed. It operates at the speed of light, in principle.
What is happening is that workers are picking up apples at random along the way, sometimes replacing them after a random time, and sometimes placing them on a belt going the opposite direction.
But my real objection is to the idea that we can’t just describe the phenomenon as it is. If you are trying to educate a (sincere, unlike Mack) student, why not describe the physics, and work with them to see where any misunderstanding might arise?
How is my description of it at #94 harder to understand than the approximation of my analogy above? If people want to learn, they will; there’s no easy magic trick to accomplish that.
1) I presume the following quote refers to the “dynamic effects” Gavin mentions?
Through feedbacks involving latent heat fluxes to the atmosphere and marine stratus clouds, surface shortwave forcing drives increases in atmospheric water vapor and global precipitation, enhances greenhouse forcing, and raises global surface temperature.
2) So, where does the oxygen go during low-O2 periods? Not, presumably, the oceans, as warmer ocean waters mean decreased solubility. And lower dissolved oxygen means less productive waters, so maybe not marine biological reservoirs. (“Maybe”, because there’s still phytoplankton, I guess.) Terrestrial reservoirs, then? But what? Anyone have anything on that?
Al Bundysays
Donald Condliffe: I think the problem with idealized plans like this is that the term ivory tower applies in spades.
AB: Yes, I agree. That’s why I always keep my carbon fiber foot firmly on the ground, and it’s been on lots of different ground, enough to see the wisdom, and the missing piece in what you speak of:
None of them, ivory tower nor ancient wisdom, was designed to carry an ecosystem from what is fast becoming unsustainable to whatever will be sustainable whenever sustainability is possible (I am not talking resource extraction here, just ecosystems themselves). And frankly, to me this is the most important thing. Evolution needs to be turbocharged so as to keep up with the rate of change. We’ve got to do reefs (good luck), forests, and pretty much everything in between.
I wouldn’t apply a framework. As you noted, that sort of thing just won’t fit. The landscape and its use, by various species, is a locally-known variable. “That valley is….” and whatnot.
With the slow start to the Arctic freeze season, JAXA’s Arctic Sea Ice Extent remains strongly below all previous years for the time of year (with the anomaly dropping quicker that Maniac Mack managed in his descent into the Bore Hole). The Arctic SIE anomaly did drop off the bottom my Arctic SIE anomaly graph. Rather than re-scale it, I’m plotting the points in the bottom margin (usually 2 clicks to ‘download your attachment.).
Comparing 2020 with previous years, it is now 430,000 sq km below 2019 (the previous lowest-for-time-of-year) and 1,860.000 sq km below 2017 (the last year not to have a slow autumn freeze-up). Another measure of it is 2020 has reached the SIE level 2019 reached 3½ days ago and 2017 reached 18 days ago. The Daily map (different base period) shows the ice is missing from the Russian side.
It could all just freeze up in a hurry as winter takes control, as happened in 2019 with Extent & Volume actually reaching higher values by winter’s-end than in the years immediately previous. But presumably there will come a point where the factors slowing these recent autumn freezes will have longer-lived impacts.
Dominik Lennesays
I have a problem to reconciliate two pieces of work about global CO2 induced greening.
Zhu, Z., Piao, S., Myneni, R. et al. Greening of the Earth and its drivers. Nature Clim Change 6, 791–795 (2016). https://doi.org/10.1038/nclimate3004
and
Yuan et al., Increased atmospheric vapor pressure deficit reduces global vegetation growth, Science Advances 14 Aug 2019:
Vol. 5, no. 8, eaax1396
DOI: 10.1126/sciadv.aax1396
The former finds an unbroken greening trend, while the latter states, that the global greening trend stopped around 2000 because of water stress kicking in.
Any constructive comment welcome.
Al Bundysays
Kevin M: I think the first couple of years after the typical clear-cut are not so easy to defend. The total biomass is of course much lower, but typically there is dead ‘slash’ lying everywhere. And it’s both highly flammable–being dead and usually dry!–and very awkward to traverse.
Timber companies could, of course, be required to do post-harvest controlled burns to mitigate this, but that wouldn’t be The American Way, would it?
The long and thin nature of the cuts lend themselves to trail-hauling to a rail line. The digester could sit on the rails wherever it’s needed.
The American Way, like Edith Keeler, must die.
_____
Mike: I think you have jumped over the big problem here in step 2. How do you think we could attain a netzero civilization?
AB: Not our job. Our job is to keep the wheels from falling off the biosphere so that those who are at the bottom of “Niagara Falls” can attain such a thing using what we’re stuffing into barrels.
My suggestion is more barrel stuffing and less waterfall extending.
Ravenpawsays
Zebra, 102
Situation A
– with the drain closed, turn on the faucet to your bathtub.
– when the water is 8” deep, open and adjust the drain so that outflow equals inflow.
– the water level is now steady at 8”
Situation B
– again, with the drain closed, turn on the faucet to your bathtub.
– this time, when the water is 8” deep, turn off the faucet.
The water level is the same in both, but in A, the water in the bathtub is constantly draining and constantly replaced. In B, the water is simply trapped.
It would be a mistake to describe the two situations in the same way.
zebrasays
Ravenpaw #108,
?????…. Sounds like you didn’t read my #102 at all.
And it also sounds like you don’t really understand the physical mechanism involved in the GHG effect.
If you have a question about what I said in #102, you are welcome to ask, but you should also read my #94 first; perhaps that will clear things up for you.
nigeljsays
Once again Killian @100 deflects and resorts to verbal abuse. Once again Zebra @109 gets caught out by Ravenpaw this time, and deflects, and resorts to supercilious preaching. Its always these same two people I find intensely irritating, along with KIA and Victor.
Ravenpawsays
Zebra, 109
I read both of your comments. even if it doesn’t sound like it. I’m curious, though, do you still think “heat trapping” is just fine?
If so, consider what would happen if there was no longer a solar input. The Earth system would quickly lose all of the energy it has accumulated. Like turning off the faucet in situation A.
Killiansays
110 nigelj: Once again Killian @100 deflects and resorts to verbal abuse. Once again Zebra @109 gets caught out by Ravenpaw this time, and deflects, and resorts to supercilious preaching. Its always these same two people I find intensely irritating, along with KIA and Victor.
Deflect? From non sequitur stupidity? None of what you said in that worst-ever of your posts had a shred of accuracy. Shooting at a target a mile away in 150 mph winds would have been more accurate.
I.e., there was nothing to respond to.
This is what happened. You posted an article that said “blue, green, and yellow.” I responded, “That’s all well and good, but blue, green, and yellow are stupid choices when we need grey.” You said, “NOBODY SAID ANYTHIG ABOUT GREY!!!!!!”
zebrasays
James McDonald #101,
I understand your question but I don’t see how you can realistically pose it for the actual atmosphere.
If we do an experiment with a fixed IR source in a horizontal tube, it should be possible to calculate the difference in absorption as you describe.
If you remove all the other gases, the probability of energy transfer by collision is greatly reduced. So re-radiation has some time interval for each CO2 molecule…I recall it is greater than that for the typical collision transfer(?). During that time, the molecule will not absorb any incident IR.
So, you are asking if this results in a different rate of transmission, and I am sure you could find someone competent to do the math. Or you could just do the experiment.
The problem is that, as the referenced article suggests, changing the density of the atmosphere has other effects; it’s not possible to hold the other variables constant as we would in the lab. So we get back, again as the article says, to actual climate models as the way to answer your question.
Al Bundysays
nigelj: Its always these same two people I find intensely irritating, along with KIA and Victor.
AB: We choose who to interact with. For example, my guess is that if I were to count keystrokes I’d find that the vast majority of yours have been invested in those four people.
Now you know a bit more about why humans suck at sociopolitical stuff.
@Adam Lea 15 Oct 2020 at 4:37 AM The simple answer is Muscle tension is generated by the release of Calcium ions by nerve signals which cause molecular motors to consume chemical energy from converting ATP to ADP. If the total tension of many mmolecular motors in many muscle fibers is larger than the load, the motors slide, the muscle contracts, and the weight in your example is lifted. Calcium ions are constantly being pumped away, allowing the absorption of another ATP which releases the tension on the motors and the muscle to relax, and lengthen under load. When you are holding a load at a constant position against gravity, your nerve signaling is releasing Ca ions at a rate that balances the pump rate, and individual motors are relaxing and tensioning so that the aggregate tension of all motors activate just balance the weight. There is no work being done on the weight macroscopically, but at the microscopic level ions are being pumped around, and micromotors are moving microscopically under cycles of tension and relaxation, and that consumes energy from the micromotor work and chemical losses. Fro a more comprehensive answer, see https://en.wikipedia.org/wiki/Muscle_contraction
One of Murphy’s lesser known laws unfortunately applies to economies as well as ecosystems:
You can’t go over the same waterfall twice.
Barry Finchsays
@101 James McDonald “…tracked the energy of a single outgoing longwave photon…..escaping to space as opposed to returning to earth”. There is no such outgoing longwave photon returning to earth. Photons are continuously both created from other energy by GHG molecules & destroyed by GHG molecules by converting them to other energy. A certain portion, statistically highly constant, reaches surface and a certain portion, statistically highly constant, reaches space. You imply in the next comment phrases that you perhaps know that but your cartoon version that I just quoted is best not used in my opinion because it fogs clarity too much. I don’t know the answer to 10x, 0.1x non GHGs but I see 2 basic effects and they oppose each other:
– The maximum (“saturated”) GHG effect for a gas (its IR absorption/emission band(s)) is determined by global average temperature difference from surface to top of troposphere and the GHG fraction determines how far up the troposphere the radiation reaching space or surface average altitude is. The 10x, 0.1x non GHGs must affect this with 10x being more “greenhouse effect” but I’ll not be attempting to quantify it.
– The 10x, 0.1x non GHGs with GHGs quantity unchanged will alter the ppmv and this will be with 10x being less “greenhouse effect”.
Since the 2 effects above oppose each other I’ve no idea of the net effect because I don’t know how average global tropospheric temperature lapse rate would change with taller or shorter troposphere.
—————–
This is how the so-called “greenhouse effect” in Earth’s troposphere causes warming. The so-called “greenhouse effect” effect is nothing at all like the effect that warms a greenhouse. A vast “shimmer” of transverse electromagnetic radiation (TER) in the long-wave band (LWR) is caused by molecules of water vapour (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (NO2) and some other gases in the troposphere due to their collisions (averaging 2,700,000,000 collisions / second) with other molecules, which are almost always going to be nitrogen (N2) or oxygen (O2) because they are almost all of the gas quantity in the troposphere. The H2O, CO2, CH4, NO2 and some other gases are being called “greenhouse gases (GHGs)” because the overall effect (not just this part) ends up causing warming of Earth’s troposphere. All except H2O are called “well-mixed greenhouse gases” because their boiling and freezing points are so low that they don’t condense or freeze in the troposphere, not even near the top, so they get spread out well mixed around Earth and well mixed vertically in the troposphere. The well-mixed GHGs now punch above their weight compared with water vapour (H2O) because the upper half of the troposphere is so cold that almost all H2O forms on dust/salt particles in liquid or solid form there rather than being a GHG but the others remain as GHGs. The lowest quarter or so of the troposphere where it’s warmer and water vapour (H2O) is king is already highly “saturated” without much additional “enhanced greenhouse effect” possible (still, H2O has such a broad absorption band that it still manages to match the “well-mixed greenhouse gases” pretty much exactly 1:1 net as a 100% +ve feedback).
——————
The GHG molecules don’t emit a photon (LWR unit) of LWR when they collide and they don’t later get to emit a photon of LWR after every collision, only after a few of them (note 1). What happens is that a collision might cause a GHG molecule to vibrate in a certain way (so with a certain energy) of which the GHG molecule has the capability of any one of a selection (called its “vibrational modes”). GHG molecules with more vibrational modes are more powerful GHGs because they have a broader absorption/emission band. The GHG molecule now has “molecular vibrational energy (MVE)” if the collision did cause it to vibrate. Energy cannot be created without destroying matter and matter doesn’t get destroyed by this. What happens is that one or both of the two molecules slows down such that the total “molecular translational energy (MTE)”, aka “molecular kinetic energy”, aka “heat”, is reduced by precisely the same amount as the MVE that the GHG molecule acquired, so (m1*v1**2 + m2*v2**2)/2 after collision is less than (m1*v1**2 + m2*v2**2)/2 before collision because either v1 or v2 or both was reduced, thus obeying the Law Of Conservation Of Energy. Effectively, the temperature of the 2 colliding molecules was reduced by an energy amount equaling the MVE that the GHG molecule acquired, what happened was energy transmutation from one form to another. When this vibrating GHG molecule hits another molecule it loses its vibration (note 1) and one or both of the two molecules speeds up such that the total MTE, aka “heat”, is increased by precisely the same amount as the MVE that the GHG molecule lost. So it just moved speed/heat from one N2 or O2 (almost always) molecule to another. However, ==here we go==, very occasionally/rarely and not very often at all compared with the 2,700,000,000 collisions / second that happen to this GHG molecule the GHG molecule with MVE will spontaneously emit a photon of LWR and lose its MVE. Now it has converted one-photon’s-worth of “heat” in the troposphere to one photon of LWR. It has cooled the troposphere by one-photon’s-worth of “heat”. This “relaxation time” of the covalent bond harmonic motion (with a photon emitted) happens over 10ths of one second (a very long time indeed).
——————
LWR is also radiated from the surfaces of liquids & solids such as the surface of the ocean, the surfaces of water droplets in spray above the ocean, the surfaces of water droplets in clouds, the surfaces of any water droplets at all, the land surface, the surfaces of trees & grass, the skins of animals, the surfaces of dust, salt, volcanic ash, any ash and any surface whatsoever on the ocean or land or in the troposphere. Except for 8% of the LWR from the ocean+land surface whose photons happen to have wave-lengths in a band called “the atmospheric window” this LWR goes into the vast “shimmer” of LWR in the troposphere with a distribution of energy quantity at each wave-length in the LWR band that you’ve all seen hundreds of plots of all over the place.
——————
GHG molecules also absorb LWR provided that the photon’s energy (which is its wave-length) perfectly matches one of that GHG molecule’s MVE mode energies and the photon goes through (or tries to go through) the area of the GHG molecule that absorbs that wave-length (obvious example, CO2 isn’t at all fussy what part of its molecule a photon of wave-length 15.00 microns goes through, it’ll swallow it and vibrate). Obviously, a GHG molecule neither knows nor cares whether a photon of a certain wave-length trying to go through it was emitted by the surface of the ocean, the surfaces of water droplets in spray above the ocean, the surfaces of water droplets in clouds, the surfaces of any water droplets at all, the land surface, the surfaces of trees & grass, the skins of animals, the surfaces of dust, salt, volcanic ash, any ash and any surface whatsoever on the ocean or land or in the troposphere, or emitted by another GHG molecule (H2O, CO2, CH4, NO2 and any other GHG molecule) because all photons of the same wave-length are the same. A GHG molecule with MVE that it got by absorbing LWR can, of course, ==here we go again==, very occasionally/rarely and not very often at all compared with the 2,700,000,000 collisions / second that happen to this GHG molecule (note 2) spontaneously emit a photon of LWR and lose its MVE. In this case the GHG molecule transmuted LWR back to LWR, it transmuted a photon to an identical photon, so it did nothing at all other than change the direction in which the photon is going. This is the cartoon that scientists show the public because it’s a simple analog that Earth tried to cool itself to space and failed, but since there are 2,700,000,000 collisions / second there’s just about a bat’s chance in hell that the GHG molecule will spontaneously emit a photon of LWR and lose its MVE before it collides and loses its MVE (note 1). The coal/oil shills use the highly-incorrect nature of this ludicrously-over-simplified cartoon to “disprove” the physics theory but it isn’t the physics theory that’s incorrect, it’s the cartoon that’s incorrect. It doesn’t describe the physics theory hardly at all as I’ve explained in detail above. This is why I dislike this cartoon. When a vibrating GHG molecule hits another molecule it loses its vibration (note 1) and one or both of the two molecules speeds up. This means that “heat” increased, what happened was energy transmutation from one form to another, energy transmutation from LWR to “heat” with MVE as the intermediary step.
————-
Now the so-called “enhanced greenhouse effect” explanation that I think is clearest, obvious and difficult to challenge by mis-direction disinformation and subterfuge per the memes concocted by the coal/oil shills. 8.5% +/- 1.7% of the LWR that Earth sends to space is emitted by the ocean or land surface because the photons are in a wave-length band called “the atmospheric window” that doesn’t get absorbed by the GHGs. It’s my understanding that this will narrow slightly with increased GHGs, but this isn’t the prime “enhanced greenhouse effect” and I’m not addressing any additional warming it might cause. 91.5% of the LWR that Earth sends to space is emitted by the GHG molecules in the troposphere, tropopause and stratosphere (note 2). This 91.5% of the LWR is the part that gets reduced by increased tropospheric GHGs and causes an energy imbalance with insufficient energy going out, which causes global warming, ocean heating and ice fusion, which causes climate change, which causes a variety of nuisances that I haven’t studied.
——————
The troposphere has an upper and a lower surface. The upper surface is the top of the troposphere (the tropopause) and the lower surface is the surface of the ocean or land. LWR produced in the troposphere that reaches the lower surface will warm that surface so it stays in Earth’s ecosphere but LWR produced in the troposphere that reaches the upper surface has a good chance to make it through the increasingly-thin tropopause, stratosphere and the ultra-thin extended atmosphere to space and be energy lost to Earth’s ecosphere, thus cooling it. LWR reaching the upper/lower surfaces was produced by GHG molecules, the surfaces of water droplets and the surfaces of solid particles (sea salt, ash, dust) throughout the troposphere sending photons upwards/downwards as described in detail earlier.
– There is an average altitude in the troposphere of the LWR quantity that reaches space. If you could float at this altitude and watch/count photons with special eye balls and brain you’d see 50% of those photons that reach space are heading up from below you. If you counted it at 48% then you’d need to float upward to get more of the LWR photon production below you. If you counted it at 52% then you’d need to float downward to get more of the LWR photon production above you. This is obvious. When you float to the place where 50.0000000% of those photons that reach space are heading up from below you then you are at the average altitude in the troposphere of the LWR quantity that reaches space.
– There is an average altitude in the troposphere of the LWR quantity that reaches the surface of the ocean or land. You could float and find that the same way as the preceding.
These 2 altitudes in the troposphere are approximately for illustration only and as a global average (I’m not quantifying the so-called “enhanced greenhouse effect” in this comment, only describing its operation accurately):
—- average — —- average global —-
—- altitude — —- temperature —-
5,700 metres -23.8 degrees 50% of the “shimmer cloud” of LWR photons that will
———————————— make it to the tropopause are emitted by GHG
———————————— molecules and the surfaces of cloud droplets ———————————— and atmospheric particles below this altitude.
1,650 metres 3.7 degrees 50% of the “shimmer cloud” of LWR photons that will
——————————— make it to the surface of the ocean or land are emitted
———————————- by GHG molecules and the surfaces of cloud droplets and
———————————- atmospheric particles below this altitude.
These values are approximate. They are to demonstrate how the so-called “enhanced greenhouse effect” works, not to provide quantities. They are approximately correct though. They are based on a global average ~12,000 metres height of the troposphere but it varies geographically from 9,000 to 16,000 metres.
——————-
If tropospheric GHGs are increased then 2 changes occur per my explanations above since the start of my comment:
1) More LWR than before is produced by the GHGs, and
2) More LWR than before is absorbed by the GHGs because the LWR photons have to make it through more GHG molecules that might absorb them before they can reach their goal of going up past the top of the troposphere or going down past the bottom of the troposphere and being absorbed into the ocean or land.
Note that I have not included “(3) The LWR photons emitted by the surface of the ocean and land have to make it through more GHG molecules that might absorb them before they can reach space” because I’m dealing with the 91.5% of the LWR reaching space that’s created by GHG molecules in the troposphere obtaining, then losing, MVE with spontaneous photon emission caused. I’m not dealing with the 8.5% of the LWR in a wave-length band called “the atmospheric window” that gets directly to space after being emitted by the surface of the ocean and land. If that 8.5% is reduced by increased tropospheric GHGs (I’m not sure) then that’s an additional, unrelated, means of the so-called “enhanced greenhouse effect” (there’s no reason why there has to be only one mechanism).
—————
The result of combined effects/changes (1), (2) above is that the average altitude in the troposphere of the LWR quantity that reaches the top of the troposphere gets higher, so perhaps it raises from the 5,700 metres to 5,800 metres (as an example). Also, the LWR quantity is reduced slightly (the so-called “enhanced greenhouse effect”) for reason of the tropospheric temperature lapse rate explained below.
—————
Likewise, identically, the average altitude in the troposphere of the LWR quantity that reaches the surface of the ocean or land gets lower, so perhaps it lowers from the 1,650 metres to 1,550 metres (obviously, it depends on the change quantity. I just showed a random example) because it has to get past more GHG molecules that might absorb the photon.
—————
In either case GHG photons were trying to reach their goal of the top or bottom of the troposphere but now there are more GHGs in the way so it needs, == on average ==, to be a bit closer to make it. So that’s why the “cloud” of LWR that will reach the top is a higher cloud than before and the “cloud” of LWR that will reach the bottom (ocean or land) is a lower cloud than before
—————
The tropospheric temperature lapse rate is required to cause the so-called “enhanced greenhouse effect”.
The average altitude for LWR to space got higher (5,700 metres —> 5,800 metres in my example) which means LWR to space is from colder (slower) molecules on average because tropospheric temperature decreases with altitude and LWR to space is from higher-up-than-before molecules on average, so there are fewer GHG molecular collisions / second which leads to less MVE which leads to less LWR production. The quantity of LWR energy (power flux) provided by a mass of gas is proportional to its temperature(Kelvin)**4 (to the fourth power) so, as explained in detail above, the increasing of tropospheric GHGs ==must== cause less LWR than before to be passing upwards through the top of the troposphere.
That’s the upper end of how the so-called “enhanced greenhouse effect” works.
————–
The tropospheric temperature lapse rate is required to cause the so-called “enhanced greenhouse effect”.
The average altitude for LWR to ocean and land got lower (1,650 metres —> 1,550 metres in my example) which means LWR to the surface of the ocean and land is from warmer (faster) molecules on average because tropospheric temperature decreases with altitude and LWR to ocean/land is from lower-down-than-before molecules on average, so there are more GHG molecular collisions / second which leads to more MVE which leads to more LWR production. The quantity of LWR energy (power flux) provided by a mass of gas is proportional to its temperature(Kelvin)**4 (to the fourth power) so, as explained in detail above, the increasing of tropospheric GHGs ==must== cause more LWR than before to be passing downwards to the surface of the ocean and land. This latter is called “downwelling LWR radiation at the surface” and I’ve explained why it must increase and this must, of course, warm the land and ocean surface.
That’s the lower end of how the so-called “enhanced greenhouse effect” works.
———
Note 1: I haven’t yet found the collision MVE production & destruction spectra so I don’t know what %age make MVE and what %age destroy MVE. I looked a few hours 4 years ago but couldn’t find it (not for free anyway). It makes no difference to the description of the mechanism above but it would be needed to confirm the quantity of effect for doubling CO2.
Note 2: Removed because I’ve gotten confirmation.
Note 3: 80% of Earth’s atmosphere is in the troposphere (the top of which is 16 km in the tropics and 9 km in the polar regions, averaging ~12,000 metres). The “greenhouse effect” warming can only happen in Earth’s troposphere, there’s no effect in Earth’s tropopause and the effect is “backwards” in Earth’s stratosphere with =increased= stratospheric GHG gases causing =cooling= of the stratosphere because the stratospheric temperature lapse rate has temperature increasing with altitude (that’s how it’s known with total certainty that it’s increased “greenhouse gases (GHGs)” doing the global warming for the last several decades). Since there’s no temperature lapse rate in the tropopause then any change in the quantity/type of GHGs in the tropopause cannot have any warming or cooling effect on the tropopause or the entire atmosphere, ocean or land. No effect at all. If you follow my description of the effect above for the troposphere but apply it to the tropopause then you’ll clearly see that any change in the quantity/type of GHGs in the tropopause cannot have any warming or cooling effect That’s the reality. The increasing GHGs in the stratosphere are a slight -ve feedback to global warming because downwelling LWR radiation from the stratosphere decreases with increased GHGs, but it’s a very slight -ve feedback because only 6.3% of the well-mixed GHGs (and all molecules) are above the tropopause and they are initially colder than the average of the troposphere so they make even less LWR than the 6.3% factor. By the time the stratosphere warms more than the average of the troposphere there’s only 0.4% of Earth’s atmosphere’s molecules above, negligible.
Note 4: FTIR power flux vs wave-length spectra recorded by the IRIS Infra-Red Interferometer Spectrometer instruments on the Nimbus-1 (1964 – 1964), Nimbus-2 (1966 – 1969), Nimbus-3 (1969 – 1972) satellites show which wave-lengths of LWR heading to space past the satellite came from the surface of the ocean and land and which wave-lengths came, on average, from the GHG molecules and surfaces of solid particles and water droplets in the atmosphere. Examples of these measured FTIR power flux vs wave-length spectra (for western tropical Pacific Ocean, Sahara Desert, Antarctica & southern Iraq) can be seen at: http://climatemodels.uchicago.edu/modtran/modtran.doc.html (IRIS-C spectrum on the Nimbus 3 satellite over the Sahara Desert to demonstrate the U.S. Armed Forces MODTRAN model’s general accuracy) https://publishing.cdlib.org/ucpressebooks/view?docId=ft8r29p2m6;chunk.id=d0e1726;doc.view=print (Sahara Desert as observed by IRIS-D instrument on the Nimbus-4 satellite) https://www.youtube.com/watch?v=Oog7-KOtpEA&t=1713s at 18:07 (4 FTIR samples for western tropical Pacific Ocean, Sahara Desert, Antarctica & southern Iraq)
From these spectra atmospheric physicists have calculated the 91.5% of the LWR that Earth sends to space that is emitted by the atmosphere rather than by the surface of the ocean and land. Also, the MODTRAN tool on the internet can be used to play with a theoretical calculation of the FTIR power flux vs wave-length spectra by adjusting GHGs.
Note 5: 2020-01-25 edited example altitudes. The Kevin Trenberth & other Earth’s energy budgets show 17% (40 w/m**2) in the atmospheric window but “Outgoing Longwave Radiation due to Directly Transmitted Surface Emission” of S.M.S. COSTA & K. P. SHINE 2012 states that as ad hoc and assesses instead 8.5% (20 w/m**2 +/- 4 w/m**2). I don’t attempt quantifying anything in the effect explanation but I made my examples for illustration as close to reality as is reasonable to do (Stefan-Boltzmann equation & average tropospheric temperature lapse rate).
Barry Finchsays
@103 Kevin McKinney The only thing I can think of is that perhaps the rate of calcium carbonate CaCO3 formation varies during those periods and that’s where the O2 goes to at greater or lesser rates.
nigeljsays
Killian @112
“Deflect? From non sequitur stupidity? None of what you said in that worst-ever of your posts had a shred of accuracy. Shooting at a target a mile away in 150 mph winds would have been more accurate.”
Every word I said @83 was accurate. I said neither I or the article made reference to getting emissions down below 350 ppm. This is a simple fact. I said the desirability of getting emissions under 350mm is obvious,(to us anyway). How is that not accurate? I said the article suggested its too late to stop the artic melting even with some cooling (for right or wrong). Are you disputing they said this? I said they didn’t define how much cooling. Are you disputing this? I said calling me crazy is gaslighting. It certainly is. Do I really need to post a definition of gaslighting? I said you are on record complaining about people gaslighting you. Are you going to deny that as well?
Your accusations are literally 100% disconnected from what I said.
Yes if we get a degree of cooling this would stop melting, but according to the article cooling might not be enough to slow down the pace of the flow of the glaciers because the whole thing has become destabilised, or it could take decades to reach a new stable state. But 1) I hope this is wrong and 2) yes obviously you are right we should try really hard to do what we can to reduce emissions. The authors probably meant a small fraction of a degree of cooling, but the road to hell is paved with making assumptions. instead of wasting your time clowning around defending the indefensible again, email them.
Karsten V. Johansensays
Re: # 59 nigelj:
You wrote: “https://www.livescience.com/greenland-melt-point-of-no-return.html
“Glacier retreat has knocked the dynamics of the whole ice sheet (Greenland) into a constant state of loss,” study co-author Ian Howat, an Earth scientist at The Ohio State University, said in a statement. “Even if the climate were to stay the same or even get a little colder, the ice sheet would still be losing mass.””
But: “point of no return”? Meaning: there is no way to save the Greenland ice sheet? Really? The scientific research behind the widespread dramatic news you refer to is this:
“(…) assuming that icedynamical losses and ice sheet topography stay similar to the recent past, linear extrapolation gives a corresponding GrIS global sea-level rise (SLR) contribution of 10.0–12.6 cm by 2100, compared with the 8–27 cm (mean 15 cm)
“likely” model projection range reported by IPCC in 2019 (SPM.B1.2) (…)” (abstract)
This research seems to be somewhat at odds with the dramatic newsheadings about it. Constant loss is bad enough surely, but is the ice sheet doomed? Not according to this research, it does not consider that subject. And other research on the subject of Greenland ice sheet response to warming periods back in time: Leading studies on the fate of the Greenland ice sheet during the last interglacial – the Eem period or marine isotope stage 5e – shows that by far most of the Greenland ice sheet survived the warmth then, which was up to eight degrees C higher than late Holocene climate in central Greenland.
Eem-aged glacier ice is found in deep boreholes at the bottom layers of the ice sheet from the far north to the far south and from the far east to the far west. The (warmest period of) the Eemian was globally a couple of degrees C warmer than the climatic optimum 9000-6000 years BP in our current interglacial, the Holocene (which of course also the Greenland ice sheet survived). During the Eemian warmth the main global sea level was between five and six meters above the current level. But was Greenland the cause of that? Total melting of the Greenland ice sheet is calculated to make global sea level rise around six meters, but the even the very strong Eemian melt for a couple of thousand years was indeed not even beginning to melt it all, even if there was a lot of melting going on:
“Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North Greenland Eemian Ice Drilling (‘NEEM’) ice core and show only a modest ice-sheet response to the strong warming in the early Eemian. We reconstructed the Eemian record from folded ice using globally homogeneous parameters known from dated Greenland and Antarctic ice-core records. On the basis of water stable isotopes, NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 ± 4 degrees Celsius above the mean of the past millennium, followed by a gradual cooling that was probably driven by the decreasing summer insolation. Between 128,000 and 122,000 years ago, the thickness of the northwest Greenland ice sheet decreased by 400 ± 250 metres, reaching surface elevations 122,000 years ago of 130 ± 300 metres lower than the present. Extensive surface melt occurred at the NEEM site during the Eemian, a phenomenon witnessed when melt layers formed again at NEEM during the exceptional heat of July 2012. With additional warming, surface melt might become more common in the future.”
The five to six meters higher sea-levels than now could, according to the abovementioned facts, only for a small part be due to melting of the Greenland ice sheet. So what may have caused it? The main suspect is – and that is indeed very relevant to us today! – the West Antarctic ice sheet (WAIS), which has been shown to fluctuate hugely in the past, especially much further back in time (even as far back as 33 million years BP, in the initial stages of the creation of the Antarctic ice, which came about both due to both slowly sinking CO2-levels since 50 million years BP (reason: chemical weathering of new orogens, mainly the Himalayas) and due to the disappearance of the connection between the Antarctic peninsula and the southern tip of Latin America, Tierra del Fuego, which gave the sea currents and wind systems around the Antarctica free way, isolating it climatically more and more from its surroundings).
Those abovementioned late warming periods – the Eemian and the Holocene climatic optimum – were warmer not because of higher levels of CO2 or any other greenhouse gases than now (on the contrary: those levels were around the preindustrial levels of ca. 280 ppmv, shown by ice core data from Antarctica), but because of the socalled Milankovitch-cycles: the solar summer solstice insolation to around 65 degrees north was up to 30 pct. higher than present values (mainly because of greater tilt of the earth’ rotation axis and the precession of the equinoxes). The interesting point concerning this is that it shows that the level of summer insolation to the far northern latitudes for some reason is far more important for the global mean temperature than the level of summer insolation to the same southern latitudes (which is 30 pct. lower when it is 30 pct. higher to the same northern latitudes, because it is northern summer when it is southern winther and vice versa: changing the rotation axis tilt and the precession of the equinoxes doesn’t change the total amount of energy the earth recieves from the sun, it only changes how this amount of energy is spread over different parts of the earth’s surface at different times of the year).
So, how come most of the Eemian melting came about in West Antarctica, when it was the far north that got more insolation in that period? (And as other possible explanation than Greenland we have only the WAIS). Here we must consider this possible chain of events: 1) first the northern warmth melts enough of the Greenland ice and other northern glaciers to make global sea levels rise let’s say half a meter, 2) at the same time the northern warming spreads in the global atmosphere, rising among other effects the amount of warmer intermediate depth seawater reaching underneath the outer reaches of the huge West Antarctic ice shelves, and then 3) those two processes together starts to melt these shelves from beneath (just as registered today on several iceshelves in West Antarctica, fx the Pine Island Glacier) enough to let the higher sea level force them to begin floating, which again makes them surge: i.e. collapse, just as we have seen happen very fast with the two northernmost smaller iceshelves Larsen A 1995 and Larsen B 2002. When glacier ice begins floating in fiords etc. it very fast breaks up, and then the pressure from the accumulated ice masses on the inland, higher reaches of these mainly cold-based ice-sheets makes them surge forward, as meltwater reaching the bottom through moulins, just as seen in the collapse of Larsen B and similar events: https://nsidc.org/news/newsroom/larsen_B/index.html and https://nsidc.org/cryosphere/sotc/iceshelves.html .
So what we should be worrying about concerning melting ice sheets is the WAIS, because it seems to be much more vulnerable to warming than the Greenland ice sheet. And aldready in 1978 glaciologist John H. Mercer published research about exactly this:
Russell: One of Murphy’s lesser known laws unfortunately applies to economies as well as ecosystems: You can’t go over the same waterfall twice.
AB: And I always say that most everyone messes up the first time they do most anything.
Which is probably why we’re getting so good at building really high waterfalls.
Western Hikersays
Barry Finch 117
[This is how the so-called “greenhouse effect” in Earth’s troposphere causes warming. The so-called “greenhouse effect” effect is nothing at all like the effect that warms a greenhouse.]
The greenhouse effect is very straightforward. The absorbing molecule emits as much downwelling IR as upwelling. This is perfectly described by a greenhouse in a vacuum. Obviously the troposphere is not a vacuum and things get very messy. Confounding variables.
Still, the basic concept holds true.
zebrasays
Ravenpaw #111,
“The Earth system would quickly lose all of the energy it has accumulated.”
It would lose all of the energy, and Greenhouse Gas molecules would slow that process by trapping heat. You should try to read more carefully; here’s what I said at #94:
“Heat” is the energy that is transferred from a volume at a higher temperature to a volume at a lower temperature.
So, it is reasonable to think of the photons of IR as ‘the heat’. (The random kinetic energy of molecules in either volume is not heat, nor is any other form of energy.)
and
This is why I keep pointing out that you can’t do/discuss science if you don’t all agree to use the correct definitions, or at least agree on some terminology that is clearly explained.
So, it makes no sense for you to argue about the terminology that professionals use by trying to apply colloquial usages. It’s like when Creationists say “The Theory of Evolution is only a theory!”… two different meanings for the word theory.
Western Hikersays
Regarding the Greenland ice sheet…
At first glance, I couldn’t figure out how a higher temperature could produce a complete collapse, rather than the ice sheet just getting smaller (and stabilizing). In North America, for example, glaciers advanced to lower elevations during cold periods, then retreated to higher elevations during the warmer interglacials:
“Glaciologists have discovered evidence of glaciation in Alaska reaching back 5 million years, and suspect the area has been glaciated for nearly 15 million years. Few other places on the planet have experienced such a prolonged period of glaciation. In cooler periods, glaciers covered all of the coastal plateaux. During warmer periods, they retreated to the mountains. About 20,000 years ago, the Earth’s climate cooled and the last of the great Pleistocene ice age glaciers advanced down from the Chugach Mountains. Glaciers formed in the stream beds of the coastal plateau and carved deep valleys.”
Why would this not also be true for Greenland and Antarctica? Turns out the bedrock beneath those huge ice sheets is near, or in some places below sea level. IOW, for the most part, the ice sheets do not have the option of retreating to higher ground!
Now, you could argue that there is a ring of mountains surrounding the Greenland ice sheet. True, but based on the photos I’ve seen, my thinking is that most of those mountains are too steep and pointy to support a large glacier. The snow that falls ends up sliding down to the much lower base, joining the main flow.
Maps of the topography beneath the Antarctic/Greenland ice sheets:
@120 Karsten V. Johansen I heard climate scientists a few years back saying Eemian Optimum was 0.5 to 1.0 degrees above present but more recently I keep hearing climate scientists say Eemian Optimum was 0.5 degrees above present “or perhaps about the same as now”. If I’m understanding the 12k year multiple-proxy (many proxies) paper correctly it’s now 0.8 degrees above the Holocene Optimum so with the 0.5 degrees or less option that puts Eemian Optimum at 1.3 degrees above Holocene Optimum or perhaps a small fraction of a degree less, rather than a couple of degrees C.
Barry Finchsays
@120 Karsten V. Johansen It was estimated about half (3 m of SLR) from Greenland ice sheet (GrIS) mass loss for Eemian Optimum (Cuffey & Marshall, 2000) per 17:24 to 19:03 at: https://www.youtube.com/watch?v=KTTlAAiwgwM I don’t know whether there’s improved paleo analysis since 2010 AD. The top-of-atmosphere (TOA) forcings/feedbacks of the most recent de-glaciation per the same video of a talk at 8:00 were:
0.5 +- 1 w/m**2 8% Milankovitch cycles orbital eccentricity, axial tilt & precession of the equinoxes changes
forcing (what pulled the trigger that started it)
3.5 +- 1 w/m**2 53% ice sheets & vegetation changes albedo-change feedback
1.8 +- 0.3 w/m**2 27% CO2 change feedback
0.4 +- 0.1 w/m**2 6% CH4 change feedback
0.4 +- 0.1 w/m**2 6% N2O change feedback
:::::::::::::::::::::::::::::::::::::
6.6 +- 1.5 w/m**2 total
James McDonald @101,
I might at some stage find the time to read through other answers to your question so this reply may be already said.
If the O2 & N2 is taken from the Earth’s atmosphere the pressure would be mostly gone leavng 0.2psi mainly of Argon with CO2 constituting 40,000ppm(v) and adding 0.008psi to a very thin atmosphere. I am reminded of the atmosphere of Mars which has about half this total Ar-CO2-etc pressure (0.09psi) but almost all of it CO2. So Mars has ten-times the CO2 that Earth has but the pressure is low enough to negate any pressure broadening leaving the greenhouse effect with far too many holes in the 15 micron band. Additionally Mars has very little H2O working elsewhere across the spectrum. (An ineffective greenhouse on an chilly Earth would greatly reduce H2O concentrations but probably not down to the low levels found on Mars.)
Ravenpawsays
Zebra, 123
If suddenly no solar input –
you believe that photons of IR, ‘the heat’ would remain trapped….. but not the energy?
I’m beginning to agree with Nigel.
Western Hikersays
MA Rodger 128,
“If the O2 & N2 is taken from the Earth’s atmosphere the pressure would be mostly gone……”
Right, and as mentioned in an earlier thread, with such low pressure the atmosphere would (at least initially) not be able to support liquid H20. The GHE would end up off the chart.
Mr. Know It Allsays
25 – Al Bundy
“Mrkia: fire fighting are not practical in wilderness due to the no-mechanized-tools rules
AB: what a doofus. As if laws and rules can’t be changed. Really? You are claiming that mechanical systems are impossible because laws can NEVER change?”
Good luck getting The Wilderness Act of 1964 changed. You’ll be skewered by The Sierra Club, The Wilderness Society, and every other environmental organization who cares about it.
32 – Al Bundy
“In short, this game-changing new scientific understanding suggests that humanity can turn down the heat almost immediately by slashing heat-trapping emissions.”
Emissions should be low this year – think we will see a slowing of AGW soon?
50 – nigelj
““Climate change is largely responsible for a doubling in the number of natural disasters since 2000, the United Nations said on Monday, warning that the planet was becoming uninhabitable for millions of people…..””
In this short video you can see the UN in action. Best to just ignore the UN:
56 – mike
“The Arctic is in a death spiral. How much longer will it exist?”
I’m going to go out on a limb here and guess that the area north of the Arctic Circle will still be the Arctic for a very long time. ;) Who wants to go camping in the Arctic while it still exists? Weather looks balmy:
114 – Al Bundy
“AB: We choose who to interact with. For example, my guess is that if I were to count keystrokes I’d find that the vast majority of yours have been invested in those four people.”
His computer is contributing to AGW because of his obsession with them. :)
117 – Barry Finch
Can you expand on that a little bit?
:)
Killiansays
119 nigelj:
You’re like a mangey dog with a ratty bone, I swear to god…
Killian @112
“Deflect? From non sequitur stupidity? None of what you said in that worst-ever of your posts had a shred of accuracy. Shooting at a target a mile away in 150 mph winds would have been more accurate.”
Every word I said @83 was accurate. I said neither I or the article made reference to getting emissions down below 350 ppm.
Yes, but, dumbass, I NEVER SAID YOU HAD. <— Just amazing I had to point that out.
Criminy… learn to shut your trap when you've been knocked on your ass already.
Lynn Vincentnathansays
Here’s a recent article of interest. While it says there was more CO2 in the atmosphere at the end Permian extinction then than possible now (and someone here at RC told me years ago that life then was more fragile than now), we’re doing it 14 times faster & there are many other environmental threats. Not to mention even minor disruptions can throw complex human societies into a tail-spin.
ABSTRACT:
The Permian/Triassic boundary approximately 251.9 million years ago marked the most severe environmental crisis identified in the geological record, which dictated the onwards course for the evolution of life. Magmatism from Siberian Traps is thought to have played an important role, but the causational trigger and its feedbacks are yet to be fully understood. Here we present a new boron-isotope-derived seawater pH record from fossil brachiopod shells deposited on the Tethys shelf that demonstrates a substantial decline in seawater pH coeval with the onset of the mass extinction in the latest Permian. Combined with carbon isotope data, our results are integrated in a geochemical model that resolves the carbon cycle dynamics as well as the ocean redox conditions and nitrogen isotope turnover. We find that the initial ocean acidification was intimately linked to a large pulse of carbon degassing from the Siberian sill intrusions. We unravel the consequences of the greenhouse effect on the marine environment, and show how elevated sea surface temperatures, export production and nutrient input driven by increased rates of chemical weathering gave rise to widespread deoxygenation and sporadic sulfide poisoning of the oceans in the earliest Triassic. Our findings enable us to assemble a consistent biogeochemical reconstruction of the mechanisms that resulted in the largest Phanerozoic mass extinction.
Barry Finchsays
@124 Western Hiker Modelled estimates of Greenland ice sheet equilibrium sizes for a range of Greenland surface temperatures relative to present Greenland surface temperature, based on Eemian Optimum retreat, is at 38:00 at https://www.youtube.com/watch?v=FqJLwJwndLI What’s missing is any workable estimate of the time ranges to adjust to equilibrium size when the sustained surface temperature changes much faster than the equilibriating time, as has happened the last ~50 years (and in the near future).
Barry Finchsays
@122 Western Hiker I disagree that your description of the so-called “greenhouse effect” which is “The absorbing molecule emits as much downwelling IR as upwelling” will be sufficient to convince an impartial person that it exists. For example, that person might respond “OK then so suppose the atmosphere was sending 240.1 w/m**2 to space and 240.1 w/m**2 to the suface and my non-EV Hummer burned all that petrol. Well now there’s more CO2 so it must be sending more so it’s now sending 240.2 w/m**2 to space and 240.2 w/m**2 to the suface. So CO2 cools Earth. It’s emitting as much downwelling IR as upwelling and it cools Earth”.
———-
Your competing description of the so-called “greenhouse effect” is woefully inadequate.
Barry Finchsays
@94 zebra Your “(The random kinetic energy of molecules in either volume is not heat, nor is any other form of energy.)” is incorrect because kinetic energy of molecules due to their (random) motion is precisely what “heat” is.
zebrasays
Heat:
From Wikipedia (my bolds):
In thermodynamics, heat is energy in transfer to or from a thermodynamic system, by mechanisms other than thermodynamic work or transfer of matter.[1][2][3][4][5][6][7] The various mechanisms of energy transfer that define heat are stated in the next section of this article.
Like thermodynamic work, heat transfer is a process involving more than one system, not a property of any one system. In thermodynamics, energy transferred as heat contributes to change in the system’s cardinal energy variable of state, for example its internal energy, or for example its enthalpy. This is to be distinguished from the ordinary language conception of heat as a property of an isolated system.
The quantity of energy transferred as heat in a process is the amount of transferred energy excluding any thermodynamic work that was done and any energy contained in matter transferred. For the precise definition of heat, it is necessary that it occur by a path that does not include transfer of matter.[8]
End quote.
Please, stop with the childish rhetorical word play… this is supposed to be a science-y venue, where science is the source of our language.
zebrasays
Ravenpaw #129,
“you believe the photons of IR would remain trapped”
I didn’t say that; I said:
“It would lose all of the energy, and Greenhouse Gas molecules would slow that process by trapping heat.”
And you should read my comment titled “Heat”, particularly the part about childish rhetorical word play.
Western Hiker @130,
Indeed you are correct.
As I was completing the end of that comment @128, the small H2O component of Mars’s atmosphere did make me think about the H2O component on Earth if all O2 & N2 were removed. I decided to not mention any boost to atmospheric H2O levels resulting from the atmospshere losing 99% of its pressure as such discussion would be too weighty a consideration for the rest of the comment.
In terms of a lower temperature with a deficient greenhouse, Lacis et al (2010) suggest H2O will drop to 10% of today’s levels (so 0.3% of the atmosphere).
Mind, I do wonder if the ‘hot’ bits of such a greenhouse-free planet will tend to lose perhaps the majority of its surface ice to the cold bits where the lower temperatures would ensure even less of it finds its way into the atmosphere.
But there is also the loss of atmospheric pressure which will boil away a great deal of the oceans and lead potentially to an H2O-rich atmosphere with a significant greenhouse effect. I wouldn’t care to speculate on the actual H2O levels or the temperature outcomes of such a situation.
Steven Emmersonsays
@Barry Finch (137), not quite. The “kinetic energy of molecules due to their (random) motion” is temperature and not heat. Heat is the energy that flows from a hotter object to a colder one.
James McDonaldsays
Many thanks to the various people who responded to my 10X, 0.1X scenarios.
As I suspected/feared it doesn’t seem to be a simple calculation with a well-known answer. Such is life.
@117 Barry — lots to read there, still digesting it all. (But yes I was aware that individual photons don’t survive the round-trip, which is why I referred to the energy contained in the originating photon, as opposed to the photon itself.) I understand your misgivings, but the cartoon version following a packet of energy still seems like a plausible way to calculate an order-of-magnitude result. There are a limited number of paths that energy can follow, with reasonably well understood transition probabilities, so it should be possible to average over representative ensembles.
@128 MA Rogers — looking at Mars is a good idea.
At any rate, food for thought, but back to my day job, entirely unrelated to climate matters…
John Pollacksays
Mr. Know It All @132 “There has never been a period when the temperature was constant. The “system” is dynamic and changes constantly.”
Yes, I agree with you on this.
But as a dynamic system, it has some implications that you seem to ignore. First, while the system IS always changing, the speed and intensity of the changes have a lot to do with what states it can reach. We, and the rest of the life on the planet, are passengers that will have to adapt and absorb the changes. In the current case, we are changing the carbon dioxide forcing with a speed and intensity not seen in millions of years. The exact state we will end up in is uncertain, but it is certain that we will be getting a hell of a shock, and things will be a LOT different when it’s over – in a few thousand years. Any “hiatus” in the action now is bound to be puny and temporary.
As an analogy, I’m going out for a drive. My car is always moving, no stasis. It’s a dynamic system. Now, I drive over bump. If it’s a little bump, and I’m going 5 mph, the shock absorbers will take most of the impact, the seat belt will hold me down, the seat will cushion me, and I’ll get a gentle jostle and keep going. Next, I will try jamming on the gas pedal for a while, just for fun, and see what happens if I hit a curb at 100 mph. The shock absorbers will kick in, just like before, but there’s too much shock. Part of the shock will be absorbed by the car frame, as metal bends and breaks. The seat belt will hold me in, but my body has a huge amount of momentum, anyhow. There will be a hiatus lasting milliseconds as the air bag inflates and absorbs some of my forward motion. Then, my last shock absorber will kick in as my internal organs press against my skeleton, and I have a concussion. After the dust settles, things will be quiet, but my car will be wrecked. I might be in equilibrium too, if I’m dead. If I am alive, I will have a lot of internal damage to heal, and it will take a long time.
So, when it comes to dynamic systems, there’s change, and then there’s CHANGE. We’re having fun, but we are going to find out what CHANGE feels like. Right about now, the shock absorbers are giving out.
I call BS on the idea that you can’t fight fires with mechanized/motorized gear in protected wilderness areas. The actual text of the applicable policy:
Administrative use of motorized equipment or mechanical transport will be authorized only
· if determined by the superintendent to be the minimum requirement needed by management to achieve the purposes of the area, including the preservation of wilderness character and values, in accordance with the Wilderness Act; or
· in emergency situations (for example, search and rescue, homeland security, law enforcement) involving the health or safety of persons actually within the area.
Such management activities will also be conducted in accordance with all applicable regulations, policies, and guidelines and, where practicable, will be scheduled to avoid creating adverse resource impacts or conflicts with visitor use.
While actions taken to address search and rescue, homeland security and law enforcement issues are subject to the minimum requirement concept, preplanning or programmatic planning should be undertaken whenever possible to facilitate a fast and effective response and reduce paperwork.
Now, whether you *should* or not is a whole other question, given that the total fire suppression policy in place for most of the 20th century helped set the table for some of the problems we have now. Fire is natural, and some ecosystems–eg., our longleaf pine forest here in the Southeast, of which mere crumbs still survive–are dependent upon it for their very survival.
So, zebra spends three paragraphs on a Wikipedia discusion of heat (in thermodynamics), presumably because “this is supposed to be a science-y venue, where science is the source of our language,” and hence it is important to get the language right.
But when other people try to get the language right they are told to:
“Please, stop with the childish rhetorical word play…”
And that, folks, is in a nutshell why I don’t directly engage zebra anymore.
Ray Ladburysays
Dudes, Talking of photons as if they have continuous existence and that if a photon passes from point A to point be, that the photon at point B is necessarily the same photon that passed through point A misses the point. Photons are quantum-mechanical entities. If you discuss them in classical terms, you will mislead yourself.
And yes, heat IS random molecular motion.
Western Hikersays
Barry Finch, #136
“Your competing description of the so-called “greenhouse effect” is woefully inadequate.”
Not competing, just simplified.
On an airless planet, the only downwelling would be from the sun. But if you surrounded the planet with a pane of glass that would no longer be the case, and the surface would get warmer as a result. That, to me, is the basic idea.
What you described in #117 includes the GHE, but is complicated by conduction, convection, an atmosphere that gets thinner and colder with altitude, buoyancy…. etc. Extra stuff.
nigeljsays
Zebra @138 responds to a statement :” @94 zebra Your “(The random kinetic energy of molecules in either volume is not heat, nor is any other form of energy.)” is incorrect because kinetic energy of molecules due to their (random) motion is precisely what “heat” is.” (which is also my understanding as a non expert).
Zebra states a standard definition of heat from wikipedia as “In thermodynamics, heat is energy in transfer to or from a thermodynamic system, by mechanisms other than thermodynamic work or transfer of matter…” then says “Please, stop with the childish rhetorical word play… this is supposed to be a science-y venue, where science is the source of our language”
But is it not Zebra who indulges in word play? Generally heat is ALSO defined as the following from heat in simple wikipedia: “Heat is the sum of the kinetic energy of atoms or molecules. In thermodynamics, heat means energy which is moved between two things, when one of them is has a higher temperature than the other thing.”
KIA 132: There has never been a period when the temperature was constant.
BPL: For the past several thousand years the global mean annual temperature was 287-288 K. It doesn’t have to be perfectly stable, but it does have to be stable enough to allow for predictable agriculture.
I note–following up on some of MAR’s comments–that the Arctic SIE continues to lag far behind seasonal norms, being currently more than a million km2 behind last year (which was itself record-low at the time).
But at least the rate of increase now appears more congruent with the past.
Thanks Gavin, for the quick response.
From what I can gather, the cited paper argues that O2 is effectively a weak anti-greenhouse gas since it scatters incoming solar radiation back to space. That’s not the direction I expected an answer to come from, but interesting.
Since that seems to be viewed as the most significant effect of increasing O2, would it then be safe to assume that increasing density of the non-GH gases has little or no effect on the rate of outward energy transfer?
For example, if there were no N2 or O2 in the atmosphere, but the same amount of CO2, would the rate of outward energy transfer be essentially unchanged?
To perhaps refine the question, if I tracked the energy of a single outgoing longwave photon, would it have the same probability under both high and low O2 levels of escaping to space as opposed to returning to earth, in spite of a difference in the number of molecule-to-molecule collisional transfers in the atmosphere en route to a final disposition?
Not trying to be dense, just trying to get a crisper understanding of the relevant mechanisms…
Ravenpaw #91,
The problem with analogies…and I use them sometimes, reluctantly… is that they often are not necessary, and rarely precisely correct.
So, we would have to go into further detail.
The conveyor belt is not variable in speed. It operates at the speed of light, in principle.
What is happening is that workers are picking up apples at random along the way, sometimes replacing them after a random time, and sometimes placing them on a belt going the opposite direction.
But my real objection is to the idea that we can’t just describe the phenomenon as it is. If you are trying to educate a (sincere, unlike Mack) student, why not describe the physics, and work with them to see where any misunderstanding might arise?
How is my description of it at #94 harder to understand than the approximation of my analogy above? If people want to learn, they will; there’s no easy magic trick to accomplish that.
Inline @ #98:
Fascinating. A couple of questions.
1) I presume the following quote refers to the “dynamic effects” Gavin mentions?
That’s from the paper abstract, here:
https://science.sciencemag.org/content/348/6240/1238
2) So, where does the oxygen go during low-O2 periods? Not, presumably, the oceans, as warmer ocean waters mean decreased solubility. And lower dissolved oxygen means less productive waters, so maybe not marine biological reservoirs. (“Maybe”, because there’s still phytoplankton, I guess.) Terrestrial reservoirs, then? But what? Anyone have anything on that?
Donald Condliffe: I think the problem with idealized plans like this is that the term ivory tower applies in spades.
AB: Yes, I agree. That’s why I always keep my carbon fiber foot firmly on the ground, and it’s been on lots of different ground, enough to see the wisdom, and the missing piece in what you speak of:
None of them, ivory tower nor ancient wisdom, was designed to carry an ecosystem from what is fast becoming unsustainable to whatever will be sustainable whenever sustainability is possible (I am not talking resource extraction here, just ecosystems themselves). And frankly, to me this is the most important thing. Evolution needs to be turbocharged so as to keep up with the rate of change. We’ve got to do reefs (good luck), forests, and pretty much everything in between.
I wouldn’t apply a framework. As you noted, that sort of thing just won’t fit. The landscape and its use, by various species, is a locally-known variable. “That valley is….” and whatnot.
With the slow start to the Arctic freeze season, JAXA’s Arctic Sea Ice Extent remains strongly below all previous years for the time of year (with the anomaly dropping quicker that Maniac Mack managed in his descent into the Bore Hole). The Arctic SIE anomaly did drop off the bottom my Arctic SIE anomaly graph. Rather than re-scale it, I’m plotting the points in the bottom margin (usually 2 clicks to ‘download your attachment.).
Comparing 2020 with previous years, it is now 430,000 sq km below 2019 (the previous lowest-for-time-of-year) and 1,860.000 sq km below 2017 (the last year not to have a slow autumn freeze-up). Another measure of it is 2020 has reached the SIE level 2019 reached 3½ days ago and 2017 reached 18 days ago. The Daily map (different base period) shows the ice is missing from the Russian side.
It could all just freeze up in a hurry as winter takes control, as happened in 2019 with Extent & Volume actually reaching higher values by winter’s-end than in the years immediately previous. But presumably there will come a point where the factors slowing these recent autumn freezes will have longer-lived impacts.
I have a problem to reconciliate two pieces of work about global CO2 induced greening.
Zhu, Z., Piao, S., Myneni, R. et al. Greening of the Earth and its drivers. Nature Clim Change 6, 791–795 (2016). https://doi.org/10.1038/nclimate3004
and
Yuan et al., Increased atmospheric vapor pressure deficit reduces global vegetation growth, Science Advances 14 Aug 2019:
Vol. 5, no. 8, eaax1396
DOI: 10.1126/sciadv.aax1396
The former finds an unbroken greening trend, while the latter states, that the global greening trend stopped around 2000 because of water stress kicking in.
Any constructive comment welcome.
Kevin M: I think the first couple of years after the typical clear-cut are not so easy to defend. The total biomass is of course much lower, but typically there is dead ‘slash’ lying everywhere. And it’s both highly flammable–being dead and usually dry!–and very awkward to traverse.
Timber companies could, of course, be required to do post-harvest controlled burns to mitigate this, but that wouldn’t be The American Way, would it?
The long and thin nature of the cuts lend themselves to trail-hauling to a rail line. The digester could sit on the rails wherever it’s needed.
The American Way, like Edith Keeler, must die.
_____
Mike: I think you have jumped over the big problem here in step 2. How do you think we could attain a netzero civilization?
AB: Not our job. Our job is to keep the wheels from falling off the biosphere so that those who are at the bottom of “Niagara Falls” can attain such a thing using what we’re stuffing into barrels.
My suggestion is more barrel stuffing and less waterfall extending.
Zebra, 102
Situation A
– with the drain closed, turn on the faucet to your bathtub.
– when the water is 8” deep, open and adjust the drain so that outflow equals inflow.
– the water level is now steady at 8”
Situation B
– again, with the drain closed, turn on the faucet to your bathtub.
– this time, when the water is 8” deep, turn off the faucet.
The water level is the same in both, but in A, the water in the bathtub is constantly draining and constantly replaced. In B, the water is simply trapped.
It would be a mistake to describe the two situations in the same way.
Ravenpaw #108,
?????…. Sounds like you didn’t read my #102 at all.
And it also sounds like you don’t really understand the physical mechanism involved in the GHG effect.
If you have a question about what I said in #102, you are welcome to ask, but you should also read my #94 first; perhaps that will clear things up for you.
Once again Killian @100 deflects and resorts to verbal abuse. Once again Zebra @109 gets caught out by Ravenpaw this time, and deflects, and resorts to supercilious preaching. Its always these same two people I find intensely irritating, along with KIA and Victor.
Zebra, 109
I read both of your comments. even if it doesn’t sound like it. I’m curious, though, do you still think “heat trapping” is just fine?
If so, consider what would happen if there was no longer a solar input. The Earth system would quickly lose all of the energy it has accumulated. Like turning off the faucet in situation A.
110 nigelj: Once again Killian @100 deflects and resorts to verbal abuse. Once again Zebra @109 gets caught out by Ravenpaw this time, and deflects, and resorts to supercilious preaching. Its always these same two people I find intensely irritating, along with KIA and Victor.
Deflect? From non sequitur stupidity? None of what you said in that worst-ever of your posts had a shred of accuracy. Shooting at a target a mile away in 150 mph winds would have been more accurate.
I.e., there was nothing to respond to.
This is what happened. You posted an article that said “blue, green, and yellow.” I responded, “That’s all well and good, but blue, green, and yellow are stupid choices when we need grey.” You said, “NOBODY SAID ANYTHIG ABOUT GREY!!!!!!”
James McDonald #101,
I understand your question but I don’t see how you can realistically pose it for the actual atmosphere.
If we do an experiment with a fixed IR source in a horizontal tube, it should be possible to calculate the difference in absorption as you describe.
If you remove all the other gases, the probability of energy transfer by collision is greatly reduced. So re-radiation has some time interval for each CO2 molecule…I recall it is greater than that for the typical collision transfer(?). During that time, the molecule will not absorb any incident IR.
So, you are asking if this results in a different rate of transmission, and I am sure you could find someone competent to do the math. Or you could just do the experiment.
The problem is that, as the referenced article suggests, changing the density of the atmosphere has other effects; it’s not possible to hold the other variables constant as we would in the lab. So we get back, again as the article says, to actual climate models as the way to answer your question.
nigelj: Its always these same two people I find intensely irritating, along with KIA and Victor.
AB: We choose who to interact with. For example, my guess is that if I were to count keystrokes I’d find that the vast majority of yours have been invested in those four people.
Now you know a bit more about why humans suck at sociopolitical stuff.
@Adam Lea 15 Oct 2020 at 4:37 AM The simple answer is Muscle tension is generated by the release of Calcium ions by nerve signals which cause molecular motors to consume chemical energy from converting ATP to ADP. If the total tension of many mmolecular motors in many muscle fibers is larger than the load, the motors slide, the muscle contracts, and the weight in your example is lifted. Calcium ions are constantly being pumped away, allowing the absorption of another ATP which releases the tension on the motors and the muscle to relax, and lengthen under load. When you are holding a load at a constant position against gravity, your nerve signaling is releasing Ca ions at a rate that balances the pump rate, and individual motors are relaxing and tensioning so that the aggregate tension of all motors activate just balance the weight. There is no work being done on the weight macroscopically, but at the microscopic level ions are being pumped around, and micromotors are moving microscopically under cycles of tension and relaxation, and that consumes energy from the micromotor work and chemical losses. Fro a more comprehensive answer, see https://en.wikipedia.org/wiki/Muscle_contraction
107
One of Murphy’s lesser known laws unfortunately applies to economies as well as ecosystems:
You can’t go over the same waterfall twice.
@101 James McDonald “…tracked the energy of a single outgoing longwave photon…..escaping to space as opposed to returning to earth”. There is no such outgoing longwave photon returning to earth. Photons are continuously both created from other energy by GHG molecules & destroyed by GHG molecules by converting them to other energy. A certain portion, statistically highly constant, reaches surface and a certain portion, statistically highly constant, reaches space. You imply in the next comment phrases that you perhaps know that but your cartoon version that I just quoted is best not used in my opinion because it fogs clarity too much. I don’t know the answer to 10x, 0.1x non GHGs but I see 2 basic effects and they oppose each other:
– The maximum (“saturated”) GHG effect for a gas (its IR absorption/emission band(s)) is determined by global average temperature difference from surface to top of troposphere and the GHG fraction determines how far up the troposphere the radiation reaching space or surface average altitude is. The 10x, 0.1x non GHGs must affect this with 10x being more “greenhouse effect” but I’ll not be attempting to quantify it.
– The 10x, 0.1x non GHGs with GHGs quantity unchanged will alter the ppmv and this will be with 10x being less “greenhouse effect”.
Since the 2 effects above oppose each other I’ve no idea of the net effect because I don’t know how average global tropospheric temperature lapse rate would change with taller or shorter troposphere.
—————–
This is how the so-called “greenhouse effect” in Earth’s troposphere causes warming. The so-called “greenhouse effect” effect is nothing at all like the effect that warms a greenhouse. A vast “shimmer” of transverse electromagnetic radiation (TER) in the long-wave band (LWR) is caused by molecules of water vapour (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (NO2) and some other gases in the troposphere due to their collisions (averaging 2,700,000,000 collisions / second) with other molecules, which are almost always going to be nitrogen (N2) or oxygen (O2) because they are almost all of the gas quantity in the troposphere. The H2O, CO2, CH4, NO2 and some other gases are being called “greenhouse gases (GHGs)” because the overall effect (not just this part) ends up causing warming of Earth’s troposphere. All except H2O are called “well-mixed greenhouse gases” because their boiling and freezing points are so low that they don’t condense or freeze in the troposphere, not even near the top, so they get spread out well mixed around Earth and well mixed vertically in the troposphere. The well-mixed GHGs now punch above their weight compared with water vapour (H2O) because the upper half of the troposphere is so cold that almost all H2O forms on dust/salt particles in liquid or solid form there rather than being a GHG but the others remain as GHGs. The lowest quarter or so of the troposphere where it’s warmer and water vapour (H2O) is king is already highly “saturated” without much additional “enhanced greenhouse effect” possible (still, H2O has such a broad absorption band that it still manages to match the “well-mixed greenhouse gases” pretty much exactly 1:1 net as a 100% +ve feedback).
——————
The GHG molecules don’t emit a photon (LWR unit) of LWR when they collide and they don’t later get to emit a photon of LWR after every collision, only after a few of them (note 1). What happens is that a collision might cause a GHG molecule to vibrate in a certain way (so with a certain energy) of which the GHG molecule has the capability of any one of a selection (called its “vibrational modes”). GHG molecules with more vibrational modes are more powerful GHGs because they have a broader absorption/emission band. The GHG molecule now has “molecular vibrational energy (MVE)” if the collision did cause it to vibrate. Energy cannot be created without destroying matter and matter doesn’t get destroyed by this. What happens is that one or both of the two molecules slows down such that the total “molecular translational energy (MTE)”, aka “molecular kinetic energy”, aka “heat”, is reduced by precisely the same amount as the MVE that the GHG molecule acquired, so (m1*v1**2 + m2*v2**2)/2 after collision is less than (m1*v1**2 + m2*v2**2)/2 before collision because either v1 or v2 or both was reduced, thus obeying the Law Of Conservation Of Energy. Effectively, the temperature of the 2 colliding molecules was reduced by an energy amount equaling the MVE that the GHG molecule acquired, what happened was energy transmutation from one form to another. When this vibrating GHG molecule hits another molecule it loses its vibration (note 1) and one or both of the two molecules speeds up such that the total MTE, aka “heat”, is increased by precisely the same amount as the MVE that the GHG molecule lost. So it just moved speed/heat from one N2 or O2 (almost always) molecule to another. However, ==here we go==, very occasionally/rarely and not very often at all compared with the 2,700,000,000 collisions / second that happen to this GHG molecule the GHG molecule with MVE will spontaneously emit a photon of LWR and lose its MVE. Now it has converted one-photon’s-worth of “heat” in the troposphere to one photon of LWR. It has cooled the troposphere by one-photon’s-worth of “heat”. This “relaxation time” of the covalent bond harmonic motion (with a photon emitted) happens over 10ths of one second (a very long time indeed).
——————
LWR is also radiated from the surfaces of liquids & solids such as the surface of the ocean, the surfaces of water droplets in spray above the ocean, the surfaces of water droplets in clouds, the surfaces of any water droplets at all, the land surface, the surfaces of trees & grass, the skins of animals, the surfaces of dust, salt, volcanic ash, any ash and any surface whatsoever on the ocean or land or in the troposphere. Except for 8% of the LWR from the ocean+land surface whose photons happen to have wave-lengths in a band called “the atmospheric window” this LWR goes into the vast “shimmer” of LWR in the troposphere with a distribution of energy quantity at each wave-length in the LWR band that you’ve all seen hundreds of plots of all over the place.
——————
GHG molecules also absorb LWR provided that the photon’s energy (which is its wave-length) perfectly matches one of that GHG molecule’s MVE mode energies and the photon goes through (or tries to go through) the area of the GHG molecule that absorbs that wave-length (obvious example, CO2 isn’t at all fussy what part of its molecule a photon of wave-length 15.00 microns goes through, it’ll swallow it and vibrate). Obviously, a GHG molecule neither knows nor cares whether a photon of a certain wave-length trying to go through it was emitted by the surface of the ocean, the surfaces of water droplets in spray above the ocean, the surfaces of water droplets in clouds, the surfaces of any water droplets at all, the land surface, the surfaces of trees & grass, the skins of animals, the surfaces of dust, salt, volcanic ash, any ash and any surface whatsoever on the ocean or land or in the troposphere, or emitted by another GHG molecule (H2O, CO2, CH4, NO2 and any other GHG molecule) because all photons of the same wave-length are the same. A GHG molecule with MVE that it got by absorbing LWR can, of course, ==here we go again==, very occasionally/rarely and not very often at all compared with the 2,700,000,000 collisions / second that happen to this GHG molecule (note 2) spontaneously emit a photon of LWR and lose its MVE. In this case the GHG molecule transmuted LWR back to LWR, it transmuted a photon to an identical photon, so it did nothing at all other than change the direction in which the photon is going. This is the cartoon that scientists show the public because it’s a simple analog that Earth tried to cool itself to space and failed, but since there are 2,700,000,000 collisions / second there’s just about a bat’s chance in hell that the GHG molecule will spontaneously emit a photon of LWR and lose its MVE before it collides and loses its MVE (note 1). The coal/oil shills use the highly-incorrect nature of this ludicrously-over-simplified cartoon to “disprove” the physics theory but it isn’t the physics theory that’s incorrect, it’s the cartoon that’s incorrect. It doesn’t describe the physics theory hardly at all as I’ve explained in detail above. This is why I dislike this cartoon. When a vibrating GHG molecule hits another molecule it loses its vibration (note 1) and one or both of the two molecules speeds up. This means that “heat” increased, what happened was energy transmutation from one form to another, energy transmutation from LWR to “heat” with MVE as the intermediary step.
————-
Now the so-called “enhanced greenhouse effect” explanation that I think is clearest, obvious and difficult to challenge by mis-direction disinformation and subterfuge per the memes concocted by the coal/oil shills. 8.5% +/- 1.7% of the LWR that Earth sends to space is emitted by the ocean or land surface because the photons are in a wave-length band called “the atmospheric window” that doesn’t get absorbed by the GHGs. It’s my understanding that this will narrow slightly with increased GHGs, but this isn’t the prime “enhanced greenhouse effect” and I’m not addressing any additional warming it might cause. 91.5% of the LWR that Earth sends to space is emitted by the GHG molecules in the troposphere, tropopause and stratosphere (note 2). This 91.5% of the LWR is the part that gets reduced by increased tropospheric GHGs and causes an energy imbalance with insufficient energy going out, which causes global warming, ocean heating and ice fusion, which causes climate change, which causes a variety of nuisances that I haven’t studied.
——————
The troposphere has an upper and a lower surface. The upper surface is the top of the troposphere (the tropopause) and the lower surface is the surface of the ocean or land. LWR produced in the troposphere that reaches the lower surface will warm that surface so it stays in Earth’s ecosphere but LWR produced in the troposphere that reaches the upper surface has a good chance to make it through the increasingly-thin tropopause, stratosphere and the ultra-thin extended atmosphere to space and be energy lost to Earth’s ecosphere, thus cooling it. LWR reaching the upper/lower surfaces was produced by GHG molecules, the surfaces of water droplets and the surfaces of solid particles (sea salt, ash, dust) throughout the troposphere sending photons upwards/downwards as described in detail earlier.
– There is an average altitude in the troposphere of the LWR quantity that reaches space. If you could float at this altitude and watch/count photons with special eye balls and brain you’d see 50% of those photons that reach space are heading up from below you. If you counted it at 48% then you’d need to float upward to get more of the LWR photon production below you. If you counted it at 52% then you’d need to float downward to get more of the LWR photon production above you. This is obvious. When you float to the place where 50.0000000% of those photons that reach space are heading up from below you then you are at the average altitude in the troposphere of the LWR quantity that reaches space.
– There is an average altitude in the troposphere of the LWR quantity that reaches the surface of the ocean or land. You could float and find that the same way as the preceding.
These 2 altitudes in the troposphere are approximately for illustration only and as a global average (I’m not quantifying the so-called “enhanced greenhouse effect” in this comment, only describing its operation accurately):
—- average — —- average global —-
—- altitude — —- temperature —-
5,700 metres -23.8 degrees 50% of the “shimmer cloud” of LWR photons that will
———————————— make it to the tropopause are emitted by GHG
———————————— molecules and the surfaces of cloud droplets ———————————— and atmospheric particles below this altitude.
1,650 metres 3.7 degrees 50% of the “shimmer cloud” of LWR photons that will
——————————— make it to the surface of the ocean or land are emitted
———————————- by GHG molecules and the surfaces of cloud droplets and
———————————- atmospheric particles below this altitude.
These values are approximate. They are to demonstrate how the so-called “enhanced greenhouse effect” works, not to provide quantities. They are approximately correct though. They are based on a global average ~12,000 metres height of the troposphere but it varies geographically from 9,000 to 16,000 metres.
——————-
If tropospheric GHGs are increased then 2 changes occur per my explanations above since the start of my comment:
1) More LWR than before is produced by the GHGs, and
2) More LWR than before is absorbed by the GHGs because the LWR photons have to make it through more GHG molecules that might absorb them before they can reach their goal of going up past the top of the troposphere or going down past the bottom of the troposphere and being absorbed into the ocean or land.
Note that I have not included “(3) The LWR photons emitted by the surface of the ocean and land have to make it through more GHG molecules that might absorb them before they can reach space” because I’m dealing with the 91.5% of the LWR reaching space that’s created by GHG molecules in the troposphere obtaining, then losing, MVE with spontaneous photon emission caused. I’m not dealing with the 8.5% of the LWR in a wave-length band called “the atmospheric window” that gets directly to space after being emitted by the surface of the ocean and land. If that 8.5% is reduced by increased tropospheric GHGs (I’m not sure) then that’s an additional, unrelated, means of the so-called “enhanced greenhouse effect” (there’s no reason why there has to be only one mechanism).
—————
The result of combined effects/changes (1), (2) above is that the average altitude in the troposphere of the LWR quantity that reaches the top of the troposphere gets higher, so perhaps it raises from the 5,700 metres to 5,800 metres (as an example). Also, the LWR quantity is reduced slightly (the so-called “enhanced greenhouse effect”) for reason of the tropospheric temperature lapse rate explained below.
—————
Likewise, identically, the average altitude in the troposphere of the LWR quantity that reaches the surface of the ocean or land gets lower, so perhaps it lowers from the 1,650 metres to 1,550 metres (obviously, it depends on the change quantity. I just showed a random example) because it has to get past more GHG molecules that might absorb the photon.
—————
In either case GHG photons were trying to reach their goal of the top or bottom of the troposphere but now there are more GHGs in the way so it needs, == on average ==, to be a bit closer to make it. So that’s why the “cloud” of LWR that will reach the top is a higher cloud than before and the “cloud” of LWR that will reach the bottom (ocean or land) is a lower cloud than before
—————
The tropospheric temperature lapse rate is required to cause the so-called “enhanced greenhouse effect”.
The average altitude for LWR to space got higher (5,700 metres —> 5,800 metres in my example) which means LWR to space is from colder (slower) molecules on average because tropospheric temperature decreases with altitude and LWR to space is from higher-up-than-before molecules on average, so there are fewer GHG molecular collisions / second which leads to less MVE which leads to less LWR production. The quantity of LWR energy (power flux) provided by a mass of gas is proportional to its temperature(Kelvin)**4 (to the fourth power) so, as explained in detail above, the increasing of tropospheric GHGs ==must== cause less LWR than before to be passing upwards through the top of the troposphere.
That’s the upper end of how the so-called “enhanced greenhouse effect” works.
————–
The tropospheric temperature lapse rate is required to cause the so-called “enhanced greenhouse effect”.
The average altitude for LWR to ocean and land got lower (1,650 metres —> 1,550 metres in my example) which means LWR to the surface of the ocean and land is from warmer (faster) molecules on average because tropospheric temperature decreases with altitude and LWR to ocean/land is from lower-down-than-before molecules on average, so there are more GHG molecular collisions / second which leads to more MVE which leads to more LWR production. The quantity of LWR energy (power flux) provided by a mass of gas is proportional to its temperature(Kelvin)**4 (to the fourth power) so, as explained in detail above, the increasing of tropospheric GHGs ==must== cause more LWR than before to be passing downwards to the surface of the ocean and land. This latter is called “downwelling LWR radiation at the surface” and I’ve explained why it must increase and this must, of course, warm the land and ocean surface.
That’s the lower end of how the so-called “enhanced greenhouse effect” works.
———
Note 1: I haven’t yet found the collision MVE production & destruction spectra so I don’t know what %age make MVE and what %age destroy MVE. I looked a few hours 4 years ago but couldn’t find it (not for free anyway). It makes no difference to the description of the mechanism above but it would be needed to confirm the quantity of effect for doubling CO2.
Note 2: Removed because I’ve gotten confirmation.
Note 3: 80% of Earth’s atmosphere is in the troposphere (the top of which is 16 km in the tropics and 9 km in the polar regions, averaging ~12,000 metres). The “greenhouse effect” warming can only happen in Earth’s troposphere, there’s no effect in Earth’s tropopause and the effect is “backwards” in Earth’s stratosphere with =increased= stratospheric GHG gases causing =cooling= of the stratosphere because the stratospheric temperature lapse rate has temperature increasing with altitude (that’s how it’s known with total certainty that it’s increased “greenhouse gases (GHGs)” doing the global warming for the last several decades). Since there’s no temperature lapse rate in the tropopause then any change in the quantity/type of GHGs in the tropopause cannot have any warming or cooling effect on the tropopause or the entire atmosphere, ocean or land. No effect at all. If you follow my description of the effect above for the troposphere but apply it to the tropopause then you’ll clearly see that any change in the quantity/type of GHGs in the tropopause cannot have any warming or cooling effect That’s the reality. The increasing GHGs in the stratosphere are a slight -ve feedback to global warming because downwelling LWR radiation from the stratosphere decreases with increased GHGs, but it’s a very slight -ve feedback because only 6.3% of the well-mixed GHGs (and all molecules) are above the tropopause and they are initially colder than the average of the troposphere so they make even less LWR than the 6.3% factor. By the time the stratosphere warms more than the average of the troposphere there’s only 0.4% of Earth’s atmosphere’s molecules above, negligible.
Note 4: FTIR power flux vs wave-length spectra recorded by the IRIS Infra-Red Interferometer Spectrometer instruments on the Nimbus-1 (1964 – 1964), Nimbus-2 (1966 – 1969), Nimbus-3 (1969 – 1972) satellites show which wave-lengths of LWR heading to space past the satellite came from the surface of the ocean and land and which wave-lengths came, on average, from the GHG molecules and surfaces of solid particles and water droplets in the atmosphere. Examples of these measured FTIR power flux vs wave-length spectra (for western tropical Pacific Ocean, Sahara Desert, Antarctica & southern Iraq) can be seen at:
http://climatemodels.uchicago.edu/modtran/modtran.doc.html (IRIS-C spectrum on the Nimbus 3 satellite over the Sahara Desert to demonstrate the U.S. Armed Forces MODTRAN model’s general accuracy)
https://publishing.cdlib.org/ucpressebooks/view?docId=ft8r29p2m6;chunk.id=d0e1726;doc.view=print (Sahara Desert as observed by IRIS-D instrument on the Nimbus-4 satellite)
https://www.youtube.com/watch?v=Oog7-KOtpEA&t=1713s at 18:07 (4 FTIR samples for western tropical Pacific Ocean, Sahara Desert, Antarctica & southern Iraq)
From these spectra atmospheric physicists have calculated the 91.5% of the LWR that Earth sends to space that is emitted by the atmosphere rather than by the surface of the ocean and land. Also, the MODTRAN tool on the internet can be used to play with a theoretical calculation of the FTIR power flux vs wave-length spectra by adjusting GHGs.
Note 5: 2020-01-25 edited example altitudes. The Kevin Trenberth & other Earth’s energy budgets show 17% (40 w/m**2) in the atmospheric window but “Outgoing Longwave Radiation due to Directly Transmitted Surface Emission” of S.M.S. COSTA & K. P. SHINE 2012 states that as ad hoc and assesses instead 8.5% (20 w/m**2 +/- 4 w/m**2). I don’t attempt quantifying anything in the effect explanation but I made my examples for illustration as close to reality as is reasonable to do (Stefan-Boltzmann equation & average tropospheric temperature lapse rate).
@103 Kevin McKinney The only thing I can think of is that perhaps the rate of calcium carbonate CaCO3 formation varies during those periods and that’s where the O2 goes to at greater or lesser rates.
Killian @112
“Deflect? From non sequitur stupidity? None of what you said in that worst-ever of your posts had a shred of accuracy. Shooting at a target a mile away in 150 mph winds would have been more accurate.”
Every word I said @83 was accurate. I said neither I or the article made reference to getting emissions down below 350 ppm. This is a simple fact. I said the desirability of getting emissions under 350mm is obvious,(to us anyway). How is that not accurate? I said the article suggested its too late to stop the artic melting even with some cooling (for right or wrong). Are you disputing they said this? I said they didn’t define how much cooling. Are you disputing this? I said calling me crazy is gaslighting. It certainly is. Do I really need to post a definition of gaslighting? I said you are on record complaining about people gaslighting you. Are you going to deny that as well?
Your accusations are literally 100% disconnected from what I said.
Yes if we get a degree of cooling this would stop melting, but according to the article cooling might not be enough to slow down the pace of the flow of the glaciers because the whole thing has become destabilised, or it could take decades to reach a new stable state. But 1) I hope this is wrong and 2) yes obviously you are right we should try really hard to do what we can to reduce emissions. The authors probably meant a small fraction of a degree of cooling, but the road to hell is paved with making assumptions. instead of wasting your time clowning around defending the indefensible again, email them.
Re: # 59 nigelj:
You wrote: “https://www.livescience.com/greenland-melt-point-of-no-return.html
“Glacier retreat has knocked the dynamics of the whole ice sheet (Greenland) into a constant state of loss,” study co-author Ian Howat, an Earth scientist at The Ohio State University, said in a statement. “Even if the climate were to stay the same or even get a little colder, the ice sheet would still be losing mass.””
But: “point of no return”? Meaning: there is no way to save the Greenland ice sheet? Really? The scientific research behind the widespread dramatic news you refer to is this:
https://rmets.onlinelibrary.wiley.com/doi/epdf/10.1002/joc.6771
“(…) assuming that icedynamical losses and ice sheet topography stay similar to the recent past, linear extrapolation gives a corresponding GrIS global sea-level rise (SLR) contribution of 10.0–12.6 cm by 2100, compared with the 8–27 cm (mean 15 cm)
“likely” model projection range reported by IPCC in 2019 (SPM.B1.2) (…)” (abstract)
This research seems to be somewhat at odds with the dramatic newsheadings about it. Constant loss is bad enough surely, but is the ice sheet doomed? Not according to this research, it does not consider that subject. And other research on the subject of Greenland ice sheet response to warming periods back in time: Leading studies on the fate of the Greenland ice sheet during the last interglacial – the Eem period or marine isotope stage 5e – shows that by far most of the Greenland ice sheet survived the warmth then, which was up to eight degrees C higher than late Holocene climate in central Greenland.
Eem-aged glacier ice is found in deep boreholes at the bottom layers of the ice sheet from the far north to the far south and from the far east to the far west. The (warmest period of) the Eemian was globally a couple of degrees C warmer than the climatic optimum 9000-6000 years BP in our current interglacial, the Holocene (which of course also the Greenland ice sheet survived). During the Eemian warmth the main global sea level was between five and six meters above the current level. But was Greenland the cause of that? Total melting of the Greenland ice sheet is calculated to make global sea level rise around six meters, but the even the very strong Eemian melt for a couple of thousand years was indeed not even beginning to melt it all, even if there was a lot of melting going on:
“Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North Greenland Eemian Ice Drilling (‘NEEM’) ice core and show only a modest ice-sheet response to the strong warming in the early Eemian. We reconstructed the Eemian record from folded ice using globally homogeneous parameters known from dated Greenland and Antarctic ice-core records. On the basis of water stable isotopes, NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 ± 4 degrees Celsius above the mean of the past millennium, followed by a gradual cooling that was probably driven by the decreasing summer insolation. Between 128,000 and 122,000 years ago, the thickness of the northwest Greenland ice sheet decreased by 400 ± 250 metres, reaching surface elevations 122,000 years ago of 130 ± 300 metres lower than the present. Extensive surface melt occurred at the NEEM site during the Eemian, a phenomenon witnessed when melt layers formed again at NEEM during the exceptional heat of July 2012. With additional warming, surface melt might become more common in the future.”
https://www.researchgate.net/publication/235228877_Eemian_interglacial_reconstructed_from_a_Greenland_folded_ice_core
All also explained in this lecture by the leading danish researcher on this, Dorthe Dahl-Jensen: https://video.ku.dk/dorthe-dahl-jensen-iskerneforsker (in danish).
The five to six meters higher sea-levels than now could, according to the abovementioned facts, only for a small part be due to melting of the Greenland ice sheet. So what may have caused it? The main suspect is – and that is indeed very relevant to us today! – the West Antarctic ice sheet (WAIS), which has been shown to fluctuate hugely in the past, especially much further back in time (even as far back as 33 million years BP, in the initial stages of the creation of the Antarctic ice, which came about both due to both slowly sinking CO2-levels since 50 million years BP (reason: chemical weathering of new orogens, mainly the Himalayas) and due to the disappearance of the connection between the Antarctic peninsula and the southern tip of Latin America, Tierra del Fuego, which gave the sea currents and wind systems around the Antarctica free way, isolating it climatically more and more from its surroundings).
Those abovementioned late warming periods – the Eemian and the Holocene climatic optimum – were warmer not because of higher levels of CO2 or any other greenhouse gases than now (on the contrary: those levels were around the preindustrial levels of ca. 280 ppmv, shown by ice core data from Antarctica), but because of the socalled Milankovitch-cycles: the solar summer solstice insolation to around 65 degrees north was up to 30 pct. higher than present values (mainly because of greater tilt of the earth’ rotation axis and the precession of the equinoxes). The interesting point concerning this is that it shows that the level of summer insolation to the far northern latitudes for some reason is far more important for the global mean temperature than the level of summer insolation to the same southern latitudes (which is 30 pct. lower when it is 30 pct. higher to the same northern latitudes, because it is northern summer when it is southern winther and vice versa: changing the rotation axis tilt and the precession of the equinoxes doesn’t change the total amount of energy the earth recieves from the sun, it only changes how this amount of energy is spread over different parts of the earth’s surface at different times of the year).
So, how come most of the Eemian melting came about in West Antarctica, when it was the far north that got more insolation in that period? (And as other possible explanation than Greenland we have only the WAIS). Here we must consider this possible chain of events: 1) first the northern warmth melts enough of the Greenland ice and other northern glaciers to make global sea levels rise let’s say half a meter, 2) at the same time the northern warming spreads in the global atmosphere, rising among other effects the amount of warmer intermediate depth seawater reaching underneath the outer reaches of the huge West Antarctic ice shelves, and then 3) those two processes together starts to melt these shelves from beneath (just as registered today on several iceshelves in West Antarctica, fx the Pine Island Glacier) enough to let the higher sea level force them to begin floating, which again makes them surge: i.e. collapse, just as we have seen happen very fast with the two northernmost smaller iceshelves Larsen A 1995 and Larsen B 2002. When glacier ice begins floating in fiords etc. it very fast breaks up, and then the pressure from the accumulated ice masses on the inland, higher reaches of these mainly cold-based ice-sheets makes them surge forward, as meltwater reaching the bottom through moulins, just as seen in the collapse of Larsen B and similar events:
https://nsidc.org/news/newsroom/larsen_B/index.html and https://nsidc.org/cryosphere/sotc/iceshelves.html .
See also:
https://www.researchgate.net/publication/322179906_Dating_Antarctic_ice_sheet_collapse_Proposing_a_molecular_genetic_approach
So what we should be worrying about concerning melting ice sheets is the WAIS, because it seems to be much more vulnerable to warming than the Greenland ice sheet. And aldready in 1978 glaciologist John H. Mercer published research about exactly this:
https://www.commonspaces.eu/oer/west-antarctic-ice-sheet-and-co2-greenhouse-effect-a-threat-of-disaster/view/
Russell: One of Murphy’s lesser known laws unfortunately applies to economies as well as ecosystems: You can’t go over the same waterfall twice.
AB: And I always say that most everyone messes up the first time they do most anything.
Which is probably why we’re getting so good at building really high waterfalls.
Barry Finch 117
[This is how the so-called “greenhouse effect” in Earth’s troposphere causes warming. The so-called “greenhouse effect” effect is nothing at all like the effect that warms a greenhouse.]
The greenhouse effect is very straightforward. The absorbing molecule emits as much downwelling IR as upwelling. This is perfectly described by a greenhouse in a vacuum. Obviously the troposphere is not a vacuum and things get very messy. Confounding variables.
Still, the basic concept holds true.
Ravenpaw #111,
“The Earth system would quickly lose all of the energy it has accumulated.”
It would lose all of the energy, and Greenhouse Gas molecules would slow that process by trapping heat. You should try to read more carefully; here’s what I said at #94:
and
So, it makes no sense for you to argue about the terminology that professionals use by trying to apply colloquial usages. It’s like when Creationists say “The Theory of Evolution is only a theory!”… two different meanings for the word theory.
Regarding the Greenland ice sheet…
At first glance, I couldn’t figure out how a higher temperature could produce a complete collapse, rather than the ice sheet just getting smaller (and stabilizing). In North America, for example, glaciers advanced to lower elevations during cold periods, then retreated to higher elevations during the warmer interglacials:
“Glaciologists have discovered evidence of glaciation in Alaska reaching back 5 million years, and suspect the area has been glaciated for nearly 15 million years. Few other places on the planet have experienced such a prolonged period of glaciation. In cooler periods, glaciers covered all of the coastal plateaux. During warmer periods, they retreated to the mountains. About 20,000 years ago, the Earth’s climate cooled and the last of the great Pleistocene ice age glaciers advanced down from the Chugach Mountains. Glaciers formed in the stream beds of the coastal plateau and carved deep valleys.”
Why would this not also be true for Greenland and Antarctica? Turns out the bedrock beneath those huge ice sheets is near, or in some places below sea level. IOW, for the most part, the ice sheets do not have the option of retreating to higher ground!
Now, you could argue that there is a ring of mountains surrounding the Greenland ice sheet. True, but based on the photos I’ve seen, my thinking is that most of those mountains are too steep and pointy to support a large glacier. The snow that falls ends up sliding down to the much lower base, joining the main flow.
Maps of the topography beneath the Antarctic/Greenland ice sheets:
https://sites.uci.edu/morlighem/dataproducts/bedmachine-greenland/
https://www.scientificamerican.com/article/map-of-antarcticas-bedrock-reveals-vulnerabilities/
@120 Karsten V. Johansen Dorthe Dahl-Jensen also has a talk (in a version of English that I very like) at https://www.youtube.com/watch?v=FqJLwJwndLI
@120 Karsten V. Johansen I heard climate scientists a few years back saying Eemian Optimum was 0.5 to 1.0 degrees above present but more recently I keep hearing climate scientists say Eemian Optimum was 0.5 degrees above present “or perhaps about the same as now”. If I’m understanding the 12k year multiple-proxy (many proxies) paper correctly it’s now 0.8 degrees above the Holocene Optimum so with the 0.5 degrees or less option that puts Eemian Optimum at 1.3 degrees above Holocene Optimum or perhaps a small fraction of a degree less, rather than a couple of degrees C.
@120 Karsten V. Johansen It was estimated about half (3 m of SLR) from Greenland ice sheet (GrIS) mass loss for Eemian Optimum (Cuffey & Marshall, 2000) per 17:24 to 19:03 at: https://www.youtube.com/watch?v=KTTlAAiwgwM I don’t know whether there’s improved paleo analysis since 2010 AD. The top-of-atmosphere (TOA) forcings/feedbacks of the most recent de-glaciation per the same video of a talk at 8:00 were:
0.5 +- 1 w/m**2 8% Milankovitch cycles orbital eccentricity, axial tilt & precession of the equinoxes changes
forcing (what pulled the trigger that started it)
3.5 +- 1 w/m**2 53% ice sheets & vegetation changes albedo-change feedback
1.8 +- 0.3 w/m**2 27% CO2 change feedback
0.4 +- 0.1 w/m**2 6% CH4 change feedback
0.4 +- 0.1 w/m**2 6% N2O change feedback
:::::::::::::::::::::::::::::::::::::
6.6 +- 1.5 w/m**2 total
James McDonald @101,
I might at some stage find the time to read through other answers to your question so this reply may be already said.
If the O2 & N2 is taken from the Earth’s atmosphere the pressure would be mostly gone leavng 0.2psi mainly of Argon with CO2 constituting 40,000ppm(v) and adding 0.008psi to a very thin atmosphere. I am reminded of the atmosphere of Mars which has about half this total Ar-CO2-etc pressure (0.09psi) but almost all of it CO2. So Mars has ten-times the CO2 that Earth has but the pressure is low enough to negate any pressure broadening leaving the greenhouse effect with far too many holes in the 15 micron band. Additionally Mars has very little H2O working elsewhere across the spectrum. (An ineffective greenhouse on an chilly Earth would greatly reduce H2O concentrations but probably not down to the low levels found on Mars.)
Zebra, 123
If suddenly no solar input –
you believe that photons of IR, ‘the heat’ would remain trapped….. but not the energy?
I’m beginning to agree with Nigel.
MA Rodger 128,
“If the O2 & N2 is taken from the Earth’s atmosphere the pressure would be mostly gone……”
Right, and as mentioned in an earlier thread, with such low pressure the atmosphere would (at least initially) not be able to support liquid H20. The GHE would end up off the chart.
25 – Al Bundy
“Mrkia: fire fighting are not practical in wilderness due to the no-mechanized-tools rules
AB: what a doofus. As if laws and rules can’t be changed. Really? You are claiming that mechanical systems are impossible because laws can NEVER change?”
Good luck getting The Wilderness Act of 1964 changed. You’ll be skewered by The Sierra Club, The Wilderness Society, and every other environmental organization who cares about it.
32 – Al Bundy
“In short, this game-changing new scientific understanding suggests that humanity can turn down the heat almost immediately by slashing heat-trapping emissions.”
Emissions should be low this year – think we will see a slowing of AGW soon?
50 – nigelj
““Climate change is largely responsible for a doubling in the number of natural disasters since 2000, the United Nations said on Monday, warning that the planet was becoming uninhabitable for millions of people…..””
In this short video you can see the UN in action. Best to just ignore the UN:
https://www.youtube.com/watch?v=qypnQkdg89g
56 – mike
“The Arctic is in a death spiral. How much longer will it exist?”
I’m going to go out on a limb here and guess that the area north of the Arctic Circle will still be the Arctic for a very long time. ;) Who wants to go camping in the Arctic while it still exists? Weather looks balmy:
https://www.wunderground.com/forecast/ca/resolute
88 – zebra
“Let’s go back to before we humans messed things up, when the system was in equilibrium, and the temperature was constant.”
There has never been a period when the temperature was constant. The “system” is dynamic and changes constantly.
106 – Dominik Lenne
You might ask these guys if they’ve done any research on it:
https://www.ars.usda.gov/pacific-west-area/albany-ca/wrrc/
114 – Al Bundy
“AB: We choose who to interact with. For example, my guess is that if I were to count keystrokes I’d find that the vast majority of yours have been invested in those four people.”
His computer is contributing to AGW because of his obsession with them. :)
117 – Barry Finch
Can you expand on that a little bit?
:)
119 nigelj:
You’re like a mangey dog with a ratty bone, I swear to god…
Killian @112
“Deflect? From non sequitur stupidity? None of what you said in that worst-ever of your posts had a shred of accuracy. Shooting at a target a mile away in 150 mph winds would have been more accurate.”
Every word I said @83 was accurate. I said neither I or the article made reference to getting emissions down below 350 ppm.
Yes, but, dumbass, I NEVER SAID YOU HAD. <— Just amazing I had to point that out.
Criminy… learn to shut your trap when you've been knocked on your ass already.
Here’s a recent article of interest. While it says there was more CO2 in the atmosphere at the end Permian extinction then than possible now (and someone here at RC told me years ago that life then was more fragile than now), we’re doing it 14 times faster & there are many other environmental threats. Not to mention even minor disruptions can throw complex human societies into a tail-spin.
I hope RealClimate does a post on this.
ARTICLE: “Permian–Triassic mass extinction pulses driven by major marine carbon cycle perturbations”
https://www.nature.com/articles/s41561-020-00646-4#citeas
Jurikova, H., Gutjahr, M., Wallmann, K. et al. Permian–Triassic mass extinction pulses driven by major marine carbon cycle perturbations. Nat. Geosci. (2020). https://doi.org/10.1038/s41561-020-00646-4
ABSTRACT:
The Permian/Triassic boundary approximately 251.9 million years ago marked the most severe environmental crisis identified in the geological record, which dictated the onwards course for the evolution of life. Magmatism from Siberian Traps is thought to have played an important role, but the causational trigger and its feedbacks are yet to be fully understood. Here we present a new boron-isotope-derived seawater pH record from fossil brachiopod shells deposited on the Tethys shelf that demonstrates a substantial decline in seawater pH coeval with the onset of the mass extinction in the latest Permian. Combined with carbon isotope data, our results are integrated in a geochemical model that resolves the carbon cycle dynamics as well as the ocean redox conditions and nitrogen isotope turnover. We find that the initial ocean acidification was intimately linked to a large pulse of carbon degassing from the Siberian sill intrusions. We unravel the consequences of the greenhouse effect on the marine environment, and show how elevated sea surface temperatures, export production and nutrient input driven by increased rates of chemical weathering gave rise to widespread deoxygenation and sporadic sulfide poisoning of the oceans in the earliest Triassic. Our findings enable us to assemble a consistent biogeochemical reconstruction of the mechanisms that resulted in the largest Phanerozoic mass extinction.
@124 Western Hiker Modelled estimates of Greenland ice sheet equilibrium sizes for a range of Greenland surface temperatures relative to present Greenland surface temperature, based on Eemian Optimum retreat, is at 38:00 at https://www.youtube.com/watch?v=FqJLwJwndLI What’s missing is any workable estimate of the time ranges to adjust to equilibrium size when the sustained surface temperature changes much faster than the equilibriating time, as has happened the last ~50 years (and in the near future).
@122 Western Hiker I disagree that your description of the so-called “greenhouse effect” which is “The absorbing molecule emits as much downwelling IR as upwelling” will be sufficient to convince an impartial person that it exists. For example, that person might respond “OK then so suppose the atmosphere was sending 240.1 w/m**2 to space and 240.1 w/m**2 to the suface and my non-EV Hummer burned all that petrol. Well now there’s more CO2 so it must be sending more so it’s now sending 240.2 w/m**2 to space and 240.2 w/m**2 to the suface. So CO2 cools Earth. It’s emitting as much downwelling IR as upwelling and it cools Earth”.
———-
Your competing description of the so-called “greenhouse effect” is woefully inadequate.
@94 zebra Your “(The random kinetic energy of molecules in either volume is not heat, nor is any other form of energy.)” is incorrect because kinetic energy of molecules due to their (random) motion is precisely what “heat” is.
Heat:
From Wikipedia (my bolds):
In thermodynamics, heat is energy in transfer to or from a thermodynamic system, by mechanisms other than thermodynamic work or transfer of matter.[1][2][3][4][5][6][7] The various mechanisms of energy transfer that define heat are stated in the next section of this article.
Like thermodynamic work, heat transfer is a process involving more than one system, not a property of any one system. In thermodynamics, energy transferred as heat contributes to change in the system’s cardinal energy variable of state, for example its internal energy, or for example its enthalpy. This is to be distinguished from the ordinary language conception of heat as a property of an isolated system.
The quantity of energy transferred as heat in a process is the amount of transferred energy excluding any thermodynamic work that was done and any energy contained in matter transferred. For the precise definition of heat, it is necessary that it occur by a path that does not include transfer of matter.[8]
End quote.
Please, stop with the childish rhetorical word play… this is supposed to be a science-y venue, where science is the source of our language.
Ravenpaw #129,
“you believe the photons of IR would remain trapped”
I didn’t say that; I said:
“It would lose all of the energy, and Greenhouse Gas molecules would slow that process by trapping heat.”
And you should read my comment titled “Heat”, particularly the part about childish rhetorical word play.
Western Hiker @130,
Indeed you are correct.
As I was completing the end of that comment @128, the small H2O component of Mars’s atmosphere did make me think about the H2O component on Earth if all O2 & N2 were removed. I decided to not mention any boost to atmospheric H2O levels resulting from the atmospshere losing 99% of its pressure as such discussion would be too weighty a consideration for the rest of the comment.
In terms of a lower temperature with a deficient greenhouse, Lacis et al (2010) suggest H2O will drop to 10% of today’s levels (so 0.3% of the atmosphere).
Mind, I do wonder if the ‘hot’ bits of such a greenhouse-free planet will tend to lose perhaps the majority of its surface ice to the cold bits where the lower temperatures would ensure even less of it finds its way into the atmosphere.
But there is also the loss of atmospheric pressure which will boil away a great deal of the oceans and lead potentially to an H2O-rich atmosphere with a significant greenhouse effect. I wouldn’t care to speculate on the actual H2O levels or the temperature outcomes of such a situation.
@Barry Finch (137), not quite. The “kinetic energy of molecules due to their (random) motion” is temperature and not heat. Heat is the energy that flows from a hotter object to a colder one.
Many thanks to the various people who responded to my 10X, 0.1X scenarios.
As I suspected/feared it doesn’t seem to be a simple calculation with a well-known answer. Such is life.
@117 Barry — lots to read there, still digesting it all. (But yes I was aware that individual photons don’t survive the round-trip, which is why I referred to the energy contained in the originating photon, as opposed to the photon itself.) I understand your misgivings, but the cartoon version following a packet of energy still seems like a plausible way to calculate an order-of-magnitude result. There are a limited number of paths that energy can follow, with reasonably well understood transition probabilities, so it should be possible to average over representative ensembles.
@128 MA Rogers — looking at Mars is a good idea.
At any rate, food for thought, but back to my day job, entirely unrelated to climate matters…
Mr. Know It All @132 “There has never been a period when the temperature was constant. The “system” is dynamic and changes constantly.”
Yes, I agree with you on this.
But as a dynamic system, it has some implications that you seem to ignore. First, while the system IS always changing, the speed and intensity of the changes have a lot to do with what states it can reach. We, and the rest of the life on the planet, are passengers that will have to adapt and absorb the changes. In the current case, we are changing the carbon dioxide forcing with a speed and intensity not seen in millions of years. The exact state we will end up in is uncertain, but it is certain that we will be getting a hell of a shock, and things will be a LOT different when it’s over – in a few thousand years. Any “hiatus” in the action now is bound to be puny and temporary.
As an analogy, I’m going out for a drive. My car is always moving, no stasis. It’s a dynamic system. Now, I drive over bump. If it’s a little bump, and I’m going 5 mph, the shock absorbers will take most of the impact, the seat belt will hold me down, the seat will cushion me, and I’ll get a gentle jostle and keep going. Next, I will try jamming on the gas pedal for a while, just for fun, and see what happens if I hit a curb at 100 mph. The shock absorbers will kick in, just like before, but there’s too much shock. Part of the shock will be absorbed by the car frame, as metal bends and breaks. The seat belt will hold me in, but my body has a huge amount of momentum, anyhow. There will be a hiatus lasting milliseconds as the air bag inflates and absorbs some of my forward motion. Then, my last shock absorber will kick in as my internal organs press against my skeleton, and I have a concussion. After the dust settles, things will be quiet, but my car will be wrecked. I might be in equilibrium too, if I’m dead. If I am alive, I will have a lot of internal damage to heal, and it will take a long time.
So, when it comes to dynamic systems, there’s change, and then there’s CHANGE. We’re having fun, but we are going to find out what CHANGE feels like. Right about now, the shock absorbers are giving out.
I call BS on the idea that you can’t fight fires with mechanized/motorized gear in protected wilderness areas. The actual text of the applicable policy:
https://www.nps.gov/policy/mp/policies.html#_Toc157232813
Now, whether you *should* or not is a whole other question, given that the total fire suppression policy in place for most of the 20th century helped set the table for some of the problems we have now. Fire is natural, and some ecosystems–eg., our longleaf pine forest here in the Southeast, of which mere crumbs still survive–are dependent upon it for their very survival.
#138, zebra–
So, zebra spends three paragraphs on a Wikipedia discusion of heat (in thermodynamics), presumably because “this is supposed to be a science-y venue, where science is the source of our language,” and hence it is important to get the language right.
But when other people try to get the language right they are told to:
“Please, stop with the childish rhetorical word play…”
And that, folks, is in a nutshell why I don’t directly engage zebra anymore.
Dudes, Talking of photons as if they have continuous existence and that if a photon passes from point A to point be, that the photon at point B is necessarily the same photon that passed through point A misses the point. Photons are quantum-mechanical entities. If you discuss them in classical terms, you will mislead yourself.
And yes, heat IS random molecular motion.
Barry Finch, #136
“Your competing description of the so-called “greenhouse effect” is woefully inadequate.”
Not competing, just simplified.
On an airless planet, the only downwelling would be from the sun. But if you surrounded the planet with a pane of glass that would no longer be the case, and the surface would get warmer as a result. That, to me, is the basic idea.
What you described in #117 includes the GHE, but is complicated by conduction, convection, an atmosphere that gets thinner and colder with altitude, buoyancy…. etc. Extra stuff.
Zebra @138 responds to a statement :” @94 zebra Your “(The random kinetic energy of molecules in either volume is not heat, nor is any other form of energy.)” is incorrect because kinetic energy of molecules due to their (random) motion is precisely what “heat” is.” (which is also my understanding as a non expert).
Zebra states a standard definition of heat from wikipedia as “In thermodynamics, heat is energy in transfer to or from a thermodynamic system, by mechanisms other than thermodynamic work or transfer of matter…” then says “Please, stop with the childish rhetorical word play… this is supposed to be a science-y venue, where science is the source of our language”
But is it not Zebra who indulges in word play? Generally heat is ALSO defined as the following from heat in simple wikipedia: “Heat is the sum of the kinetic energy of atoms or molecules. In thermodynamics, heat means energy which is moved between two things, when one of them is has a higher temperature than the other thing.”
https://simple.wikipedia.org/wiki/Heat
KIA 132: There has never been a period when the temperature was constant.
BPL: For the past several thousand years the global mean annual temperature was 287-288 K. It doesn’t have to be perfectly stable, but it does have to be stable enough to allow for predictable agriculture.
I note–following up on some of MAR’s comments–that the Arctic SIE continues to lag far behind seasonal norms, being currently more than a million km2 behind last year (which was itself record-low at the time).
But at least the rate of increase now appears more congruent with the past.
https://ads.nipr.ac.jp/vishop/#/extent/&time=2020-10-26%2000:00:00