Is it just basic physics?

I noticed a discussion on Twitter about whether or not, from basic physics, we know that most of the warming since the 1800s has been anthropogenic. Of course, it’s probably not basic physics, because it is quite complicated. However, I do think – given our current understanding – that we can use some basic physics to show just how difficult it is to construct a plausible scenario under which most of our warming was not anthropogenic. I had thought of writing a post, but realised I had already largely done so, so am reblogging the one below. Admittedly, I wrote this one with respect to 1950, but a similar argument could be made based on warming since the 1800s.

Essentially, given how much we’ve warmed (~ 1K), given the estimates for the external changes (solar, volcanoes, anthropogenic, …), and given that we still have a planetary energy imbalance (we’re still accuring energy) it is very difficult to construct a physically plausible scenario under which most of the warming is not anthropogenic. Of course, this isn’t some kind of claim of formal attribution, just a back-of-the-envelope approach to illustrate the point. It may also be possible to construct an alternative that is both physically plausible, and not inconsistent, but I can’t think of how. If anyone can, feel free to point out how in the comments. Of course, I’m looking for more than just hand-waving.

The latest critique of consensus studies is an attempt to re-analyse the data from Verheggen et al. (2014) to suggest that the consensus amongst climate scientists is only 47%, not 97%. I only have two things to say about this. Firstly, As Michael Tobis points out, you do need to consider who you include as a scientist, what question you are asking, and how you go about asking it. Secondly, these consensus studies are not to inform those who work in – or understand – this scientific area; it’s for those who do not and for those who dispute the existence of a strong consensus. If you analyse survey data that aims to address this issue and conclude that the level of consensus with respect to AGW is less than 50%, then you’re wrong. It’s clear (whether you look in the scientific literature or speak to relevant…

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126 Responses to Is it just basic physics?

1. russellseitz says:

Absent presentable naysayers, Trump faces a quandry in keeping his fundamentalist fans happy about Presidential science advice.

There is, however a solution that could appeal to fiscal conservatives as well as the oil patch.

https://vvattsupwiththat.blogspot.com/2017/01/transition-team-unveils-trumpclimate.html

2. But, but, but what if there is a force X that cancels the greenhouse warming and a force Y that produces warming just like the greenhouse effect would?

3. Steven Morris says:

I’ve got several questions. Here are a few.
How does Nitrogen and Oxygen, ~99.5% of the Earth’s Atmosphere, heat and cool?

We know that the Greenhouse Effect is a misnomer, Greenhouses work by preventing Convection. If more CO2 heats the atmosphere, then that increases the lower atmosphere temps more than higher altitudes, more CO2 concentrated near surface, so won’t that simply increase the rate of Convection (cooling)?

This really isn’t physics related, perhaps it is.
If Sea Levels rose 3 meters higher during the last Interglacial, why would you be surprised or alarmed if they reached that level again during this Interglacial?

If you look at the Vostok and related EPICA surveys, they show the Earth was about 9K cooler during the last several Glacial Maximums, and ~2-3K warmer during the last Glacial Minimums. Is a 1K degree movement up or down any cause for alarm? We are talking a range of 279K to 291K, right? If the Earth’s Modern average temp is indeed 15C or 288K, would you as a scientist be all that surprised or alarmed if temps increased or decreased 1K over 10 years? Why? Is the Earth’s Average temp really (279K+291K)/2 = 285K? How do we define Normal?

This is only the tip of the iceberg, I’ve got some Back Radiation questions, but they are more complicated and need a bit of research.

Regards,

Steve

4. Hans Erren says:

Navier-Stokes is not basic physics is it, there is a huge amount of pre-emptive parameter fitting.

5. Steven,

How does Nitrogen and Oxygen, ~99.5% of the Earth’s Atmosphere, heat and cool?

The mostly radiatively inactive so don’t play much of a role in setting surface/atmospheric temperatures.

We know that the Greenhouse Effect is a misnomer, Greenhouses work by preventing Convection.

Yes, it’s just an analogy, none of which are perfect.

If more CO2 heats the atmosphere, then that increases the lower atmosphere temps more than higher altitudes, more CO2 concentrated near surface, so won’t that simply increase the rate of Convection (cooling)?

However, if we simply add GHGs, the temperature gradient at which the atmosphere would become convectively unstable doesn’t change (it depends only on the gravitational acceleration and the specific heat capacity at constant pressure). What happens is that the effective radiative surface moves to a higher altitude, which increases the temperature at this height and, because of the temperature gradient in the atmosphere, the surface warms. However, if you also consider water vapour, then there is actually a change in the temperature gradient, largely because some of the energy is transported by evaporation from the surface and then released when this water vapour condenses. This slightly reduces what is called the moist adiabatic lapse rate and in fact slightly reduces how much we would warm if we added GHGs to the atmosphere. The water vapour feedback is positive, but the lapse rate feedback is negative.

Okay, that’s a bit lengthy and I hope I’ve explained it correctly. The bottom line, though, is that this has mostly been considered and is included in estimates of how we would warm as we add GHGs to the atmosphere.

Is a 1K degree movement up or down any cause for alarm?

Whether or not you’re alarmed is up to you. It seems clear that 1K isn’t really all that alarming (we’ve already done it). The issue is that we have sufficient fossil fuels to potentially much more than double atmospheric CO2 and to then warm the planet by 4K, or more. This means that we have the potential, on timescales of a couple of centuries, to produce a change comparable in magnitude to the change between a glacial and an inter-glacial, which normally occurs over a timescale of a few thousand years. It’s not only the magnitude that might be of concern, but the rate at which we’re producing these changes.

6. Hans,

Navier-Stokes is not basic physics is it, there is a huge amount of pre-emptive parameter fitting.

Not sure your point, because mine was simply that one can use basic physics to show that it is difficult to produce a scenario in which most of the warming is not anthropogenic. However, Navier-Stokes is essentially just physics; it’s essentially the conservation laws being used to describe the flow of fluids. There are situations when they wouldn’t apply (if the fluid approximation were not valid, for example) but that’s not the case for our atmosphere, or ocean.

7. Ed Davies says:

Steven Morris: “If Sea Levels rose 3 meters higher during the last Interglacial, why would you be surprised or alarmed if they reached that level again during this Interglacial?”

We probably would be surprised if it happened this century (3 m is at or above the top end of most estimate ranges) but we shouldn’t be if it happened in the longer run.

On the other hand, we should be alarmed as we’ve built our civilization on the basis of sea level being roughly where they have been for the last few thousand years. Lots of cities are on coasts. Much food is grown on low-lying land. Rising sea levels will cause a lot of disruption.

8. Steven Morris says:

First let me thank you for taking some time to answer, but I have some issue with your answers.

“The mostly radiatively inactive so don’t play much of a role in setting surface/atmospheric temperatures.”

Are you saying that N2 and O2 within Earth’s atmosphere are without Temperature?
Are you saying that N2 and O2 do not Radiate energy?

Let me rephrase. How are N2 and O2 heated AND cooled within the Earth’s atmosphere? What process allows them to heat up and what process allows them to cool?

Reading over the Convection and misnamed Greenhouse Effect now.

Quickly though, if you were to describe the misnamed Greenhouse Effect correctly, what would that be? Emissitivity Effect? Absorption Effect?

9. Steven,

Are you saying that N2 and O2 within Earth’s atmosphere are without Temperature?
Are you saying that N2 and O2 do not Radiate energy?

Let me rephrase. How are N2 and O2 heated AND cooled within the Earth’s atmosphere? What process allows them to heat up and what process allows them to cool?

I just mean that they don’t absorb much in the way of incoming or outgoing radiation. They are probably mostly heated/cooled by collisions.

Quickly though, if you were to describe the misnamed Greenhouse Effect correctly, what would that be? Emissitivity Effect? Absorption Effect?

I don’t have a better term.

10. guthrie says:

Radiatively inactive in this context means they don’t absorb/ emit IR at the wavelengths under discussion. They do of coruse interact with some wavelengths of light etc.
The molecules can gain or lose energy by colliding with other molecules, e.g. ‘hot’ CO2 ones. But it’s the CO2 that is doing the absorbing/ radiating of the IR.

Other means of transfer of energy to N2, O2 etc involves colliding with hot matter on the ground, e.g. leaves on trees, rocks, etc, which have absorbed various wavelengths of light from the sun.

— Everyone – it’ll be easier if we tag team this, no point everyone writing their own answer and wasting everyone’s time.

11. JCH says:

Just my experience, but people who have no knowledge of radiation don’t usually ask the types of questions that are being asked. Be careful… could be a mindless gallivant that is intentionally going nowhere. Think Mike Flynn.

12. Magma says:

@JCH: Yes.

I’ve been on this merry-go-round long enough to spot a time-waster too.

13. izen says:

@-“How does Nitrogen and Oxygen, ~99.5% of the Earth’s Atmosphere, heat and cool?”

Direct transfer of kinetic energy by collision with Radiatively excited dipolar molecules. (and each other)

@-“If Sea Levels rose 3 meters higher during the last Interglacial, why would you be surprised or alarmed if they reached that level again during this Interglacial?”

Because in every past interglacial the peak sea level has been almost coincident with the peak temperature which is immediately after the sharp rise from the maximum interglacial state. In every past interglacial that peak last for a brief time and then cools over the nect few thousand years into the next glacial period. This interglacial statrted to follow the same pattern. Peak temperature, the Holocene optimum, and peak sea level were both after the rapid (less than 2000 years) rise from the glacial max. Then things started slowly cooling and the glaciers and ice sheets started reforming. Around half of the Greenland ice-cap formed since the last melt~7000 years ago.
No previous interglacial period shows a sudden return to fast warming, sea level rise and re-melting of accumulating land ice so long after the initial interglacial melt.
But then all previous cycles show a fall in CO2 after the short warming peak.
Unfortunately during the ~6000 years of slow cooling and falling sea levels we built a large amount of our infrastructure within a few feet of sea level.

@-” Is a 1K degree movement up or down any cause for alarm? … would you as a scientist be all that surprised or alarmed if temps increased or decreased 1K over 10 years? Why? Is the Earth’s Average temp really (279K+291K)/2 = 285K? How do we define Normal? ”

The definition of normal is a matter of choice. In practise it is often what we expect, prepare for and predict conditions will be based on past experience.
The reason why 1K may be alrming is roughly the same reason that a 1K rise in body temperature would be alarming if it was not part of the ‘normal’ expected part of a body metabolic cycle.
The biosphere on which we depend is extremely sensitive to temperature. As it increases water evaporation increases exponentionly and the biochemistry of most organisms become unstable. This why the biomass in hot deserts is so low. around half of the food crops we grow are grown in areas where yeild is reduced because it is above the optimum growing temperature for those plants. A rise of 1K can half production. Biological systems respond to temperature in non-linear ways. 1K was probably all it took in a previous interglacial around 1.5 million years ago to wipe out most of the then extant species of coral so that most of those we see today are recently evolved species.

Given the close dependence we have on the biochemistry operating on the Earth, a 1K rise in the global temperature out of the normal should be as alarming as a Doctor telling you your temperature has risen to 100.4degF in the last ten hours and appeared to be heading higher…

14. Willard says:

> it’ll be easier if we tag team this, no point everyone writing their own answer and wasting everyone’s time.

Good idea.

+1 on “gallivant” too.

***

> If you look at the Vostok and related EPICA surveys […]

Good idea, dear Steven Morris. If you can look at these surveys, then I’m not sure why you’re just asking the questions you ask.

If you have a point to make, now is the time.

15. Steven Morris says:

[Not a good idea to start your comment by showing you know AT’s name, Steven Morris. Following through just asking questions is also suboptimal. -W]

16. Magma says:

Does Gish always gallop? Does he never pace or trot or canter?

17. Michael Hauber says:

If only basic physics is allowed, then how do we know circulation changes aren’t driving changes in clouds to change albedo and cause the warming. IRIS effect etc. Seems that more than basic physics is needed to investigate this idea. Depends on how far you stretch basic physics to get the generally agreed upon low amount of warming for the 0 feedback case. That requires a detailed calculation of Co2 absorption layer by layer throughout the atmosphere, and if you treat the atmosphere as a single layer you get saturation (A saturated Gassy argument posted on Realclimate years ago).

I’d guess that with only basic physics we’d be saying we don’t really know for sure what is causing the warming, but Co2 is the obvious leading suspect, with no other good suspects. It depends on where you push the boundary of basic physics to. Maybe a working definition would be stuff that can be done without a computer. So excluding general circulation models, and detailed global satellite observations (e.g. UAH temp which requires significant calculations on every pixel to convert brightness observation into a temperature etc).

18. russellseitz says:

Steven could answer a lot of his questions by by proceeding to Singapore and climbing into a white plastic bathtub full of clear, tepid water left out in the noonday sun.

If he adds a drop per second of india ink he shoud learn there’s something to this radiative forcing business well before teatime,

19. izen says:

@-Michael Hauber
” then how do we know circulation changes aren’t driving changes in clouds to change albedo and cause the warming. IRIS effect etc. ”

I don’t think you can get more warming at night, winter and at the poles rather than day, summer and equatorial warming from a cloud/albedo/iris process.

20. Harry Twinotter says:

Steven Morris.

“First let me thank you for taking some time to answer, but I have some issue with your answers.”

You are not fooling me, you have an agenda. And you are “just asking questions” and Gish Galloping to either waste people’s time, or in the hope of tripping someone up somewhere.

If you genuinely have these questions, do some research by reading documentation from credible sources.

21. Harry Twinotter says:

JCH.

“Be careful… could be a mindless gallivant that is intentionally going nowhere. Think Mike Flynn.”

Yes, that Flynn bloke is pretty transparent. If he finds a sucker, he will just keep ratcheting up the nonsense until he finally claims that CO2 is not a greenhouse gas. He doesn’t sound like a stupid person, so my guess is he knows exactly what he is doing.

22. No need to pile on. Let’s sleep on it.

23. Michael,

If only basic physics is allowed, then how do we know circulation changes aren’t driving changes in clouds to change albedo and cause the warming.

Well changes in clouds are essentially a response to changes in temperature. You could argue that a large fraction of our warming is natural and is somehow changes in clouds respondings to internally driven changes in temperature. The problem here, though, is that this would essentially be arguing that somehow clouds respond to internally driven temperature changes, but not to externally driven temperature changes. I guess there is a possibility that internally driven changes could produce a change in the surface temperature distribution that cannot be produced by externally driven changes and that, therefore, there could be a cloud response to internally driven changes, despite there be no response to externally driven changes. This, however, seems rather contrived.

24. No need to pile on. Let’s sleep on it.

Indeed.

25. verytallguy says:

Michael

Maybe a working definition would be stuff that can be done without a computer.

That means you can’t rely even on the most basic no feedback CO2 warming calculation. Or should I look forward to reviewing your hand done line by line computation of atmospheric radiative heat transfer? (as an aside, as I understand it even the absorption lines themselves are not measured either, but calculated. Others more knowledgeable may wish to put me right on this)

My take would be that circulation models are advanced, heat transfer is basic.

“Basic physics” is then the application of radiative heat transfer to the atmosphere with an assumption of constant relative humidity. That gives ECS=3C or thereabouts. I think formally it needs to be done in different latitudes/times of year and averaged as the structure of the atmosphere changes and gives a different response eg antarctic winter is very different from equatorial. Again, others here more knowledgeable may correct me.

There are then several orthogonal ways to validate that this isn’t miles off:

1. Paleoclimate ECS estimates
2. Circulation models (GCMs)
3. Fundamental physics (bottom up calculation of other feedbacks such as clouds)
4. Direct measurement of back radiation
5. Direct measurement of earth IR from satellites
6. Measurement of humidity and temperature profile in the atmosphere (radiosondes)
etc

It’s the consilience of 1-6 and other methods too that gives the confidence in the overall science.

26. Steven Morris says:

Gentlemen,

Yes I have an agenda. I’d like to know if N2, O2, and Ar play ‘any’ role in the heating and cooling of the Earth’s atmosphere.

I cannot fathom that H2O, CO2, and CH4 are responsible for all the heating and cooling. If they are, I’d like to understand the mechanisms that take place to transfer the energy necessary to heat and cool daily ~4,000 Trillion Metric tons of matter (matter within Troposphere). I’m excluding the stratosphere and above because I am aware they heat and cool differently.

The subject here is Simple Physics. I haven’t taken physics in 25 years, but I do have a basic understanding. Andthentheresphysics (my apologies for mentioning a name before) states “that we can use some basic physics to show just how difficult it is to construct a plausible scenario under which most of our warming was not anthropogenic.’

I’m curious if we can use some basic, intermediate, or even advanced physics to construct a plausible scenario where N2, O2, and Ar (99% of the matter in our atmosphere) play little to no role in the heating and cooling of our atmosphere. The Topic is the same. Not anthropogenic is Natural. If N2, O2, and Ar do play a major role as I suspect, then we are on our way to constructing a plausible scenario where most of our warming is natural, not anthropogenic.

27. There is more than consilience. Here’s how we could apply Hill’s criteria to AGW:

I did not know thst Ronald Fisher was into statistical smoke and mirrors.

28. Steven,

I’d like to know if N2, O2, and Ar play ‘any’ role in the heating and cooling of the Earth’s atmosphere.

I don’t think that they do play any particular role in heating/cooling the Earth’s atmosphere. As already mentioned, they don’t absorb much energy in the relevant wavebands. If we had a pure O2, N2, Ar atmosphere, then the surface could radiate directly to space and the surface temperature would be set by balancing the amount of energy it receives from the Sun with the amount of energy being radiated directly from the surface. If the albedo were unchanged, a pure O2, N2, Ar atmosphere would lead to a surface temperature about 33K lower than we have today.

It seems to me that you’re thinking directly about heating and cooling processes in the atmosphere, but that isn’t all that relevant (apart from things like convection setting the temperature profile which can depend on the composition of the atmosphere). The basic picture is that if we have an atmosphere with GHGs, these impede the transfer of energy from the surface to space, causing the surface and lower atmosphere to warm. However, we would expect this to tend towards an equilibrium in which the amount of energy radiated into space matches the amount of energy that we’re receiving. There are various processes that transfer energy through the atmosphere to the height at which it can be radiated to space, but these mechanisms themselves are not really responsible for the enhanced warming; the enhanced warming is a consequence of the GHGs in the atmosphere.

29. Marco says:

Steven Morris, how would O2 and N2 warm (step 1) and how would they subsequently release their energy into space (step 2). Step 2 is an absolute necessity, otherwise the atmosphere would warm ad infinitum.

The argument from incredulity you’d better leave at the door, otherwise we’re not going anywhere.

30. Steven Morris says:

I’d like to fully disclose that I am a Skeptic of Man Made Climate Change. That I thought was evident from my questions. Perhaps I should have made that crystal clear in my first post. That skepticism may lie in an incomplete understanding of the processes/forces at play. It may also lie in an incomplete hypothesis being presented. I don’t know everything, but I am not stupid either.

AT made a claim, I questioned it. If you all can’t or won’t answer questions, I won’t badger anyone about it. Not here to gish or gallivant. An understanding that 99% of the matter within a region plays little to no role in the temperature of that region, to me, needs a more detailed explanation than it is ‘radiatively inactive’. I think another example in nature where this is evident would be helpful.

Again, AT, I’d like to apologize for using your name. You provided a link it and you were addressing me by name and out of courtesy I did the same. I have no want, need, nor desire to make use of it.

Have a good day

31. Magma says:

@ATTP, getting away from the tedious JAQs digression, this 2012 GRL paper on the minor but non-zero GHG effects of O2 and N2 might be worth a look.

I haven’t read it in detail or looked for any subsequent reaction/follow-up to it, but it seemed sound.

‘The natural greenhouse effect of atmospheric oxygen (O2) and nitrogen (N2)’

32. Steven,

I’d like to fully disclose that I am a Skeptic of Man Made Climate Change. That I thought was evident from my questions.

The evidence in support of AGW is pretty strong. You’d probably get a Nobel Prize if you could find an alternative for which you could provide convincing evidence.

Again, AT, I’d like to apologize for using your name. You provided a link it and you were addressing me by name and out of courtesy I did the same. I have no want, need, nor desire to make use of it.

No problem; I tend to avoid using it directly on the site, but not for any good reason.

33. > AT made a claim, I questioned it.

Which claim, again?

34. Steven Morris says:

Marco,

From my understanding the N2, O2, and Ar are primarily ‘heated’ from contact/conduction from the surface as Guthrie states as well. It also makes sense to me that the Earth’s Gravity and the Mass of the atmosphere work to Compress the atmosphere to heat it up as well. PV=nrT comes to mind.

Now just because N2 and O2 are heated via conduction, does not mean that is the only mechanism that will be used to cool them. Radiation for any matter that is above 0K, from my understanding, is constantly Radiating at a rate determined by the Temperature and the Specific Heat Capacity. I mention SHC because time is also a component.

N2 and O2 are not exceptions from what I understand. I keep hearing about wavelengths that are ‘relevant’. I agree that IR is relevant, but I am puzzled why the wavelengths that N2 and O2 emit and absorb in are not relevant. If it is in the observation, then it is relevant. To what degree may be in question. My gut feeling is that 99% of the matter within a region plays a major role in how fast and slow the region heats and cools and how much energy is stored there at a given moment in time.

We can tell from spectral lines that Titan’s atmosphere is ~98% N2. While very cold, the N2 on Titan is not Radiatively Inactive. We can see it from trillions of kilometers away. It is as active as the temperature and mass make it. If we were to use the same instruments from Titan to view the Earth, we would be able to detect the Temp and Composition of Earth’s Atmosphere. I think. Is that not the case? Wouldn’t we be able to see N2 and O2 buy measuring the radiation/light being emitted from Earth? I’m not sure how accurate they are, but the exoplanet researchers are giving Temp and Composition of planets that are light years away.

Again, I don’t pretend to know all the answers, but the lack of answers around 99% of our atmosphere (N2, O2) make me uneasy about the claims being made about the roles CO2, CH4, and to some degree H2O play.

35. Ed Davies says:

Steve Morris: “An understanding that 99% of the matter within a region plays little to no role in the temperature of that region, to me, needs a more detailed explanation than it is ‘radiatively inactive’.”

I don’t think anybody said they play little to no role. The N₂, O₂ and Ar don’t absorb or radiate much of either the short-wave radiation from the Sun or the long-wave radiation up from the earth and the lower atmosphere. That’s what people mean by ‘radiatively inactive’. However, they do play a very large role in setting the temperature of the atmosphere in that they a) provide most of its heat-capacity so there aren’t wide temperature swings between day and night (as there are on the Moon, for example) and b) they transfer a lot of energy upwards by convection thereby largely setting the temperature profile of the troposphere.

The second of these points has already been made a number of times in this thread so it’s difficult to understand why you think a detailed explanation of why these gases play little to no role is likely to be forthcoming.

36. Ed Davies says:

Steve Morris: “It also makes sense to me that the Earth’s Gravity and the Mass of the atmosphere work to Compress the atmosphere to heat it up as well.”

No, it doesn’t make sense. These gasses were originally heated by compression when the Solar System and Earth were formed but the residual heat from that is now negligible (unlike for Jupiter where it does form a noticeable part of the planet’s energy balance). In much the same way, the air in your car tyres are probably not noticeably warmer than the air around them except for, at most, an hour or so after they were filled (or you’ve driven much).

37. Steven,

It also makes sense to me that the Earth’s Gravity and the Mass of the atmosphere work to Compress the atmosphere to heat it up as well. PV=nrT comes to mind.

If the atmosphere is transparent, then the surface radiates directly to space and will have a temperature set by the balance between the energy radiated from the surface and the energy received from the Sun. This will also set the temperature at the base of the atmosphere. The gravity and mass of the atmosphere can’t produce a temperature that exceeds this because if it did, the surface would then warm and radiate the excess energy back into space and the surface and atmosphere would cool back own again (and the atmosphere would be compressed compared to before). Over time, the atmosphere would simply contract until it had a density and scale height that was set by the temperature of the surface, which will be in radiative balance with the energy being received from the Sun.

38. A back of the envelope calculation.

Imagine the entire atmosphere is located 100km above the Earth’s surface. It’s potential energy is then

$m g h = 10^{19} \times 10 \times 100000 = 10^{25} {\mathrm J}.$

The surface is 33K warmer than it would be without the greenhouse effect (which we are arguing doesn’t really exist but comes from compression of the atmosphere). Therefore the excess energy radiated into space is

$4 \pi R_E^2 \sigma (288^4 - 255^4) = 7.7 \times 10^{16} {\mathrm J/s}.$

So, we have a total amount of energy and a rate at which that energy would be lost. The timescale over which it would be lost is then

$\dfrac{10^{25}}{7.7 \times 10^{16}} = 1.3 \times 10^8 {\mathrm s} = 4 \ {\mathrm years}.$

So, the atmosphere has approximately enough potential energy to sustain an enhanced surface temperature for maybe a few years. Doesn’t sound plausible to me.

39. Steven Morris says:

@nevaudit

“I don’t think that they do play any particular role in heating/cooling the Earth’s atmosphere.”

My guess is they (N2, O2) play a major role in heating since 99% of the atmosphere in contact with the surface is N2 and O2. That is a great deal of Conduction going on. Wind chill comes to mind. The transfer of energy from solid matter to air via conduction is measurable. We could probably measure in zero gravity to remove convection from the scenario to see how quickly a surface cools from conduction to air, and purely radiatively in a vacuum. Use the same apparatus on Earth to introduce Convection to see what role it plays.

I do not believe we are without a means to test these scenarios.

My guess is that they play a major role in Cooling since ~99% of the energy stored in the atmosphere is being emitted by N2 and O2. If we couldn’t detect N2 on Titan and other extraterrestrial places I’d be convinced that N2 was radiatively inactive. From my limited Education I was taught that if matter is above 0 Kelvin, then there is a 100% chance it is at a minimum radiating energy however small that might be, higher the Temp, greater the rate of radiative transfer. Entropy it seems demands that cooling uses the most efficient means to transfer energy so if Convection and/or Conduction are available, they will be used in parallel.

I’ve heard of scientists stopping a photon, but they used a great deal of energy to make that happen. Trapping Radiation in the laboratory, at least for any length of time (nano seconds), is not very easy from what I understand. Does the same hold true in Nature? My guess would be Yes.

Does that sound completely foolish?

40. Steven Morris says:

@Magma

They are restricting the study to particular Long wavelengths. Radiatively Inactive is an inaccurate description. It needs to be restated as Long Wave Radiatively Inactive. As I understand it, nothing is this Universe, save Dark Matter, is 100% Radiatively Inactive.

Let’s ignore the wavelengths the misnamed GHG’s absorb and emit and only look at the wavelengths that 99% of the atmosphere absorbs and emits in. And let’s forget absorption for a moment as well. N2 and O2 emit energy in some wavelength that is different than CO2, H2O, CH4, etc. It is my understanding that they would have to be 0 Kelvin for that not to be the case. My assumption is they are emitting at rate in concert with the average temp of a region of space. Does any of that energy escape to outer space? Do you think there is such a thing as Outgoing Radiation ‘OR’ in the wavelengths that N2 and O2 emit?

@Ed Davies

“However, they do play a very large role in setting the temperature of the atmosphere in that they a) provide most of its heat-capacity so there aren’t wide temperature swings between day and night (as there are on the Moon, for example) and b) they transfer a lot of energy upwards by convection thereby largely setting the temperature profile of the troposphere.”

That makes perfect sense to me, save I’d say ‘almost all’ rather than ‘most’.

@AT

I think your analogy for Potential Energy is missing something that I can’t quite put my finger on. If PV=nrT is not at play in our atmosphere, then I think that it should fail to be present at all in nature. I need some time to ponder all this.

You all have a great day, I have some other items that need my attention. I’ve learned more about the Hypothesis, but I must admit that I am still uneasy about its foundations.

41. Steven,
$PV = NRT$ is at play in our atmosphere. However, it alone, doesn’t define the temperature since it is a relationship between Pressure, density and temperature. The pressure is set by the mass of the planet and the mass/weight of the atmosphere, but that does not define the temperature, since – for the same pressure – you can have a high density atmosphere at a low temperature, or a low density atmosphere at a high temperature. If there were no greenhouse effect, then the atmosphere would collapse down onto the surface, until the temperature at the base of the atmosphere matched the surface temperature and this – together with the pressure at the base of the atmosphere – would set the density.

42. Magma,
Thanks for that paper. It looks like O2 and N2 have an effect that is about 1% that of CO2 and about 0.3% that of CO2 plus water vapour.

43. russellseitz says:

If Steven Morris climbs back into the by now steaming bathtub in the gedanken experiment already thoughtfully provided , it may dawn on him that the relatively transparent water corresponds to the N2 and O2 in the atmosphere, and the few hundreds of parts per million of carbon black ink dispersed in it soaks up solar enegy, warming the water much as vibrationally active CO2 and other GHG molecules do the air.

As a prerequisite to understanding why, he really should take a thermodynamics course or two.

44. Marco says:

Steven Morris, N2 and O2 are diatomic molecules. Consider carefully what that means for their radiative properties. Hint: most transitions relevant for thermal activation are ‘forbidden’. This explains why N2 does not appreciably absorb (and thus also not emit) above 145 nm, and oxygen above 200 nm – at least at atmospheric pressure.

N2 in Titan’s atmosphere was based on absorption of light in the very far UV region and detected well after we already knew that the atmosphere contained methane and hydrogen. You can read the paper below to find out how N2 was detected:
http://www-personal.umich.edu/~atreya/Articles/1981_Extreme_UV_Voyager.pdf

Also note that Titan has an atmospheric pressure at the surface of about 1.5-1.6 atm. And yet, its surface temperature is a mere 98 Kelvin. So, if PV = nRT, explain why Titan has a lower temperature than earth. I’m sure you can, and you will realize that PV = nRT isn’t very helpful in explaining the temperature of the earth.

45. verytallguy says:

Steven Morris

…My gut feeling… …My guess would be…

After (or perhaps before) taking Russel’s suggested Thermo course, I’d recommend a History of Science course.

There are many, many key elements of modern science that are entirely at odds with gut feel or educated guesses.

Evolution, quantum mechanics, relativity, the list of scientific advances dismissed on these grounds is long and distinguished.

46. Steven Morris,

The claim you identified is dated January 18, 2017 at 12:11 pm.

You started questioning on January 17, 2017 at 8:26 pm.

47. Ed Davies says:

Steven Morris: “Does that sound completely foolish?”

Yes, it’s so muddled it’s difficult to know where to begin.

“My guess is they (N2, O2) play a major role in heating since 99% of the atmosphere in contact with the surface is N2 and O2.”

I’m not sure of the numbers for a windy outdoor surface with evaporation and transpiration of water but it’s fairly easy to show that a warmed floor (e.g, one with underfloor heating) releases roughly half its heat by conduction/convection and half by radiation:

So it’s not obvious that N₂ and O₂ dominate completely.

“My guess is that they play a major role in Cooling since ~99% of the energy stored in the atmosphere is being emitted by N2 and O2.”

This really is very muddled so your guess is just wrong. The amount of energy stored does not necessarily correlate at all with the power emitted. The diatomic gasses just have very low emissivities over the bands relevant to thermal radiation at atmospheric temperatures; not everything is a black body.

If the N₂ and O₂ are doing significant amounts of absorption/radiation then can you please explain why the stratosphere is stable? The air there is cold compared with the surface but compared with deep space it is very warm so, according to your thinking, it should be radiating to space and therefore cooler at the top with consequent convection. It isn’t primarily because the diatomic gasses there aren’t doing a lot other than the oxygen molecules absorbing some solar ultraviolet. That heat gets transferred to CO₂ which then radiates it away.

48. Steven Morris says:

To the crowd,

I understand I may as well be a Expanding Universe guy in a room full of Static Universe people, or vice versa however you want to look at it. We don’t agree. One of my science professors a long time ago explained that if you have a view very different from the crowd, expect to get every sort of insult possible hurled at you. Smart people, especially scientists, have very big egos and the larger the ego, the more of a jerk they can be when opportunities present themselves. He said if you plan to go into science and publish work, expect to meet all of them and expect no mercy. It’s part of the industry, don’t take it personal. I’m unknown here and I’m asking questions that many may feel are unnecessary and/or insincere.

That said, don’t hold back, I have very thick skin, and I don’t earn my living in Climate Science. Some of you may, so I can understand any hostility or frustration exhibited. I am however sincere in better understanding your position, and I am amicable in expanding on mine if queried.

I have a good bit to consider, but here’s what I’m pondering until I can respond in detail.

@russelseitz
Let’s stay away from analogies if we can. Liquid water does not behave like N2 or O2 and CO2 does not behave like Ink. Honestly I don’t feel like wasting my time trying to discover how they are different in every way. If you insist there is some great value, I may consider pondering you analogy. Perhaps you can explain how you get a Greenhouse Effect (prevention of Convection) without a Greenhouse Cause (something that prevents convection). See what I mean? Analogies so often lead to nonsense when talking about this subject.

@marco
It’s been 25 years since I’ve studied energy states and diatomic molecules. I have however found some material to refresh my understanding. It just may be that N2 and O2 are forbidden from cooling unless certain conditions are right, but I’m reminded that the Temp of a thermodynamic region is averaged and within that region each molecule is unlikely to have the same state as the next. Energy is likely be emitted at some level at any given moment.

I am certainly not saying that PV= nrT explains all the energy within a thermodynamic region, but I do believe it has some part. Oddly enough if you calculate the Specific Heat Capacity of a cubic meter of Dry Air at Sea Level at different Temperatures and account for the different densities of Air at Sea Level given a certain temp (warmer the air the less density & vice versa), you will find each cubic meter of air has roughly the same Specific Heat Capacity. 373K, 323K, 273K, etc. That I found interesting to and it seems to fit with PV=nrT.

Will need to get back to you on your statement that N2 and O2 are forbidden to cool unless the conditions are correct, but my gut feeling is that a thermodynamic region is quite variable within this respect and that regions of matter, including diatomic gases, are in a constant state of cooling, unless of course they are being heated.

@verytallguy
My gut feeling is that you are not going to add or subtract from this discussion very much 😉 You are obviously much more intelligent than I, so you just want to say it, or do you have issue with what I’ve written? I do read a great deal, mostly non-fiction if you have any suggestions, I’m all ears.

@willard
Is that better? My primary issue is the absence of N2 and O2 being represented when calculating the heating and cooling of our atmosphere. Are you just trying to split hairs?

@Ed Davies
Very interested in the distribution of the energy transfer via Conduction and Radiation from the surface. I will read you paper on the subject. As for diatomic molecules not cooling at the ‘relevant’ temps, I need to ponder that for a moment.

@AT
Thank you for your time. I will be getting back to you as well regarding your potential energy analogy and PV=nrT.

49. russellseitz says:

“Perhaps you can explain how you get a Greenhouse Effect (prevention of Convection) without a Greenhouse Cause (something that prevents convection). See what I mean? Analogies so often lead to nonsense when talking about this subject.”

Steven doesn’t need analogies to talk nonsense: radiative transfer doesn’t interfere with convection inside a greenhouse, it drives it , and the same is true of atmospheric circulation.

50. Willard says:

> Is that better? My primary issue is the absence of N2 and O2 being represented when calculating the heating and cooling of our atmosphere. Are you just trying to split hairs?

What if I told that no, AT’s comment is no better to justify your questioning because it started earlier?

What’s the relationship between your questioning and the post?

Do you want me to start arguing by leading or rhetorical questions so that you come to realize how annoying this is?

51. Steve Morris – I’m not sure where you picked this theory up from — many deniers have touted it at one time or another; Steve Goddard, the family Connolly, and many more. Hotwhopper has dealt with the subject in the past. Skeptical Dr Roy Spencer even got fed up with the “slayers” and finally asked them to put up or shut up.

Since this theory has been around for many years one has to believe that a) it is incorrect or b) it is correct and there is a vast global conspiracy preventing it from being acknowledged as correct.

“a)” would seem the parsimonious answer.

52. Michael Hauber says:

ATTP: ‘ I guess there is a possibility that internally driven changes could produce a change in the surface temperature distribution that cannot be produced by externally driven changes and that, therefore, there could be a cloud response to internally driven changes, despite there be no response to externally driven changes. This, however, seems rather contrived.’

I think this is what ENSO is. Can you prove using only basic physics (whatever that actually is) that something like ENSO cannot happen over a century timescale?

53. Michael Hauber says:

Very Tall Guy,

we appear to be violently agreeing. My point is that what I’d think to be basic physics cannot say too much about climate change in general, as you need to add those complicated calculations on radiative transfer etc

Of course this depends on exactly what is meant by basic physics. Do you have a good definition of basic physics?

54. anoilman says:

Michael Hauber: I would take Basic Physics to mean that with a BSC could possibly learn and understand the material. But with all things in life, the devil is in the detail, and it takes a lot of work to figure out those exact details.

FYI, Radiative Transfer was first year physics for me, and that’s pretty much what causes global warming. Namely short waves come (high frequency heat from the sun) in… heats the planet, then long waves radiate out (low frequency because the earth is cooler). Because the bulk of the energy is in different distributions of the spectrum, you get more heat coming in, and less making it all the way back out.

I learned a fair bit more about global warming on the job… namely ocean heat content is gathered by all allied navies. Its used in applied engineering to hunt submarines, and that’s why we’ve measured ocean temperatures in detail since 1937. I’ve also build sensors for the oil and gas industry which require detailed knowledge of energy absorption by gasses. You pick it up.

ENSO isn’t considered climate.

55. Michael,

I think this is what ENSO is.

Except my point was that you need to find some kind of internal cycle that can produce a substantial radiative response while similarly externally driven warming does not.

Can you prove using only basic physics (whatever that actually is) that something like ENSO cannot happen over a century timescale?

Given that ENSO is a pile-up of energy on one side of the ocean, it might be possible to show that there is a limit to how much you can pile up.

56. Andrew Dodds says:

Michael Hauber –

You could imagine there being two quasi-stable oceanic circulation modes, one of which gave a net heating of deep water (and hence a cooler surface) and the other a net cooling of deep water (with a warmer surface), for exactly the same incoming radiation. IIRC, there is enough heat storage capacity in the deep ocean for this to work on the century-plus timescale, flipping from one mode to the other when it gets too hot/cold.

Of course, we know this isn’t happening because you’d then see the sea level fall when the surface warmed and vice versa. But I don’t think that basic physics rules it out. Complex physics may be another matter.

57. Steven,

I am certainly not saying that PV= nrT explains all the energy within a thermodynamic region, but I do believe it has some part.

I don’t really get what kind of part you think it can play. $PV = NRT$ is an equation of state that presents a relationship between pressure, density and temperature. It’s often referred to as a closure relation. If you do computational modelling of fluids then you have a set of equations that describe mass conservation, momentum conservation, and energy conservation. These equations can be used to describe the flow of mass, momentum and energy through a system. However, they also need a closure relation to relate pressure, density and temperature, and this is what something like $PV = NRT$ does. Alone it can’t tell you much about the absolute values of these quantites, or how they quantities will evolve in your system, but it does present an equation of state that tells how, for example, temperature will vary if you change the pressure and density (and vice versa).

58. PV = nrT is one of those things where I like citing Spencer just to see how that plays.

I can also cite myself as an example of how deep this rabbit hole can get (and how quickly I can get in over my head — I cringe at the number of errors I’ve unwittingly made and still not corrected).

59. verytallguy says:

@verytallguy
My gut feeling is that you are not going to add or subtract from this discussion very much 😉 You are obviously much more intelligent than I, so you just want to say it, or do you have issue with what I’ve written? I do read a great deal, mostly non-fiction if you have any suggestions, I’m all ears.

As I pointed out, “gut feel” is not a very useful way to approach scientific or technical problems. The “issue” with what you have written is that it is entirely reliant on “gut feel”. So my suggestion is that you either
or
(2) do the very hard work necessary to have sufficient understanding to challenge experts.

You currently give the impression of challenging *without* understanding.

(1) IPCC AR5 WGI Summary for policymakers. This is the expert judgement of the current state of the art in understanding of the climate system. If you think they’re wrong, you’d better have a really good reason why.
(2) Spencer Weart’s “The Discovery of Global Warming”
http://history.aip.org/climate/index.htm
(3) Basic Physics from Realclimate
http://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/
(4) If your physics is up to it, “Principles of Planetary Climate”

60. Ed Davies says:

Steven Morris: “As for diatomic molecules not cooling at the ‘relevant’ temps, I need to ponder that for a moment.”

Why do you keep twisting things like this? Nobody says diatomic molecules would not cool, just that they have a low emissivity so will cool slower.

61. matt says:

Only skimmed comments so may be way off track but the argument sounded like the presence of nitrogen and oxygen reduces the amount of expected warming. Since oxygen levels are dropping due to human activities (?mainly FF combustion, then land-use changes?), wouldn’t this be arguing for more anthropogenic warming. So at least for oxygen, even if his premise is true, he got the conclusion backwards. But perhaps I’ve missed the point entirely, and of course their is N2 (no idea which way it has been going, nor what is driving it).

62. matt,
The radiative impact of O2 is very small (see the paper that Magma highlighted). I’m not entirely sure what Steven’s argument is, but I think it is related to the O2 and N2 clearly being warm and then an argument that this is because of the pressure in the atmosphere producing this warming, rather than the Greenhouse Effect. Just for clarity, this is clearly wrong.

63. JCH says:

Assuming no background warming due to an enhanced GHE, if there were to be a period of prolonged El Niño dominance, it would seem to me the warming global situation we associate with that would eventually fade away as the Western Pacific would grow progressively colder.

64. Phil says:

With regard to the topic of N2 and O2 contributing to the GHE (the Steven Morris sub-thread), its worth also noting that for gases to act as greenhouse gases, they must absorb IR radiation at the frequencies that the Earth actually emits. Given Earths emission frequencies the vibrational frequencies that overlap with Earthlight are almost exclusively bending vibrations (which occur at lower frequencies than stretch vibrations). Diatomic molecules (N2, O2, etc.) do not bend, since you need three points (nuclei) to form an angle, so bending vibrations only occur in molecules of 3 atoms or more. This point is in addition to the selection rule point that Marco (correctly, IMO) raises above.

65. Ken Fabian says:

Whilst it may be conceivable that surface temperature changes over the longer term result from redistributions of heat already within the system rather than accumulation of overall heat – as occurs over shorter time frames – it hasn’t been shown convincingly that that is in fact the case. Wouldn’t rising heat content – ocean heat content mostly – constitute clear evidence of ongoing accumulation of heat and be inconsistent with the kinds of mechanisms Steven Morris is hypothesising?

66. Ken,

Wouldn’t rising heat content – ocean heat content mostly – constitute clear evidence of ongoing accumulation of heat and be inconsistent with the kinds of mechanisms Steven Morris is hypothesising?

Yes, that is indeed one reason why Steven’s hypothesis has problems. It is possible, maybe, that some kind of redistribution of internal heat could lead to radiative responses (clouds, water vapour,..) that then lead to both surface warming and increases in OHC. The problem here is that – on average – we expect these radiative responses to be smaller – in magnitude – than the Planck response, so sustaining such a process would seem extremely difficult and one would also need to explain why they respond to internally-driven warming, but not to externally-driven warming.

67. graemeu says:

ATTP I was surprised that you didn’t correct Steven Morris’s simplistic understanding of how a greenhouse works, way back up at the top of the comments, instead you concurred. While modern poly-tunnels do simply trap warm air and therefore require heating. Not so long ago greenhouses were glass and it is for these that the metaphor is appropriate. Glass admits incoming solar radiation while reflecting the outgoing infra-red radiation retaining warmth better than a double skinned poly-tunnel.

68. graemeu,
I didn’t correct it, because I think he is roughly right. Even with glass, one of the reasons why a greenhouse works is because convection is inhibited (I, however, haven’t studied greenhouses in any detail, so happy to be corrected). However, the main reason I didn’t get into detail is because I didn’t see the point in arguing about an analogy; they’re never perfect and are just meant to be illustrative.

69. Ron Graf says:

Ken Fabian: Wouldn’t rising heat content – ocean heat content mostly – constitute clear evidence of ongoing accumulation of heat and be inconsistent with the kinds of mechanisms Steven Morris is hypothesising?

The paleo-climate proxies (notwithstanding Mann et al) show significant millennial variability. This means if net forcings were essentially zero over millennial periods then fluctuations could only occur by ocean heat content OHC rising in periods where the global surface temperature fell and the reverse. If unforced millennial variability happened frequently over the last several millennia it would reason it could be happening presently.

Also, it the battle over accepting the adjustments to the surface record is far from settled as seen over at CE https://judithcurry.com/2017/01/20/a-case-study-of-the-norther-colorado-front-range-temperature-history/

70. Ron,

This means if net forcings were essentially zero over millennial periods then fluctuations could only occur by ocean heat content OHC rising in periods where the global surface temperature fell and the reverse.

I don’t think anyone thinks that net forcings were essentially zero on millenial timescales. The Sun, Volcanoes, orbital variations, can all contribute to changes in external forcing. There are some changes that might have been internally-forced (Dansgaard-Oeschger events, for example) but these are still associated with changes in albedo (ice sheets) not just changes on OHC. The problem with long-timescale warming being driven by release/take-up of OHC is that the heat capacity of the atmosphere is small enough that it should lose any excess energy (or regain any energy deficit) pretty quickly, and so you would need some process to continually – for decades/centuries – feed energy from the ocean into the atmosphere. I don’t think we see any evidence for such a process.

Alternatively, you need some kind of feedback response that acts to maintain the higher/lower temperatures. This is possible, but these responses are expected on average to be smaller than the Planck response, so it is hard to see how they could sustain these changes for a long period of time (the surface should ultimately warm back up, or cool back down). Also, if you invoke this, you’re essentially arguing for high climate sensitivity since these processes should also respond to externally forced warming.

If unforced millennial variability happened frequently over the last several millennia it would reason it could be happening presently.

See above.

71. JCH says:

Yes, we should be deep in the trough of a millennial cold cycle, but ACO2 (the control knob of the climate) has knocked the holy crap out of it.

72. Ron Graf says:

Anders: I don’t think anyone thinks that net forcings were essentially zero on millennial timescales. The Sun, Volcanoes, orbital variations, can all contribute to changes in external forcing.

I agree. I am simplifying a model for the purpose of study.

The problem with long-timescale warming being driven by release/take-up of OHC is that the heat capacity of the atmosphere is small enough that it should lose any excess energy (or regain any energy deficit) pretty quickly, and so you would need some process to continually – for decades/centuries

Ocean uptake changes are shifts in steady-steady state of overturning currents. Changes in path or depth or any cyclical dynamic could shift the steady state for an extended period. Currents depend on the convergence of many complex variables.

Also, if you invoke this, you’re essentially arguing for high climate sensitivity since these processes should also respond to externally forced warming.

Not necessarily. The variation could be enhanced by feedback but does not require it.

73. Ron,

Changes in path or depth or any cyclical dynamic could shift the steady state for an extended period. Currents depend on the convergence of many complex variables.

The Planck response is 3.2W/m^2/K. If the surface is warmed via some internal process by 1K, then we we will radiate $5 \times 10^{22} J$ more energy into space than we’re receiving. This is about 5 times bigger than the rate at which we’re currently accruing energy. In the absence of some kind of radiative response in the atmosphere, the oceans would have to continually supply this much energy to the atmosphere to maintain some kind of temperature enhancement. Similarly if there were some kind of temperature decrease.

Not necessarily. The variation could be enhanced by feedback but does not require it.

Unless you can find some way for the ocean to continually pump large amounts of energy into the atmosphere (or, similarly, take up large amounts of energy from the atmosphere) then this is needed.

Can you at least indicate that you understand this, because it mostly seems as though you’re simply hand-waving wildly.

74. Ron Graf says:

Anders, these are not assertions by proclamation (hand waving). The sea already does in fact take up enormous amounts of energy, and conversely release it, in the ENSO, AMO and PDO. There is also plenty of consensus evidence that climate changing events of geologic magnitude have occurred from unforced shifts in the steady-state dynamic between sea and atmosphere, including the Younger Dryas period and the merging of N and S America being associated with the start of the Pleistocene and the Quaternary Ice Age, which we are still in. It makes perfect sense that such shifts could occur on a centennial and millennial scale as well.

75. Ron,

There is also plenty of consensus evidence that climate changing events of geologic magnitude have occurred from unforced shifts in the steady-state dynamic between sea and atmosphere, including the Younger Dryas

Yes, but I’ve already pointed out that these were associated with changes in ice sheets/albedo. You’re arguing that you could cool/heat the planet for an extended period of time by simply transferring energy to and from the ocean.

It makes perfect sense that such shifts could occur on a centennial and millennial scale as well.

Unless you also have some kind of radiative change too, it doesn’t make perfect sense.

76. Ron Graf says:

Yes, but I’ve already pointed out that these were associated with changes in ice sheets/albedo.

Yes. I don’t think anyone disputes that ice sheet albedo is a major positive feedback (especially when freshly created and before it gets dusty dirty). It’s the most obvious cause of the glacial cycle. It seems to make sense there could be mini-triggers (unforced) that don’t quite manifest in full blown glacial state but who’s effects linger by extending the ice caps until they can gradually diminish. I believe there has been evidence of such glacial advance in the LIA but I can’t cite it at the moment.

77. Ron,
The point is that even if some earlier changes could have been internally forced, we still have a reasonable understanding of the physical processes that drove the warming/cooling. There are, therefore, little indications that something other than enhanced CO2 has been a major driver of change in the last hundred years or so.

78. BBD says:

Ron

There is also plenty of consensus evidence that climate changing events of geologic magnitude have occurred from unforced shifts in the steady-state dynamic between sea and atmosphere, including the Younger Dryas period

The YD was probably caused by abrupt drainage of proglacial Lake Agassiz into the N Atlantic. The freshwater flux halted the AMOC and caused a cooling event centred on the N Atlantic. It was therefore a *feedback* to orbital forcing.

It was not a global climate shift of ~10C as confused ‘sceptics’ invariably claim. YD cooling globally was only about ~0.6C (ref.).

79. anoilman says:

Ron.. In any case, we’d need to figure out what is heating the ocean today. Its not a small amount, and its way more than the atmosphere can contain without freezing or cooking us.

80. JCH says:

The amazing thing looking at that graph is just a few years ago some were arguing at CargoCult Etc. that the oceans had stopped warming.

No matter how huge their errors, their fans never hold them accountable. It’s just onto the next spoon bending trick.

81. Ken Fabian says:

But we do have GHG driven warming and it has a lot of strong supporting evidence and sound reasoning behind it – that would have to be set aside by anyone seeking to show that it is not
GHG driven. Sound grounds for setting all that aside would be needed. I haven’t seen that, just speculations.

Understanding of the other factors doesn’t seem to have been neglected – that improving understanding appears to support rather than weaken the conclusion that the GHG mechanism is the dominant driver of modern global climate change.

82. Ron Graf says:

Anders: The point is that even if some earlier changes could have been internally forced, we still have a reasonable understanding of the physical processes that drove the warming/cooling.

I agree that many, even most, of the individual mechanisms that drive global climate are understood by someone. I would dispute that humanity has sufficiently clean data to validate a model recreating the interaction of all those mechanisms, thanks to the complexities and instabilities coupled multi-phase fluid dynamics.

Multiple paleo-climate reconstructions confirm the start of the modern warming trend, the LIA minimum, pre-dates burning of fossil fuels by ~200 years. Additionally, that warming trend was not perturbed during the first century of industrialization despite there were two major volcanic aerosol events that dwarf anything since. Do you dispute this?

Anoilman, although 200 zetta-joules over the last 30 years might be significant but it leaves me puzzled as to why Kevin Trenberth infamously confided to team members: “The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t.” I realize this was pre-SST adjustments declaring that the ships and buckets were warm biased after they were phased out of use, (a neat way to cool the past SST without threat of having the correction affect the future).

JCH, The graph could be more amazing if it went earlier than 1958 or plotted sampling density to give a rough idea of error in the trend. (I know some amazing grafs too 😉

Ken Fabian, “We know because we know” is, I think what Anders calls hand-waving. I respect and presume you believe you have plenty of support for your statement but are not taking the time to state it, and thus, using your credentials (argument from authority) to assert. But the null hypothesis is: “the theory is incorrect until it is proven correct,” (at least if you love and respect science).

To relieve Anders from obligatory response I will submit on the point that “it is all basic physics.” And, there is no political driven bias that can affect assertions. All proclamations from individuals with scientific degrees or titles must be accepted. Disputes are settled by who has the most supporters. And, finally, it’s okay to censor bad or unscientific reasoning.

Cheers all!

83. Ron Graf says:

BBD, I missed you. You said” The freshwater flux halted the AMOC and caused a cooling event centred on the N Atlantic. It was therefore a *feedback* to orbital forcing.

I agree that massive fresh water flux was a feedback to orbital Milankovitch forcing, as was the entire Holocene transition to some extent. But, what the YD was randomly triggered by is irrelevant. The point is that it was internally forced or “unforced” (whichever you prefer,) and it lasted ~3000 years, about 2990 longer than Anders argues that unforced cooling (or warming) can overpower atmospheric energy imbalance.

It was not a global climate shift of ~10C as confused ‘sceptics’ invariably claim. YD cooling globally was only about ~0.6C.

NOAA says it was a 3-5C drop in the NH, which a back of the envelope calculation gives 1.5-2.5C, globally. ref.

84. anoilman says:

Ron Graf: I have no clue why you’re talking about Sea Surface Temperatures (SSTs) when I was talking about ocean heat content. No clue at all. The heat is in the water, not just at the surface. Your tactic is a disingenuous bait and switch.

You could read up on what Trenbirth was talking about; (hint: deep ocean data, which is not the same as SSTs.)
https://skepticalscience.com/Kevin-Trenberth-travesty-cant-account-for-the-lack-of-warming.htm

Are you really claiming that the NOAA data is a sham? Do you even know who gathers that data?
https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/
This is a picture of what that data is used by;

We started gathering it in 1937 (first use of military XBTs), and its used to hunt these;

We use the Levitus database to sink submarines. We know exactly how accurate the data is. Its used actively by all allied navies to predict ocean temperature profiles in order to determine where submarines are likely to hide. Do you need a basic description of how sonar and acoustics work?

Now since you did bring up an interesting paper on the first ocean temperatures (not SSTs) using buckets, here it is. Its a re-calibration of the data set gathered by the HMS challenger from 1872 or so;
http://www.nature.com/nclimate/journal/v2/n6/full/nclimate1461.html%3FWT.ec_id%3DNCLIMATE-201206?message-global=remove&WT.ec_id=NCLIMATE-201206

Now you make it sound like something untoward happened with re-calibration of the data, when nothing could be further from the truth. Namely, they bucket would be dragged behind the moving boat, so, using remedial trig, you can tell that a boat moving fast would drag a bucket at a higher depth than a boat moving slowly. That meant that for this particular data set, they had to calculate what depth the measurements were actually taken at. Oh look, here’s a simple explanation for you.
https://arstechnica.com/science/2012/04/modern-ocean-temperatures-compared-to-challenger-expedition-data/

We don’t do it that way anymore because its a bad method. Everything is manual, and not standardized, so its subject to inconsistencies, its difficult to tie the data to the ships moment to moment logs, etc. So… toss it.

85. Marco says:

“NOAA says it was a 3-5C drop in the NH, which a back of the envelope calculation gives 1.5-2.5C, globally. ref.”

Your ref does not support your claim. Nowhere is “3-5C drop in the NH” mentioned. Two times numbers are mentioned: 10C for Greenland, and 3C for a lake in Venezuela, and that’s it.

Please do not make up things. People here actually check references.

86. BBD says:

Ron Graf

What Marco said. By way of contrast, the reference that I provided does support what I wrote.

But, what the YD was randomly triggered by is irrelevant.

No, it isn’t. You were talking about internally-forced climate change and the YD was a feedback to external forcing.

The point is that it was internally forced or “unforced” (whichever you prefer,)

Um, no. It was a feedback to Milankovitch forcing.

87. BBD says:

And this:

it [YD] lasted ~3000 years

No. The YD took place between ~12.9 and ~11.7ka so it lasted about 1.2ka. Less than half the length you claim. IMO you are bullshitting again.

88. Ron Graf says:

Anoilman, thanks for your detailed reply. My point was not that it was impossible that ocean temperature had been measured before or that we needed to do it, as well as measure salinity, to properly calibrate sonar, my point is that the data sampling was never intended to create a global OHC reconstruction. It was just re-purposed for that use, just like the buckets and engine intake SST measurements which you suggested we should “toss.” The Argo data from ~3600 buoys that constantly cycle through a measurement protocol from 2-2000m every 10 days or so is a good global data source. Unfortunately, it goes back only to 2005. The OHC uncertainty travels steeply up as one uses data prior to then.

Marco, BBD, I thought my assertion of 3-5C for the YD was fair. Did you look at the graphs?

BBD, I will accept your correction ~12.9 and ~11.7ka. That means an internally forced (perturbing of the AMOC) caused a climate event that lasted 1190 years longer than the 10 years Anders thought was the limit for unforced effects on the atmospheric energy profile. And just because the Milankovitch orbital influence may have contributed to the collapse of the NH glaciation that transitioned to the Holocene does not make it a forced influence. For sake of argument, lets say it is found that Scafetta’s theory that Jupiter’s magnetic field is the trigger for the AMO. This does not mean it is forced because the influence is so minuscule it is only useful to be the footstep that causes the avalanche. This is Milankovitch relationship to the YD. Do you agree?

89. Marco says:

Ron, it isn’t a fair assertion, because that came from graphs from GISP2 and a lake in Venezuela (where a clear caveat was mentioned, too). You cannot just take two locations and come with a wild guess, and ignore the reference provided by BBD, which does a LOT more than just look at two locations and then handwave a number.

90. Ron,

longer than the 10 years Anders thought was the limit for unforced effects on the atmospheric energy profile.

Now you’re misrepresenting me. I’ve written before about Dansgaard-Oeschger events. I’m well aware that there may be examples of internally events that last for longer than 10 years. These, however, are normally associated with changes in large ice sheets, not simply the transfer of energy from the oceans to the surface, and vice versa. I was simply suggesting that the oceans alone can’t produce a long-term warming/cooling event because of the heat capacities of the system. If they could produce a significant in ice sheets that could then trigger something that lasted much longer, but that isn’t really relevant to what we’re experiencing today.

91. BBD says:

Marco, BBD, I thought my assertion of 3-5C for the YD was fair. Did you look at the graphs?

It was wrong. The correct dating is ~12.9 – 11.7ka, as stated.

That means an internally forced (perturbing of the AMOC)

No, the meltwater flux from proglacial Lake Agassiz resulted directly from orbital forcing. The consequent interruption of the AMOC and subsequent N Atlantic cooling follow a direct chain of causality. The YD was a feedback to orbital forcing not an ‘internally forced’ event. Stop pushing counterfactuals please. Especially as this has already been addressed once.

And just because the Milankovitch orbital influence may have contributed to the collapse of the NH glaciation that transitioned to the Holocene does not make it [the YD] a forced influence.

Yes it does. Stop bullshitting.

This is Milankovitch relationship to the YD. Do you agree?

No.

92. BBD says:

It was wrong. The correct dating is ~12.9 – 11.7ka, as stated.

Coffee needed.

* * *

Marco, BBD, I thought my assertion of 3-5C for the YD was fair. Did you look at the graphs?

It is incorrect. See Shakun & Carlson 2010 (emphasis added):

The magnitude of the Younger Dryas climate anomaly (cooler/drier) increases with latitude in the Northern Hemisphere, with an opposite pattern (warmer/wetter) in the Southern Hemisphere reflecting a general bipolar seesaw climate response. Global mean temperature decreased by ~0.6C during the Younger Dryas. Therefore, our analysis supports the paradigm that while the Younger Dryas was a period of global climate change, it was not a major global cooling event but rather a manifestation of the bipolar seesaw driven by a reduction in Atlantic meridional overturning circulation strength.

And:

4) The Bølling/Allerød – Younger Dryas climate oscillations were an expression of this bipolar seesaw with the Antarctic Cold Reversal representing the opposite sign response of the Southern Hemisphere. However, these climate events are most clear at mid to high latitudes with a complex climate response in the tropics and subtropics of both hemispheres.

(5) While the Younger Dryas may have been a near-global scale climate change, in the sense that climatic anomalies occurred in many regions during this time, it was not a major global cooling event (approximately -0.6C change), with many records showing warming or a shift toward interglacial conditions through the Younger Dryas. This is particularly evident in the low latitudes of the Northern Hemisphere and in many areas of the Southern Hemisphere. Globally, the Younger Dryas was by no means a return to ice age climate.

93. Ron Graf says:

Anders, It seems like your argument is that changes in ocean currents and overturning dynamics (unforced events) can lead to long-term changes if they are long-lasting enough to be fixed into summer-surviving polar ice, which would change albedo, and thus producing a long-term scale positive feedback. I agree. So how long does that unforced event have to last in order to take hold to create a mark in the geologic record? Certainly it is more than 10 years. 100 years? 1000?

BBD, regarding YD being a forced event, I understand the term forcing in climate to mean direct effects on radiative flux, for example, solar, GHG, surface albedo and changes in the reflective of emissive properties to the atmosphere (aerosols). And feedbacks are changes in radiate flux that result in a predictable response to direct forcings. Relative to these definitions the YD event is an unforced event. Just because we have a recent theory as to what triggered it does not make it any less an unpredictable chaotic effect caused internal dynamics. As to Shakun and Carlson(2010), they set out to show the YD was not global climate change, and surprise, they succeeded. They say it was mostly a polar see-saw, implying it was a warming event for the SH. Okay, but under this logic, it must be extremely difficult to sustain the positive feedback of polar ice sheets. However, I agree with Anders that a sustained summer-proof ice sheet would change albedo and thus the energy balance and thus result in a lasting change in GMST.

So Anders, BBD, which of these things to you believe:
1) Unforced events do not have the ability change GMST for more than 10 years unless they are reinforced by the positive feedback of ice advance. (I agree.)

2) Ice advance in the NH will be offset by a see-saw of ice decline in the SH. (I disagree.)

3) Climate is extremely sensitive to changes in GMST due to powerful positive feedbacks.
(I disagree.)

4) Climate is so insensitive as to withstand, with little deflection in GMST, a 3-5C cooling in the NH leading to ice sheet advance over a 1000-year+ period. (I disagree.)

5) Unforced events that last less than a few hundred years result in some ice sheet advance or retreat but recover, resulting in centennial and millennial oscillations. Climate has some positive feedback but it is not extremely sensitive. (I agree.)

94. Ron,

It seems like your argument is that changes in ocean currents and overturning dynamics (unforced events) can lead to long-term changes if they are long-lasting enough to be fixed into summer-surviving polar ice, which would change albedo, and thus producing a long-term scale positive feedback.

Not really. My point is that the atmosphere has a relatively low heat capacity and, given a Planck response of 3.2W/m^2/K, if you want to sustain warming (or cooling) for a long period of time (many decades, or centuries) then you need some kind of radiative response, such as a change in albedo, change in clouds, change in water vapour, etc. These are essentially the same processes that respond to externally forced warming. Hence even if there have been internally forced events in the past is not some kind of indicator that current warming is internally forced.

2) Ice advance in the NH will be offset by a see-saw of ice decline in the SH. (I disagree.)

Who suggested this?

3) Climate is extremely sensitive to changes in GMST due to powerful positive feedbacks.
(I disagree.)

What do you mean by extremely? The best estimate for ECS is around 3K (with a range of something like 1.5K to 4.5K).

4) Climate is so insensitive as to withstand, with little deflection in GMST, a 3-5C cooling in the NH leading to ice sheet advance over a 1000-year+ period. (I disagree.)

I’ve no idea what you mean by this.

5) Unforced events that last less than a few hundred years result in some ice sheet advance or retreat but recover, resulting in centennial and millennial oscillations. Climate has some positive feedback but it is not extremely sensitive. (I agree.)

Again, no idea what you’re suggesting here. You keep throwing around words like extremely without defining what they mean.

95. BBD says:

And feedbacks are changes in radiate flux that result in a predictable response to direct forcings.

Feedbacks are responses to changes in radiative flux.

Relative to these definitions the YD event is an unforced event.

The YD was a feedback to a forcing change, not an ‘unforced event’. This is pretty textbook stuff really.

As to Shakun and Carlson(2010), they set out to show the YD was not global climate change, and surprise, they succeeded.

No, they didn’t. Perhaps reading the paper might be a good idea.

96. Ron Graf says:

BBD: Feedbacks are responses to changes in radiative flux.

Ron: And feedbacks are changes in radiate flux that result in a predictable response to direct forcings.

We are saying the same thing if you are agreeing that feedbacks are both responding to changes in radiative flux and causing changes in radiative flux.

Anders: You keep throwing around words like extremely without defining what they mean.

I was mostly addressing BBD’s assertions that:
1) The YD was a natural physical feedback to Milankovitch forcing.
2) The YD, although able to leave a clear geological record of its impact was really not a significant excursion from the established slope of transition out of the ice age, thus implying that GMST is very stable and simply flows gradually according to the tiny Milankovitch forcing. The point I believe BBD is trying to make is that GMST is static, like the shaft of a hockey stick until there is a change in radiative forcing and then it is very sensitive with powerful feedbacks.

My points are:
1) A feedback is a direct predictable and reversible response to change in temperature globally. The YD is in no way to be classified as a feedback to Milankovitch forcing. I would also argue against the glacial transitions being a feedback to Milankovitch forcing.
2) Milankovitch forcing is extremely weak and relies on the inherent instability in the glacial cycle to trigger changes in state. There must be other circumstances working, the most obvious are the positive feedback of ice albedo first and the positive feedback of ocean modulated atmospheric CO2 concentration second.
3) And since the Milankovitch forcing is so weak, the abrupt ends of the interglacials must be triggered by either significant externally forced events or significant internally forced events. The is especially true if one considers that ice albedo was at a minimum, and CO2 concentration at its peak, at the termination of any past interglacial.
4) The YD provides a test tube example of the climates sensitivity to a change in the ocean dynamics.
5) I agree with Anders’ statement: My point is that the atmosphere has a relatively low heat capacity… The ocean, on the other hand, has immense heat capacity. And if it decides to take up atmospheric energy it can do so in a significant amount over a significant time and sustaining that change by positive feedback, first by increasing albedo, whiting out the NH, and second by shifting the equilibrium of ocean CO2 uptake.
6) As far as high climate sensitivity claimed by Hansen from study of the LGM, that get’s weighted against his bias, which is clearly evident his alarmist message right in his abstracts. An impartial observer would weight it against the logic that shows past interglacials show remarkable consistency in peak temperature, as if there is a negative feedback reached at some temperature, or at least there are no more positive ones.
7) Internally forced GMST is evidenced in ENSO at short term and AMO/PDO in decadal scale and YD on geologic scale. There is plenty to infer that centennial and millennial variability in impartial proxy reconstructions, and there is a clear observational evidence to assume internal variability is a prime suspect.
8) The title to this post and many of Anders’ posts imply “and then there’s physics” that it must take someone brain dead or who is religious zealot not to get the elementary nature of the questions involved. I think its a tad more complicated than that. I want to find the true answers.

97. Ron Graf:

And if it decides to take up atmospheric energy it can do so in a significant amount over a significant time and sustaining that change by positive feedback, first by increasing albedo, whiting out the NH, and second by shifting the equilibrium of ocean CO2 uptake.

I always love this. We are left to the *moods* of the ocean. Will it *decide* to take up energy or not this year dear, I have a headache?

And then there’s:

As far as high climate sensitivity claimed by Hansen from study of the LGM, that get’s weighted against his bias

No, it gets discounted when someone shows an error in his calculations or uses new/better data to come up with a preferred estimate. Last I checked he believed fast-feedback climate sensitivity was 3 ± 0.5°C for 4 W/m2 CO2 forcing.

98. Ron,

The title to this post and many of Anders’ posts imply “and then there’s physics” that it must take someone brain dead or who is religious zealot not to get the elementary nature of the questions involved. I think its a tad more complicated than that. I want to find the true answers.

How you choose to interpret my post titles and the name of my blog is up to you. However, your interpretation isn’t what is intended.

99. Susan Anderson says:

The patience exhibited by this community in responding to queries is not matched by the faultfinding from questioners! They’re *sure* there has to be something they can get at – remarkable. Maybe they’re playing to an unseen gallery.

I don’t think a “true” answer would be accepted because it isn’t the desired result. It’s almost a perfect case of projection:

All proclamations from individuals with scientific degrees or titles must be accepted. Disputes are settled by who has the most supporters. And, finally, it’s okay to censor bad or unscientific reasoning.

Offensive given the careful and detailed replies which are dismissed and ignored. Attacks like this demonstrate bad faith; the replies do not. Here was a good stairway to understanding from Verytallguy. It’s fashionable to dismiss expertise as “elitism” but in fact those who do the work do know more than those who don’t, won’t, or can’t.

either
or
(2) do the very hard work necessary to have sufficient understanding to challenge experts.

(1) IPCC AR5 WGI Summary for policymakers. This is the expert judgement of the current state of the art in understanding of the climate system. If you think they’re wrong, you’d better have a really good reason why.
(2) Spencer Weart’s “The Discovery of Global Warming”
http://history.aip.org/climate/index.htm
(3) Basic Physics from Realclimate
http://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/
(4) If your physics is up to it, “Principles of Planetary Climate”

I get bogged down early in (3) but assuming bad faith won’t get you there

If one is convinced that no matter what anyone replies there’s something wrong here and won’t accept genuine answers, one is wasting people’s time or grandstanding.

100. Given Susan’s comment, I thought I would respond a bit more to this

I think its a tad more complicated than that. I want to find the true answers.

It’s almost certainly a tad more complicated but that doesn’t necessarily imply that our understanding of the basics is wrong. It probably simply means that we don’t yet have a complete understanding of the details. Also, we’re all wanting to find true answers, so the implication that some of us don’t, while Ron does, is a bit insulting. Just asking questions is not the typical route to the true answers.

101. BBD says:

1) A feedback is a direct predictable and reversible response to change in temperature globally. The YD is in no way to be classified as a feedback to Milankovitch forcing.

Wrong yesterday and still wrong today. The causal chain from orbital forcing to YD has been explained. The YD is unambiguously a (negative) feedback to orbital forcing change. You are persitently arguing a counterfactual by assertion (aka peddling bullshit).

I would also argue against the glacial transitions being a feedback to Milankovitch forcing.

And I would argue that they do not happen by magic and that belief in a unicorn-fart-propelled climate system is silly.

3) And since the Milankovitch forcing is so weak

You need to look up the insolation change at 65N latitude across the obliquity cycle. Hint: it is not trivial.

the abrupt ends of the interglacials must be triggered by either significant externally forced events or significant internally forced events.

Or perhaps ice sheets extending to 30N latitude are inherently prone to collapse when obliquity cranks up summer insolation.

The is especially true if one considers that ice albedo was at a minimum, and CO2 concentration at its peak, at the termination of any past interglacial.

The glacial state is the equilibrium for icehouse earth. The Milankovitch peaks concentrate enough of the (almost constant) solar radiation in the latitude band where most of the land ice is which temporarily shifts the equilibrium, and the feedbacks take over to do the rest. Once the Milankovitch peak is over the feedback alone is not sufficient to maintain the interglacial state, causing a gradual descent back into a glacial. Across the Pleistocene, CH4 and CO2 levels typically fall in the later phase of interglacials. Ice albedo increases slowly as the NH ice sheets begin to grow in the cooling late-phase interglacial.

You are just bullshitting relentlessly, Ron.

102. BBD says:

The title to this post and many of Anders’ posts imply “and then there’s physics”

One possible reading would be: there’s bullshit, and then there’s physics.

103. Maybe we can tone this down a little bit 😉

104. BBD says:

Always used in the Frankfurtian sense, ATTP.

It’s not just a cheap jab.

105. BBD,
I know, and I do sympathise, but I’m still willing to consider that Ron may be acting in good faith (this may be naive).

106. Ron Graf says:

Anders: How you choose to interpret my post titles and the name of my blog is up to you. However, your interpretation isn’t what is intended.

I do believe you that it was not your intention. I hope, conversely, you can believe that for those who are studying climate in good faith often see the things differently. I also thank you for keeping an open mind about my good faith. Finding scientific truth and being always skeptical is my nature. One of the most powerful biases is the desire to conform and enforce conformity, as can be seen by the history of religious propagation, for example. Thus, I am skeptical of crowd-think, even of crowds of experts. At the same time I give weight to expert opinion.

Susan Anderson: If one is convinced that no matter what anyone replies there’s something wrong here and won’t accept genuine answers, one is wasting people’s time or grandstanding.

I believe this is a common justification used to close down debate. It is particularly easy to see the other side of the debate as “blinded” or acting in bad faith. I do respond to good arguments combining testable facts and logic. I actually come here to find the most persuasive evidence that the non-skeptics can present. Thank you for presenting yours. I will kindly consider it.

BBD, although I can agree with you that past interglacials did not end in a week, their behavior to me looks rather chaotic and abrupt as compared to the gradual 41K cycle of obliquity changing from 22deg to 24.5deg and back. And, of course as you know, interglacials only appear every third obliquity cycle, and even then, not on perfect que (even with consideration of eccentricity and precession). I agree with you that Earth’s radiative equilibrium is significantly affected by ice albedo. Milankovitch forcing is an incomplete answer. The build up of glacial height and surface dust and dirt could provide instability to account for abrupt reversals. You and I will just have to disagree about interruptions in the AMOC or other internal forcing as being considered feedbacks in the cases where they can plausibly be linked to an external trigger. Perhaps others can weigh in on this and provide their consensus (yes I said consensus).

It occurs to me that one of the alarms of the non-skeptics is that the AMOC could collapse and trigger the return to ice age. Even if this is caused by interruption of salinity from too much fresh water melt from too much warmth from too much CO2 from human emissions, I still would call it an unforced event until we can show it could not happen in past interglacials.

107. Ron,

I also thank you for keeping an open mind about my good faith. Finding scientific truth and being always skeptical is my nature.

I think you should be careful of confusing skepticms and being dubious. Simply asking lots of questions is not necessarily being skeptical. Being skeptical does require some actual investigation, not simply questioning what is being presented by others.

108. verytallguy says:

Even if this is caused by interruption of salinity from too much fresh water melt from too much warmth from too much CO2 from human emissions, I still would call it an unforced event until we can show it could not happen in past interglacials.

Even if caused by forcing, you would call it an unforced event.

I can see why you’re struggling.

109. vtg,
I’d missed that. Indeed, if Ron gets to redefine what most would call a forced event, as an unforced event, then clearly he can claim there is a lot of unforced warming. This would simply be because he’s redefined the terminology, not because external forcings are not producing warming.

110. Actually, to follow up on that, it seems that’s Ron’s view is that if one can show that an event has happened before, then if it’s happening now, it’s somehow not anthropogenic, or something. Of course, that’s rather silly, since the underlying processes are the same. That we’re emitting CO2 into the atmosphere does not mean the system will respond differently to what would happen were the release natural. If anything, our understanding of past changes give us additional confidence in our understanding of changes happening now.

111. BBD says:

This would simply be because he’s redefined the terminology, not because external forcings are not producing warming.

Well, when you are wrong, what else can you do but change the definitions of key terms?

112. BBD says:

Ron Graf

BBD, although I can agree with you that past interglacials did not end in a week, their behavior to me looks rather chaotic and abrupt as compared to the gradual 41K cycle of obliquity changing from 22deg to 24.5deg and back.

Glacial climates are tippy. Lots of NH ice under constantly varying orbital forcing makes for jumpy, albedo feedback amplified behaviour.

The build up of glacial height and surface dust and dirt could provide instability to account for abrupt reversals.

Which *always* occur at times of peak obliquity. Always. Given the timescales involved, coincidence is effectively ruled out which leaves orbital forcing change as the key trigger. Why there was a shift from the 41ka obliquity cycle of the earliest glacial cycles ~2.75Ma to the ~100ka cycle dominant in the Pleistocene is very interesting and may involve dust and or ice sheet dynamics but it doesn’t change the fact that deglaciation always triggers during peak obliquity.

113. BBD says:

I also thank you for keeping an open mind about my good faith.

Speaking for myself, I would find it easier to assume good faith on your part if you stopped insinuating that scientists (eg. Hansen and Shakun and Carlson) are skewing their results to reflect their personal biases. That’s scientific misconduct. Even fraud. It’s a very serious accusation and you have made it twice too often in this discussion with zero evidence to back it up.

I *really* don’t like that kind of toxic insinuation and it biases me against you.

114. Ron Graf says:

In caution of getting sucked into the goo I will defer any defense of my personal worthiness or address whether I really accused anyone of fraud. Instead I will get back to the physics.

BBD: Why there was a shift from the 41ka obliquity cycle of the earliest glacial cycles ~2.75Ma to the ~100ka cycle dominant in the Pleistocene is very interesting and may involve dust and or ice sheet dynamics but it doesn’t change the fact that deglaciation always triggers during peak obliquity.

Yes, I agree that obliquity is an important forcing variable in the polar regions, and thus has its fingerprint in the glacial cycle. Also, I agree that it is likely that glacial age must lead to fragility and enhanced vulnerability. The interesting part to me about the gradual transition of glacial cycle to every second, then every third, obliquity cycle is that it shows what must be a gradual change in ocean current dynamics. I believe the YD was an anomalous event affecting the ocean currents For a period of over 1000 years the NH returned to ice age temperatures even if full-blown re-glaciation did not occur. The YD may very well have been a successful trigger for rejection of the interglacial had it occurred at an earlier obliquity maximum. The YD could very well have been a negative feedback to deglaciation, which is driven by an increase in polar insolation due to obliquity maximum and the positive feedbacks for decreased ice albedo and increased CO2. But I am not aware that any climate studies claim that there is such a predicable negative feedback as of this writing. My view is the literature supports the belief ocean current changes, due to continental movements, are the underlying cause of the cooling observed in the current ice age. And the YD event was yet a test-tube confirmation of the importance of ocean currents (whether you consider them as forcings or not).

So circling back to Anders upstring claim that ocean currents are incapable of causing centennial or millennial fluctuations, I am interested in your explanation for the cause of the ice age.

PS. I can’t believe every reader here believes that the YD was not an internally (ocean current) forced event, as BBD stubbornly claims. Really? no dissenter to that claim? This is why I am skeptical of group approved product.

.

115. BBD says:

The interesting part to me about the gradual transition of glacial cycle to every second, then every third, obliquity cycle is that it shows what must be a gradual change in ocean current dynamics.

Or alternatively, it could be about ice sheet dynamics. As successive glacial cycles scour topsoil and expose bedrock they provide an ever-more robust foundation for the land ice of the next glacial cycle. Ice sheets formed directly onto bedrock are much more stable than those formed over soils and so less prone to disintegration during peak obliquity. They grow thicker, and are colder year-round at their surface as a result. Eventually, the ice survives peak obliquity and ‘skips’ an interglacial. When the ice sheets eventually extend to ~30N latitude they become inherently unstable at such low latitude and collapse during the peak of the next 41ka obliquity cycle. So interglacials moved from the early 41ka cycle to every second or third instance of peak obliquity, producing the very approximate ‘100ka’ cycle dominant after the mid-Pleistocene Transition.

PS. I can’t believe every reader here believes that the YD was not an internally (ocean current) forced event, as BBD stubbornly claims. Really? no dissenter to that claim? This is why I am skeptical of group approved product.

Alternatively, you might be wrong, hence the absence of dissent. Perhaps you might consult a textbook or two? It’s all in there.

as BBD stubbornly claims.

Nope, not ‘BBD stubbornly claims’. I’m just reporting the palaeoclimate science. I’m only a messenger. The person out on their own stubbornly making the leftfield claims here is you, not me. And we need to be clear about that at this point, since you are pretending to a legitimacy that you do not have.

This is why I am skeptical of group approved product.

Says the chap stubbornly refusing to accept that his claims are at variance with the science.

116. Ron Graf says:

BBD, are you claiming that a geologic change affecting ocean currents is not the primary source for the cooling we see in the geologic record for the last 50 million years, since the breakup of Pangea? If not, then the Quaternary Ice Age (our ice age) was caused when the ocean dynamics ran at a sufficiently cool steady state that ice caps formed, triggering the positive feedbacks of glacial advance reinforced secondarily be CO2 drop. What is your theory?

Glaciers get up to 4 Km thick. Don’t you think they could scrape turf clean to bedrock on the first go round? I do like the theory though. Science is about testing ideas, in the lab as well as in debating them.

117. BBD says:

BBD, are you claiming that a geologic change affecting ocean currents is not the primary source for the cooling we see in the geologic record for the last 50 million years,

Yes. Cenozoic cooling was caused by CO2. No other forcing change came close to being large enough. See eg. Hansen & Sato (2012) (emphasis mine):

The fact that CO2 is the dominant cause of long-term Cenozoic climate trends is obvious Earth’s energy budget. Redistribution of energy in the climate system via changes of atmosphere or ocean dynamics cannot cause such huge climate change. Instead a substantial global climate forcing is required. The climate forcing must be due to a change of energy coming into the planet or changes within the atmosphere or on the surface that alter the planet’s energy budget.

Solar luminosity is increasing on long time scales, as our sun is at an early stage of solar evolution, “burning” hydrogen, forming helium by nuclear fusion, slowly getting brighter. The sun’s brightness increased steadily through the Cenozoic, by about 0.4 percent according to solar physics models (Sackmann et al., 1993). Because Earth absorbs about 240 W/m2 of solar energy, the 0.4 percent increase is a forcing of about 1 W/m2. This small linear increase of forcing, by itself, would have caused a modest global warming through the Cenozoic Era.

Continent locations affect Earth’s energy balance, as ocean and continent albedos differ. However, most continents were near their present latitudes by the early Cenozoic (Blakey, 2008; Fig. S9 of Hansen et al., 2008). Cloud and atmosphere shielding limit the effect of surface albedo change (Hansen et al., 2005), so this surface climate forcing did not exceed about 1 W/m2.

In contrast, atmospheric CO2 during the Cenozoic changed from about 1000 ppm in the early Cenozoic (Beerling and Royer, 2011) to as small as 170 ppm during recent ice ages (Luthi et al., 2008). The resulting climate forcing, which can be computed accurately for this CO2 range using formulae in Table 1 of Hansen et al. (2000), exceeds 10 W/m2. CO2 was clearly the dominant climate forcing in the Cenozoic.

118. JCH says:

My 1950s grade school class was situated on the bleachers. Out the window to the east lay the vast flat farmland on which the fathers raised bountiful crops. The soil was black and exceedingly fertile. Out the windows to the the west was a range of hills, and beyond that rolling prairie… pastures. Nobody farmed out there. It was ranch land… cattle… vast herds of cattle with huge pastures and hay fields. It was 3rd grade. The teacher explained that a massive glacier flattened the land to the east and deposited a thick layer of Canadian topsoil. The range of hills to the west represented what farmland looked like before the glacier came down from Canada. Our little community lay over the glacier’s western edge. She then explained that the glacier was coming back. We gathered, the boys, at recess. We were all worried. We decided our Dads, almost all WW2 veterans, would gather up a bunch of Sherman tanks and blast the glacier to kingdom come.

119. BBD says:

Glaciers get up to 4 Km thick. Don’t you think they could scrape turf clean to bedrock on the first go round?

This is confused. The early NH glaciations were much smaller in scale and duration (41ka deglacial cycle, remember) than the ~100ka glaciations following the mid-Pleistocene transition. That’s when ice sheets got several km thick.

120. Andrew Dodds says:

Ron –

Although ocean circulation changes – notably the separation of Antarctica from South America, and latterly the closure of the Panama isthmus seem to have a role in cooling the earth, full glacial conditions now as at earlier times require a major mountain building episode, which increases erosion rates and hence CO2 drawdown. Without the formation of the Tibetan plateau it is unlikely that we would have seen full glaciations.

121. BBD says:

It’s amazing how deep-rooted this misconception is among ‘sceptics’. To them, the ocean (magically) controls climate. They do not see that on geological timescales atmospheric composition controls climate and it itself determined by ‘tectonic forcing’. This being the interplay between volcanic outgassing of CO2 and drawdown of CO2 by uplift and weathering.

Ocean gateways are rare and discontinuous events that redistrubute energy within the climate system. They do not create or remove energy. They cannot drive a ~50Ma cooling trend.

122. BBD writes: “They cannot drive a ~50Ma cooling trend.”

I am sorry, you have forgotten free will. As Ron so eloquently wrote above:

the ocean, on the other hand, has immense heat capacity. And if it decides to take up atmospheric energy it can do so in a significant amount over a significant time and sustaining that change by positive feedback ….

Why do you question the free will of oceans?

123. I think this exchange is far beyond its point of diminishing returns.

124. Ron Graf says:

BBD, Hansen forgot one factor in his detailed inventory of forcings; the polar gradient. You might be aware that the Earth would be much cooler if there was not meridional radiation transport from the equator to the poles. This is because the more the Earth’s surface energy dissipates the less efficient its black body radiation profile. This is one factor that cooled the Earth in the YD when the Atlantic Meridonal Overturning Current was truncated, terminating off Labrador rather than the North Sea and polar regions. If one supposes that the separation of the continents interfered with an earlier much more powerful meridonal overturning current, that would explain accompanied cooling.

Andrew, limestone erosion making the poor sea creatures ocean alkalinity, and CO2 starvation from enhanced ocean uptake may have occurred as well. But the Ice age shows CO2 to be a follower of GMST and very weak and governing anything.

JCH: She then explained that the glacier was coming back.

This must be a thing teachers from all generations must feel they have to do; scare kids.

Oneills, when something is said to be unforced its really that we don’t know what the mechanism is or know it is unpredictable by sensitivities to initial parameters. It then may as well have a mind of its own. When BBD maintains that an interruption in the AMOC is a feedback just because there is a theory of a specific triggering event, well, that’s just not what a feedback is, any more than a tree falling on your house is a feedback from wind.

125. BBD says:

BBD, Hansen forgot one factor in his detailed inventory of forcings; the polar gradient.

There was no ‘forgetting’ involved and the ‘polar gradient’ isn’t a forcing. The fact is that the only forcing change across the Cenozoic sufficient to account for the overarching cooling trend was CO2, which *fell* by nearly 10W/m^2. That is a very large change and its effects on climate are obvious in the gradual transition from Eocene hothouse to Pleistocene icehouse. Rare, discontinuous ocean gateway opening/closure events cannot drive a ~50Ma cooling trend. Basic physics.

If one supposes that the separation of the continents interfered with an earlier much more powerful meridonal overturning current, that would explain accompanied cooling.

The Tasmanian Gateway opened ~34Ma. So, what caused the cooling trend between ~50Ma (Eocene Climatic Optimum) and ~34Ma? Not the opening/closure of an ocean gateway, because there were no such events. Which returns us to the diminishing forcing from falling CO2 levels as the most likely physical mechanism driving a long-term trend. Or we are left with ~16Ma of magically-induced cooling, which won’t do at all.

I don’t know what you are reading but the ocean gateway hypothesis for Cenozoic cooling is decades old and now considered obsolete. Yes, there is an interplay between the effects of ocean gateway opening/closure and levels of atmospheric CO2, but it is CO2 which ‘sets the stage’ for relatively abrupt events like the Antarctic glaciation at ~34Ma (Oi-1) and the onset of Pleistocene glaciation (DeConto et al. 2008). It’s very important to distinguish between relatively abrupt events and long-term trends as each likely has a different physical cause.

* * *

This is one factor that cooled the Earth in the YD when the Atlantic Meridonal Overturning Current was truncated

But the global cooling was actually relatively minor (0.6C) because inhibiting the AMOC turns off the NH ‘heat sink’ which causes the SH to warm. You, er, forgot the hemispheric antiphase – read Shakun & Carlson.

When BBD maintains that an interruption in the AMOC is a feedback just because there is a theory of a specific triggering event, well, that’s just not what a feedback is, any more than a tree falling on your house is a feedback from wind.

Still wrong and still with the ‘BBD maintains’ rhetoric even after being reminded that this is the scientific position and I am just repeating it here.

126. Ron,
I think BBD is quite right. The ‘polar gradient’ isn’t a forcing. I think this discussion has run its course, so maybe we could draw it to a close.