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Climate modeling and decision milestones


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22 hours ago, mistermack said:

What interests me, is the situation of the peaks in the graphs. You get a situation where the temperature graph peaks, and begins to drop like a stone. But the CO2 graph continues sharply upwards and doesn't drop for another 900 years (from memory). So you have a 900 year period, where CO2 is still rising sharply, but temperatures are plunging. And it often goes all the way, into a major glaciation. 

900 years of sky-high record CO2 levels, with plunging global temperatures. Hard to match up with a world so sensitive to CO2. And worryingly, we are at a similar stage in the cycle now. Albeit with even higher CO2 levels.

We could be dodging a bullet, with our CO2 emissions. 

You know, there are several people on SFN who have discussed this and might be willing to dive into the science again, if that was going to be fruitful. Based on the veneer of argument that you've made, though, you are signaling that you aren't really interested in pursuing that.

If you are interested in a substantive discussion, though, just say so. But you will need to back up any claims you make, actually delve into science, and would be expected to refrain from rhetoric.

On 2/6/2022 at 9:26 AM, mistermack said:

Studiot, CO2 lags. If you read up on the Vostok ice cores, you wil find that it's always lagged. It's not in dispute, and it would take a monumental fraud to make the data say otherwise, so that won't happen. 

One example. The reason CO2 lagged in the past but why we are in a different situation now would be something to discuss. But it has to go beyond the denialist talking points.

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19 minutes ago, swansont said:

You know, there are several people on SFN who have discussed this and might be willing to dive into the science again, if that was going to be fruitful. Based on the veneer of argument that you've made, though, you are signaling that you aren't really interested in pursuing that.

If you are interested in a substantive discussion, though, just say so. But you will need to back up any claims you make, actually delve into science, and would be expected to refrain from rhetoric.

One example. The reason CO2 lagged in the past but why we are in a different situation now would be something to discuss. But it has to go beyond the denialist talking points.

Yes, since my question was referred to here, I posted information from NASA, new to me, although now about 10years old.

I was aware of Gore's chicanery, but the NASA article claimed that the CO2 rise had historically long been lagging, but recently changed to leading.

So if anyone is interested in discussing this or better has information as to whether this new lead has been maintained since the NASA article i would be interested.

However all the CO2 stuff is measured.

This thread is about models.

And I asked a serious question about the difficulty of defining 'average global temperature' which has not been taken up.

Again it is an important point (to models) worthy of discussion.

Thank you for bringing these points up. +1

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A 2013 paper by Shakun and colleagues examined a network of 80 climate proxy records around the world during the end of the last ice age.

https://www.nature.com/articles/nature10915

They found that while CO2 generally lagged temperatures in the southern hemisphere – consistent with Antarctic reconstructions – the same was not true for the rest of the world.

Both the northern hemisphere and overall global temperatures actually lagged CO2; in other words, for the world as a whole, warming happened after atmospheric CO2 concentrations increased. The reasons for this are complex and are driven in part by changes in ocean currents as ice ages end.

Specifically, Shakun and colleagues argue that changes in orbital cycles triggered initial melting of ice sheets in the northern hemisphere. This caused large amounts of freshwater to pour into the oceans as ice sheets melted, disrupting the AMOC, which, in turn, cooled the northern hemisphere and warmed the southern hemisphere. 

This southern hemisphere warming caused ocean releases of CO2, which, in turn, warmed the entire planet. Shakun et al suggest that the vast majority of the global warming at the end of the last ice age occurred after CO2 increased, though this warming was driven by a combination of albedo (reflectivity) changes and the greenhouse effect.

https://www.carbonbrief.org/explainer-how-the-rise-and-fall-of-co2-levels-influenced-the-ice-ages#:~:text=Both the northern hemisphere and,currents as ice ages end.

 

Also. this study of Antarctic ice cores may be relevant...

https://www.science.org/doi/10.1126/science.1226368

 

No Leader to Follow

Changes in the concentration of atmospheric CO2 and surface air temperature are closely related. However, temperature can influence atmospheric CO2 as well as be influenced by it. Studies of polar ice cores have concluded that temperature increases during periods of rapid warming have preceded increases in CO2 by hundreds of years. Parrenin et al. (p. 1060; see the Perspective by Brook) present a revised age scale for the atmospheric component of Antarctic ice cores, based on the isotopic composition of the N2 that they contain, and suggest that temperature and CO2 changed synchronously over four intervals of rapid warming during the last deglaciation.

Abstract

Understanding the role of atmospheric CO2 during past climate changes requires clear knowledge of how it varies in time relative to temperature. Antarctic ice cores preserve highly resolved records of atmospheric CO2 and Antarctic temperature for the past 800,000 years. Here we propose a revised relative age scale for the concentration of atmospheric CO2 and Antarctic temperature for the last deglacial warming, using data from five Antarctic ice cores. We infer the phasing between CO2 concentration and Antarctic temperature at four times when their trends change abruptly. We find no significant asynchrony between them, indicating that Antarctic temperature did not begin to rise hundreds of years before the concentration of atmospheric CO2, as has been suggested by earlier studies.
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12 hours ago, joigus said:

Erm... I'm assuming you know correlation doesn't depend on the number of variables involved in the linear regression. Not even on the number of measurements. The number of measurements is used to build the confidence interval --those error bars that Swansont was talking about. Correlation is just the mean <xy>-<x><y> for two variables x and y, so it can be interpreted to represent a measure of how much measurements of two variables cluster around a line.

Once we agree on what correlation is, maybe it would be time to go to "hard" references. Or maybe you will teach me new aspects of it I didn't know. Either way, I find the discussion interesting.

This constant appeal to "hard" references, TBH, doesn't impress me. I can give you plenty of references --in my specialty, which is not climate science, I admit-- for articles that were peer-reviewed and abysmally wrong, if you're interested. Others that were rejected and dead right. Of course the wrong ones have been kindly forgotten, and the right ones --sometimes published in so-called obscure journals--, elevated to the standard of "seminal papers." It's when scientific results permeate to the scientific communities, and different cross checks are conducted, that we can start talking about scientific consensus, and a well-established scientific idea.

Joigus, thank you for your response. But I'm left a little confused. In the graph you displayed, the value 'r' represents the correlation coefficient. In that case, it was a high 0.87. To my mind, there were only two variables -- one was  the temperature and the other (a single figure), was the sum of 1. The Sunspot Cycle, 2. Dust from volcanic explosions, 3. The el-nino southern oscillation, and 4. The atmospheric CO2 build-up.

I was curious as to how that latter figure was derived. After all, a correlation coefficient (0.87) was provided as if a comparison was made between two variables only. There are no error bars in a correlation coefficient. 

My own attitude to correlations is that a low 'r' indicates that there is probably no connection or interaction between the the 2 variables being compared, but a high 'r' suggests that there could be an association between the two variables directly, or a common association with another third variable. 

I hope this response was what you were asking, but like you, I'm not sure whether I've misunderstood the point you were making. 

........................................................................

SwansonT, I'll take a bit more time to respond to your last comments about my posts

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10 hours ago, studiot said:

And I asked a serious question about the difficulty of defining 'average global temperature' which has not been taken up.

studiot, I may have misinterpreted the basis of your question, but I did find a reasonably good site that explains the processes of obtaining, collating and publishing average global temperatures -- https://www.carbonbrief.org/explainer-how-do-scientists-measure-global-temperature. Apparently 4 different bodies are actively engaged in this. It's roughly 15 degrees C at present.

If you are talking about the estimation that the Earth would have a temperature of -18 degrees C without an atmosphere, I'm not sure of that, but it could be researched. The net effect is that our atmosphere seems to be responsible for a gain of c33 degrees C.

My apologies for wasting your time if you were looking for something else. 

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14 hours ago, mistermack said:

It's a very silly question, if you think I'm going to mine the internet for such examples. My post was clearly worded as giving my opinion. You're free to disagree, and you can certainly do hours of internet searching to rebut it if you like. But for future reference, my post are my opinions, and if there is supporting documentation, I will list it with the post. 

I feel like that's stating the obvious, but never mind. 

I read it as making a factual claim, which, as I have explained, it could easily have been.

But OK, so it's just what you think. We can leave it at that, then.   

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i watched a film called “Get the gringo”, the other night, and your last post, SwansonT, sounds as if it should have the title of “Get Doogles31731”. You’ve certainly done a number on my “science”, and you’ve been supported from the stands by at least 3 grandstanders shouting “Ole”.

Anyhow I’m old enough and ugly enough to take it.

I’m just thankful that it’s not legal to burn heretics alive any more. ‘

SwansonT, I will deal with just one item in your last post, viz “  On 2/4/2022 at 4:35 PM, Doogles31731 said: If 156 Wm-2 is reaching the surface and near-surface temps are measured 4 feet of the ground, then each 1 degree C in the shade equates to 156/33 Wm-2, which equates to 4.7 Wm-2 per 1 degree C at the surface. If you had looked at the Stefan-Boltzmann law, you would see that radiated power is not linearly proportional to temperature - it depends on T4. Your use of a linear relationship is incorrect. The number is wrong (except at some specific temperature, where it will be approximately correct), and the idea that a power will have a constant relation to a temperature change is also wrong.”

The fact of the matter is that I did not know what the Stefan-Boltzmann Law was when you first mentioned it, so I looked it up, only to find that the Stefan-Boltzmann law is a statement that the total radiant heat power emitted from a surface is proportional to the fourth power of its absolute temperature. The law applies only to blackbodies, theoretical surfaces that absorb all incident heat radiation.

I have admitted my ignorance. So naturally, I asked you how that Law applies to climate science, and this is your first reply to that question.

When I divided 156 Wm-2 by 33, I can see now that I made an assumption that the temperature association with the energy at the level of the recording temperature gauges was linear. I used the wording that each degree C equates to 4.7 Wm-2.

Please accept this queation in the spirit of a student seeking information from a teacher. Can you, or anybody else, explain how the Stefan-Boltzmann Law applies here.

What exactly are you regarding as the energy emitter in the system, and what are you regarding as the black body? This is meant as a question from a curious person and not someone trying to be a smart arse. I’m interested in any opinions.

I could guess that the emitter is the radiative forcing and that the black body is the surrounding environment (including the temperature recording devices.) But that’s only a guess.

The reason I ask is because I’m having trouble imagining how it applies. If I use the reference supplied by TheVat of a figure of a 1.6+ Wm-2 increase in radiative forcing from a doubling of CO2, it would that mean that the temperature of the atmosphere has increased by the fourth root of 1.61 degrees C. That would be just over 1 degree C, and sounds as if it’s in the current ball park expected figure.

But if the increase of radiative forcing was theoretically 20 Wm-2, it would arrive from a source whose temperature had gone up 1.45 degrees C, the 4th root of 20. If it went up 50 Wm-2, the temperature rise causing it would be 1.63 degrees C.

As I said previously about my maths, “Nah, that can’t be right.”

You must have a different scenario in mind. I don’t mind being wrong, but I like to know why I’m wrong. Would you, or anyone else, mind giving me a hint as to what is regarded as the emitter and what is regarded as the ‘black body’ within the atmosphere that is explained by the Stefan-Boltzmann Law?

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43 minutes ago, Doogles31731 said:

What exactly are you regarding as the energy emitter in the system, and what are you regarding as the black body? This is meant as a question from a curious person and not someone trying to be a smart arse. I’m interested in any opinions.

The earth. The earth ultimately loses energy via radiation, and will emit in a blackbody spectrum. There are a number of processes involved in global warming, but that's all modifications of internal processes.

You were discussing why were are at 15ºC rather than -18 and the implications for the power involved. Being warmer means you radiate more heat, but the amount goes up as T4.  

If you use the S-B law, you can figure out why the earth would be at -18C without an atmosphere. It's explained in the wikipedia article 

 https://en.wikipedia.org/wiki/Stefan–Boltzmann_law#Effective_temperature_of_the_Earth

You can also see what effect the atmosphere and other processes have by looking at the radiated power at 15C. (note that the number that goes into the equation has to be in Kelvins, as in the link. This impacts some of your calculations)

Then we could look at the other errors you made in your analysis. Your linear assumption was just the big one that jumped out at me.

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1 hour ago, Doogles31731 said:

Would you, or anyone else, mind giving me a hint as to what is regarded as the emitter and what is regarded as the ‘black body’ within the atmosphere that is explained by the Stefan-Boltzmann Law?

There is more you need to know about energy transfer in general and heat transfer in particular apart from Stefan-Boltzman.

There are two coefficients called emissivity and absorbtivity which relate to energy in the general case and heat in a particular case.

 

An ideal 'black body has an absorbtivity and an emissivity of 1.

There are no known ideal balck bodies in the universe.

Actual amounts of absorbtion or emission are multiplied by the appropriate emissivity or absorbtivity coefficient.

There are lots of these coefficients for different wavelengths, different body surface conditions and (thank you Stefan-Botlzman) different temperatures/ temperature ranges.

All bodies are in a state of both continual emission and continual absorbtion.
Emission depends upon the absolute surface temperature, absorbtion does not.
So  the balance between emission and absorbtion is a dynamic one.

A hot enough (high enough temperature) body will emit more than it absorbs.
At a low enough temperature a body will absorb more than it emits.

Oops pressed the submit by mistake.

The importance of the S_B law and Planck's law come from that low temperature emission.

Sunlight is emitted by a very high temperature body.
This is absorbed by bodies in the atmousphere (both liquid droplets, gaseous, and particulate solids) which are at a much lower temperature.

These heat radiations will be at longer wavelength than the received sunlight.
It is this fact that forms the basis of the greenhouse effect.

Please note this is a very broad brush treatment so ask for clarification/amplification of any point.

I have highlighted the word surface in my text.
This is because you kindly replied to my comment and query on the Earth's (surface) temperature to which I shall make a separate reply.

Edit2

Real bodies are modelled as gray or grey bodies.

https://www.comsol.com/blogs/understanding-classical-gray-body-radiation-theory/

Quote

A gray body is an imperfect black body; i.e., a physical object that partially absorbs incident electromagnetic radiation.

 

However if you read the articles you will find references to my coefficients and many more factors, some of which also play a part in the 'surface temperature' of the Earth.

 

Edited by studiot
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14 hours ago, Doogles31731 said:

I was curious as to how that latter figure was derived. After all, a correlation coefficient (0.87) was provided as if a comparison was made between two variables only. There are no error bars in a correlation coefficient. 

Of course the average of an average is just the original average, so you're right, error bars don't enter into it. I didn't say they do, though. Error bars are only used to build the confidence interval, which is not what we're talking about here, but correlation. That's why I was careful to distinguish both:

On 2/7/2022 at 12:09 PM, joigus said:

The number of measurements is used to build the confidence interval --those error bars that Swansont was talking about. Correlation is just the mean <xy>-<x><y> for two variables x and y, so it can be interpreted to represent a measure of how much measurements of two variables cluster around a line.

It would have been clearer had I said, "Correlation, on the other hand, is just..." I thought I'd been clear, and I apologise for my obscurity. I should have avoided mentioning them at that point altogether.

  • Correlation 

Correlation is a measure of how much one variable affects the other even when you average over all the other variables that may enter the problem, including x, y (the ones you mean to measure the correlation of). If correlation varies wildly by varying z (meaning all other variables in the problem), then there is no correlation between x, and y at all, because contributions from variations of different z's would tend to cancel out. So you'd be back to <xy>-<x><y>=0 even though for some particular values of z they would display correlation.

  • Periodicity

But the thing you're missing here from a mathematical POV, I think, is periodicity --or lack of it. Periodicity gives you a much more robust inkling, IMO, that something's going on here between anthropogenic CO2 and temperature markers. In the time-scale of volcanic events, astrophysical variation, and ocean temperature oscillations, there are several intrinsic periodicities whose overlap shows very clearly in the graph, while the biological factor builds up across time-scales that was the order of tens of millions of years before humans appeared, and in the case of the surging of human intelligence (Anthropocene), in the scale of tens of thousands of years.

You can detect periodicities even through non-linear relations*. Consider the simple harmonic function \( f\left( t \right) = F \sin 2t \). You can build an arbitrary function of variable \( f \) and it will still be periodic of the same period even if it's non-linear. For example: \( F\left( t \right) = \exp\left( f\left( t \right) \right) = \exp{F\sin2t}  \) is still periodic of same period.

  • Stefan-Boltzmann

As to the Stefan-Boltzmann law, Swansont and Studiot have given you a very good account. I just wanted to add about something that's sometimes confusing: What does the Earth have to do with a black body? Indeed, the Earth is not a black body, but you can rest assured that the part of the radiation spectrum from any physical body that contains thermal information about that body (that is, excludes reflected light, or light that goes through it) nicely fits that of a black body. A black body does not reflect any light, that way you get to the part of radiation from anything made of atoms that's only due to radiation having been in thermal equilibrium (or bouncing around long enough inside the body) and then started to re-radiate those photons. Most of the light you receive from a rock that's sitting on your desk is reflected light. Certainly the one in the visible frequencies is (at room temperature). But if you were sensitive enough to see the infrared, you would see a frequency-dependent graph that agrees with the black-body spectrum.

*You can even get an idea of the periodicity of solutions of completely unsolvable, untractable systems of differential equations that model a complicated non-linear system by using the periodicity of the coefficients. So yes, mathematically speaking, periodicity is extremely robust when trying to ascertain dependence of behaviours.

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3 hours ago, joigus said:

Indeed, the Earth is not a black body, but you can rest assured that the part of the radiation spectrum from any physical body that contains thermal information about that body (that is, excludes reflected light, or light that goes through it) nicely fits that of a black body.

IOW, the deviations from a blackbody (perfect radiator and absorber) can either be compensated for in the calculations (e.g. reflection by knowing the albedo) or they aren't going to meaningfully affect the result at our level of discussion.

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SwansonT, studiot, and joigus, thank you for your responses. I studied all of the references you suggested, but unfortunately, the mathematical equations were beyond my comprehension. I was left with just general impressions.

............................................................

SwansonT, my minor problem in response to a question by studiot, wasn’t an understanding of the 15 degrees C and the -18 degrees C, but the reference to how the -18 degrees C was calculated. You at least gave me a source for that. and I thank you accordingly. I can understand that our atmosphere discharges some heat energy into space and that this probably conforms to some extent to the SB Law.

This student is dumber than you imagine, and can only understand the very basics.

......................................................

studiot may have provided a better understanding for me concerning the role of SBL principles within our atmospheric dynamics. He points out that “There are two coefficients called emissivity and absorbitivity which relate to energy in the general case and heat in a particular case...... All bodies are in a state of both continual emission and continual absorbtion. He suggests that a grey body is an imperfect black body; i.e., a physical object that partially absorbs or emits incident electromagnetic radiation.

So, in one sense he seems to be suggesting that the SBL is not restricted to ideal black bodies and that virtually every body at molecular or macro- level can be regarded as an emitter or absorber to some extent, depending on temperature and other factors.

Now I may have totally misunderstood studiot, and misquoted him, but it is becoming obvious to me that I’m not going to be able to satisfy my curiosity about climate science matters by persisting in this thread.

.....................................................................

joigus spoke about ‘periodicity’ or lack of it, being the aspect that I’m missing in  the whole picture. To some extent he re-inforces studiot’s notion when he statesIndeed, the Earth is not a black body, but you can rest assured that the part of the radiation spectrum from any physical body that contains thermal information about that body (that is, excludes reflected light, or light that goes through it) nicely fits that of a black body. A black body does not reflect any light, that way you get to the part of radiation from anything made of atoms that's only due to radiation having been in thermal equilibrium (or bouncing around long enough inside the body) and then started to re-radiate those photons. Most of the light you receive from a rock that's sitting on your desk is reflected light. Certainly the one in the visible frequencies is (at room temperature). But if you were sensitive enough to see the infrared, you would see a frequency-dependent graph that agrees with the black-body spectrum.

.............................................................

My thinking about climate change commences basically with my own mental images initially of temperature-recording devices in Stevenson Screens on land, in ships and buoys, and in satellites. I picture the gases in the atmosphere around the land and sea becoming active due to absorbed energy at the molecular level and transmitting emitted energy to the temperature sensors. To my mind, that is what climate change is all about. If the average global annual temperatures weren’t rising due to increasing energy fluxes at the temperature-sensing device mechanisms, there would be no problems associated with ‘climate change”.

I can understand the science of how the the energy reaching the surface from the sun and radiative forcing appears to be calculated as a global average at about 156 Wm-2, and how this results in a change in the Earth’s near surface annual average temperature from 255 K to 288. If it’s mathematically incorrect to equate that 33 degrees K with the 156 Wm-2 affecting the atmosphere near the temperature-recording devices, my question would be whether there’s a more complicated mathematical connection, or is it an indirect association. I’ve not received an answer that I can comprehend.

I’m unable to glean that from the answers I’ve received, so my curiosity has turned to confusion.

I’ve concluded that I can’t learn any more in this forum about the basics. I concede that the reason is most probably my own inability to comprehend the mathematical equations used in the science you’ve all provided but I thank you for your efforts.

I’ve decided to retire from this thread because of my own inability to comprehend the responses you have all made in an effort to satisfy my curiosity.

I repeat that I thank you all for your efforts..

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1 hour ago, Doogles31731 said:

I’ve concluded that I can’t learn any more in this forum about the basics. I concede that the reason is most probably my own inability to comprehend the mathematical equations used in the science you’ve all provided but I thank you for your efforts.

Don't give up now that you have started to do so well. +1 for encouragement.

1 hour ago, Doogles31731 said:

Now I may have totally misunderstood studiot, and misquoted him, but it is becoming obvious to me that I’m not going to be able to satisfy my curiosity about climate science matters by persisting in this thread.

 

1 hour ago, Doogles31731 said:

I’m unable to glean that from the answers I’ve received, so my curiosity has turned to confusion.

I'm sorry if you feel confused, but remember that Rome wasn't built in a day.

And yes, it's complicated.

But your last post, in particular,  shows that you are now understanding my comments.
See below about the application of black bodies.*

It's also true that if you want numbers then some mathematics is unavoidable.

But a great deal can still be achieved by discussing the principles and their application.

It is also worth noting that obtaining something from discussion is two way.
I certainly am grateful for the personal clarification I often gain when trying to explain something to others.

 

*I did promise to reply separately to the other point about temperature and I have come to the conclusion that that particular point is so important that it deserves a thread all of its own so watch for further developments.

The S_B law is quite precise when it is applied to small bodies which have surfaces at essentially the same temperature.
But the Earth is (in this context) a large body with substantial variation of temperature over its surface and in time.

In such cases one possibility is to introduce the idea of an 'equivalent black body'.
An equivalent black body is a BB with the same heat radiation flux as the Earth's actual flux.
This is definable and manageable with the formulae so calculations can be performed using the temperature this equivalent black body must have.
This equivalent BB temperature might be (probably will be) different from any of the different ways of averaging measurements over the Earth's surface.

What temperature to use and how to arrive at that temperature is therefore of vital importance to climate science and is the proposed subject of my new thread to be.

 

I hope this encouragement helps.

 

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1 hour ago, studiot said:

Don't give up now that you have started to do so well. +1 for encouragement.

 

I'm sorry if you feel confused, but remember that Rome wasn't built in a day.

And yes, it's complicated.

But your last post, in particular,  shows that you are now understanding my comments.
See below about the application of black bodies.*

It's also true that if you want numbers then some mathematics is unavoidable.

But a great deal can still be achieved by discussing the principles and their application.

It is also worth noting that obtaining something from discussion is two way.
I certainly am grateful for the personal clarification I often gain when trying to explain something to others.

 

*I did promise to reply separately to the other point about temperature and I have come to the conclusion that that particular point is so important that it deserves a thread all of its own so watch for further developments.

The S_B law is quite precise when it is applied to small bodies which have surfaces at essentially the same temperature.
But the Earth is (in this context) a large body with substantial variation of temperature over its surface and in time.

In such cases one possibility is to introduce the idea of an 'equivalent black body'.
An equivalent black body is a BB with the same heat radiation flux as the Earth's actual flux.
This is definable and manageable with the formulae so calculations can be performed using the temperature this equivalent black body must have.
This equivalent BB temperature might be (probably will be) different from any of the different ways of averaging measurements over the Earth's surface.

What temperature to use and how to arrive at that temperature is therefore of vital importance to climate science and is the proposed subject of my new thread to be.

 

I hope this encouragement helps.

 

Very constructive thoughts there.

I think the equivalent black body would be taken into account by correcting for the albedo, as Swansont suggested.

I regret that the arguments based on periodicity against a clearly growing term were either not understood, or perhaps not relevant, but to me they are very clear.

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3 hours ago, Doogles31731 said:

SwansonT, my minor problem in response to a question by studiot, wasn’t an understanding of the 15 degrees C and the -18 degrees C, but the reference to how the -18 degrees C was calculated. You at least gave me a source for that. and I thank you accordingly. I can understand that our atmosphere discharges some heat energy into space and that this probably conforms to some extent to the SB Law.

All of the energy goes into space - where else could it go? (for the -18C calculation there is no atmosphere)

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Another thing to regret: Mathematics are frequently used to dress up crackpot ideas, and other times to dismiss arguments, no matter how qualitatively and clearly they are presented.

The very question concerning lagging vs leading which has surfaced before I find very interesting, but it's a question that has to be formulated with a bare-minimum mathematics after all.

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1 hour ago, joigus said:

The very question concerning lagging vs leading which has surfaced before I find very interesting, but it's a question that has to be formulated with a bare-minimum mathematics after all

The basics are pretty simple. CO2 lagged in previous warming episodes. The difference now is that we have anthropogenic sources that were not present in those cases. CO2 causes warming, regardless of being part of a feedback (e.g. release of dissolved CO2 as oceans warm up), or if it’s a forcing (CO2 from burning fossil fuels)

What was missing in this thread was the mention of other effects such as Milankovitch cycles (orbital effects); various ones that have periods measured in tens of thousands of years, but which have negligible effect over the course of a couple of hundred years. Changing the axial tilt, the precession of that tilt, and the eccentricity of the orbit all change the effect of solar radiation. 

IOW, focusing only on CO2 is a sin of omission.

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6 hours ago, swansont said:

The basics are pretty simple. CO2 lagged in previous warming episodes. The difference now is that we have anthropogenic sources that were not present in those cases. CO2 causes warming, regardless of being part of a feedback (e.g. release of dissolved CO2 as oceans warm up), or if it’s a forcing (CO2 from burning fossil fuels)

What was missing in this thread was the mention of other effects such as Milankovitch cycles (orbital effects); various ones that have periods measured in tens of thousands of years, but which have negligible effect over the course of a couple of hundred years. Changing the axial tilt, the precession of that tilt, and the eccentricity of the orbit all change the effect of solar radiation. 

IOW, focusing only on CO2 is a sin of omission.

Ok. Yes, I left out the Milankovitch cycles precisely because of that. Dan Britt does mention them in his talk at some point, but does not include them in the couple of graphs that I pasted there for reasons I guessed exactly as you said. I do remember that he mentions we are something like 100 years within one of them (glaciation), and yet glaciers are melting. That should be significant too, I surmise.

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On 2/10/2022 at 2:59 AM, swansont said:

IOW, focusing only on CO2 is a sin of omission.

Well, this thread might omit things like milankovich cycles and I'd be surprised if climate modeling includes it - after confirming it is insignificant at the time scales they work with. Climate science doesn't focus only on CO2. But it is the biggest forcing, second only to the atmospheric aerosol pollution that masks a large part of how much we've been enhancing the greenhouse effect. In their role of advising the likely climate consequences of economically significant activities climate scientists are right to make CO2 the headline act - without neglecting the others - (a bit old, but..

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Given the dominant role CO2 has in current warming, it's propensity to exceed the capacity of vegetation and ocean carbon sinks and accumulate, along with the susceptibility of carbon sinks to stop being sinks and cross tipping points to become sources aka carbon feedbacks (aka CO2 driven warming preceding rising natural releases of CO2) it is right for policy making to give it high priority.

It is not the greenhouse potential of relevant atmospheric gases that is presenting challenges for improving climate change projections. In that sense climate science is a lot less about CO2 as about the internal climate responses and feedbacks.

The overall, ongoing gain of heat in air, land and water is not in doubt. It is clearly evident, eg in the ocean heat content data, so "no change" has stopped being a valid null assumption. How that heat gain plays out in terms of the weather and climate we experience is challenging climate modelers; itmay be hard to pin down precisely but climate models are doing it more than well enough to on with.

 

Edited by Ken Fabian
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On 1/23/2022 at 12:25 PM, skydelph said:

Our view on climate change, the point where we are today and predictions are the result of scientific breakthroughs, steady developments and of course technological leaps.

All of the above components are the keys for the climate models, upon which we fully rely.

Firstly, I would like to share a link, which is different from popular climate change and modeling discussions with its analysis approach.

https://medium.com/our-changing-climate/climate-modelling-from-manabe-and-wetherald-to-supercomputer-jasmin-1c8d5d11431b

My second point would be human impact and actions planned and being done for the nearest future. Net zero 2050 might be unrealistic. But there should be a reasonable deadline, to sharpen international initiatives and economies. Even if a lot of plans exist only on paper or contradict the budgets, even environmentally unfriendly infrastructure cannot stop in that short period.

My third point would be that climate changing is not only about emissions, models and personal carbon print. The whole technology and knowledge, which is  in our hand should be used to follow the 2050 deadline, including space manufacturers, dedicated to global changes and local ecosystems monitoring as well as data sharing.

Yes you are right there should be a reasonable deadlines. Because since the emergence of Covid-19, the usage of disposable gloves and masks has increased. And by the end of the day this medical waste is creating a new kind of pollution. 

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