Guest commentary from Eric Guilyardi (IPSL) and Valérie Masson-Delmotte (IPSL/IPCC)
[This is a translation of an article in Le Monde (Jan 11).]
In recent weeks in France, there has been a profusion of articles about the “climate scientist blues” (Le Monde 21/Dec, JDD 9/Dec, France Info 26/Sep), which has apparently affecting them “scientifically”. This follows a spate of similar articles in the US and Australian media (Esquire, 2015; The Monthly, 2018; Sierra Club Magazine, 2018). But what is the point of knowing the mood of scientists, or whether so-and-so is optimistic or pessimistic?
Are epidemiologists asked if they are depressed when they anticipate an epidemic outbreak, or meteorologists polled about their anxiety because they predicted a storm or a heatwave? In these cases, society organizes to manage the risk related to these forecasts (orange or red alerts, weather watches and warnings) and does not care about the emotions of the scientists. The main reason most climate scientists come out of the lab and engage publicly is not to share their subjective emotions about the state of the world, but rather to discuss the results and consequences of our science.
On an individual basis, the scientists can sometimes be proud if their forecast has been useful for better managing the consequences of an event, or be upset that it wasn’t, but the quality and relevance of their expertise does not depend on their state of mind. But the principal role for climate scientists is to inform the public debate about the outcome of collective science efforts and the risks associated with the different trajectories of greenhouse gas emissions, not how they feel about it.
More broadly, climate change science also provides multiple insights into how to manage climate risks. It offers new opportunities for partnership between the scientific researchers and society as a whole to help make decisions in a context of uncertainty about the future evolution of the climate, especially at the local and regional scale. New knowledge is emerging on how to build ethical and just transitions, to maximize the synergies between climate action and the other aspects of sustainable development.
With more than 20,000 scientific publications each year with the key word “climate change”, the production of new knowledge is proceeding quickly. The challenge in interpreting this is not the state of mind of researchers, but the regular synthesis of this knowledge and how to share it with the whole of society in order to encourage solutions to manage climate risks, preserve biodiversity, and allow everyone to live with dignity by improving the well-being of all.
As the last IPCC special report on 1.5°C reminded us, the real issue is that we currently face three types of major risk. The first risk is related to each additional fraction of warming, with humanitarian, agricultural, environmental and migratory crises, increasingly challenging to manage. The second risk is the burden passed on to today’s younger generations, who would face the triple trouble of coping with the impacts of global warming; having to accelerate abruptly the transitions to a low-carbon economy if we delay in putting it in place; and lastly, to have to choose options that are potentially very risky for both biodiversity (for example through massive use of biomass energy) or global governance (for example, geo-engineering) in an attempt to contain global warming or its consequences. The third risk is rapid transition to the economy and the current global financial system through the ‘stranded assets’ of capital invested in the fossil fuel industry.
The real challenge is therefore the mobilization of collective intelligence and democratic debate on the choices of risk that we are willing to take. The Paris Agreement seems to indicate that nations who have ratified it want to avoid the first two risks and organize themselves to face the third.
What if the focus on the moods of climate scientists was a way to disengage emotionally from the choices of risk or solutions to global warming? Since the experts are worrying about it for us (it’s their daily life, isn’t it?), let’s continue our lives in peace. If feelings and expressing emotions – fear, anger, anguish, feelings of helplessness, guilt, depression – in the face of risks are legitimate, even necessary, to take action demands that we go beyond that. Catastrophism often leads to denial, a well-known psychic mechanism for protecting oneself from anxiety. Managing risk is part of our daily lives and supposes that we are not in such denial (active or passive) as it prevents clear and responsible action. Because we know that many hazards carry predictable risks, human societies have learned to anticipate and cope, for example, to limit the damage of storms or epidemics. The challenge of climate change is to build a strategy not in response to an acute and clearly identified risk, but in anticipation of a gradual, chronic increase in climate risks.
The climate scientists are alright (mostly), but that’s not the important question. The dispassionate management of climate risk will require that everyone – citizens, decision makers, teachers, intermediate bodies, companies, civil society, media, scientists – in their place and according to their means, take the time for a collective reflection, first of all through mutual listening. The news shows it every day: this process is hobbling along, too slowly for some, too fast for others. It will need to overcome emotional reactions, vested interests, and false information from the merchants of doubt. Those who are unable to review their strategy and have everything to lose from the exit from fossil-fuel based energies will use nit-picks, manipulation, short-termism, and promote binary and divisive visions, all of which undermine trust and pollute the debate. But despite that…
Every degree of warming matters, every year counts, every choice counts. The challenge is immense because of the nature and magnitude of the unprecedented risk. It requires doing everything to overcome indifference and fatalism.
Re #41
Michael,
You are quite correct. The standard climate model was described here:
https://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument/ It is based on the idea that increasing CO2 reduces the amount of radiation leaving the atmosphere and, consequently, the surface has to warm to restore the energy balance at the top of the atmosphere. Judge Alsup, an ex-engineer, asked what was the mechanism by which the Earth’s surface is warmed, but the scientists were unable to understand that question and ignored it.
As Gavin has shown, far from reducing, the outgoing longwave radiation has increased, which proves that the current model is wrong.
What really happens is that, as proposed by Tyndall, the air near the surface of the Earth is warmed by the increase in greenhouse gases. This causes the altitude and latitude of the snowline to increase. It is the subsequent loss of albedo which causes global warming.
Alastair@51,
That post is utter horseshit, and arrogant horseshit to boot. Gavin has shown nothing that supports your contention that the consensus model is wrong. You do not have the expertise to assess the situation correctly. And finally, you are passing your opinions off as if a) you were an expert; and b) your ill considered opinions were not considered wrong by all the smart people who’ve looked at them.
Al Bundy @47, I don’t think capitalists and conservatives are literally morons (in the main) but they certainly reject the science. You are right its more lazy thinking. Capitalist business people also probably reject the science because it leads to mitigation requirements they don’t like.Conservatives deny the science because it leads to government programmes they dont like.
Conservatives also filter the science through a particularly complex set of ideological and religious beliefs, and the views of authority figures they admire (Fox news, Heartland Institute). If even one element in this chain doesn’t make sense (and most of it doesn’t make sense) the science will be rejected.
Wait a minute, Alastair. You point to the 2007 thread, which says in part
I know you have your own theory, which as far as I’m aware you’ve only published here. But I don’t see what Michael wrote at #41 as consistent with your concept of physics, though you like his question.
More to add to the confusion:
https://www.sciencedaily.com/releases/2019/01/190122104611.htm
Source: The Hebrew University of Jerusalem
Summary:
New research shows that the degree to which aerosols cool the earth has been grossly underestimated, necessitating a recalculation of climate change models to more accurately predict the pace of global warming.
Journal Reference:
Daniel Rosenfeld, Yannian Zhu, Minghuai Wang, Youtong Zheng, Tom Goren, Shaocai Yu. Aerosol-driven droplet concentrations dominate coverage and water of oceanic low level clouds. Science, 2019; eaav0566
DOI: 10.1126/science.aav0566
Hank Roberts, excerpting Scott Adams:
Ric Merritt:
I’m glad to hear Adams guardedly acknowledges the consensus of climate science is mostly correct. I used to read Dilbert daily, as it was a close match to my workplace – whose isn’t? I was about convinced I was working in a comic strip. Then, in an infamous post on his blog a few years back, Adams appeared to take a number of undead long-debunked AGW-denier memes seriously, and professed skepticism of climate scientists’ motives. I didn’t feel like reading his comic strip anymore.
What bothers me still, is his apparent presumption that climate scientists are trying to fool him (“doesn’t pass the sniff test”) if he doesn’t understand some finding. That’s seldom the least hypothesis, is it? Why wouldn’t Adams assume he’ll just have to work harder to understand? He says “the majority of what the skeptics says is just ridiculous”. Doesn’t that call the rest of what they say into question, at the very least? Adams appears to offer the argument from personal incredulity, also called the argument from ignorance. Doesn’t he wonder if scientists might know things he doesn’t? Does he know they rely on more than their noses? Yawn. Sounds like garden-variety Dunning Kruger Effect to me.
Nigel,
You are correct. Insulting adjectives greatly subtract from the value of a post.
If the Davos Economic Forum needed a reason to panic, Soros, not Thunberg provided it–
His ivindictment of China’s embrace of AI as a dystopian tool for totalitarian social engineering may rival George Kenanns Long Cable from Moscow as cause for global alarm– the thermal mass of the oceans may constrain the rate of runaway climate change, but the ungoverned acceleration of history in Xi’s China is still being driven by Moore’s law.
Michael Hammer and responses,
In the traditional view of the enhanced greenhouse effect, raising CO2 decreases the outgoing radiative flux (OLR) to space, while the increased temperature increases the OLR to space. The equilibriated climate is a tug of war between these things.
In reality, OLR typically increases (relative to the unperturbed value) in CMIP5 models, which can be viewed as a cooling of the system.
The reduction in OLR associated with GHG forcing is wiped away only within a few decades, and the subsequent energy accumulation (increasing ocean heat content and sustaining global warming) is caused by enhanced absorbed shortwave radiation. Thus, viewed from the lens of shortwave and longwave flux values relative to the initial climate, in a time-integrated sense global warming is caused by enhanced shortwave absorption, not reduced OLR.
This is similar to what would happen for increased solar irradiance experiments, in which the energy accumulated as a function of time is the difference between the SW energy accumulation and the longwave increase (which cools the system)- see this figure from Donohoe et al. (2014) which articulated this argument, as well as Trenberth and Fasullo, 2009, “Global warming due to increasing absorbed solar radiation.” The integrated planetary warming due the forcing + longwave feedback is near zero in most models before the end of the century.
Anthropogenic aerosols over the historical period have decreased SW energy accumulation (directly) and decreased the longwave energy increase to space (indirectly by offsetting temperature increase).
The timescale over which OLR returns to its unperturbed value, and whether it increases or decreases with time in general (i.e., whether the CO2 forcing or temperature increase is “winning” the tug of war), thus depends very much on the magnitude of shortwave feedbacks, and also details of ocean heat uptake efficiency. See some details from this blog post by Isaac Held.
The observed OLR rise in the Dewitte and Clerbaux paper Gavin linked to is suggested to be correlated to rising SSTs, which is almost certainy correct, although there’s other things going on here (including rising GHGs and a volcanic eruption and internal variability).
You can read what Soros had to say in Davos at Wired :
https://www.wired.com/story/mortal-danger-chinas-push-into-ai/
A humble attempt to get back on topic: the writers say:
On an individual basis, the scientists can sometimes be proud if their forecast has been useful for better managing the consequences of an event, or be upset that it wasn’t, but the quality and relevance of their expertise does not depend on their state of mind. But the principal role for climate scientists is to inform the public debate about the outcome of collective science efforts and the risks associated with the different trajectories of greenhouse gas emissions, not how they feel about it.
More broadly, climate change science also provides multiple insights into how to manage climate risks. It offers new opportunities for partnership between the scientific researchers and society as a whole to help make decisions in a context of uncertainty about the future evolution of the climate, especially at the local and regional scale. New knowledge is emerging on how to build ethical and just transitions, to maximize the synergies between climate action and the other aspects of sustainable development.
With more than 20,000 scientific publications each year with the key word “climate change”, the production of new knowledge is proceeding quickly. The challenge in interpreting this is not the state of mind of researchers, but the regular synthesis of this knowledge and how to share it with the whole of society in order to encourage solutions to manage climate risks, preserve biodiversity, and allow everyone to live with dignity by improving the well-being of all. [end quote]
Sounds reasonable on the surface. But where is the scientific references to support such conclusions are valid? I cannot see how the “the state of mind mind of researchers” is irrelevant to the stated goals here.
A little quote from Chomsky & Krauss: An Origins Project Dialogue
https://youtu.be/tbxp8ViBTu8?t=760
Krauss: “okay well let’s, speaking of language, a question from Anna: Do you think language ever limits science as in we lack the language or words to effectively communicate scientific ideas or do you believe that language enlivens science, makes it more relatable?”
Chomsky: “well what we all know if you stop to think for a minute as soon as you start doing scientific work you depart from language.
Krauss: Exactly (nodding and smiling)
Chomsky: “And in crucial ways. So for example the words of human language like say River or person or tree or whatever you like, they do not pick out Mind independent entities in the external world. For those of you who know philosophical literature there is no reference or denotation relation in natural language. In science there is – the goal of science if you postulates a quark or electron or phoneme or whatever it is you’re hoping that it picks out something that’s in the mind external world. you may not achieve it but that’s what you’re aiming for. A normative element of science is to create a system that does have literal reference – the symbols pick out something extra mental – that’s already departing from language and when you go on it departs even faster. So in science it’s using say mathematics.”
Krauss: “well just going to say, the point or the other aspect of language is at least in my field and I think you try to do this and in linguistics is it’s clear for whatever reason still really not known that the appropriate language is not any of the languages that we use but mathematics. Mathematics isn’t a language like the other languages.”
Chomsky: “Yeah mathematics is the language of science“.
Krauss: “But it’s not a language in the sense of any of the other languages.”
Chomsky: “It’s only a language metaphorically, the way airplanes flying is metaphoric. It’s a symbolic system. It has some of the properties of natural language, differs in other respects. And it’s invented, created to serve a certain purpose. (normal) Language isn’t created! Human language isn’t created. It’s there just part of your, if you don’t mind, Nature.” [end quotes]
In part one Chomsky mentioned how scientists when working “scientifically” actually use a part of their brain that is not activated in normal life. (sorry I can’t find the section as no transcript for that) But what he says here matches up nicely with work from other cognitive scientists and linguists as reported by George Lakoff and others.
Such as all thought, reasoning and language is embodied. It’s much more complex than simply a disconnected function in “the mind”. Studies have also shown how empathetic/emotional thought (belief driven) mental content deactivates or rather suppresses the more logical analytical regions of the brain/mind and vice versa.
What Chomsky above seems to be saying (in my own words) is that when doing scientific work researchers are operating in a different brain/mind domain than in normal life. They then need to bring what they find discover back into the regular domain of thought, and human language in order to communicate their findings via normal everyday language the rest of the world uses. I think that is quite significant. It’s surely no easy task. And only a small number of people seem to have this capacity to transcend these “Domains” to cross back and forth between them with ease.
But I cannot see how scientists “feel” about their work and it’s implications as they try to communicate this to the public and policy makers is of no importance. They are as human as the rest of us and “their state of mind” is critical to how they relate to the rest of the world and to their themselves, when alone in a room with their own thoughts and feelings.
If there are scientists who are consciously trying to suppress or deny their own emotional content while bring their work to light via normal human language then I see a potential problem there. Both for the quality of that communication (as in which domain are they operating from when communicating?) as well as their overall mental health long term.
Climate scientists cannot simply be expected or demand of themselves to “just rise above it all” and not be emotional human beings with feelings, fears, hopes or values. That’s potentially dangerous to their health and their peace of mind imho. And to their “state of mind” contrary to what was expressed in the article quote above.
Maybe I can explain my thoughts this way. Be logical. It’s illogical to deny one’s feelings and emotional life. Intelligence comes in multiple forms, not only intellectual IQ. There’s also EQ. So, watch your thoughts, then, and reason with yourself rationally and logically and emotionally.
Always drive a carriage with a pair of horses. The “carriage” represents yourself and the “two horses” represent emotion and reason. Never drive with the single “horse” of Emotion only nor Reason only. One is incomplete without the other! So be logical in all your thinking, all the time.
Realise that the emotional, mental and physical life together is the truly balanced one. Be careful not to get obsessed, fanatical, cranky or goofy about anything at all. Do not fall into the trap of denying core aspects of your whole self. That only leads to trouble for the individual.
Emotional, empathetic, passionate content and a state of mind that embodies all these things is of critical importance to effectively and successfully communicate the existential climate risks to the public and politicians. imho. Research it further, ask the experts in the field, if you have any doubts about this.
Thanks Chris (@60). Things often seem simple at first (to a hobbyist, not a scientist) because one’s own view is so limited and ignorance so great. I’ve gathered up ideas from time to time (never enough); such as an effective radiation altitude (itself a fiction, but a useful one for thinking about some things) rising upward with increasing CO2, the pressure broadened bands of CO2, the different meaning of low and high altitude cloud patterns, and how much the oceans may absorb (which appears to be enjoying some new ideas added, lately.) I appreciate what you wrote because I suspect I’ll be adding, or at least improving, some of the ideas I can simultaneously hold at one time while thinking about this specific issue.
Thanks for the time you offered us.
Alastair (51) and Hank (54). To answer your points, some very basic spectroscopy. Imagine a block of a substance which transmits half of the incident light at some wavelength. How much will 2 identical blocks one after the other transmit? Answer, the first block transmits 50% of the incident light and the second also transmits 50% of the light INCIDENT ON IT. But the light incident on it is what is passed by the first block so the net amount transmitted is 50% * 50% or 25%. For 3 blocks it would be 0.5*0.5*0.5 and for N blocks it would be 0.5^N so the amount absorbed in 1- 0.5^N. Thus the variation in light transmitted is logarithmic. Using 2 blocks instead of 1 is exactly equivalent to doubling the concentration in one block. Instead of talking a terms of concentration, spectroscopists talk in terms of absorbance where 1 absorbance means 90% of the incident light is absorbed, 2 absorbance means 99% is absorbed and so on.
GHG that absorb infrared also emit infrared at the same wavelengths depending on their temperature. At the surface where the atmosphere is more or less at the same temperature as the surface the first 1 abs thickness will absorb 90% of the surface emission but will emit at 90% of the surface emission intensity as well. Thus, using the CO2 absorption at 14.7 microns as an example, 14.7 micron radiation is continuously absorbed and emitted throughout the atmosphere. The net intensity at any given altitude depends on the temperature at that altitude. It is only the last 1-2 abs of the ghg column that can radiate to space, any radiation from lower down will be absorbed by the CO2 gas above it.
So where is the top 1-2 abs of the CO2 column? Well the total absorbance of the CO2 column on Earth is currently around 3000 abs so the 14.7 micron emission to space comes from them last 0.00067 of the gas column. If CO2 were well mixed throughout the total atmosphere that would be way up in the stratosphere where the temperature INCREASES with altitude. Except the Nimbus data shows the effective emission intensity at 14.7 microns corresponds to the temperature of the tropopause or lower stratosphere. Strong evidence that CO2 is pooled in the lower stratosphere. If increasing the concentration increased the effective emission altitude it would mean emission from a higher temperature region so emission intensity would increase not decrease. Of course what would actually happen would be that the extra emission would cool that altitude so the stratosphere would cool but emission would probably not change.
What we have not discussed however is that as concentration increases the effective line widths slightly increase (this is also logarithmic with concentration) and that means surface emission is attenuated over a very slightly greater range of wavelengths hence slightly greater retained heat. All of this is not under conjecture but it would only cause about 1C per doubling of CO2. The BIG question is whether there is net positive of negative feedback in the climate system. To get from 1C to 3C per doubling would require massive positive feedback and personally I must say I find that thesis very questionable.
Chris (60) comments that the rise in OLR must be due to more absorbed solar energy, which I would agree with. The question is, what is causing more of the suns energy to be absorbed (a decrease in albedo). Note; most of the solar energy falls in the visible spectrum and water vapour is extremely transparent in the visible and UV. In this context I think it is well worth looking closely at Svensmark’s theory that cosmic ray flux is modulating cloud density, a major contributor to albedo. The existence and widespread use of the Wilson cloud chamber in the 1950’s and 1960’s proves beyond doubt that cosmic rays do seed clouds and solar magnetic activity is known to modulate cosmic ray flux. The theory does seem very plausible to me. I note the data shows albedo and cloud cover has been decreasing during the second half of the 20th century.
Nick:
Perhaps great minds think alike ;^), as Aldo Leopold had a similar thought over 70 years ago (my emphasis):
“One of the penalties of an ecological education is that one lives alone in a world of wounds. Much of the damage inflicted on land is quite invisible to laymen. An ecologist must either harden his shell and make believe that the consequences of science are none of his business, or he must be the doctor who sees the marks of death in a community that believes itself well and does not want to be told otherwise.”
From The Round River: a Parable of Conservation, 1940-1948.
Gavin, do you think that your refusal to debate Roy Spenser and your current decision to toss all questions about “denial” into the borehole are related?
[Response: Absolutely. Both are correlated to my strong desire not to waste time. Thanks for asking. – gavin]
Hank and Ray,
Michael wrote “I have one very simple question. The theory of AGW states that rising CO2 acts as a blanket reducing Earth’s energy loss to space (which it undoubtedly does) and that this CO2 induced reduction in outgoing longwave radiation is the dominant cause of Earth’s warming. How is this compatible with NCEP’s experimental data showing OLR has been rising not falling since 1950? Also, the more recent NASA data showing the same thing.”
Note that Gavin confirmed that OLR is increasing by posting Fig. 4 from Dewitte and Clerbaux(2018). It is obvious that that old theory is incorrect, which I have known for about 20 years but only now do I have a handle on the correct model and the data to prove it is emerging.
Chris Colose writes that we have to consider short wave radiation. Incoming shortwave radiation (ISR) has not changed, but outgoing short wave (OSR)radiation, reflected by clouds and ice sheets, called the albedo, is changing due to the greenhouse effect. The reduction in OSR is the cause of global warming not the increase in OLR. BTW, OLR has increased because in the upper atmosphere the increasing CO2 is absorbing and emitting more radiation. OLR at the TOA is emitted from the upper atmosphere, not the surface of the Earth.
I have presented my ideas in posters, see my website, but in general, they have been ignored. I think that you, Hank, refused to read one when I linked to it here. It is pointless trying to get a paper published when it is likely to peer-reviewed by scientists like Ray Ladbury.
PS, my apologies if I have already inadvertently posted sections of this response already.
At the time of this writing, I see “Comments (17),” on the front page of this site for this topic, “67 Responses to “The Climate Scientists are Alright”” on page 1 of the comments section, and 60 Responses to “The Climate Scientists are Alright” on the 2nd page. Now, since it only shows the last comment marked as “60” on the 2nd page, I guess the 2nd page is correct. By why the errors on the front page and on the first page of the comments??
Just curious.
[Response: Could be the cache showing slightly out of date pages? – gavin]
If the follow-up comments look at the figure in the first link of my post, they will see that (either in the idealized case of a rapid increase in CO2 with no shortwave feedback, or with a gradual increase in CO2), you expect to “see” OLR increasing at most points in observing time. This is because the climate is coming to equilibrium with the forcing. If CO2 reduces the OLR, and the amount of sunlight being received does not change, increasing the OLR is how the system balances. That’s precisely the conventional explanation.
The shortwave component is not really relevant to this except to cause an overshoot relative to the “pre-industrial” (or whatever) OLR value. Perhaps this was confusing in my original post…
There’s no obvious inconsistency with the data and in fact you see this behavior in the model runs that supposedly aren’t getting the physics right.
Michael Hammer @62
“To get from 1C to 3C per doubling (of CO2) would require massive positive feedback and personally I must say I find that thesis very questionable.”
The warming period following the ice ages included changes of 5 degrees c for changes of CO2 from only 200 – 300 ppm, and this warming has been mostly attributed to changes in CO2. Sure looks like a big positive feedback to me.
Just a layperson, but when people make statements, I do look at the DATA, and this tells a big story.
https://www.bbc.com/news/science-environment-17611404
http://www.johnenglander.net/chart-of-420000-year-history-temperature-co2-sea-level/
Alastair (67) I am sorry to say I must disagree with some of what you wrote. You imply that the greenhouse effect (ie: increasing CO2) is causing Earth to warm but that the warming is due to the reduction in OSR not any decrease in OLR. The impact of CO2, or any GHG, is to reduce OLR. If this is not the direct cause of global warming then CO2 is NOT responsible. If you want to say that reduction in OLR is the trigger but the reduction in OSR is the amplifying factor, that’s a different story.
You also state that OLR is increasing because CO2 is emitting more radiation from the TOA. The amount of emission from CO2 at any specific wavelength within its emission band depends only on the temperature at the TOA (a thick enough layer of gas will look like an almost perfect black body radiator at the GHG wavelengths. Emissivity of a 1 abs layer is 0.9, a 2 abs layer 0.99, a 3 abs layer 0.999 and so on). Remember the total atmospheric column of CO2 is about 3000 abs. If the CO2 was emitting more it would have to be warmer yet this emission comes from the lower stratosphere which as I understand it is cooling. Yes as CO2 increases it will absorb and emit over a slightly greater range of wavelengths but the extra emission from the TOA is more than balanced by the reduction in emission from the surface and cloud tops so that would reduce OLR not increase it. After all the entire AGW thesis is that rising CO2 reduces OLR causing warming, to argue that OLR is increasing due to the extra CO2 is, I am sorry to say, illogical. If it were true then rising CO2 should cause cooling not warming.
There are 2 ways OLR could increase. The first is if the Earth as a whole gets warmer so that emission at all wavelengths increases (more or less established). The second is if the impediment for radiation to space is reducing. In the latter context, you imply that cloud and ice sheet cover is reducing. Ice and bare ground are both pretty good thermal IR emission surfaces so reduction in ice cover probably wouldn’t change OLR much but clouds are a different matter. Clouds block surface emission and replace it with emission from the cloud top which is colder so they significantly reduce OLR. Thus a reduction in cloud cover would increase OLR, which by itself would cause cooling but such a reduction also reduces OSR and this impact is the greater so the net overall effect is warming.
The data I have seen suggest that cloud cover did indeed reduce during the 2nd half of the 20th century so suggesting this is at least partly the cause of the rise in OLR is very plausible. However it raises the question as to why cloud cover is reducing. AGW suggests that the CO2 induced warming causes more water to evaporate (constant relative humidity as the temperature rises means greater absolute humidity). But if more water evaporates would that not need to be balanced by more rain and rain only comes from clouds? So how would AGW cause more rain to come from less cloud mass? This is one of the points I find confusing. It is why I find it difficult to completely discard Svensmark’s theory. What he is saying is, a more magnetically active sun increases the solar magnetic field which deflects cosmic rays away from the inner solar system. Since cosmic rays cause cloud seeding, less cosmic rays means less cloud formation. Fewer clouds cause Earth to warm because it reduces Earth’s albedo but it also increases the fraction of incoming solar energy absorbed.
I am very interested to hear your views.
Michael at #64,
Thank you for your response. However, the climate system is not quite as simple as you describe. Here is a rough outline of why.
You wrote that ”
a GHG which absorbs infrared also emits infrared at the same wavelength depending on its temperature. At the surface where the atmosphere is more or less at the same temperature as the surface, the first block will absorb 90% of the surface emission but will emit at 90% of the surface emission intensity as well.”
That is only true when the air is in local thermodynamic equilibrium (LTE). At the surface, a greenhouse gas absorbs radiation and loses that energy to air molecules through collisions, so it cannot reemit 90% of the surface emission intensity. Eventually, the air and the greenhouse gas will reach a temperature where the absorbed radiation equals the emitted radiation, and the block above will then be warmed. This only happens during the day while the surface is being warmed by solar (including diffuse) radiation. The region of the atmosphere where this happens is called the boundary layer. Above the boundary layer, ignoring the effects of water vapour convection and condensation, the atmosphere is in LTE as you describe here:
“Thus, using the CO2 absorption at 14.7 microns as an example, 14.7 micron radiation is continuously absorbed and emitted throughout the atmosphere. The net intensity at any given altitude depends on the temperature at that altitude. It is only the last block of the GHG column that it can radiate to space, any radiation from lower down will be absorbed by the CO2 gas above it.”
You then write
“… the 14.7 micron emission to space comes from the last 0.00067 of the gas column. If CO2 were well mixed throughout the total atmosphere that would be way up in the stratosphere where the temperature INCREASES with altitude.”
and you wrote:
“If increasing the concentration increased the effective emission altitude it would mean emission from a higher temperature region, So emission intensity would increase not decrease.”
But emission intensity is INCREASING!
Then you wrote:
“… the extra emission would cool that altitude …”. No, the GHG from the block below that layer would hold more CO2 and so its steady state emissions would be greater which would compensate for the additional emissions from the top layer.
However, if solar radiation remained unchanged, then the global temperature would fall because of the imbalance at the TOA. That did happen in the 1950s and the 2000s.
Your BIG question is “whether there is net positive of negative feedback in the climate system?” This is where I come back to the boundary layer where the greenhouse gases absorb the radiation and warm the air. Absorbance depends on the path length and concentration of the gas. If we double the concentration, then we effectively halve the path length. In other words, the heating effect at the base of the atmosphere would double, raising the temperature at the surface. This causes the snow line to rise in altitude and latitude bringing in the positive ice-albedo feedback. The Arctic sea ice is particularly vulnerable because its altitude is only a few meters.
The good news is that there is also a negative feedback from clouds. As the surface warms, more water is evaporated from the oceans, resulting in an increase in cloud density. This means that any loss of albedo caused by (sea) ice melting will eventually be compensated by an increase in clouds as the oceans warm – but not instantaneously!
I won’t comment on Chris’s (60) post at present as I need to study it first. But it seems as if the models are getting the physics right, even if the theory of a simple radiative model with no boundary layer is wrong.
@59 Russell: Comment 59 illustrates the first rule of the tactics and practice of disinformation: Change the Subject.
Holy Climateball, Pat- you chose to raise the subject of Davos:
49
patrick says:
26 Jan 2019 at 1:51 PM
Greta (Thunberg) says, “I want you to panic.”
https://www.theguardian.com/science/video/2019/jan/25/i-want-you-to-panic-16-year-old-greta-thunberg-issues-climate-warning-at-davos-video
Alastair at (72). Alastair I simply cannot agree with our comments. The are contrary to all I know about spectroscopy (and I worked for 42 years as a research scientist for a spectroscopy company).
No emission does not require LTE. You say the since the CO2 is losing energy to the surrounding air it cannot emit 14.7 micron radiation at the same intensity as the surface. This is NOT true, emission depends only on emissivity and temperature. If the emitting layer is thick enough (say in engineering terms 2 abs thick giving an emissivity of 0.99) then the emission will be determined by Planks law which depends on the instantaneous temperature of the gas. (Note the Stefan Boltzmann law is simply Planks law integrated over all wavelengths). It has nothing whatsoever to do with whether the gas is receiving or losing energy to the surrounding gas. If it is also losing energy to the surrounding gas that simply means it is losing more energy than it is gaining so the air mass would cool down.
You also say that as CO2 rises the downwelling radiation increases. Again NO! Remember we discussed that radiation from lower down is re-absorbed by the CO2 above so it cannot escape to space. Exactly the same applies to downwelling radiation. The radiation originating from higher in the atmosphere is reabsorbed by CO2 below it. 99% of the downwelling radiation reaching the surface comes from the bottom 2 abs of the atmospheric column (90% from the bottom 1 abs). With the total CO2 column amounting to about 3000 abs (at the line center) the bottom 1 abs is about 3 meters. So 90% of the 14.7 micron downwelling radiation at the surface comes from the 3 meters height column of air adjacent to the surface (99% form the bottom 6 meters). If we double the CO2 concentration the only change is that now 90% will come from the 1.5 meters adjacent to the surface. You certainly would not double the heating effect at the base of the atmosphere as you claim. Unless you claim the bottom 1.5 meters is significantly warmer than the bottom 3 meters of air there will be no change in downwelling radiation. But then, are you claiming you can feel a drop in temperature when you climb up a 1.5 meter ladder?
In response to my comment that if the emission altitude were increasing it would be coming from a warmer region you comment in bold capitals that it is increasing. But remember OLR is a measure of energy the earth is losing. If you claim rising CO2 and thus a rising emission altitude is increasing OLR then you are saying rising CO2 concentration is COOLING the planet. This is clearly questionable. If CO2 is a GHG which causes warming yet further rise in CO2 causes cooling then there must be a point of inflection and we must have already passed it so further increase in CO2 would cause cooling which would mean AGW would be a non event.
A more genral point; emissivity cannot be greater than 1 which means the gas cannoe emit at more than the level calculated from Planks law. An emissivity or absorptivity of 1 means it is an ideal black body at that wavelength. For a solid one can have emission absorption and reflection but for a transparent gas such as CO2 there is no reflection so there is only emission and absorption. An abs of 1 corresponds to an emissivity/absorptivity of 0.9, abs 2 gives 0.99 and so on. It means that a GHG of sufficient concentration and thickness will always look like a black body at the wavelengths corresponding to the absorption lines. By the way emissivity and absorptivity at any specific wavelength must always be exactly equal to each other. If they were not it is easy to show it would mean there were cases where net spontaneous (ie: not pumped) heat transfer would be from colder to warmer object which of course we know is impossible.
I note also you state that cloud feedback is negative. One important point I would make in regard to this. Rising water vapour increases retained heat due to greenhouse action but that increase is logarithmic. However, as you state, rising water vapour also means more cloud which is cooling. Since cloud cover is far from saturated (only about 60% of Earth is covered by cloud) the effect of rising cloud cover is close to linear. Logarithmic warming, linear cooling. This is a classic example of a system which generates a system setpoint which is maintained by strong negative feedback. At very low water vapour concentrations the greenhouse effect dominates and rising water vapour causes warming. Once the cooling impact of clouds matches the warming impact of water vapour (in watts/sqM) further rise increases cooling faster than warming (linear cooling logarithmic warming) giving net cooling. If you look at the net impact of water vapour warming and cloud cooling in watts/sqM you will see they are very similar. Again this is one of the things that I feel needs to be considered.
Title: The Climate Scientists are Alright
Are you certain about that? For example
Michael E. Mann (@MichaelEMann)
1/29/19, 1:51 PM
Great convo today at U.S. Capitol w/ Senators @SenWhitehouse, @EdMarkey, @BenCardinforMD & (not pictured) @brianschatz & @SenStabenow.
We talked about what it will take to get #ClimateAction in the U.S.
I feel more confident than ever 2019 will be the year we turn the corner!
https://twitter.com/michaelemann/status/1090321499884523520
imho that is not a rational / grounded in reality belief to hold in 2019.
Hope dies last!
The first stage of Grief is a Denial of what is.
@74 Russell: Look again. That’s not so. It’s false. I didn’t raise the subject, you did. You took something peripheral (the place where the video was made), found something else to talk about–and associated it (in #59) by implication to my remarks (49).
The subject I raised was the subject of Greta Thunberg, and what she said.
Uncut video of what she said, posted Jan 25 ’18 (6:03):
https://www.youtube.com/watch?v=M7dVF9xylaw
Greta Thunberg tells her story and the story of the Children’s Climate Strike– anyone who doesn’t know her story can get it in her own words in the first 2.5 minutes, posted Dec 12 ’18 (11:10):
https://www.youtube.com/watch?v=EAmmUIEsN9A
Her panic is a rational one, so to speak. “I want you to panic as if the house is on fire. (video #1) “Once we start to act, hope is everywhere [video #2].” Which is pure Katherine Hayhoe to me.
Also Greta Thunberg: “The climate crisis is already solved.” (video #2) She’s getting at what Dr. Kate Marvel is getting at in the Scientific American, I think, though it may seem quite different on the surface.
https://twitter.com/DrKateMarvel/status/1077947018788655105
77 “Her panic is a rational one, so to speak ”
Sounds like a palaeotweet from the Children’s Crusade or Helen Caldicott.
Lo and behold, this article (20 Feb) cites Greta Thunberg on panic, in the five last sentences of her address to the World Economic Forum (video #1, comment 77–me).
https://truthout.org/articles/its-possible-to-face-climate-horrors-and-still-find-hope/
“Our house is on fire”–the first sentence of her address–is seen here on a placard in the photo at the top of this Guardian article, about academics in solidarity with the School Strike for Climate:
https://www.theguardian.com/environment/2019/feb/13/school-climate-strike-childrens-brave-stand-has-our-support
Along with: “…the summer of 2018 has been confirmed by the Met Office as the hottest on record for England.”
Dear Gavin,
in your comment to #41 you give some OLR satellite data, which show an increase of OLR over the last decades.
Given the heat uptake has not decreased from Ocean temperatures, there must be a similar increase of the absorbed shortwave radiation.
Are there similar data for either absorbed or reflected shortwave radiation from the satellites? This would enable to cross check the OLR data.
Can you please tell me where I could find such data to compare? Thank you.
I have not found time series of shortwave satellite date.
[Response: here. I’m not sure it’s accurate enough to do what you want though. – gavin]
Thank you Gavin.
I will try this data. I hope the accuracy is sufficient. The data starts in 2000. Is there also earlier data to cover the interesting Pinatubo period?
[Response: Unfortunately not. There is the earlier ERBE data (1985-1989) though. – gavin]
“The emissions are increasing and that is the only thing that matters. I think that needs to be our focus.” …
A handful of fossil fuel lobbyists, politicians and journalists have argued Thunberg is not what she seems…
On social media there have been crude attacks on Thunberg’s reputation and appearance. Already familiar with bullying from school, she appears unfazed. “I expected when I started that if this is going to become big, then there will be a lot of hate,” she says. “It’s a positive sign. I think that must be because they see us as a threat. That means that something has changed in the debate, and we are making a difference. … I think we are only seeing the beginning. I think that change is on the horizon and the people will stand up for their future.”
https://www.theguardian.com/world/2019/mar/11/greta-thunberg-schoolgirl-climate-change-warrior-some-people-can-let-things-go-i-cant
This is Greta Thunberg now. She explains herself quite well. It’s the best report yet, with some of the best video.
#75 Interesting subject. If processes are occurring that reduce outgoing SWR (and they certainly are with e.g. snow cover) then to achieve thermal balance the outgoing LWR must increase to compensate. Of course there is some imbalance from oceanic heat absorption but that is small relative to the change in outgoing LWR.
A very complicated system.