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jef12506 at 01:30 AM on 8 January 20192019 SkS Weekly Climate Change & Global Warming Digest #1
I hope everything will be OK.
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Evan at 01:13 AM on 8 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
nigelj@10 Here is another perspective. The way we deal with hurricanes is that we try to get everybody back from the shore and out of the way. We let the hurricane do its damage, then we clean up the mess and move everybody back (I mean no disrespect for those who suffer during hurricanes, just trying to summarize).
We seem to take comfort if we can convince ourselves that the sea level rise due to ice loss will be slow. How do we do that with sea level rise that occurs over millenia? It would almost be better if sea level rise happened fast (like a Hurricane) and we got it over with quickly so that we had something like a single, focused event to deal with. Slow sea level rise might actually be harder to deal with than rapid sea level rise.
I think the only thing that matters is continually monitoring all of the world's ice so that we can improve ice-loss forecasting. We need to budget for this from now on just as we budget for tsunami and hurricane monitoring systems.
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Philippe Chantreau at 00:31 AM on 8 January 2019CO2 effect is saturated
I recall Gavin Schmidt going at length over this at RC and saying basically the same thing: the absorbtion in the "wings" is where the additional watts/sq.m happen as concentration goes up. It adds up significantly. This may even figure still in the "Saturated gassy argument" posts linked below the thread.
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MA Rodger at 20:27 PM on 7 January 2019CO2 effect is saturated
LTO @486,
I'm conscious that directly answering some of your queries would lead toward some rather incongruous implications with complex explanations required to sort them out. So I'm torn between simply answering #486, going back to first principles as an explanation or introducing a mathematical model into the mix. Haven't decided which yet.
But I will pitch in with (1).
michael sweet @487 mixes up the broadening of the CO2 dip in the IR spectrum (most important) and pressure broadening (not important). These are two different phenomena.
The 15 micron wave band absorbed by CO2 is flanked by weaker bands which result from spinning CO2 molecules. Spin being a quantum process, there are only certain speeds of spin that can happen, resulting in the graph below (I assume it is for 1 atm).
It is the strenghtening in these flanking bands that broadens the CO2 IR dip.
But you will also note there is a small probability of absorption at wavelengths between the seperate bands. This is the pressure broadening which is a big effect on Venus with its 90bar atmosphere.
As for your actual question, the effect of this broadening of the CO2 dip with an increase 400-to-800ppm relative to a 280-to-400ppm increase (=100). I think, as a component of a logorithmic ratio of 194/100, it would possibly be something like 400/100. By 800ppm, the emissions height for the central part of the band is increasingly in the stratosphere and so acts as a cooling mechanism counteracting much of the warming through the strengthened absorption at the edges of the CO2 dip. You may find Zhong & Haigh (2013) 'The greenhouse effect and carbon dioxide' Figure 5b a useful reference.
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nigelj at 16:11 PM on 7 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
Evan @9, thank's for the video link. Given this is a climate expert talking about more than 5 metres sea level rise per century, I agree he cannot be simply dismissed. Shame the video was so short.
Basically this is how I have approached the sea level rise issue, fwiw. I have been aware for quite some time of claims of 5 metres sea level rise per century versus the 1 metre IPCC estimate. Its hard for me to know who to believe short of cracking open a textbook or two. My own instincts fwiw have always been that the IPCC have been too conservative in their estimates, but I try to avoid confirmation bias, and catastrophic mindset thinking, so I looked at the historical record for guidance. This is something that is happened, it does not rely on " ifs, buts and maybes" and pages of differential equations.
The historical record does have periods of multi metre sea level rise per century, associated with ice sheet destabilsation. They appear to be around 2 - 3 metres per century for several centuries. So that is what I would see as a very strong possibility.
Here's another thought. I design infrastructure. Obviously the 200mm sea level rise last century is not too problematic. Its unlikely to devastate anything and is easy to design for and it was reasonably constant. Get up towards 500mm and we have serious problems. Florida is already in this territory. It threatens existing infrastructure and making planning for the future difficult. Much land would just have to be put off limits.
At one metre and even assuming its constant over time, building is a big problem. It would be absurd building foundations to cope. Huge areas of land would simply have to be put off limits for development.
Now we have this scenario that it "could" be more than one metre, who knows, perhaps two metres, or more than five metres. I dont even think it matters too much which, because a) it is all going to lead to huge loss of coastal land and b) the unpredicatbility of it all makes design impossible.
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Evan at 14:00 PM on 7 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
Riduna@8, thanks for the links. I take it seriously when people like James Hansen and Richard Alley talk multi-meter sea-level rise this century. nigelj was citing a background rate that is low multimeter due to historical precedence, and I realize that some of the best researchers are talking 5m or more. I cannot see that anything we will do will change the conclusion that it is time to start building coastal defenses where it makes sense, and time to start retreating where it does not make sense. In that light I found it interesting that there are already places where the retreat has started, even if climate change is not specifically identifed as the reason for the retreat.
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Riduna at 13:22 PM on 7 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
Evan
In 2018 I wrote an article There Will Be Consequences in which I cited work by Dr. Hansen and some leading glaciologists showing that under certain conditions mass loss from the polar ice caps could produce sea level rise of >5m. within a century.
The likelihood of multi-metre sea level rise this century is seen as inevitable by many experts in the field. While some may reject that conclusion, they must do so in the light of increasing loss of ice from the Greenland Ice Shelf, Dr Rignots assessment of Antarctic instability and Hansen et al 2016.
We may naïvely take comfort from those who espouse sea level rise of <1m. this century (5AR) but the evidence is compelling that without sustained reduction in greenhouse gas loading and emissions, we are very likely to be assured of multi-metre sea level rise in the latter part of this century.
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Tom Dayton at 11:39 AM on 7 January 2019Sea level rise is exaggerated
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scaddenp at 11:35 AM on 7 January 2019CO2 measurements are suspect
billev - perhaps you are unaware of this satellite and its mission? There are several ways to determine what the increase in CO2 can be attributed to from carbon mass balance (we know pretty accurately how much FF is burned), O2 depletion, changing carbon isotope composition (FF has no C14), ocean pH. In fact nature is so far mopping up about half our emissions. More here.
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scaddenp at 11:25 AM on 7 January 2019Sea level rise is exaggerated
I think Miami is already struggling with sealevel rise. Cant help with Houston Ship Channel sorry.
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michael sweet at 10:47 AM on 7 January 2019CO2 effect is saturated
LTO:
I found a Boltzmann Equation calculator on line (Google)
It finds 239.8 W/m2 at 255 K and only 228.7W/m2 at 252K. That means the Earth heats up faster than if the difference was only 1W/m2 but in the end the temperature at the escape altitude must increase to 255K so all the energy is emitted.
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michael sweet at 10:27 AM on 7 January 2019CO2 effect is saturated
LTO,
SkS is always happy to help those who want to learn the science.
1) My understanding is that line broadening is a very small effect on Earth. It is important on Venus. It is not necessary to understand line broadening to get the basic greenhouse effect.
2) CO2 molecules emit a variety of radiation lines with15 micron being the most important. The number of photons emitted by a section of the atmosphere (with a great many CO2 molecules in it) is determined by the black body equation. Most of the CO2 molecules that absorb a photon coming up from below transfer the energy of the photon to other molecules in the air through collisions. They do not re-emit the photon they absorbed.
There is always a population of excited CO2 molecules that can emit a photon. These molecules are excited by collisions with other molecules. The size of this population is determined by the black body equation. When it is hotter there are more molecules that are excited and more photons emitted. When cooler less excited molecules, less photons. The number of photons increases with Temperature to the fourth power. The population of excited molecules is the important idea, not individual molecules.
3) Let us imagine the escape altitude is 10.00 km and the Earth is at equilibrium. Exactly the same amount of energy is emitted from the molecules at the escape altitude as is absorbed by the Earth (the energy comes from the Sun and is primarily absorbed on the surface). The Earth receives 240 W/m2 and emits 240 W/m2. The Earth is at a stable temperature. The temperature at the escape altitude is 255.0K.
Someone adds 1,000 gigatons of CO2 to the atmosphere. This causes the CO2 concentration to double. This causes the escape altitude to increase to 10.50 km (500 meters).
The temperature of the atmosphere decreases with height according to the lapse rate (6C per km). The temperature at the new altitude is only 252.0K (255 - [0.5km x 6C/km]). Because it is colder less energy is emitted from the Earth (the amount can be calculated using the Boltzman equation. It takes me a long time to calculate with this equation.). For the purpose of discussion let us say at the new altitude only 239 W/m2 is emitted.
The Earth is no longer at equilibrium. It is absorbing 1 W/m2. It starts to heat up. The temperature at the escape altitude must increase to 255.0K in order for the Earth to emit 240W/m2 again. (There are some complications like a small increase in surface area that do not matter).
The atmosphere always has a lapse rate of 6C/km. Since the temperature at 10.30 km has increased 3.0C the rest of the atmosphere also increases. The lapse rate is a measured physical property so it must be applied.
I do not understand your question about energy. Most of the absorbed energy is transferred to the surrounding atmosphere. That is how energy reaches the escape altitude and is emitted to space.
The main effect is sometimes in the eye of the beholder. I think the main effect is to increase the temperature of the atmosphere. That occurs because CO2 (and other greenhouse gases) absorb upwelling IR radiation and slow the emission of energy into space. Both re-radiating energy back to the surface and heating the surrounding air are important. The most important effect is increasing the escape altitude.
4) The maintenance of the lapse rate in the atmosphere is complex (scientists who study the lapse rate understand how it works). See this article for background information (found using Google). Convection is involved but there are other factors.
When we say the escape altitude is 10 km that is an average over the entire Earth: Tropics to Arctic, night and day (a few wavelengths escape from the surface). The escape altitude is not the same everywhere on Earth. In the Tropics it is higher than in the Arctic. The lapse rate is an average property of the entire atmosphere, individual storms or other phenomena can violate the lapse rate (and the escape altitude) for periods of time.
I recommend you accept the lapse rate and escape altitude on faith while you learn how the greenhouse effect works. After you understand the basics you can add other effects that you are interested in. Line broadening, convection, heat transfer by phase changes, clouds and other effects all occur in the atmosphere and alter the greenhouse effect. Climate models have to deal with all these effects but they do not alter the basics.
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AFT17170 at 07:47 AM on 7 January 2019Sea level rise is exaggerated
I encounter some extreme fringe RWNJ deniers on various investor sites. They literally don't care if the West Coast or Northeast have issues with SLR "because Democrats live there" (no, I'm not kidding). So I would like to put it in terms that they might care about. At approximately what year does SLR become "a problem" for Florida (that big swing state needed to win elections)? The Houston Ship Channel (which would be supremely ironic)? Has there been any science done at that kind of level?
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rcass at 06:28 AM on 7 January 2019Other planets are warming
What amazes me about this discussion is the absense of any explicit mention of the earth's moon. The moon has been monitored for decades. It has more or less the same spatial position with regard to the sun as the earth and it has no atmosphere. In other words, it provides the perfect 'control' to assess whether earth is warming due to solar or atmospheric causes. Yet t is almost impossible to obtain an online plot of the moon's average temperatures over time - I've tried. If the moon's averages are stable or declining - out of synch with temperatures on earth - that obviously and clearly settles the argument. Skeptics talk about Mars and Pluto, where there is insufficient data. They at least appreciate that this kind of data, if reliable, is persuasive. Why do not climate change believers produce reliable plots of the moon's temperature averages against time. They are very fond of plotting earth temperature's against time. Why is this blindingly obvious 'crucial' experimental comparison never discussed?
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Evan at 06:25 AM on 7 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
nigelj@6, thanks for your thoughts. I've seen a lot of this material and agree with your analysis. We are talking varying shades of bad.
Have you seen Richard Alley's short video clip where he says (not predicting) that 15-20' this century is possible? Here is an article in Rolling Stones that contains Richard Alley's video clip.
Needless to say Richard Alley knows this stuff better than any of us, and he is a seasoned scientist, not given to making exaggerated claims. His message is sobering. But we all agree, even if he is wrong, it is still time to prepare. So here is a feel-good PBS story about a town that is taking the right steps, right now, to prepare for what is coming.
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nigelj at 05:02 AM on 7 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
Evan @5, as far as I can figure out The IPCC currently predict 1 metre of sea level rise per century (worst case scenario) spread out over many centuries and based on medium to high climate sensitivity. If we burn all fossil fuels we are talking 30 metres plus of sea level rise but over a lengthy period.
But some of us think they are being too conservative and that it could be more than 1 metre per century at least for a period of time. Maybe not by 2100 but soon after this
Anyway I would think 2 metres per century for maybe 5 centuries for example 'would' fall into the categorisation of a quick pulse! And it would be devastating for infrastructure.
I was simply trying to get a handle on what has happened in the past known with some certainty, and that is 2 metres per century as far as I can tell.
However I would definitely agree we cannot rule out more than 2 metres. J Hansen has written a paper somewhere finding that 5 metres per century is possible based on physics and modelling, but many worst case factors have to coincide for this to happen.
I do not know nearly enough physics really, but I know warming is looking like a quadratic curve, so you would expect melting of ice and expansion of sea water to follow this, and this suggests about 1 metre of sea level rise per century over many centuries. However the wild card is ice sheet destabilisation, where glaciers speed up, or the face of ice sheets starts to collapse. This looks like it would cause a step change in a quadratic curve. Glaciers would however come up against limiting facor of friction. The article suggests the face of ice sheets could collapse rapidly from undercutting and the possibility of 4 metres per century for a couple of centuries at least perhaps until things reach a new equilibrium.
2 metres per century. 4 metres per century. All bad.
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Philippe Chantreau at 03:32 AM on 7 January 20192nd law of thermodynamics contradicts greenhouse theory
AFT, anyone who thinks seriously about it undertands that thermodynamics are not violated. This argument is just part of larger campaign undertaken by some actors because they know where the morally defensible position is and that people will in their majority adopt the morally right position if there is no doubt about it.
The depth of the denial is compounded by numerous factors. Some scientists, like G&T, are unscrupulous enough to write such nonsense. The general population is science illiterate and innumerate enough to buy into it. The ambient attitude that anyone is free to have whatever opinion they choose is stretched to the point that it implies said opinion has validity. The overall anti elite and anti intellectual sentiment has been cultivated by crooks purely for the fostering of their financial interest.
There is little to gain by arguing with those who go for the 2nd law argument; they are ready to cling to any straw, no matter how feeble and likely won't be convinced by any level of reasoning or evidence. Look how long this thread is. Waddle in it if you want, it's saddening. Almost 1500 post devoted to the least valid "skeptic" argument of all. It says something.
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Evan at 01:39 AM on 7 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
Thanks for the clarification nigelj@4.
I assume you've seen Fig. 1 in the paper by Alley et. al. (2005) where they present a graph of sea level vs. CO2 concentration. Using a climate sensitivity of 3C/doubling CO2, their graph works out to about 12m/1C warming, at least for the first 2C of warming or so. If we assume that we stabilize at 2C, that implies 24m of sea-level rise. At 2m/century that's 1200 years.
The engineer in me says that given how rapidly we've warmed the planet, that we will get a sizable chunk of that 24m much, much sooner than using 2m over 1200 years. I'm not disagreeing with your analysis nigelj, but rather noting that we might get a quick pulse that then settles down into a long tail that approximates 2m/century, because we are causing a warming pulse that represents more of an impulse to the system than what we expect happened during deglaciation cycles.
And of course this assumes that we stabilize at 2C.
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AFT17170 at 23:06 PM on 6 January 20192nd law of thermodynamics contradicts greenhouse theory
I'm fairly new to this site and just catching up on a lot of articles and comment streams. Is this myth still used? The way I explain it to laymen is...
The CO2 greenhouse effect was discovered in the 1890's. Much of its fundamental underpinnings were discovered and confirmed with Cold War era military research. So I find it exceptionally hard to believe that this theory was studied for ~90 years before the existence of the IPCC and nobody noticed that it violated basic laws of physics.
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LTO at 22:23 PM on 6 January 2019CO2 effect is saturated
MA, Michael - thank you for this; very helpful, and it's tht first time Ive heard about the lapse rate as an explanation for how global warming works. There are a few things I'm still not following:
1. How much of a difference does the effective widening lf the bands actually makw at the concentrations werew talking about? Eg if the effective drop in radiance (ie area under thr curve) at 400 ppm co2 was 100, what would it be at 800 ppm?
2. I'm not following the black body radiation argument, because co2 excitation and subsequent emission of 15 um isn't a black body phenomena (correct me if I'm wrong here). A single co2 molecule in an excited state will release a 15 um photon, and this is separate to black body radiation.
3. I'm not sure I'm following why the temperature of the escape altitude increases. As indicated by MA earlier, there isn't necessarily energy transfer to the surrounding gas as excited co2 molecules increasing the temp of surrounding air through collision then in principle increases the number of co2 molecules excited through collisions with surrounding air, hence minimising net energy transfer. I'd thought thr main mechanism behind the greenhouse effect was re-radiation of 15 um photons back to the surface (or water vapour), not through heating of surrounding air. Is that wrong? Or are these minor secondary effects that are only really relevant once you get past the primary saturation point?
4. Even if the temperature of the escape altitude is increased, it's not clear to me why that is necessarily transmitted to the ground through the lapse rate. What is the mechanism? Presumably not convection. Given the existence of eg temperature inversions in the troposphere and the day-night temperature cycling, it isn't clear to me why that is necessarily the case.
Thanks!
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Feneley at 22:16 PM on 6 January 2019CO2 increase is natural, not human-caused
The arguments presented are helpful and fairly comprehensive, but I was surprised the author, dana1981, did not address what, in my view, is the most important scientific publication on this issue: “The phase relation between atmospheric carbon dioxide and global temperature” by Ole Humlum, Kjell Stordahl and Jan-Erik Solheim in Global and Planetary Change 100: 51-69, 2013. These authors showed, using published temperature time series from multiple sources and global CO2 and anthropogenic CO2 data that, for the years 1980 to 2011:
1. There was a good temporal correlation between global CO2 and ocean temp, land temp, global temp and lower troposphere temp BUT the global CO2 FOLLOWED the ocean temp, then the land temp, then the lower troposphere temp, in that order, with lags of 9-12 months.
2. In contrast, there was poor temporal correlation between anthropogenic CO2 emissions and both global CO2 and temperature.
3. While anthropogenic CO2 was emitted overwhelmingly from the northern hemisphere, the time sequence of ocean temperature variation commenced in the Southern Hemisphere, reasonably close to the equator, then spread north and south to the poles, always preceding the global CO2 time sequence.
These carefully determined temporal sequences and correlations, based squarely on the published temperature and CO2 data, clearly indicate a causal sequence in which global temperature changes PRECEDE global CO2 changes by 9-12 months, commencing with changes in the ocean surface temperature, then the land temperature, then the lower troposphere temperature. These observations are the complete OPPOSITE of what should be expected if anthropogenic CO2 emissions were driving both the global CO2 levels and then causing a secondary increase in temperatures.
So, while I appreciate the energy balance and other arguments advanced above, causality requires a demonstrated temporal sequence of changes that the data I describe here simply do not support. I would be very interested in your explanation for these observations.
Moderator Response:[TD] Humlum is wrong. Type "Humlum" into the Search field at the top left of this (or any) SkepticalScience page.
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Ari Jokimäki at 17:03 PM on 6 January 2019New research, December 24-31, 2018
Thank you, Jonas! :)
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nigelj at 10:37 AM on 6 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
Evan @3
I agree melwater pulse 1a is associated with 5 metres per century, but read the wikipedia article. Only half this is at most is attributed to destabilisation of the antarctic, the remainder to the melting of ice sheets over north america which do not exist anymore, so my conclusion is a destabilising antarctic as discussed in the article above would perhaps cause 2 metres of sea level rise per century. Which would be catastrophic.
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Evan at 09:55 AM on 6 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
nigelj, am I missing something. What I've read Meltware Pulse 1A was associated with about 5m/100 years for 4-500 years. Or are you saying that 2m/century is the amount associated with Meltwater Pulse 1A that was on top of the background declatiation rate top give a total of 5m/century?
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AFT17170 at 09:18 AM on 6 January 2019It's the sun
Hello Michael — indeed, as a layman observer, I perceive that the battle started at "it's not warming", moved to "it's warming but not us", and is indeed now at "it's not that bad" or "not worth the cost to mitigate".
No, I cannot point to any recent "stored up past solar activity" arguments, I was reacting to those arguments that appeared on this thread.
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Jonas at 08:41 AM on 6 January 2019New research, December 24-31, 2018
Hello Ari,
as already posted for Baerbel for this start of the year and from time to time to John Hartz, I want to thank you and all of the SkS team for your work: as a small multiplicator in my semi-private network, I depend on you ..
The science overview is mostly to specific for me, but I get a broad impression of what's going on in climate related research via the titles (very valuable background info) and view some 4-6 articles you link per post: enough to keep me going with Johns links ..
My saturday evening is devoted to SkS (you and John and other posts and as needed the general resources).
Best,
Jonas -
Jonas at 07:58 AM on 6 January 20192018 in Review: a recap of the Skeptical Science year
Hallo Bärbel,
ab und zu schreibe ich einen Dank an John Hartz, weil ich dessen Posts inzwischen am meisten nutze, aber zum Jahresanfang will ich auch Dir und SkS allgemein Danke für euer Engagement sagen.
Ich weiß nicht, wer die direkten Leser von SkS sind, aber ich vermute, die indirekten sind noch deutlich mehr .. Ich jedenfalls filtere SkS (und andere Quellen) und verlinke ein paar Posts oder Graphiken in einem kleinen Forum für die Bio-Selbsternte-Gärten in meiner Heimatstadt, das ich betreue und an anderen Stellen. Für Klein-Multiplikatoren wie mich sind Seiten wie SkS sehr wichtig (deshalb unterstütze ich das auch per Spende).
Angesichts der unguten Perspektiven (die ich als bedrohlich empfinde) sind insbesondere auch die Posts zur psychologisch sinnvollen Kommunikation hilfreich.
Viele Grüße,
Jonas.Moderator Response:Thanks for your feedback & donation, Jonas!
For those not able to read German, here is a quick translation of Jonas' comment
Hello, Bärbel,
every now and then I write thanks to John Hartz, because I use his posts the most, but at the beginning of the year I also want to thank you and SkS in general for your commitment.
I don't know who the direct readers of SkS are, but I guess the indirect ones are much more ... I filter SkS (and other sources) and link a few posts or graphics in a small forum for the organic self harvest gardens in my hometown, which I take care of and elsewhere. For small multiplicators like me, sites like SkS are very important (that's why I support it with a donation).
In view of the unpleasant perspectives (which I find threatening), the posts on psychologically meaningful communication are especially helpful.
Many greetings,
Jonas. -
One Planet Only Forever at 06:17 AM on 6 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
nigelj,
I agree. The Bold main title gets used without the important context.
It would have been better to reverse the two.
Experts continue to warn that our overall picture of sea-level rise looks far scarier today than it did even five years ago - However, a recent more terrifying sea-level prediction now appears to be far less likely.
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nigelj at 06:08 AM on 6 January 20192019 SkS Weekly Climate Change & Global Warming News Roundup #1
Regarding the article published in the magazine Science: "A Terrifying Sea-Level Prediction Now Looks Far Less Likely. But experts warn that our overall picture of sea-level rise looks far scarier today than it did even five years ago."
This is a very good article, but the title is so badly worded and immediately creates the impression sea level is not an issue. I know the second part of the title is a cavet that hints at problems, but the impression is made in the first sentence, that there's no problem. Please just stop this naive journalism.
It's only when you read half way through the article that you find they are still predicting about 5 metres of sea level rise by year 2300, which is huge, and not so far into the future. This is buried away and would be easily missed. Sigh.
Meltwater pulse 1a was 16,000 years ago and associated with destabilisation of the antarctic and about 2 metres of sea level rise per cenury is attributed to this, spread over several centuries. I often quote this because its an event that happened, so is particularly pertinent. Modelling the future is challenging, but we have this known information from our past to consider as well.
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Tom_S at 06:00 AM on 6 January 2019We're heading into cooling
I'm new to this site. After a quick read I have two initial observations:
(a) Evidentally only Climate Scientists are "real" scientists so input from other closely related fields of science e.g. meteorology, astronomy etc. can cheerfully be discounted or ignored
(b) I see several exhorations such as "Then prove it: do the analysis, write it up, publish it." but have to ask - since the Science is Settled, why bother?
Tom S.Moderator Response:[DB] Thank you for taking the time to share with us. Skeptical Science is a user forum wherein the science of climate change can be discussed from the standpoint of the science itself. Ideology and politics get checked at the keyboard.
Please take the time to review the Comments Policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
Off-topic snipped. -
One Planet Only Forever at 03:08 AM on 6 January 2019CO2 measurements are suspect
billev @89,
Your clarifying of what you are suggesting or asking about has been helpful.
As Eclectic has pointed out, politics related to climate science can be discussed on Weekly Digests.
I can add more science related points to what Eclectic mentioned.
All global leaders, in business and politics, have been increasingly informed about the constantly improving awareness and understanding of climate science through the collective global expertise evaluating the science and consolidating summaries of scientific understanding (with regular updates - because science by its nature is constantly increasing and improving awareness and understanding).
The IPCC is the global body that does that. Many IPCC Reports have been produced, starting with the AR1 series of reports that were published in 1990. The IPCC is currently working on the AR6 series of reports planned for publication starting in 2021 with the last document of the series planned to be published in 2022.
So there is very little 'climate science' awareness and understanding that the Governor of any state (or elected official at a Federal level) would be 'unaware of'.
Consider that understanding of history of availability of awareness and understanding of climate science the next time you read about some elected official questioning how much is really understood about climate science. You should seriously question, be skeptical of, the motives of such a questioner.
Climate science has confirmed that future negative climate change consequences are being caused by the continued increase of CO2 in the atmosphere due to human activity, mainly the burning of fossil fuels. And the scientifically understood solution is to stop increasing the CO2 in the atmosphere. So every regional leadership is tasked with the responsibility of figuring out how to get their portion of the global population to stop contributing in any way to the increase of CO2 or other human activity created GHGs.
That is as far as the science goes. And that understanding is not going to be changed by new research. All evidence indicates that the urgency to stop the creation of new CO2 is only going to increase as business and political leadership fail to effectively correct the problem that has been developed.
I hope that helps you understand this issue.
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michael sweet at 21:18 PM on 5 January 2019It's the sun
AFT,
My feeling is that the "skeptics" have given up. 10 years ago they argued that it was not warming. Now most of them say they have always said it was warming but the warming will not be bad. They also argue that it will crash the economy to take action even though all peer reviewed studies say it will be beneficial.
Not very many people argue that it is past solar activity stored up. Can you link an example of a serious argument? Scientists have identified the sources of heat. During El Nino some stored heat is released while more heat is stored during La Nina. Longer term storing of heat is global warming. Can you link an example of someone claiming a war of statistics?
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Eclectic at 13:52 PM on 5 January 2019CO2 measurements are suspect
Billev @ 85/89 , if you are talking about science ~ then the sources of atmospheric CO2 are already well-known (and have been, for decades).
If you are talking about politics (the best policies for abating the global warming problem, and the most speedy but economical & socially-advantageous ways of achieving zero nett carbon emission) ~ then this is not the right thread for such discussion [perhaps try one of the Weekly Digests?]. As always, you would need to give consideration to jobs lost versus jobs gained in advancing renewable-type industries & services . . . and put everything in perspective wrt past & present out-sourcing of jobs to China, Mexico, etcetera, in both the short term and longer term.
B. Your comment at #86 is bizarre. Please read Climate Myths 12 and 91.
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billev at 12:14 PM on 5 January 2019CO2 measurements are suspect
My point is this. The Governor of California is attempting to install laws to limit the use of fossil fuels in order to reduce GHG emissions. This may prove to be costly to the citizens of California in terms of higher operating costs and the departure of manufacturers and jobs. If a better understanding of the sources of GHG (particularly CO2) can demonstrate that the laws limiting human consumption of fossil fuels will not significantly diminish the growth of CO2 levels then unnecessary costs caused by those laws can be avoided. In other words if it is found that increasing vegetation due to a warming Earth is the only significant source of increased atmospheric CO2 then the futility of costly policies to limit fossil fuel use might be avoided. To this end it would be valuable to political leaders to have much more detailed measurement and analysis of the sources of atmospheric CO2 than is now available.
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AFT17170 at 11:29 AM on 5 January 2019It's the sun
I discovered this site about a month ago and have been working my way through several of the articles and thousands of comments. The comment traffic on this article has been quite light since mid 2017. Have the skeptics given up this argument?
My layman's absorption of all this is the following (expressed in my layman's language) — it seems that any argument along the lines of "it's current solar activity (of some variety)" is devastated by the broad array of evidence... less incoming radiation being measured, less outgoing radiation measured, nights warming faster than days, winters warming faster than summers. I think I get that, let me know if I missed or mistated something.
Does this array of evidence Is also work against the varieties of "it's past solar activity stored up and now being released", or could such forcings be consistent with the previously stated evidence? Or does that devolve into a war of statistics?
Thanks in advance.
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Eclectic at 10:08 AM on 5 January 2019CO2 effect is saturated
LTO @482 ,
forgive my bluntness, but your recent questions show that you are still floundering rather than "understanding the principles [behind the GHE]".
The GHEffect is multi-faceted, but straightforward. Take your time, think things through and put the pieces together in your mind. There is no trickery, no hidden or undiscovered "unknown unknown" factors . . . it is all simply very basic physics [high school level physics will be quite adequate].
Picture the Earth of 300 years ago, when things were very close to equilibrium [though to be more accurate, the Earth has been cooling very gradually for around 5 thousand years]. The air CO2 level was about 280ppm, and the "escape altitude" was at the appropriate level. Now look at today : CO2 level 410ppm, and the escape altitude has risen 100 or 200m higher and colder ~ fewer and slower molecular collisions. And therefore marginally less excitation and emission of 15um photons to space. And yet we still have about the same incoming heat energy from solar radiation. Result : imbalance.
Now jump 100 years into the future. Wise political leaders have (of course!) long ago brought "zero nett carbon emission" into being, and have fostered projects which incorporate carbon (dioxide) into the soil . . . bringing air CO2 levels down to the low 400's. Planetary surface temperature is 1 degreeC above 2019 levels [i.e. 2 degrees above pre-industrial levels] and is steady. The escape altitude is at (say) +300m, but the air at that point has [stabilized] become slightly warmer . . . enough for the 15um IR loss-to-space to have increased back to the pre-industrial amount ~ so the Earth is in thermal equilibrium again (solar radiational input and terrestrial radiational output are matched). But we on the surface here are 2 degrees warmer than pre-industrial.
The alternatives are rather worse, if we allow the GHE to push things up 3 or 4 or 5 degrees.
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michael sweet at 08:42 AM on 5 January 2019CO2 effect is saturated
MA Rodgers: Thanks for posting that graph.
LTO:
Black body radiation is the net of all the photon emitting events. When the temperature is higher more photons are emitted. According to the Boltzman equation, the number of photons emitted is proportional to T raised to the fourth power. A small change in T means a large change in photons emitted.
UV radiation not absorbed in the stratosphere passes through the Troposphere and is absorbed at the surface. There has to be an absorbing molecule, like ozone in the stratosphere, for the energy to be absorbed.
It appears to me that you are applying a double standard. Unknown "Global cycles" do not need evidence while scientific explainations require every T crossed and I dotted. Fortuantely, the T's and I's have all been done. Keep reading scientific sites and you will find out what you seek. Be careful of reading "Skeptic" sites as they traffic in nonsense which has to be unlearned.
1) Exact numbers are beyond my pay grade. Look at MARodgers graph.
2) The temperature at the escape altitude is essentially fixed because it must be high enough to allow all the energy incoming from the sun to be emitted. The lapse rate of the atmosphere (the decrease in temperature with increasing altitude) is a physical constant and is also fixed. When the escape altitude increases, the temperature at the new escape altitude also increases to ensure conservation of energy. When the temperature increases at the new escape altitude the increase propagates down to the surface to comply with the lapse rate.
While at the surface the 15 micron absorbtion is saturated at the escape altitude it is not. Therefore increasing CO2 increases temperature. People who do not understand the greenhouse effect think because absorbtion at the surface is saturated temperature cannot increase. The escape altitude is where the action is .
Someone else suggested that the temperature at the escape altitude did not change as much as I think it does. I think there is an issue of different simplifications of a complex subject.
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One Planet Only Forever at 08:01 AM on 5 January 2019CO2 measurements are suspect
Billev @85 and 85,
In addition to RickG's question I am curious about why you mention that the Governor of California would care about the atmospheric CO2 levels in that State.
Identifying sources of CO2 emissions or other GHGs by satellite survey could be helpful. But other than identifying concentrated human production sources of GHGs, the level of CO2 in a region is rather 'beside the point'.
Increased CO2 is happening globally (it is seen at every location that measures CO2 levels).
The Global Warming and resulting Global Climate Changes are the problem.
Please provide more detail regarding exactly what you are suggesting or asking about.
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RickG at 07:46 AM on 5 January 2019CO2 measurements are suspect
@Billev (86). I'm not quite sure what you are suggesting. Are you saying that gloal warming is causing a rise in CO2 and not the reason for global warming?
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billev at 03:31 AM on 5 January 2019CO2 measurements are suspect
My previous comment is based upon the idea that the current CO2 level in the atmosphere has an effect on global warming. In fact it is more likely an effect of global warming rather than a cause of it.
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billev at 03:19 AM on 5 January 2019CO2 measurements are suspect
From the comments above, I feel that the current capability for measuring atmospheric CO2 is grossly inadequate. For example, I would think that if the Governor of California wished to concentrate on levels of CO2 in his state that might be problematic then he should have access to CO2 measurements at a number of surface CO2 measuring sites scattered across the state. He could then better determine if actions to reduce human induced CO2 emissions would have any significant impact on the overall CO2 levels in the state. He might well discover that the CO2 output from the states areas of intense vegetation could not be significantly countered by reducing the level of human induced CO2 emissions. Then again, he could receive evidence that such measures might well reduce the CO2 level to an acceptable amount.
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MA Rodger at 00:52 AM on 5 January 2019CO2 effect is saturated
LTO @482,
An unsaturated GHG (like methane) does provide for stronger warming effects with rising concentrations, these being roughly linear increases in warming with rise concentrations, rather than the logarithmic relarionship found with CO2.
(1) What you mean by "bands of absorption" is not clear. The bendy wobble absorption band at 15 microns is made up of a set of wavelengths which are weaker the further away from the central part of the band. Thus the CO2 absorption appears as a wide dip at 15 microns as per this graph below.
Note the small spike in the centre of the dip. This is the strongest part of the CO2 bendy wobble absorption. Here at this precise wavelkength you would be up into the stratosphere before a photon has a clear shot at space. (It is an upward spike because the stratosphere is warmer at that altitude than the upper troposphere.
One of the effects of adding CO2 to the atmosphere is to widen the broad CO2 dip as there are weaker wavelengths at the edges that are not saturated and in dry air would allow a photon to be emitted by CO2 and have a clear shot at space from ground level.
If you mean by "band" an energy of photon that imparts a different wobble into CO2, there are none of consequence operating in the IR range, the closest being 4.3 microns.
(2) The impact of altitude-increase is that (and here your question up-thread was hidden by your additional comments on 'rate of collision') through the troposphere temperature drops with altitude and so the Stephan-Boltzmann relationship applies. A colder gas is unable to emit as much IR. See the contours on the graph above. Less photons emitted to space, more energy accumulating on the planet, a warming planet until the energy fluxes are balanced
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LTO at 23:57 PM on 4 January 2019CO2 effect is saturated
To clarify my query: I understand well enough the principles behind the greenhouse effect. However, what I recently only became aware of was that there is already a vast overabundance of co2 to absorb all the IR emitted at 15 um, so the effect of adding more co2 at current levels must have a vastly smaller effect than adding thse same amount of co2 at much lower levels. This seems to be common ground amongst those in the know, but I'd say unknown to 99% of people.
The explanation for why it matters nevertheless seems to be twofold, and here is where I'm struggling to understand quantitatively how significsnt the effects are.
1. CO2 also has other minor bands of absorption, which may depend on concentration amongst other factors, that arent saturated. My question here is just how much additional energy this actuslly captures and re-radiates back to the ground. Is it really significant in the grand scheme.
2. Increasing CO2 increases the altitude of emission (perfectly happy here), and because 15 um photons are being released at this higher altitude therefore global warming (this is where I'm getting lost).
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LTO at 23:40 PM on 4 January 2019CO2 effect is saturated
Michael: thanks for taking the time. Apologies on the collision point, i see it's a bit of a red herring. I'm still not getting the importance of temperature on the escape altitude. I understand black body radiation (kind of) but not how that relates to the discrete emission of a photon from an excited molecule. In other words, the collision between bulk property thermodynamics and a discrete quantum event. This may just be my own deficiencies.
What i don't follow is your point on UV and stratosphere. The article you linked to https://www.wunderground.com/resources/climate/strato_cooling.asp was clesr that tbe decrease in ozone layer was the main cause in a large decrease in stratosphere temperature through decreased UV absorption. It *must* therefoelre be the case that this energy was transferred to the troposphere instead. Given ozone depletion very simply predicts a decrease in stratosphere temps, the greenhouse effect prediction would seem to carry less weight: the two effects would need to be disambiguated, increasing uncertainty, particularly as according to that article the ozone effect is dominant.
I'd suggest its unfair to call explanations based on temperature cycles post hoc - this idea is obviously very well supported by the pre-industrial historical record. The weakness in that argument is of course that it predicts anything, amd therefore predicts nothing .NNevertheless, the challenge is to show something unusual is happening, which is difficult to do persuasively when we've only been measuring certain metrics for a short period. That's a very different topic to this one though!
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michael sweet at 22:59 PM on 4 January 2019CO2 effect is saturated
LTO,
Unfortunately I do not have much time.
1) The number of collisions at the surface is about 1 million times faster than the relaxation time. The change in temeprature to 10 kmn is about 40C. That is about a 20% change in speed and collision rate. The pressure change is about 40 kPa. About a 40% change which changes the collision rate a little more than 40%. Combined they change the collision rate less than a factor of 5. At the escape altitude there are 200,000 times as many collisions as emissions.
The atmosphere is a black body. At a lower temperature it emits less energy. Science of Doom will have a graph of energy emitted compared to temperature. Black body radiation changes relative to T to the fourth power so small changes are a much larger effect.
Complex models can exactly calculate the emission spectrum of the entire atmposphere at any level or all combined but are not needed to explain the greenhouse effect. They demonstrate that scientists know what they are talking about. (I do not have time to find a reference, sorry)
2) Most of the UV light is still absorbed. There is not that much energy in the UV remaining (it can be calculated and is considered by climate scientists).
The Stratosphere is a completely different situation than the Troposphere. The Troposphere is heated by energy coming up from the surface. CO2 blocks this energy from escaping (until it reaches the escape altitude) so the Troposphere warms.
The Stratosphere is warmed by UV light from the Sun. Increased CO2 causes increased emission of IR energy. Since the Stratosphere is above the escape altitude (as discussed above) the increased IR emission results in increased loss of energy and cools the Stratosphere. The key understanding is the escape altitude (which is very complicated but we simplify to 10 km for these discussions)
Scientists predicted this effect in advance. It is a key signature of the greenhouse effect. Post hoc explainations about unknown "global oscellations" do not hold the same weight as predictions made in advance. I know of no alternate explainations for how the Troposphere could warm as the Stratosphere cools.
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MA Rodger at 22:49 PM on 4 January 2019CO2 effect is saturated
LTO @472 &475,
I think I should add to the message from Tom Dayton @473.
You talk of "unknowns in the system" and "taking someone else's word for it."
I appreciate that getting a grasp of AGW can be frustrating. I remember when I first encountered the Greenhouse Effect and the idea that there could be some equivalent to a sheet of glass allowing light in but preventing IR escaping seemed a bit much to accept. What you tend not to find, even now, is convincing explanations as to why the Earth's atmosphere is more hermitically sealed than any greenhouse or blanket. So I'll say it here. The atmosphere is incredibly well balanced vertically. Outside hurricanes, volcanic eruptions and other relatively rare events, the day-to-day reality is the motion of the Hadley Cells, They are responsible for most of the up-down movement in the troposphere and they take about two weeks to rise from surface to tropopause. Yet this is not something you will readily learn if you start asking folk. I share with you here my own frustrations from a few decades ago.
Yet there are some (probably very many) apparent incongruities that can be expressed about AGW that are not readily answerable in a simple way using non-scientific argument. This SkS site addresses many but there are always different flavours of incongruity to consider in such a complex system.Yet such incongruities do in no way support the notion of potential "unknowns in the system" where we have to "tak(e) someone else's word for it." And in particular here we are discussing an aspect of AGW that is in no way in dispute as, despite the complexity, there are absolutely no "unknowns in the system."
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Eclectic at 22:30 PM on 4 January 2019CO2 effect is saturated
LTO @477 ,
we seem to have cross-posted at 21:54 PM.
Your first paragraph shows that you are still a long, long way from understanding the Greenhouse Effect.
The "complexity in escape altitude" does not require a "model" of mathematical ingenuity & tour-de-force. You can do a good approximation on the back of the proverbial envelope, using a blunt pencil. Basically, use the temperature lapse rate of around 6.5 degrees per 1000m altitude. (Of course, the escape altitude is not a razor-thin layer, but a fuzzy zone . . .but your can treat it as one particular altitude (as described in some of the comments upthread) . . . while always remembering that other Greenhouse gases have different escape altitudes.
The stratospheric cooling is interesting, in that it demonstrates that modern global warming is not of solar initiation. But in practical terms, the stratosphere is so low density, as to have minimal effect (and similarly with the thermosphere).
Better for now, to focus your thoughts on understanding the GHE. Think about the transient condition, where (as right now) there is a nett inflow of heat into our planet . . . compared with future condition, where the Greenhouse influence has stabilized at a higher surface temperature.
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LTO at 21:54 PM on 4 January 2019CO2 effect is saturated
Michael: fantastic thank you
1. I find this a little difficult to believe in its face (which isn't to say it isn't true!) for two reasons. First, while the number of collisions is high, the relaxation rate of an excited co2 molecule is presumably quite fast, and so the net effect could be considerably more than it appears from the raw collision rate itself. Second, and more importantly, if temperature and pressure don't make much of a difference then why is the increase in escape altitude so important? I'm still not clear on why the relatively small decrease in temperature as the escapeealtitude increases affects the emission of a discrete photon so significantly.
On the ppm point, difficulty isn't a great excuse in my view! The constancy of co2 in ppm is a bit of a red herring, if i'm understanding things correctly, because really it's the molar concentration combined with pressure that gives effect to the phenomena. For example, both venus and mars have comparable (very high) co2 ppm levels, but clearly completely different effects, at least in psrt because of the difference in atmospheric pressure (as I understand it).
2. That's really useful re the troposphere thanks. The complexity in escape altitude mustmmake things very difficult to model.
That link is really interesting for two reasons. First, it implies that actually the hole in the ozone layer should uave been responsible for a significant portion of troposphere warming, as opposed to CO2. Presumably the UV light that would otherwise have warmed the stratosphere warmed the troposphere instead. Do we know how much troposphere warming is attributable to this?
Second, the point on CO2 cooling the upper atmosphere really didn't make sense to me. The argument appeared based on an assertion that the earth is always radiating the same amount of heat so an increase in troposphere temp must lead to a decrease in upper atmosphere temp, but I thought the whole point was that the earth was retaining more heat. Why isn't the increasing CO2 conc in the stratosphere leading to increased heat retention of photons released by co2 in the troposphere and concomitant warming? Could be related to the pressure point above, but in that case why isn't it a relevant consideration for increasing escape altitude?
3. I will do! May take a while - hopefully will get answered here first.
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Eclectic at 21:54 PM on 4 January 2019CO2 effect is saturated
LTO @472 ,
I must say I am puzzled by your assessment of the Science of Doom website. The Greenhouse Effect is understood through observational studies combined with well-established basic physics. Any usage of models came much later, and is certainly not foundational to the science of it all.
Please do not be discouraged. The CO2/Greenhouse Effect is actually quite simple & straightforward ~ once you have gotten your head around it. But it is not immediately intuitive.
Just like the Galileo/Tower-of-Pisa/falling-weights tale . . . and like the concept of Gravity . . . and Newton's Laws of Motion. All these things can be "unsimple" to explain in a few paragraphs ~ but are quite simple and obvious, after you have grasped the concepts. But for previous thousands of years, they were not intuitive at all ! And still are not ~ until you take a scientific approach and think things through.
As Tom mentioned in #463 : in air, the molecular collisions occur at a rate many orders of magnitude above the "relaxation times" of a CO2 molecule (where a CO2 molecule accepts the energy of a 15um InfraRed photon, and later "relaxes" to emit an equivalent IR photon in a random direction). Even where you reduce that collision rate by a hundred-fold (by reducing density & temperature, e.g. in the upper troposphere), you still get the situation where the collision rate is still vastly greater than the IR relaxation rate. When you think it through, you see that the end result gives a negligible difference in the actual effect [ e.g. comparing the bulk difference between 99.99% and 99.9999% ].
** And LTO ~ a word in your ear. While I myself am sweetly naive and unsuspicious that you might be uttering some phrasing of words which is alas too often heard coming from the mouths/keyboards of trollish science-deniers . . . nevertheless you have managed to cause Tom's ears to vibrate, by your using terms of the type: "incredulity / hoax-like / too-complex-to-be-an-honest-description / etcetera [obviously I am harshly paraphrasing your comments]."
Those sorts of phrasings are common among science-deniers [= faux-skeptics] who subconsciously wish to reject reality ~ and who summon all their powers of distraction & rhetoric, in order to deceive themselves.
( I do read the WattsUpWithThat website, for entertainment. Half the posters commenting there, are angry-crazies & political-extremists who are still in complete denial that CO2 & other Greenhouse gases have any global warming effect at all . . . and many of the other half are intelligent but so deeply affected by their Motivated Reasoning, that they distract themselves by using rhetorical smoke & mirrors ~ basically for deceiving themselves into a viewpoint that "there's nothing really unusual going on, and there's little or no global warming happening . . . and even if it is happening, then it's gonna be good for us, and with no major downsides". )
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LTO at 20:38 PM on 4 January 2019CO2 effect is saturated
Tom: I'm not sure what I did to attract your ire, but I apologize. The point I was trying to express is that the actual theory behind co2-induced global warming is significantly more complicated than I'd thought for a long time. To the extent that I genuinely wonder how many people would really claim to fully understand it, scientists (of which I'm one, albeit not a physicist) included. Is there anyone on this site who would put themselves in that category?
The impression I get (which may not be accurate) from that science of doom website is that the theory is based on modelling of complex interrelated agonistic and antagonostic phenomena, which makes it somewhat different class of scientific theory. Models are necessarily simplifications, and in highly complex systems hidden variables can often lead to very unexpected effects in the real world, which therefore leaves room for reasonable skepticism and uncertainty. Anyway, I'm on a journey of discovery here and have already learnt a lot, in part thanks to you, so once again thank you for your help and I'm sorry you feel you wasted your time.
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