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Comments 101 to 150:

  1. CO2 effect is saturated

    Hi Eclectic, it doesn't seem to me like you've correctly understood the figures quoted earlier (or my post@494), but others may have a different view. Why do you think the altitude of emission must always remain in the troposphere?

  2. CO2 effect is saturated

    LTO @494 ,

    there are worrisome ambiguities in your comments.

    The "tropopause" is a very different concept from the "escape altitude i.e.  emission altitude".  For CO2 that altitude is dependent on the absolute density of CO2, while the tropopause is a temperature-related concept.  If I have correctly understood the figures quoted earlier, the [CO2] altitude you are interested in does always remain in the troposphere (not the stratosphere).

  3. CO2 effect is saturated

    Thanks all, very useful. MA: that sounds like it would be extremely helpful for me and others.

    The point on many contributing phenomena is the key one - not just the existence of the phenomena, but how quantitatively significant it is. This no doubt varies with co2 concentration, and easily leads to confusion. The current understanding I have is that the most significant co2-induced warming mechanism (which is the one most people know about - re-radiation of IR photons to the surface) is indeed saturated at much lower co2 concs, and it is other effects that are purported to combine to trap significant amounts of energy in the troposphere. Once comfortable on this point, the point on energy balance is a given.

    One really interesting point that has come up is what happens when the altitude of emission is in the stratosphere. I understand that the tropopause varies between about 9 and 17 km, while co2 concs are relatively homogeneous across the globe, therefore the altitude of emission at ~10 km is already in the stratosphere around thr poles. it would seem that increasing co2 concs will, by raising the altitude of emission, progressively increase the proportion of the atmosphere in which this is happening. Will this offset troposphere warming effects to some extent?

  4. Republicans call for 'innovation' to tackle climate change, but it's not magic

    nigelj@4 I agree completely. Individuals must start to act now on their own. Personal action should incentivize action because politicians will, to some degree, follow the lead of their constituents. But even if they don't, we must act. To solve the problem requires all individuals, organizations, and governments pulling as hard as we all can. Anything less than an all-out effort by everyone will likely fall short. We know this from the science, but nobody says it because of how unlikely it is to happen.

    Keep pushing the button for personal action and keep talking to your friends, neighbors, and family.

  5. Republicans call for 'innovation' to tackle climate change, but it's not magic

    Its also a false dichotomy to say its either government action, or individual action.

  6. Republicans call for 'innovation' to tackle climate change, but it's not magic

    Suggesting its either innovation or regulation is an obvious false dichotomy. We not only need technically inventive solutions (and we already have some) we need some pressure from regulation, subsidies or carbon taxes to force the scaling up of the solutions.

    The tragedy of the commons is empirical and historical fact and means market forces alone wont fix the problem, or will be painfully slow.

    The Ozone hole problem wasn't fixed by market forces alone. It used a cap and trade scheme to force the phase down of the flourocarbons. Without this we would without doubt still have an ozone hole.

  7. Philippe Chantreau at 04:53 AM on 9 January 2019
    CO2 effect is saturated

    The links are in the notes below and take you to the RC threads, where Ray Pierrhumbert did most of the initial comments. In fact, I don't know that anything recently discussed above is not adequately addressed in the notes right here below the comments, where there are many good links.

    Part 2 is more interesting from the technical point of view, especially the extra absorbtion in the wings of the spectrum.

    This is old news. The RC posts are almost 12 years old. It has all been worked out with the highest level of precision in HITRAN. The appropriate physics are in the models. It is not an area of very active research or debate. HITRAN was pretty much as far it was worth going with it, from any practical point of view.

  8. Republicans call for 'innovation' to tackle climate change, but it's not magic

    It is time that we all collectively, as individuals, start to ramp down our emissions.

    We cannot wait for governments to tell us what we already know we need to do.

    The time for individual as well as government action is here.

  9. Republicans call for 'innovation' to tackle climate change, but it's not magic

    Is it safe to say GW is not a Chinese conspiracy anymore?

    Moderator Response:

    [DB] It never was.

  10. CO2 effect is saturated

    michael sweet @391,

    I cannot fault what you say. Particularly, that "there are many phenomena that contribute to the greenhouse effect" is one of the difficulties in setting out a succinct statement of how it operates. Yet the simple energy balance is an overriding principle - if energy-out is different from energy-in, there has to be consequences, in the present case a period of global warming. The point with this aspect of AGW is that it is more than "settled", it is cast in concrete! All that people are lacking is an explanation appropriate for their needs.

    I have been putting a bit of thought on a journey to introduce these GHG mechanisms in a way I've not seen before. I'm hoping it may be useful to folk like LTO. I've not quite routed out that journey yet, but it is looking useful.

  11. CO2 effect is saturated

    Chris Colose is a scientist who studies Climate Change who used to write sometimes for SkS.  He wrote a description of the greenhouse effect here.  His sumary states:

    "So…review: Because of energy balance, the planet must get rid to space as much energy as it receives from the sun. Averaged over the Earth, taking into account the albedo and geometry, this is about 240 W m-2. In the absence of an atmosphere, this flux of radiation is lost by the surface by \sigma T^{4}_{s}. With an atmosphere, this flux of radiation is allowed to emanate from upper, colder layers of the atmosphere, say on average at some altitude H. Increasing greenhouse gases increases the altitude of H, a height in the atmosphere which depends on wavelength, and characterizes a level of mean emission to space. Because the atmosphere is now emitting from colder levels of the atmosphere, the OLR has decreased, and the result is that the planet must warm to re-establish radiative equilibrium."

    I think my description is similar to his.  His summary is more technical and those who want to increase their knowledge of the greenhouse might want to read it.

    Apparently I mistook line broadening and pressure broadening.  Line broadening is important for the greenhouse on Earth.  Both these effects, and many others, contribute to the magnitude of the greenhouse effect.  If we double the concentration of CO2, the CO2 will directly cause heating of about 1C.  Some of that will be due to line broadening.  Feedbacks from other causes like increased water vapor and changes in clouds will contribute additional heating.  The feedbacks are difficult to calculate exactly but if the climate sensitivity is 3.0C (about midrange in the estimates) they will contribute 2C.

    Philippe Chantreau: can you link Gavin Schmidt's comments, I could not find them at Realclimate.

    As I said above, there are many phenomena that contribute to the greenhouse effect.  Different scientists sometimes emphasize different phenomena as important.  All these effects together make the greenhouse effect.

  12. 2018 in Review: a recap of the Skeptical Science year

    PS: Thanks for the translation and sorry for the additional work, maybe I should have written in english, but beyond expression thanks, I wanted to hint to the international audience and the excellent translations that I also often link to (e.g. the guide to skepticism, debunking handbook, posts ..).

  13. Skeptical Science takes the Pro-Truth-Pledge

    I think this type of approach is the key to getting people to understand the importance of fact checking and actuatly doing it.  I would also suggest the importance of addressing the content of what people say, not the person saying it.  That is, criticize (in a friendly way) the comment, not the commenter.

  14. Models are unreliable

    I am not sure his series amounts to a "critique". He states "Climate models are the best tools we have for estimating the future climate state."


    "There are lots of papers written by climate scientists on the difficult subject of evaluating climate models. They do some things well. They do some things badly. Different models get different results. Sometimes widely different results."

    No arguments there.

  15. Skeptical Science takes the Pro-Truth-Pledge

    This is such good advice. Sad in a way people need reminding.

    I stumbled on a so called science website, complete with advertisements for viagra and a book on the illuminati, and no list of the academic qualifications of its authors. Obviously the website could be completely ignored as unreliable. You have to filter out things that are a waste of time.

    One thing on verifying truth and intelligent opinion. Look for inconsistencies because these are the sign of poor quality thinking and a lack of intelligence. 

    I wonder if science has been just a little unlucky lately, and its just a temporary thing. We have had the climate gate emails where phrasing of certain statements created a bad impression, a mistake in one of the IPCC reports, the science community has revised its views on saturated fats, there have been a few other things that create the erroneous impression science has got things badly wrong. Of course if you look at the specifics, and put it in context its all nothing of consequence.

    Yet this has coincided with globalisation causing some problems, another apparent failure of experts, (it isnt) and the development of the internet and social media which turbo charges the exchange of conspiracy theory nonsense.

    I would say the net result is some well meaning ordinary people jump to the wrong conclusion that "elites cant be trusted". Its so frustrating because if anything expert knowledge is better than ever before!

    I hope sanity will prevail, and it will all blow over.

  16. 2019 SkS Weekly Climate Change & Global Warming News Roundup #1

    johnthepainter @12 the original article didn't say the antarctic wouldn't collapse, it just shifted the time frame forward from by the end of this century to around 2200 - 2300. 

  17. 2019 SkS Weekly Climate Change & Global Warming News Roundup #1

    Evan @11 yes true it would be better to get the worst of it out of the way relatively quickly, provided we  knew the exact extent of sea level rise so we could rebuild behind  the danger zone confidently. But we will never have that certainty. The most likely outcome is we will get the worst of both worlds, long slow sea level rise with unpredictable shorter periods of rapid sea level rise embedded in this. 

    I dont envy the people trying to understand it and model it. Its not as if we can build full size glaciers and do experiments with them.

    Anyway all I know is our climate agency did graphics of the impact of 500 and 1000mm on our coastal cities and the impacts were larger than I suspected. It's hard judging sea level rise just by visually looking at a beach, its so easy to underestimate it. Cheers.

  18. johnthepainter at 04:42 AM on 8 January 2019
    2019 SkS Weekly Climate Change & Global Warming News Roundup #1

    What I'm wondering is how we can reconcile the conclusion of this study with the following one, reported December 18: "Discovery of recent Antarctic ice sheet collapse raises fears of a new global flood"

  19. Models are unreliable

    The excellent "Science of Doom" has a critique of your debunk. 

    Someone from SKS may wish to engage.   SoD is generally an excellent site for true scepticism.

  20. 2019 SkS Weekly Climate Change & Global Warming Digest #1

    I hope everything will be OK.

  21. 2019 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.

  22. Philippe Chantreau at 00:31 AM on 8 January 2019
    CO2 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.

  23. CO2 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).

    CO2 absorption probabilities

    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.

  24. 2019 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. 

  25. 2019 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.

  26. 2019 SkS Weekly Climate Change & Global Warming News Roundup #1


    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.

  27. Sea level rise is exaggerated

    AFT: Try 

  28. CO2 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.

  29. Sea level rise is exaggerated

    I think Miami is already struggling with sealevel rise. Cant help with Houston Ship Channel sorry.

  30. CO2 effect is saturated


    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.

  31. CO2 effect is saturated


    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.

  32. Sea 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?

  33. Other 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?

  34. 2019 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.

  35. 2019 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.

  36. Philippe Chantreau at 03:32 AM on 7 January 2019
    2nd 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.

  37. 2019 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.

  38. 2nd 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.

  39. CO2 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.


  40. CO2 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.

  41. New research, December 24-31, 2018

    Thank you, Jonas! :)

  42. 2019 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.

  43. 2019 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?

  44. It'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.

  45. New 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).


  46. 2018 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,

    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,

  47. One Planet Only Forever at 06:17 AM on 6 January 2019
    2019 SkS Weekly Climate Change & Global Warming News Roundup #1


    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.

  48. 2019 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.

  49. We'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.

  50. One Planet Only Forever at 03:08 AM on 6 January 2019
    CO2 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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