Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Recent Comments

Prev  1023  1024  1025  1026  1027  1028  1029  1030  1031  1032  1033  1034  1035  1036  1037  1038  Next

Comments 51501 to 51550:

  1. WSJ, Sandy, and Global Warming - Asking the Right Questions
    David Roberts from Grist has an excellent and insightful essay on how to communicate to the public how events like Sandy are relevant when discussing AGW. His essay is titled: The moral logic of climate communication
  2. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    Chris Dudley at the open thread at RealClimate point out: "I missed this originally but it turns out that raypierre does not put a lot of stock in the new study by Trenberth and Fasullo. He ‘described the paper as “another useful data point on the spectrum of estimates of cloud sensitivity,” though not “an absolute game changer.” He pointed out, for example, that the correlation between water vapor and clouds was drawn from short-term seasonal fluctuations. Researchers cannot be certain that those same correlations would hold true in response to a doubling of carbon dioxide in the atmosphere in the future, Dr. Pierrehumbert added. “The whole problem is really the nature of the observations,” he said. “We don’t have long enough satellite records of cloud observations to really do this kind of study by directly looking at which models get the low clouds right, so we try to indirectly run around the inadequacies of the satellite record.”’" http://green.blogs.nytimes.com/2012/11/08/a-new-tweak-for-global-warming-predictions/
  3. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Brian,
    Not everything is going to get worse with AGW. To think otherwise is delusional.
    Actually, yes, everything will get worse. Everything. Some things may seem to get better for a while (say ten or twenty or even thirty years), but they will (a) quickly be drowned out by the intense gravity of the things that do worse, and (b) any improvement will be short lived (in climate terms) and overwhelmed by negative aspects. The "CO2 is plant food" meme will be a perfect example. Yes, you may see crop yields increase for a brief period in selected areas, due to benefits from increased CO2 concentrations. But over time changes in temperatures, moisture and growing seasons, disproportionate benefits to pests (like the pine bark beetle) and weeds that are better adapted to higher CO2 levels, and other effects will reduce crop production far below any meager benefits from CO2. Yes, some things won't get worse or may even get better, for a very short while. But things are going to get bad, and in some cases very, very bad. In particular, Hurricane Sandy is a whisper of a hint of what's in store. We have barely begun to warm this planet, and like opening a window in a rain storm, the wind and rain are still barely getting in. To think otherwise is delusional.
    I would recommend that everyone here get down from his/her high horse...
    Gladly, when people like you and Pielke start to be more realistic, and stop loudly clinging to every pathetic, ill-founded and cherry-picked argument as an excuse to ignore addressing the issue. It would be one thing if Pielke were suggesting moderation in action, because people are overreacting. He's not, because no one is overreacting -- no one is doing anything at all! He's pretty much promoting complete paralysis, and to date he and his ilk have succeeded, to the serious detriment of us all. To think otherwise is delusional.
    Moderator Response: [DB] Can all parties please focus on the science? Passion for accuracy is admirable, but can sometimes steer threads off-course when that passion begins detrimentally affecting the tone of the dialogue. Thanks!
  4. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Ultimately the analyses merely confirm what I stated from the beginning--there is no significant trend in the ACE data given above. Simple courtesy would require you to acknowledge that. With no detectable trends in the Atlantic basin ACE, landfalling hurricane frequency and strength, or normalized damages, there is simply no evidence that AGW has made hurricane damages worse. This does not preclude, of course, that such damages might increase in the future.
    Firstly, Brian, I am aggrieved at this comment. Let me show you what our exchange looks like from my perspective: 1. You make an unsupported claim about the ACE trend. 2. I go and do the work to check your claim for you. I present not only the result you asked for, which strongly refutes your claim, but also several others, one of which doesn't. 3. You make a claim about AMO. 4. I go and do the work to check your claim for you. I present my initial results, which suggest that ACE is predicted by SST rather than AMO. Then on the basis of further analysis I correct my claim to the weaker statement that SST is at least as good a predictor of ACE than AMO. 5. You accuse me of discourtesy. So from my perspective it feels as though you are making claims, I am doing my best to present a skeptical analysis of the data, including all my results whether or not they support my position. You do not thank me for my effort, and then you criticise me for my discourtesy. That is the basis of my grievance. Perhaps our exchange looks different from your perspective. If so, I invite you to present it. Secondly, It is possible that you have missed the point of my analysis. I assumed, wrongly, that it was obvious from context. Let's go back to the title of this article: 'Asking the right questions'. I presume you recognize that there is a rhetorical device, well used by lawyers, that when asking a question would lead to an inconvenient answer the trick is to ask a different question. The main point of the article is to suggest that this is what is happening. Here are two questions: 1. Is there a connection between global warming and Atlantic hurricanes? 2. Have US landfalling hurricanes increased over time? I would suggest that the second question is being used to distract from the first. It is harder to answer because you need to rely on coarse grained data or proxies of various kinds. The first question is both more important for understanding what might happen in the future, and is more easily answered because we can rely on fine scale meteorological data and/or meteorological models, which shows a very clear connection between SSTs and hurricanes. I can give you a load of papers, but if you are interested you can very easily find them yourself. RPJr insists that we neglect our knowledge of physics and meteorology and only accept data from the past. Firstly, no justification has been presented for rejecting that information. Secondly, even if we do so, we have to invoke AMO to reject the positive trends in favour of the neutral ones, and as I have shown AMO is certainly not a better predictor than SST, while SST has a physical basis. I hope that clarifies my claims.
  5. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Albatross: Go to RealClimate, go to Tamino, or use the search function here and you will find numerous examples of Roger's dad cherry picking, or misrepresenting or distorting the science to fit his narrative. Why is Roger Jnr. not hopping about accusing his dad of being a liar in public? As you know Roger is quick to (falsely) accusing other scientists of lying or fudging the data etc. Actually, if there's a single reasonable excuse for obvious inconsistency of the kind Albatross describes, surely it's the deference of a child to a parent.
  6. New research from last week 45/2012
    @ IanC Thanks Ian - yes I reached the same conclusions and posted same in a thread over at The Conversation "It goes to the heart of something that those who study the science already know - that the main uncertainty is to do with climate sensitivity - how much warming will be associated with increased CO2 levels and how fast will it occur. And the paper only indicates that the measured uncertainties in heat flux (more back radiation than was thought which suggests greater warming influence from CO2 but a greater latent heat flux exchanged between the surface and the atmosphere due to the evapotranspiration cycle) are much larger than thought. The trouble is such uncertainties cut both ways - warming could be much higher than the models suggest or much lower." Nevertheless I would love to be able to read the paper since climate sensitivity is one area of climate science that I think is of legitimate debate. Based on the current indicators (sea ice etc) and the potential for tipping points I worry it will be much larger than 2-3 degrees but I hope it will be much smaller.
  7. Roy Spencer finds negative feedback
    Curiousd here. Interested in communicating these things to physics trained non climate scientists. To me, if I go to the Berkeley Earth website and use their "global land surface temperature plot 12 month moving average", I see a nice looking fit that ignores obvious volcano effects and is described as "logarithmic". If I take the temperatures from that graph, look up the CO2 concentrations of corresponding years, and plot delta T versus log to the base two of the CO2 concentration ratio I get an excellent straight line with a slope giving a climate sensitivity of 3 degrees C. So "clouds/shmouds"......Spencer is wrong and over the time span of the Berkeley Earth data the C.S. is 3 degrees centigrade. What is wrong with what I am doing? Or am I right? (I could show the result if I could figure out how to post a graph on this thread.)
  8. WSJ, Sandy, and Global Warming - Asking the Right Questions
    BrianB @ 82 stated
    Not everything is going to get worse with AGW
    Oh, dear, not another round of 'CO2 is plant food', I hope. What, exactly, do you mean by 'worse'? It seems we have different understandings of the word. I am unable to detect a rosy future in any credible forecasts I have read. Where or whom are you getting your opinions from? We could all do with some good news, if it passes the sniff test.
  9. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Brian @83, Could you please cease with the bluster and assertions and actually address the scientific critique directed at Roger Pielke Junior. A careful read of Dana's post would be a good start. Then, as I have said several times now, counter those points that you disagree with using peer-reviewed journal articles from reputable journals-- and simply saying Roger published "X" does not cut it, as it does not demonstrate that you understand the material or how it is relevant to the topic at hand etc. Readers here have also identified issues that have not been dealt with or have not been dealt with satisfactorily in the literature. They are trying to advance the science and the knowledge, although I'm sure you will disagree. Thanks!
  10. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    chriskoz@11, Good to see someone taking an active interest in this important study. At your point one, you say: "the extra emissions from permafrost will be relatively minor." I assume by this you mean "extra heating from emissions from permafrost will be relatively minor" If so, then, yes, if we have already thoroughly cooked the planet by burning fossil fuels, the extra carbon released from the permafrost will only manage to singe it a bit further. As to your #2, tall vegetation in that region can actually serve to increase local warming, since it sticks up above the snow cover and changes albedo in the fall and spring. (This is effect is already underway in some areas.) Also, keep in mind that the carbon that could be released from this one source (terrestrial permafrost) is equivalent to all the carbon in all the terrestrial plants that now exist. So a bit more plant matter above ground is not going to re-sequester enough carbon to make up for the massive amounts that will be lost from the permafrost. Recall that much of the tundra is much thicker than three meters. So it becomes a surface-versus-volume problem, and volume here, of course, wins out. As for #3, I never said that permafrost carbon was more 'significant' than the permafrost carbon, whatever exactly that would mean. Just that, as I read their graphs, the MacDougal article seems to indicate that even at a climate sensitivity of 3 degrees C per doubling of CO2, and even just counting this one major carbon feedback (CO2 from top 3.5 meters of terrestrial permafrost), we end up with continued high levels of atmospheric CO2 for at least two centuries into the future, even if we stop all further burning of fossil fuels essentially immediately. --That isn't going to happen--not by a long shot --There are of course many other powerful carbon feedbacks that must be added to the equations and the graphs, even if we don't know exactly how strong they will be --The article above suggests that the climate sensitivity is closer to 4.5 than 3, which, according to the MacDougal article, spells _rising_ atmospheric CO2 levels for at least two centuries even if we stop burning fossil fuels tomorrow, and even if we only consider this one major carbon feedback (both being entirely unrealistic, of course). Again, thanks for your interest. And I'd be very much happy to be shown to be wrong on any of my points. So I would appreciate you (or anyone) taking a critical look at the whole matter and ideally telling me I have missed some crucial point or misunderstood some crucial concept. Best, wili
  11. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    Kevin@3, Thanks for the clarification. Indeed, I can see now & agree that Hansen 1988 was considering TCR (decade time-scale) rather than ECS (centennial time-scale) as in FS12, so direct comparison of those two makes little sense.
  12. WSJ, Sandy, and Global Warming - Asking the Right Questions
    “As for the surge itself, even that is more complicated than just the wall-of-water metaphor that’s so tempting to use. As explained more fully by Weather Underground’s Jeff Masters, it’s more of a bulge of water, spread out over a wide area in front of the storm. Winds account for about 85 percent of the height of the average surge, and the tremendous wind field surrounding Hurricane Sandy is maximizing that component of storm surge. “Another 5-to-10 percent comes from what’s called “wave set-up”— the fact that water can’t drain back off into the ocean because there’s more water pushing from behind. The final 5-to-10 percent comes from a tropical storm’s low atmospheric pressure, which literally sucks the ocean skyward. “But even that isn’t the whole story. Global sea level is now about 8 inches higher, on average, than it was in 1900, in connection with global warming. Sinking land has added several inches more of local sea level rise in the Mid-Atlantic. That means the storm tides from Sandy are that much higher than they would have been if the identical storm had come along back then. “And as sea level continues to rise in a warming world, a Sandy that arrives in 2100, when average sea level is likely to be about 3 feet higher than it is today, would be correspondingly more destructive.” Source: Source: Sandy’s Storm Surge Explained and Why It Matters by Michael Lemonick, Climate Central, Oct 29, 2012
  13. WSJ, Sandy, and Global Warming - Asking the Right Questions
    If damages are affected by some combination of building quality, technology, sea level rise, etc., they would show up as trends in the normalized damages.
    Not necessarily. Ignoring the question of how meaningful these "normalised" damages really are, it's entirely possible for building quality and technology to balance out the consequences of increased hazards. In fact, to a certain extent I expect people to spend "just enough" to maintain risks within a certain range in the face of increased hazards because it's often the optimal economic strategy (so rather than "gold-plating" to avoid any losses, we spend what it takes to keep losses within a "comfortable" range). So looking at losses — and especially so-called "normalised" losses — for evidence of the effects of AGW is looking at it backwards, IMO.
    Because there are no significant trends in landfalling hurricane data
    This smacks of cherry-picking, due to the relatively low numbers involved. It's better to look at the Atlantic basin ACE, as the OP does. Originally you claimed that it appeared to have "no stastically significant trend". Kevin C showed that in fact it did. You then objected that the effect of the AMO was actually the cause of the apparent trend. This appears to be assuming facts not in evidence, however. A correlation between ACE and AMO does not necessarily mean that AMO caused the rise in ACE, and Kevin C's later investigations (showing a lot more healthy scepticism of his own results and a lot more analysis of the data than you have demonstrated so far) suggest that it may actually be the increase in sea surface temperature driving the increase in ACE. This is important because not only would we expect this from the physics, but the increase in sea surface temperature is driven, in turn, by AGW! I would suggest a little more caution (and a little less red) in making assertions about what is and what isn't and what can and what cannot be done. Bold, unsupported assertions in red are "unscientific jibber jabber".
    I would recommend that everyone here get down from his/her high horse, take a careful and objective look at the science, and understand that science should not be a pawn in your own personal campaign
    Right sentiment, wrong target. BTW, ignoring all the substantive criticisms made of Pielke's work so that you can cherry-pick those explanations of why people bother criticising him and attempt to paint them as their entire argument does you no favours. Here's a simple one for you: Does Tom Curtis' characterisation in #45 of Pielke's "normalisation" method accurately describe it? If not, how is it different? If so, how does it not fall victim to the perverse outcomes I described in #77 above? Since so much of the argument hinges on this normalised data — after all, the raw data shows massively increasing losses — I think it's worth spending a bit of time justifying the normalisation (and no, simply saying it's been "peer reviewed" alone doesn't cut it — that's a necessary but not a sufficient condition). Thanks!
  14. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Brian, "What he has said repeatedly is that AGW signals are more likely to be seen in the phenomena themselves before they are seen in the resulting damages." Yes, Roger plays this game nicely (one has to be careful to keep your eye on the ball when he is up). He has indeed said that, yet he is fond of citing trends in normalized/adjusted damages as the metric (despite all the limitations of that approach), especially following a disaster, ignoring that he has claimed the contrary before. "Finally, I would be happy to provide evidence that Pielke Jr. criticized his dad, once you show me where Pielke Sr. misrepresented the science." You really must be joking Brian. Please don't be disingenuous, it is clear that you follow these proceedings, so you cannot claim ignorance. Go to RealClimate, go to Tamino, or use the search function here and you will find numerous examples of Roger's dad cherry picking, or misrepresenting or distorting the science to fit his narrative. Why is Roger Jnr. not hopping about accusing his dad of being a liar in public? As you know Roger is quick to (falsely) accusing other scientists of lying or fudging the data etc. Again, Google is your friend, or would you prefer some examples? "Let me summarize for all the point that everyone seems to have trouble either understanding or accepting, even though it is standard peer-reviewed scientific consensus." Please check your arrogant and condescending tone at the door. At #80 you have again managed to make several unsupported claims, and above you come across as lecturing people and suggesting that they are dim or something similar. There is also no need to shout at us in red, doing so makes your assertion none the more compelling. Last but not least,like I said before, you seem intent on missing the point of Dana's post. I would strongly recommend that you read it again and counter any points you disagree with using peer-reviewed journal articles from reputable journals. Thanks!
  15. WSJ, Sandy, and Global Warming - Asking the Right Questions
    I am happy to see that multiple posters have stated the real reason they are criticizing Pielke--for political, not scientific, reasons. (-snip-).
    Moderator Response: [DB] Tone-trolling is unhelpful to genuine, engaged dialogue. Please desist.
  16. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Brian, Still patiently waiting responses to my critique of your earlier posts. You evidently have had sufficient time to answer several other people in the interim.
  17. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Just a few quick responses: John Hartz (#63 - 65) It is incorrect to say that AGW has made Sandy, any other hurricane or TS, or even TS activity in general, worse. There are no significant trends for landfalling storms and the data slightly favor a negative trend for intensity and frequency. If you don't believe me, listen to Dr. Martin Hoerling at NOAA: "There’s very little confidence that climate change has affected the frequency or intensity or track of these disturbances.” (see 2:02 of interview) http://minnesota.publicradio.org/features/npr.php?id=164055672 AGW has contributed to sea-level rise, but this doesn't impact the storms themselves. It does potentially increase damage risk from hurricanes (and all flooding events), which is not to be dismissed lightly, but this damage is not yet apparent in the data. In any case, please abandon any claim that Sandy itself was worse because of sea level rise. This is just not a scientific claim, even when made by scientists. K.a.r.S.t.e.N. (#66) I see you are afflicted by the problem all too common on this blog--failing to get the point. The AMO oscillation is a natural phenomenon. Whether the amplitude of that oscillation is affected by AGW is debatable but irrelevant to my analysis. Once the oscillation is accounted for, regardless of amplitude, any remaining trend is too small to be taken seriously given the uncertainties. Regarding Pielke, I cannot give you the evidence you seek, but I never claimed that he attributed other damages to AGW. What he has said repeatedly is that AGW signals are more likely to be seen in the phenomena themselves before they are seen in the resulting damages. What about that are you having trouble understanding? Finally, I would be happy to provide evidence that Pielke Jr. criticized his dad, once you show me where Pielke Sr. misrepresented the science. I suspect I'll be waiting a long time for that one. doug_bostrom (#67) (-snip-). -AGW is causing some of the sea-level rise, which can potentially increase damages. -Grinsted found no significant trend in the seasonal average surge index. -The Grinsted trend in > 10 unit events, which cover more than hurricanes, is likely spurious because it is measured from a low point in the AMO to a high point. Either way, it does not support the claim of increased damages. -Grinsted's trend (unpublished) in top 150 events is not significant at the 2-sigma level and is even more likely to be spurious (for the same reason). The bottom line is that there is no real trend in the surge data. (See Pielke's blog for evidence of all these assertions). Kevin C (#70, 71, 78 etc.) Ultimately the analyses merely confirm what I stated from the beginning--there is no significant trend in the ACE data given above. Simple courtesy would require you to acknowledge that. With no detectable trends in the Atlantic basin ACE, landfalling hurricane frequency and strength, or normalized damages, there is simply no evidence that AGW has made hurricane damages worse. This does not preclude, of course, that such damages might increase in the future. EliRabett (#79) Ah, Eli has tumbled down the Rabett hole. Nothing in my quote "fails." Rising sea levels can make surge damages worse, but not necessarily. One is inclined to wonder whether a foot of sea level rise matters much with a 14-foot surge. Certainly not enough to be seen in the damage data. Given that the 1-foot rise happened over 150 years, I'm going to guess that none of the affected construction has been around that long. This means that coastline infrastructure is remade and redesigned many times during that sea level rise. The improvement in construction techniques and infrastructure integrity therefore occurs independent of the sea-level rise and is not a cost that can be attributed to it. Let me summarize for all the point that everyone seems to have trouble either understanding or accepting, even though it is standard peer-reviewed scientific consensus. Because there are no significant trends in landfalling hurricane data, there can be no trends in damage due to hurricanes themselves. If damages are affected by some combination of building quality, technology, sea level rise, etc., they would show up as trends in the normalized damages. The fact that no trends are seen in normalized damages implies that these effects are not yet big enough to be seen. No attribution of hurricane damage costs can be made to AGW. (-snip-).
    Moderator Response: [DB] Inflammatory tone snipped; strong hashtags converted to underlined.
  18. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    wili@10, I assume you're referring to This study. I don't have access to full text so I cannot have an opinion about it. So I have some questions about the validity of their conclusions: 1. From the abstract:
    "We show that the additional surface warming generated by the feedback between permafrost carbon and climate is independent of the pathway of anthropogenic emissions"
    How come? We know from logarithmic dependency between CO2 and dT, that in case anthropogenic emissions are large, the extra emissions from permafrost will be relatively minor. 2. They are talking long-term equilibrium (by 2300AD) warming due to positive permafrost feedback. Do they also consider negative feedback in land-cover (i.e. the land occupied by permafrost will become lush forest that will bind back the CO2 emitted)? 3. IMO, the equilibrium/earth system response CO2 level and T increase depend largely on carbon cycle perturbation. In that context, the FF carbon (100Ma old) perturbation is far more significant than the perturbation from melting permafrost C (just 1000s yold).
  19. WSJ, Sandy, and Global Warming - Asking the Right Questions
    The assertion from up post that 2) "There can be no AGW signal in hurricane losses in the U.S. because there has been no change in landfalling hurricane frequency or strength since record-keeping started. The trends, though not significant, are both down, in fact. " fails because, as has been noted, surge on a higher sea level is incredibly damaging across barrier islands and low lying areas. Moreover, increasing resistance to damage is as influenced by improved tracking as by better construction practices. Additional days and hours of time are used to harden even badly constructed structures and evacuate vulnerable populations. Roger is subject to the peer review of the insurance industry. His view is not favored.
  20. Grinsted et al. Examine Historical Hurricane Storm Surges
    (-snip-)
    Moderator Response: [DB] Off-topic snipped. Please use the Search function to find a more appropriate thread for your comment. Additionally, please also summarize what the link is about and why you feel it is relevant. Thanks!
  21. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    Tom Curtis at #9 said: "The increased outgassing from tundra and marine clathrates is a different and more concerning problem. Currently, however, the emissions are small compared to human emissions and we can hope that they remain that way if we keep temperatures under 2 C." We can hope, but hope is not likely to stop the physics, biology and chemistry that is driving tundra and clathrate melt (unfortunately). There was an excellent discussion here a couple weeks ago of a new paper on permafrost feedback (MacDougal et al. iirc) that concluded that just the CO2 from the top 3 meters of permafrost melting would lead to CO2 levels remaining at about current levels _even if all CO2 from ff burning stopped completely next year_. Action to stop carbon un-sequestration is imperative, but we should remain honest about how dire the conclusions from the science seem to be getting.
  22. Grinsted et al. Examine Historical Hurricane Storm Surges
    Not a scientist, but is there correlation with the 1920's and early 30's rapid expansion of agricultural land development and subsequent dust bowls, and the spike in the 30's?
  23. 2012 SkS Weekly Digest #45
    While I'm here, I might as well answer the What Say You? Not sure if the Weekly Bulletin series refers to the "News Roundup", but if so, I personally utilize those links. I find it useful to read climate related news items filtered through a quality check such as SkS. Basically, I know that the linked articles are worth reading for that reason.
    Moderator Response: [JH] Thanks for the positive feedback. The question should have been more explictly worded. The term "Weekly Bulletin" means the special summary of news items about Superstorm Sandy. Three have been produced to date. A fourth is in the works.
  24. 2012 SkS Weekly Digest #45
    Thanks KR.
  25. 2012 SkS Weekly Digest #45
    SeaHuck5891 - There's some discussion on one of the recent RealClimate.org open threads: search for Svensmark. It's essentially a repeat on an old idea, that passing through the arms of the Milky Way exposes Earth to more supernovae and radiation; a notion that (a) has little evidence, (b) requires both a lot of modeling and very high (and also unsupported) sensitivity to cosmic rays, and (c) absolutely zero to do with recent climate change, as we don't have a galactic arm transit coincident with the last 50 years of warming.
    Moderator Response: [DB] Fixed text and link.
  26. Book review: Rising Sea Levels: An Introduction to Cause and Impact by Hunt Janin and Scott Mandia
    We all know that average global sea level rise primarily results from melting of land based ice and thermal expansion of seawater. We also know that land based ice is melting at an accelerating rate, now indicating that ice mass loss is more than doubling per decade. Given this knowledge, it is surprising how many people cling to the notions that sea level rise is linear and that IPCC predictions of a 1 metre rise in average sea level by 2100 remain valid expectations. Nothing could be further from the truth, particularly in light of persistent failure to curb greenhouse gas emissions. Anyone with basic mathematics can easily calculate that if decadal doubling in the loss of land based ice occurs for the rest of this century, the effect on sea level will not be significant until about 2060. So for the next 40 years, no need to panic. We can all remain complacent – provided we don’t bother to look at what is likely to happen in the period 2060-2100. In that period, we can expect average sea level to rise, not by 3 feet but by around 4 metres – and sea level is not going to stop rising post 2100. It is simply not possible to “adapt” or take action to protect coastal cities or fertile, food producing flood plains and river deltas from rapid sea level rise likely to occur in the latter part of this century. Nor should we assume as does Mr Micawber that “something will turn up”. It won’t, certainly not unless we stop the loss of land based ice. Some “optimists” may argue that the present rate of ice loss will not show decadal doubling for the rest of this century and that present accelerating rates of loss are anomalous. In reality there is not a shred of evidence to support such an argument. Greenhouse gas emissions are increasing, indeed accelerating because of increasing loss of albedo and emission of CH4 and CO2 particularly in the Arctic. Global surface temperature continues to rise and is doing so at an accelerating rate. And the incidence of severe climate events are increasing.
  27. 2012 SkS Weekly Digest #45
    Can anyone point me in the direction of a summary/critique of this paper?: ftp://ftp2.space.dtu.dk/pub/Svensmark/MNRAS_Svensmark2012.pdf
  28. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    M Tucker @8, we are currently increasing atmospheric CO2 at an average rate around 2 ppmv. If we reduce that rate by 2.6% per annum (necessary to reduce the emissions to zero by 2050), we will increase the atmospheric concentration of CO2 to about 430 ppmv. Of course, if we do not start making significant reductions, we will overshoot the 450 ppmv mark well before 2050. The oceans do in fact absorb less as they warm, but so far the difference is small. Indeed, currently a greater fraction of human emissions are absorbed than in the early twentieth century, presumably because the increased absorption due to imbalanced partial pressures of CO2 has exceeded the reduction in absorption due to a warming ocean. Consequently, this effect is unlikely to represent a tipping point between now and 2050. The increased outgassing from tundra and marine clathrates is a different and more concerning problem. Currently, however, the emissions are small compared to human emissions and we can hope that they remain that way if we keep temperatures under 2 C.
  29. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    Tom Curtis @6, thanks for your response. If I am not mistaken we are increasing atmospheric CO2 at a rate of between 2 to 3 ppmv per year. What is the rate CO2 is taken up by the oceans? Given the response the world has show to even slow CO2 emissions, I’m thinking we will reach 450 before 2050. I’m also thinking the oceans and the atmosphere will continue to warm as we go forward. Warmer oceans means less CO2 will go into solution. In fact some scientists have said the oceans are even now absorbing less. So, now taking an optimistic pov, I wonder how much do we need to reduce emissions by in order to keep CO2 below 450 by 2050? And I am aware that we cannot just cut emissions while we continue to cut down the forests. We must take the forests into account with the bookkeeping. Now, going back to my natural pessimistic state, since we have already seen an alarming amount of ice melting with much less than 2 degrees of warming, I wonder what we will see as we approach the magic 2 degree number? I wonder how much more will the desert climate zones expand? I wonder how much more extreme will the already extreme weather events become? That said Tom, I sure hope we are able to at least keep the warming at or below 2 degrees regardless of what sort of climate change results from that. I sure hope someone has found the temperature brake and is keep their hand on it.
  30. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    Even with the optimistic CS of 3C and dated models that excessively draw down CO2 (so hide warming), 450ppm still only gives a 50:50 chance of avoiding 2C or a 50:50 chance of being just about below 2C (>95% being above 1.8C), and a 50:50 chance of being above above as well with a much larger tale so 3-4C easily possible. Now with a CS higher than 3C and well 450ppm means no chance at all of avoiding 2C and lets face it 1.5C is looking mighty scarey considering what is already occuring, Arctic sea ice, total changes in weather patterns and weather extremes weekly, and so on and so on. And in my previous post, my ECS was the 100 year as it was 60% of the total warming, (Hansen more recently estimated 80% so my estimates are optimistic), and thus why 350ppm gives 1.8C to 3C, and 350ppm is the most realistic estimate not 390-400ppm and 3-5C is the most reasonable estimates from most proxies for the Pliocene, (deep water tropical give 2-4C as per Hansen), but even that is no comfort as CO2 in the early Pliocene was still 350ppm and thus 20-25m sea level rise, no ice NH and a totally different climatic system in terms of tropcial boundaries etc....and look at what weather we are getting already! We have a carbon debt not a budget and that needs facing up to and asap. And don't forget the mass extinction human activities has also induced which is accelerating as well. Just pointing it all out. 450ppm for me even at 50:50 optimistic estimates is far to much risk considering the stakes, indeed 1.5C seems like an amount that is going to push the adaptive capacity of the human civilzation (e.g. New York would have to be moved for sure). Also the ascertions about the albedo changes taking eons are more hope than reality. I would suggest people read the meltfactor blog, consider the very large size of the Arcitc ocean and the very high summer insolation levels, consider the rapid loss of snow cover in occuring also, consider the rapidly changing albedo on Greenland due to surface water, and so on...and also consider that the alebedo shift from now to the Pliocene was basically just the Greenalnd Ice sheet and seasonal ice covers of snow and ice, not the large ice sheets of the last ice age. I agree we must act now, but also we have to accept we have a carbon debt not a budget.
  31. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    M Tucker @5, the temperatures and sea levels of the Pliocene represent the Earth System Climate Sensitivity, ie, the temperature response to forcing after all glaciers and ice sheets have reached equilibrium, and any changes to vegetation have also reached equilibrium. It is some consolation that the Charney (Equilibrium) Climate Sensitivity is between one and two thirds of the Earth System Response. The Charney Climate Sensitivity is the response after all rapid feedbacks (clouds, snow cover, water vapour etc) have reached equilibrium, but without changes to the albedo from the melt back of ice sheets or changes in land cover, and represents a good estimate of the near term (100-200 years) climate response to a change of forcing. The reason this is significant is that a large part of the additional CO2 added to the atmosphere by humans is drawn down into the ocean over a time scale of 200 hundred years. If we keep CO2 concentrations below 450 ppmv by 2050, and effectively cease all emissions thereafter, by 2250 CO2 concentrations will reduce to about 325 ppmv. After that it takes thousands of years for additional reductions in CO2, so we will face the full Earth System Response to the 325 ppmv; but only the Transient Climate Response (approx two thirds of the Charney Response) or the Charney (Equilibrium) Response at worst, to the full 450 ppmv. The upshot is that keeping the temperature increase below 2 degrees C is still a viable target, but we must act now. This is the time for urgency, not despair.
  32. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    First I want to say that the following is a product of my extreme pessimism and I want any who read this to know that I think we need to keep improving models and I applaud what Trenberth and others are doing and I expect them to keep it up… "...past climate changes thousands, tens of thousands, and even millions of years ago." That is what influences me. That is what I think about when I ponder what the future holds. Models are really important but they will always be an approximation of the real world. With better computers and better models we will get better predictions from the models. Climate changes thousand or tens of thousands of years ago are not in our league. In the past 800,000 years CO2 levels did not get much above 300 ppmv. Now about 3 million years ago, during the mid-Pliocene, CO2 was in our league. It was in the range of what we are currently at, about 390 to 400 ppmv. At equilibrium, the climate was about 2 to 3 degrees warmer and sea level was 35 meters higher than today. At that time the continents were in the same basic relative positions as today and ocean currents were mostly as today. That period of time has been extensively studied over the past 30 years or so with climate change in mind and the interpretation is solid. (I see that ranyl just mentioned the Pliocene warming. It is good to know that the information is out there so others can be informed) So, for me, all this talk about limiting warming to 2 degrees, or limiting sea level rise, or stopping the glaciers and ice sheets from melting, is all a bunch of fantasy arm-waving bureaucratic BS. The longer we wait to do anything the worse we can expect the outcome to be but we have already ensured a very bad outcome. We have the International Energy Agency making statements like: "No more than one-third of proven reserves of fossil fuels can be consumed prior to 2050 if the world is to achieve the 2 °C goal” Good luck with the magical temperature brake bureaucratic hogwash. Good luck with all the “we can prevent catastrophe” rah rah cheerleading. Since we are really doing nothing and since the best we can hope for is some sort of inadequate slowing of emission, not ending them, atmospheric concentrations will just keep rising. Sure, some sort of unforeseen process to take CO2 out of the atmosphere may come along but all I can think of when I hear that is: If wishes were horses, beggars would ride.
  33. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    Early Pliocene: ~350ppm from range of papers. 3-5C hotter from general range of estimates. ECS for 100 years presuming all feedbacks being equal over the milenia time scales the earth has cooled 3-5C, for a 70ppm /175 ppm = 0.4 of a halving, therefore a halving produces ~7.5C cooling, ~60% occurs in a hundred years, so that is 4.5C in a 100 years, or a 100 year ECS of 4.5C at the lower estimates. So not really a great surprise that the CS is higher than thought and might also explain why the models have underestimating, melt, tropical expansion, extremes and so on. And also the permafrost melt is going to release lots fo CO2 for sure now as well. 350ppm, we are at 395ppm. What is the carbon budget? or How much more carbon is anyone prepared to spend?
  34. Greenhouse effect has been falsified
    Adding to Sphaerica's comment: Frequent errors in these discussions are attempts to argue back from analogies. Analogies are useful "forward" explanations - complex system A is (in part) analogous to a more familiar system B (to portions thereof), and if your listener has context on B that can be useful in explaining relationships in A as "like" those in B. Energy balance in the climate is like a dam in a river, or the radiative greenhouse effect is like a blanket, for example. But those analogies cannot be used for "backward" testing, as there are portions of the complex system A that are not mapped in B, and portions of B that have no corresponding element in A - and assuming that the mapping is 1:1 is an error. Hence arguments such as from motorcycle shops to lunar regolith, or for that matter many of the "2nd law" or "Slayers" objections to the greenhouse effect, are simply meaningless nonsense, handwaving. An analogy is a useful explanation. But testing theories about complex systems needs to be done in those frameworks, using numbers, using math, with the actual relationships - not in a partially mapped analogy that is not the system in question.
  35. Greenhouse effect has been falsified
    Further to Sphaerica's comment, I might add that if, like me, you don't have the skill set to do the maths yourself, link to someone who does.
  36. 2012 SkS Weekly Digest #45
    In the cartoon, it should be "this neither" (instead of "this either").
  37. Greenhouse effect has been falsified
    To any casual reader who wanders by and reads Rosco's approach to science... This exemplifies why it is important to do the math, and to actually quantify the effects in question. It is very easy to "consider" and to do "thought experiments." With a wave of the hand, the dark side of the moon has 720 hours to cool and look, a sweltering motorcycle shop needs fans. It's so easy when you do everything by analogy, with none of that highfalutin mathematics and calculations and fancy numbers to get in the way. Don't do science by thought experiment and "obvious" conclusions. Run the numbers. All of them, not just the ones that conveniently seem to demonstrate the point that you'd dearly love to be true.
  38. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Some further details on AMO+MEI vs SST+MEI. In order to test the robustness of my results I tried rerunning the calculation with truncated data, using a whole range of start dates. The method gives good discrimination between the two models, favoring the SST model, for dates before 1880, and from 1900 to 1940. For 1880 and 1950, the results are more marginally in favor of AMO. These date ranges are similar to the date ranges showing no significant trend. In retrospect this is not unreasonable. That was a surprise: I had assumed on the basis of the p-value that the results would be more robust. My current thoughts: 1. p-value may be misleading for low values of R2. If this is the case, then presumably if I can find the appropriate statistical test for this kind of comparison then it will show that the models are similar. 2. The data violates OLS assumptions - certainly true. ACE appears to be nonlinear and the errors don't look normally distributed. Tamino could no doubt answer some of these straight off. A few other details: Best results seem to involve using AMO from Apr/May/Jun and MEI from Jul-Dec. R2 may be improved by using sqrt(ACE) rather than ACE. Best R2 I can get is about 0.4. Where does that leave us? Well, while the data doesn't favor SSTs over AMO, neither does it favor AMO over SSTs. So on the basis of the data alone we don't know which is better. On the other hand, we do have prior knowledge from meteorology. Finer scaled weather models and empirical studies both link hurricanes to SSTs, so I am a little surprised that the climate literature didn't link them to SSTs rather than AMO in the first place. Does anyone know how this came about?
  39. It's aerosols
    If you add the confidence intervals for the radiative forcing due to aerosols presented in the 4AR, you get approximately {-2.5,-0.5}W m^-2. This seems to account for the majority of the uncertainty of the total RF. To what extent has the aerosol uncertainty reduced since 2006/7?
  40. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    chriskoz: The two results are pretty much independent - indeed now you have raised it, I think that adjustment of the Hansen'88 results on the basis of ECS is probably invalid. Over decadal timescales, climate response is represented by transient response (TCR), not ECS, and assuming the two covary is not necessarily warranted. Indeed Hansen & Sato (2011) speculates that TCR in models may be a bit off because the rate of ocean overturning is underestimated. AR4 finds signficiantly different TCR from pure physics models (~1.6) and empirically adjusted models (~2.2). (This is all from memory, I may have some of the details wrong). So Hansen'88 is dependent on TCR, whereas FS12 is classifying models by ECS. It would be really interesting to reclassify the models by TCR and see if the result is the same. It would also be really interesting to revisit the Hansen'88 discussion looking at the TCR of Hansen's '88 model. I don't know if they were reporting TCR at the time, however if someone has the forcings and the temperature projections for each scenario I could make a good estimate. It's a lot of work for a purely historical question though - given all the exciting current problems to work on I can't get very excited about it.
  41. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Tom Curtis @ 45:
    Pielke's normalization procedure handles the extra expense in sea walls, hurricane proof construction etc in an obtuse way. By increasing current building costs, and hence current estimated wealth per capita, these defensive measures will inflate the normalized costs of damages done by earlier hurricanes.
    On the face of it that seems absurd — a major modern hurricane that causes widespread adoption of new and much more expensive construction standards will not have those additional costs added onto it's economic losses or even those of future hurricanes whose actual losses are reduced because of those investments but will instead make earlier hurricanes suddenly seem to be more damaging relative to the modern hurricane! But looking deeper, if you want to ask the question "What economic losses would we experience today if that particular historical hurricane were to hit now instead of 1923 (or whenever)?" then the logic behind it starts to make some sort of sense. But only briefly, because the raw loss data for the historical hurricanes were related to the actual construction standards employed at the time. In other words, you can't simply take the actual economic losses of an historic hurricane, multiply them by a correction factor to account for higher costs, and expect to get a good estimate of the economic losses were that same hurricane to hit today. Why? Because modern construction standards actually work. I have lived through many tropical cyclones in a region prone to them. Due to their regularity and severity (the worst I experienced — and the only one I can think of where the eye passed directly over us — had 240 km/h winds and a central pressure of 915 mbar/hPa) buildings were naturally built to stand them and damage is often minimal and loss of life rare. An historic cyclone that might have caused significant damage and loss of life in the early days would barely make a dent now. Yet "correcting" the historical cyclones economic losses to take into account modern construction costs would give exactly the opposite impression! This report on building damage in Goldsworthy and Port Hedland following Amy (which I referred to above) and Dean in 1980 is actually quite an interesting assessment of the effect of improved building standards that confirms my own experience. This whole exercise seems fraught with problems and a terribly indirect way to say what the consequences of global warming will be. I think "events" is a much simpler and more meaningful quantitiy to get a handle on than "normalised losses". Once a trend in "events" has been determined — magnitude and/or frequency — then you can try to figure out what the economic impacts will be going forward. After all, if New York was to experience Sandy-like events every few years, that would massively add to the costs of future construction and those additional costs should certainly be sheeted home to global warming if global warming was the reason for NY experiencing Sandy-like events every few years. Instead, Pielke's normalisation method would keep making the historic storms seem more and more expensive as more and more expensive construction techniques were employed, allowing him to continually claim there is no trend in normalised losses!
  42. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    The result of this study is indeed pessimistic if it concludes ECS > 3K However, Hansen 1988 was using ECS 4.2K, and it was shown to have overestimated the amount of current warming (Hansen's scenario B which turned out to be on track so far). Lesson learned from Hansen 1988 is: ECS should be 3.0K for his 1988 model to be spot on. Details were discussed here So, in the end, I'm not convinced that FS12 results are robust and bad news are inevitable. How do you reconcile FS12 with Hansen 1988?
  43. Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity
    Grim reading indeed. I've always hoped that sensitivity would converge at a value no higher than 3 C, although my guts have always thought that it would be higher. FS12 seems to imply that it could be appreciably higher than 3 C which, combined with the almost complete lack of action to date in addressing carbon emissions, bodes ill for our children and the biosphere in which they will live - such as that 'living' will be. I've said as much before and I'll say it again - an emergency response to AR5 is our last chance, else all our subsequent activities will simply be as aimless as Deck-chair Thimblerig on the Titanic.
  44. Philippe Chantreau at 10:31 AM on 13 November 2012
    Greenhouse effect has been falsified
    Well, Rosco, (-snip-). There is plenty of information available on the subject, from NASA and other sources, with which you are obviously not familiar. I will not bother linking anything because, if you have any sincerity, you will find it quite easily, no help needed. Your argument is not well constructed, it is a delirious case of Dunning-Krueger effect. The fact that you feel that you can come here and lecture not only on planetary science but also on moral principles is laughable. The kicker was putting together the idea of a well thought out argument and that of a square planet. Thanks for the entertainment. (-snip-).
    Moderator Response: [DB] References to deleted comments snipped by request.
  45. Greenhouse effect has been falsified
    As an interesting thought experiment - would a cubic blackbody have a different temperature to a spherical one ?
    Moderator Response: [DB] Please note that Rosco has recused himself from further participation in this venue (essentially a meltdown/temper tantrum).
  46. WSJ, Sandy, and Global Warming - Asking the Right Questions
    Brief update on my analysis at #70 and #71: Despite the convincingness of the p-values, the method fails on the robustness tests I've been performing. Results should be treated with extreme caution. More tomorrow.
  47. littlerobbergirl at 05:56 AM on 13 November 2012
    About New research from last week series
    I'm glad to see another 'lurker' was brave enough to 'de-lurk' to support you - for every poster there are 100s of readers :)
  48. New research from last week 45/2012
    Mark, The Stephen et al. paper is basically an update to the global energy budget (e.g. Trenberth et al.), in light of newly available new satellite measurements. The main changes occur in the surface budget instead of the top of atmosphere (TOA) budget. The biggest change is an increase in the estimation of downwelling long wave radiation (a.k.a. back radiation), over previous estimation given by Trenberth. The reason given by Stephen et al. is that the Trenberth estimation is largely based on reanalysis models that have a known lack of low clouds. It should be noted that Stephen et al. compared the measurement to the current CMIP5 models, and they are in fact reasonable agreement (given the large uncertainty). As pointed out by Gavin Schmidt on realclimate, the Stephen et al. paper in fact brings the estimation of longwave radiation closer to the current generation of climate models. The main point, I think, is that the Stephen et al. paper is in no way contradictory to our current understanding of climate, nor does it fundamentally change any of our current understandings.
  49. Climate of Doubt and Escalator Updates
    Tom Curtis@63 "Never-the-less, I think you need to support your claim a bit better." No strong evidence, only my own perception of that the actual problem that the engine-engineer have been trying to solve is (as you also note) the even distribution of the fuel with the intake air. Incidently (if the linked Wikipage is accurate), the O2-level of the diesel exhaust would indicate that the issue is not asmuch O2, rather some other factor. OTOH there is not any O2 in the gasoline(petrol) exhaust, but a sizeable amount of CO which could be the result of too rich mixture resulting in O2 'starvation' and incomplete oxifidation of the carbon, or reversely, not enough O2. Hmm... if only Vroomie had done some exhaust analysis on his Suburban in the different configurations, then his example would not be up for speculation. Regarding the rockets, I still am of the view that they are apples, since sincam's original claim included a possible design with high efficiency and zero emission (carbonwise I presume). Hence the rocket (in any form my limited imagination can procure) is out of the question since it does in effect rely on having the combustion gases immediately expelled to the environment as a mean of propulsion. His reference to rockets is thus an irrelevant distraction.
  50. New research from last week 45/2012
    Hi Ari - have you, or anyone, carried out an analysis on this paper from Late September in Nature Geoscience? An update on Earth's energy balance in light of the latest global observations The abstract says, in part "In light of compilations of up-to-date surface and satellite data, the surface energy balance needs to be revised. Specifically, the longwave radiation received at the surface is estimated to be significantly larger, by between 10 and 17 Wm−2, than earlier model-based estimates. Moreover, the latest satellite observations of global precipitation indicate that more precipitation is generated than previously thought. This additional precipitation is sustained by more energy leaving the surface by evaporation — that is, in the form of latent heat flux — and thereby offsets much of the increase in longwave flux to the surface." I have scanned on here and can see any reference to it. I also can't get behind the paywall to read the actual paper but a number of "sceptic" sites are claiming that it is a serious blow for AGW and associated models. I'd like to be able to read it and reach my own conclusions on that but would also really appreciate some of the more expert posters on this site and their views if they have read it?

Prev  1023  1024  1025  1026  1027  1028  1029  1030  1031  1032  1033  1034  1035  1036  1037  1038  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us