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James Wight at 19:58 PM on 13 May 2010Skeptical Science housekeeping: navigation, comments and Thai translation
John, I know you have lots to do, but may I make some suggestions to further improve the site navigation? There still remain several pages on the site which are not easy to find quickly. These include: • The About page (which should probably be more prominent since it’s likely to be what people will look for when they first arrive on your blog). • The Articles page. • The Contradictions page. • The page ordering skeptic arguments by percentage. • The explanation of how Skeptical Science measures skeptic argument frequency. • Archives (which can only be found by scrolling to the very bottom of the sidebar). • Your to-do list. (Incidentally, the purpose of this page might need more explanation – perhaps you could copy from the relevant paragraph on the Support SkS page.) One way to make all these pages more accessible would be to add drop-down menus to the navigation bar, as I recall you were intending to do at one stage. Alternately would it be possible to have two rows of links in the header? (I don’t know anything about web design so I don’t know how much effort this would involve.) A couple of other suggestions: • As I’m sure you’re aware, you currently have two pages which are called “Links” (this one in the header and this one in the footer). This could be confusing to people who haven’t been following your housekeeping updates. Perhaps you could distinguish the two by calling one “Resources” and one “Links”, and placing them next to each other in the header/footer? • In the sidebar, the text saying “Link to us” is presumably supposed to go here, but it actually goes to the iPhone icons page. As usual, all this is offered in the spirit of constructive criticism. I wouldn’t want to distract you from the more important task of updating the site content.Response: The good thing about you, James, is all the high quality feedback you supply. The bad thing is then I have to implement it! I'm still yet to go through all the suggestions you suggested on the Every skeptic argument page.
Two rows of links are not a good idea - becomes a bit of a mess (general rule of thumb, don't have more than 6 to 8 navigation links). I still plan to add drop downs - would've done it today but revamping the comments page took a while so it's been relegated to the next housekeeping session. I'll go through your other ideas at that time too. In fact, with all the comments and suggestions coming in, my dance card for the next housekeeping session is filling rapidly. -
Jacob Bock Axelsen at 19:15 PM on 13 May 2010Are we too stupid?
an emission tax? It will increase the production costs hence make the industry less competitive. You are wrong. To maximize profits the electricity producers of California are now begging consumers to use less electricity. "Jacob:OPEC is an excellent example of how powerful a coalition using reciprocity can be." I seem to remeber lots of defections during its existence. Also, Russia, one of the biggest producers, is not a member. OPEC caused the oil crisis in the 1970's. Have you never heard about that? I said that they did not succeed, so what is your point? CO2 is a pollutant. People prefer to live in less polluted areas. Thus people should be willing to pay for having less CO2 in their area. You need to read about how CO2 acts as greenhouse gas on the mean temperature of the Earth. The FAQ for policy makers from the Fourth Assessment Report from IPCC is a good start. There is also plenty of good information on this site. You were talking about "immediate" effects, they are talking about "threats". Surely you see the difference. There are serious health effects of Global Warming now. It is about the same problem of trends in statistics that people misunderstand when mixing up weather and climate. Read the reference. You completely miss my point. You were advocating immediate actions regardless of the risks. I am asking YOU if this is your attitude towards geo-engineering as well? Please point to studies that show that geo-engineering will pose a smaller risk than reducing emissions of CO2. If you argue against geo-engineering then according to YOUR own logic you have an interest in not mitigating climate change. If geo-engineering is proven less risky than reducing CO2 pollution then I would favour it, thus disproving your argument. Where are your references to the risks and what is the overwhelming scientific concensus about geo-engineering? Evolution is about the survival of the fittest - so defectors will just die. The fittest fig wasps survived and cooperate because the tree uses reciprocity. Your world police state argument is also self-contradictory. Imagine if you were right about everything we have discussed and people still wish to mitigate climate change. Then they would indeed make a world police force - and sadly history proves that people often have favoured that so why would they stop now? I argue the contrary, and the recent history with CFCs etc. and the game theory of this post indicates that it is not needed at all. If there was a truly democratic world government with a police force, then there would indeed be no need for the game theory I wrote about. This is not the case and will not be for some time. We can conclude that all that is needed is a comprehensive protocol calling for ending the use of fossil carbon. Similar measure were taken before and natural phenomena shows us that evolution has handled defection with reciprocity alone. The US may start already this year with taxing and capping carbon pollution because of global warming, money lost overseas and because China may beat them to it. Note: there is nothing about the mafia, deadly trade wars, crippling homeland competitiveness, feeling-good pious wishful thinking or the slightest concern about a potential world police state. -
RSVP at 18:14 PM on 13 May 2010Skeptical Science housekeeping: navigation, comments and Thai translation
"I've been very grateful to have the help of a number of moderators who ensure the comments all adhere to our Comments Policy. It's thanks to them that the quality of discussion... " ...however, there is a higher probability of getting a comment pruned if it isnt aligned in some way to the accepted school of thought.... and the website continues to call itself "Skeptical"Science.Response: Comments are pruned based on behaviour, not whether the comment adheres to a particular view. Lately, I've actually been deleting more comments that are pro-AGW but violate the "no ad hominem attacks" rule (calm down, people!). Regular visitors to this site have found when they post comments that stick to the Comments Policy (eg - learn to play nice), their comments are left online. This applies to both sides - many newcomers, both skeptic and pro-AGW, have had to adjust their usual online discussion style here. -
JRuss at 18:08 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
I have over a ton of hydrated CO2 stored in my garage. To prevent the hydrated CO2 from decomposing, pure CO2 was injected into the #10 cans in which it is contained. That is how I store my wheat. I highly recommend this form of storing excess CO2. -
mattnz at 17:06 PM on 13 May 2010A peer-reviewed response to McLean's El Nino paper
Interesting to see that J. Salinger, one of the authors of the rebuttal piece is at the very same university department as Chris de Freitas (School of Geography, Geology and Environmental Science, University of Auckland). That has to make for some awkward moments in the lunch room...! -
Riccardo at 16:47 PM on 13 May 2010Estimating climate sensitivity from 3 million years ago
Berényi Péter, "That's not an answer." Indeed! The question was ill posed, mine was a request for clarification. Now I see that you were not interested in asking. Lunt et al. paper looks at the equilibrium climate sensitivity, i.e. at the long (thousands of years) time scale; already in the abstract they point out that this long time scale response is often negleted. You contrasted it with a sensitivity derived over an extremely short (months) time scale. Your comparison has not much value. Let me remind you that upon looking at progressively shorter time scales you'll "discover" the strongest and fastest negative feedback we know, thermal emission. And let's not forget that feedbacks are additive. -
Bern at 16:39 PM on 13 May 2010Skeptical Science housekeeping: navigation, comments and Thai translation
I'm also an adherent of the "if it works well, it's good enough" school... I've fallen into the trap of doing things the 'right' way before, sometimes it means you end up doing 10 times the amount of work to achieve the same result (a programmer friend of mine called it 'premature optimisation' - where you spend more time optimising the code than you could possibly save by optimising it). To be honest, I've never used the "Recent Comments" page. I like it! :-D One suggestion - the title for the page the comment is on is currently placed after the comment. Is it possible to have it positioned before it? That makes more sense to my engineer's brain, and would make it a bit easier to skip comments I've already read (by way of reading the entire page).Response: Tried the titles above the comment. Don't know if I like it better but then, I'm not an engineer :-) -
Bern at 16:31 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
@HumanityRules at 42: You're right, this may never come to pass. But while we may never quite get to a Tw of 35ºC, even getting a few degrees closer to that mark will result in enormous death rates in heat waves, particularly in the very young, the elderly, and the sick. You're also right, it suggests a passive role for humans. The question is, if we get a century down the track with 'Business as usual', will there in fact be anything we *can* do about it? Is there anything we can do about it now? Well, yes, we can drastically cut our rate of carbon emission, to give nature time to soak up the excess before it gets too hot. Perhaps in 50 years we'll have sufficient non-carbon sources of power & massive CO2 capture plants that do nothing but liquefy CO2 from the atmosphere and pump it deep underground. It might take that kind of effort, but it's going to be a job and a half to sequester a few hundred billion tonnes of CO2. -
RSVP at 16:22 PM on 13 May 2010Estimating climate sensitivity from 3 million years ago
doug_bostrom at 03:13 AM on 13 May, 2010 "RSVP, you've got to make a stronger effort here." For the sake of a possible "new" reader, and so that you know I understand what you are referring to, allow me to first clarify the context of your remark. Correct me if I am wrong..., I am somehow not able to see why the Earth's temperature should stabilize to where it "should" be if all radiative forcings were to be "pre-Industrial Revolution", etc. I am actually basing my question around the radiative forcing model, which assumes that only "changes" in forcing can cause "changes" in temperature. Kind of like an aircraft's bank angle... it doesnt right until steering corrects, etc. Another analogy would be voltage or drift in a circuit. You can have unwanted voltages lingering due to poor grounding. No extra energy is needed. So if intuition leads one to think that the Earth's temperatures would return to normal if all humans just disappeared all at once, it probably has to do with the fact that the amount of IR radiated is a function of temperature, and that that radiative model is flawed as it doesnt take into account this nonlinearity. -
quokka at 16:12 PM on 13 May 2010Skeptical Science housekeeping: navigation, comments and Thai translation
Well, I like it the way it is. It renders very quickly, is reliable, decent layout and easy on the eyes. Something that half the sites on the web can't manage. If John finds CSS to be a drain on his time, I think thats sufficient reason to not use it. It is all to easy in software to place too much emphasis on technique and to forget the objective of getting the job done. As long as current technique is not leading to an unreasonable future maintenance burden it is often best to leave things the way they are.Response: I used to be a HTML code purist before the weight of the world broke my spirit. Now I use any hack solution that gets the job done. My earlier, idealistic self would despise my current self. -
Ed Seedhouse at 15:03 PM on 13 May 2010Skeptical Science housekeeping: navigation, comments and Thai translation
Actually I think the links look ever so much better as text. However as someone who has worked designing web pages I must say that the markup of your site just isn't up to current standards. I come here for the content of course, and that's always the most important thing. But still tables for layout went out ten years ago and the site would be much better and easier to use if you'd convert to modern semantic coding methods. I am not trashing tables, which have their function for marking up properly tabular data. But, for example, menus are not tabular, a menu is a list of links, and should be marked up with one of the html list structures, normally the UL element. I hasten to add that this is far less important than having good content, which you do, and it makes up for many sins. Still the basic design elements of this site are not up to scratch for a recently designed site. Sorry to be so negative, but I think you deserve to hear the truth!Response: I actually did use CSS mark-up to layout SkS but am actually transitioning back to tables. I just find it too time consuming to get the results I need using pure CSS layout. It's not as 'pure' as tables but sometimes tables just get the job done quick and dirty when I don't have much time. -
HumanityRules at 15:00 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
35.Bern I'm not sure it's even a worst case scenario. I haven't read the paper. But what John describes is the possible upper limit for human life. There's no sense in John's post that these numbers will ever be reached or approached. In that sense it's an intellectual fancy derived from a curious mind. I still contend that does suggest a fairly passive role for human society. As though we would quickly approach extra-ordinary conditions and do nothing about it. -
Doug Bostrom at 13:36 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
Joe Blog, we need to be able to evaporate water at a certain rate in order to shed metabolic waste heat resulting from a certain level of activity. Our skin surface area remains the same even as our liberation of waste heat and the ambient wet bulb temperature may vary. Realizing that at a certain wet bulb temperature we can evaporate water and thus remove heat at a certain rate from this fixed surface area, it's then not hard to see that as wet bulb temperature increases, the rate at which we may shed heat decreases. Knowing that, we can predict what levels of physical activity are sustainable at a given wet bulb temperature; for a given activity level, if the wet bulb temperature is high enough we can't evaporate a sufficient mass of water rapidly enough to maintain a stable temperature. If the rate we're able to evaporate does not keep up with the waste heat we're trying to shed, our temperature climbs. Long story shorter, no surprise: as the wet bulb temperature increases, the rate of sustained physical activity we can support drops since we know our surface area is fixed even as the rate at which we can shed waste heat via evaporation drops. So to experience hyperthermia we need not be "submersed in 35c water." Moist, warm (high wet bulb temperature) air will do the job. This is not a matter of doubt or speculation, though it may seem counterintuitive to you. Also helps to bear in mind, it's not possible to drink enough chilled water to directly cool a human body performing sustained physical activity. We stay cool by sweating, not urinating. -
Phila at 13:16 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
#33 HumanityRules "Do people not think there is a hint of alarmism about all this?" I think the only thing that's relevant here is whether the science is sound. If it is, then it's kind of silly to call it "alarmist." If it isn't, then it'd be better to point out exactly where the mistake is, instead of casting moral aspersions or making arguments from incredulity. I'm not sure what the Cretaceous has to do with anything. How many cities did we have back then? As far as the observation that "life isn't hell now" goes, I'd point out that while this may be true for you and me, a lot of people around the world are currently living in pretty hellish conditions, and there's good reason to believe that they'll be especially vulnerable to AGW. Even if alarmism were a serious problem, complacency wouldn't be the solution. -
Stephen Baines at 13:01 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
HummanityRules: "It also ignores the possibility that humanity would do something about this." I guess that's what we're talking about, right? Trying to assess whether theres a justification for doing something about "it." Re possibility of extinction, looking at the fossil record and comparing to the current situation is tricky. Climate changes over previous eons - even after glaciation - were relatively slow compared to what we're seeing now even if the final temps were higher in some instances. A "modest" shift globally of 3C or more in a little over 100 years is quite a large rate of change relative to what species can adapt to evolutionarily, especially long lived species. Species will have to shift their ranges much faster than occured during the last deglaciation over landscapes that we have made far more fragmented. I'm not sure about the danger immedaitely posed to human survival, but conservation of other species has always been based on a model of protecting crital spaces or preserves and assuming those spaces would remain good habitat. Now the game has shifted and park managers are and conservation organizations struggling to deal with it. Low dispersal species, and those endemic to mountains and poleward ends of continents, are especially sensitive. The concern of those managers is definitely real and not based on alarmism. There is a huge and still burgeoning literature on struggling to deal with this problem too. It's true there's a lot we don't know, but that doesn't make me feel more secure. -
scaddenp at 12:57 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
Well I doubt even centuries away really. Surely with even our most destructive impulses, we are going to have job maintaining a BAU CO2 emission strategy beyond 2100 even if run it till there. -
Bern at 12:45 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
@Joe Blog at #34: I don't know, some quick google-fu didn't help me out either. Can someone with access to the full article check for a reference for that figure? But this NASA page has lots of information about the heat conductivity & capacity of a typical human body (and they're talking about astronauts, so people in good physical condition). Presumably, it's possible to calculate from this (and lots of other thermodynamics) what the maximum survivable temperature is. Note, also, that there's a time-frame associated with it - you can endure high wet bulb temperatures for some time, with appropriate precautions (hydration, shade, rest), but if it goes on for too long your core temperature will rise too high and you'll be in trouble, as you mentioned. -
Rob Honeycutt at 12:30 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
@HumanityRules... If I'm not mistaken late cretaceous mammals were limited to early marsupials and other rodent-like creatures. Not a huge mammal population. -
Bern at 12:06 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
@Humanity Rules at #33: Isn't current global average temp more like 15ºC? That would but the entire Cretaceous at less than 7ºC higher than current. But just because some species of mammals have survived through that time-frame doesn't mean they weren't highly restricted in their range - mountain tops, high latitudes, other areas with cooler-than-average climates. Re the Mumbai comment - I rather suspect increases in Indian life expectancy have more to do with hygiene, nutrition, and modern medicine than temperatures. If we see this sort of nearly-worst-case warming, then life expectancy for India would start to plummet again in a few hundred years. @Berényi Péter at #32: you're right, 41ºC with 13% RH is only a wet-bulb temperature of 20ºC. But the same issues that resulted in so many deaths (heat stress, dehydration) under those conditions will, of course, only get worse as temperatures rise further. If increasing global temperatures result in more water vapour in the atmosphere, then the RH is likely to be the same or higher. The point of this posting, though, is that with sufficient increases in global temperatures, we might find areas where the heat waves are not survivable by humans, irrespective of how well hydrated you are. The frail, elderly, and sick would be the first to succumb, most likely well before we reached that cut-off point, even with the best of care. All this is assuming the absence of air-conditioning, of course, but not many people outside the US have that (although it's becoming much more common here in Australia). And even if you did, you're only a power failure away from big trouble. Moving underground (or using ground-loop heat exchange with extremely well-insulated buildings) might be the only way to cope in the affected areas. It's still most likely centuries away, though, so there's time for technological adaptation to cope with such extreme heat waves. -
Joe Blog at 12:03 PM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
Bern, thanks for the reply, unfortunatly there is no comparison between Darwin and Suai(it really is a hell hole).. but according to those tables i must have been in temperatures above this 35... there were no real weather stations mind. This was going of the battalions station they had set up on the edge o the main base, basically in jungle/grassland. So dont really know how accurate it was, hottest day tipped the mercury at 52 though. But to put this wet bulb in context... basically this paper is saying that someone submersed in 35c water for an extended period will die from heat stroke? i suppose i can see yer bodies metabolism easily enough throwing in the extra 5-7c for it to be fatal.(when yah core hits 40, its like yer on acid.. and aint long after that yah twitchin on the ground) But i do have to say, i have big doubts as to the accuracy o this claim. Speaking for myself, in those upper temps, i was drinking 15-20liters a day, which was warm, but still cooler than yer body temp. Im not going to pay to read the paper. But how exactly did he determine this survivability level? -
chris at 10:42 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
Tiny error in my long post just above. Though no one will likely notice, under (ii) it should say: "If there is a very fast negative feedback, then the increase in TOA IR will be more than this." -
chris at 10:37 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
Berényi Péter at 07:22 AM on 13 May, 2010 Although the moderator doesn't like Peter Berenyi's post here, I would have thought it was appropriate. After all the thread is about Earth climate sensitivity and that's what Peter's post is about. So in the assumption that posts about climate sensitivity are O.K. (as opposed to digressions into "waste heat"!), I'm going to respond to Peter. A problem with your post (Peter) is that the conclusion ("Therefore we should look for some explanation...") is built on a set of premises some of which are unlikely to be justified: (i) It's worth stating from the outset that Spencer and Braswell don't conclude anything about the Earth climate sensitivity from their paper in press that you refer to, and in fact state explicitly that their analysis doesn't necessarily have any bearing on Earth climate sensitivity as commonly regarded (the change in Earth surface temperature at equilibrium in response to radiative forcing equivalent to a doubling of atmospheric [CO2]; see bottom of post [***]). Nowhere in their paper do they suggest that the climate sensitivity is 0.5 oC (they don't conclude a climate sensitivity at all). I think you may have fallen for blogosphere over-interpretation, whereby someone pretends on his blog that a paper means something that it doesn't actually mean! So your major conclusion ("Therefore we should look for some explanation...") is invalid (non-sequitur). (ii) It’s also worth having a look at what Spencer and Braswell have actually done. One can usually get a good idea by looking at the abstract; it's reproduced at the bottom of this post [*****]. A previous analysis (Forster and Gregory, 2006) has made a much more substantial and quantitative analysis of this subject with a good discussion of the problems, and is rather more understandable than Spencer and Braswell. The aim is to make the most direct measure of feedback by direct analysis of the combined long wave IR emitted from the earth surface (and shortwave IR reflected by the atmosphere) in response to changes (fluctuations) in the measured sea surface temperature. If the temperature rises, the change in emitted IR (measured at the top of the atmosphere by satellites; TOA) should be equal to the “blackbody” radiation determined using the Stefan-Boltzmann relationship in a system with no very fast feedbacks. This is around 3.3 W.m-2.K-1. In other words just as the Earth should warm by around 1.1 oC per doubling of [CO2] with a climate system with zero feedbacks, so an Earth temperature rise of around 1 oC should result in an enhanced IR emission of 3.7 W.m-2 as the climate system “tries” to recover radiative equilibrium. If there is a very fast positive feedback the change in emitted IR will be less than this (because the positive feedback acts to "trap" some of the LWIR escaping to space). If there is a very fast negative feedback, then the increase in TOA IR will be less than this. Forster and Gregory found that the change in TOA IR is 2.3 +/- 1.4 W.m-2.K-1, (i.e. positive feedback since the change in TOA emission is less than the blackbody value), consistent with a (fast) climate sensitivity response of 1.0 – 4.1 oC per doubling of [CO2]. i.e. unfortunately poorly constrained. (iii) Spencer and Braswell use a variation of this in which they compare monthly averages of sea surface temperatures with monthly averaged satellite TOA measures and make regressions of the data to pull out a TOA radiative response to temperature changes. At this point their analysis becomes somewhat obscure (to me anyhow), and they compare the patterns of their regressions with model data and identify “striations” and “spiral patterns”. Their apparent change in TOA emission is 6 W.m-2.K-1. However (see [***] below), they conclude that this doesn’t necessarily relate to a climate sensitivity. (iv) There is an inherent problem with the claim of a negative fast feedback (Spencer claims this on his blog even if he doesn’t in the paper) and this relates to the fact that the fast feedback is bound to involve water vapour. There is no question that the atmosphere responds to warming with an increase in absolute humidity (see papers on this here ). So there really has to be a positive feedback to the warming from enhanced [CO2] with respect to water vapour. Cloud changes could provide a fast feedback (and presumably that is where Spencer and Lindzen – although the latter’s analysis was incorrect – would source their putative negative feedback). However Forster and Gregory conclude (with poor certainty) that the cloud response was neutral over the time of their measurements. The only other direct analysis of cloud feedback concludes that the cloud feedback is positive (over the NE Pacific anyhow!) (v) Finally, the temporal evolution of warming since the middle-late 19th century rather precludes negative feedbacks (clouds or otherwise) on the timescales relevant to climate sensitivity. Since we’ve had around 0.9 oC of warming during this period in response to enhanced [CO2] (290 ppm – 388 ppm) which should give around 0.4 oC of warming at equilibrium with a climate with zero feedbacks (let alone negative feedbacks) , significant negative feedbacks seem very unlikely (after all where have they been??), particularly as the solar contribution to this temperature rise is likely no more than 0.1 oC, and that some of the enhanced greenhouse warming has been offset by anthropogenic aerosols . Of course analyzing this properly requires a proper analysis! (try e.g. here, or here ------------------------------------------------- [***]e.g. Spencer and Braswell conclude:"Although these feedback parameter estimates are all similar in magnitude, even if they do represent feedback operating on intraseasonal to interannual time scales it is not obvious how they relate to long-term climate sensitivity."
and"Since feedback is traditionally referenced to surface temperature, extra caution must therefore be taken in the physical interpretation of any regression relationships that TOA radiative fluxes have to surface temperature variations."
[*****] abstract: “The impact of time-varying radiative forcing on the diagnosis of radiative feedback from satellite observations of the Earth is explored. Phase space plots of variations in global average temperature versus radiative flux reveal linear striations and spiral patterns in both satellite measurements and in output from coupled climate models. A simple forcing-feedback model is used to demonstrate that the linear striations represent radiative feedback upon non-radiatively forced temperature variations, while the spiral patterns are the result of time-varying radiative forcing generated internal to the climate system. Only in the idealized special case of instantaneous and then constant radiative forcing -- a situation that probably never occurs either naturally or anthropogenically – can feedback be observed in the presence of unknown radiative forcing. This is true whether the unknown radiative forcing is generated internal or external to the climate system. In the general case, a mixture of both unknown radiative and non-radiative forcings can be expected, and the challenge for feedback diagnosis is to extract the signal of feedback upon non-radiatively forced temperature change in the presence of the noise generated by unknown time-varying radiative forcing. These results underscore the need for more accurate methods of diagnosing feedback from satellite data, and for quantitatively relating those feedbacks to long-term climate sensitivity.” -
Berényi Péter at 10:21 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
#105 Moderator Response: The right place to post this comment should be Climate sensitivity is low. I see. In reply to an article claiming climate sensitivity to be high, anyone who thinks otherwise should post comments elsewhere. Makes sense. -
HumanityRules at 10:17 AM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
According to Wiki mammals evolved 200+ million years ago. What you might call modern mammals have been around for over 100 million years. Here's a reconstruction of temperatures. Looks like mammals have lived through periods with global temps 10oC greater than now. According to Wiki upper ocean temps may have even touched 17oC above todays average during the Cretaceous.
Do people not think there is a hint of alarmism about all this? Life isn't hell now so lets imagine a hell for future generations. It also ignores the possibility that humanity would do something about this.
15.mike roddy
Things might get sticky in Mumbai but it seems nobody told the indians they should be dropping dead of heat exhaustion. Life expectancy in India has almost doubled in the past 50 years.
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scaddenp at 09:58 AM on 13 May 2010Hockey stick is broken
John, another paper for you. Ice cover in Alps in 2003 at 5000yr lowResponse: That URL gives me a cookie error - is that a problem at my end or the publisher's? -
chris at 08:20 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
johnd at 07:14 AM on 13 May, 2010 "The need for postings to remain on topic is well understood.......The irony is....The subject is simply too....handy bite sizes..." Not really johnd. This thread is about an estimate of long term climate sensitivity based on analysis of CO2 temperature relationships 3 million years ago. Two people (you and RSVP) have chosen to sidetrack the thread into a tedious pretend "argument" about a very well understood subject (waste heat generation and its relation to Earth thermal energy balance). A pretence that we don't know what we do know about a subject doesn't equate to an indication that a phenomenon is inherently "chaotic". It just means that it is easy for posters on blogs to hijack discussions. It happens all the time, especially in poorly moderated blogs. The reality is that the natural world doesn't conform to one (or two) persons real or pretend ignorance of a subject. Likewise flooding threads with false arguments, pursuing inappropriate "analogies", and acting as if scientific knowledge hasn't progressed beyond the junior school level doesn't equate to "skepticism". Skepticism only really has meaning in relation to an informed and honest appraisal of a subject. In reality, while weather is "chaotic", the thermodynamics of radiative balance in the Earth system isn't. That's not to say that we understand everything - the range of likelihood in climate sensitivity (very unlikely to be below 2 oC per doubling of [CO2]; unlikely, but with greater uncertainty that climate sensitivity is greater than around 4.5 oC) is an indication of that. However the latter has got nothing to do with "chaos". It's largely to do with uncertainty in quantitating atmospheric aerosol forcings, cloud feedbacks and the various response times of the climate system. -
Berényi Péter at 08:16 AM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
#5 CBDunkerson at 21:38 PM on 11 May, 2010 The European heat wave of 2003 killed tens of thousands of people. The heat wave of 2003 has nothing to do with high wet bulb temperatures. It was worst in mid France. However, if you had a look at the weather history of Lyon, August 2003, you could see humidity was rather low on the hottest days. Dew point high there has never exceeded 21°C during August and when it was really hot (40°C on 12-13 August), relative humidity decreased to astonishingly low values (down to 12%). The high death toll is due to something else. Where people (and the government) are prepared for such a weather event, they can handle it pretty well. Unfortunately it was not the case in France. Most lonely elders died simply because they have not drunk enough water and relatives were out on holidays, not able to help them. -
Doug Bostrom at 08:12 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
Johnd, regarding residency time there are scads of information on that topic liberally sprinkled hither and thither all over the Web, as well likely in your public library. Why do you want us to go through the exercise of repeating what has already been expressed hundreds if not thousands of times, available just a few keystrokes away? Make an effort. If you can't think of where to begin, consider starting here: Weart's Discovery of Global Warming
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johnd at 07:39 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
Whilst the residency time of the various gases is often discussed, is it relevant? It is the residency time of the heat energy carried by the various gases and exchanged and transferred between the various gas molecules that is more important yet doesn't seem to be considered as something separate. -
Doug Bostrom at 07:35 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
Not the case we're speaking of, johnd. Flipping the analogy is pointless. -
johnd at 07:32 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
doug_bostrom at 03:13 AM, whilst many people try to use a blanket as a simple analogy, that is making it too simple. For a start you need to clarify whether the house is on fire or not, because if it is, and your blanket slips off........ The greenhouse effect is not really a mechanism providing our comfort as a blanket usually does, but one providing us with protection, as a blanket also can, so a more useful analogy than a blanket would be a firefighters protective gear. So what happens if the firefighters jacket slips off? -
Berényi Péter at 07:22 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
#47 Riccardo at 17:37 PM on 11 May, 2010 there's no formal definition of slow or fast feedbacks, they must be considered relative to the time scale analyzed That's not an answer. It always bothers me that all kinds of feedback loops are discussed all the time without assigning proper time constants to them. For example atmospheric water feedback (including both vapor and clouds) has to be pretty fast. Residence time of water in the troposphere is about 9 days. Even in the lower stratosphere it is a month at most. It means it should respond to any changes in SST (Sea Surface Temperature) on this timescale. That is, if the water cycle is supposed to amplify CO2 forcing threefold as claimed, we should be able to detect the effect even in short records (several years), we do not need many decades of data for this particular purpose. This is exactly what Roy Spencer is doing recently. His upcoming paper in the Journal of Geophysical Research will be an interesting read. Spencer, R. W., and W. D. Braswell (2010), On the Diagnosis of Radiative Feedback in the Presence of Unknown Radiative Forcing, J. Geophys. Res., doi:10.1029/2009JD013371, in press. (accepted 12 April 2010) He does not address water feedback directly, but claims to have found a strong short term (~1 month) negative feedback based on 7-9 years of NASA CERES radiation budget data. For detecting fast feedback loops that much data should be more than sufficient. On the other hand, it is hard to imagine that there could be a strong short term feedback in the climate system other than atmospheric water. At least no one has found one so far. Anyway, if short term (up to a month or so) feedback is negative, all feedbacks operating on longer time scales (years, decades, centuries, millennia) can only take this controlled signal as input. It means that any long term positive feedback loop that would bring temperature anomaly up to 4-5°C for CO2 doubling as claimed by Pagani should supply a gain close to 10 (Dr. Spencer has found a 0.5°C short term equilibrium value for CO2 doubling, as opposed to the 3°C IPCC "consensus" figure). With an f value of ~0.9 the climate system would be dangerously close to a runaway feedback (f > 1). In this case any number of slight structural changes over the ages could push it over the limit. As it has never happened in billions of years, there can be no such a strong positive feedback whatsoever on any timescale. Therefore we should look for some explanation of past excursions of climate other than carbon dioxide "forcing" amplified by multiple positive feedbacks of different origins operating on all timescales.Moderator Response: The right place to post this comment should be Climate sensitivity is low. Please always find the appropiate topic for your comments. -
johnd at 07:14 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
The need for postings to remain on topic is well understood for, each thread would quickly become chaotic, and people generally like to keep things neat and tidy not only in their minds, but in their forums as well. It has to be that way. The irony is that the matter being discussed, climate, is just the opposite, chaotic, and each individual factor somehow linked to interact with every other single factor. The subject is simply too vast and too complex for any single person to get their mind around, hence the need to break it down into handy bite sizes easily digestible, not only on forums such as this, but for the scientists as well. Ordered scenarios can be prodded and poked into a shape that than can be measured, and then modelled to yield results that reflect such an ordered system, but the focus is on the calculated outcome and the range of uncertainty essentially becomes off topic there also. -
WaxItYourself at 05:44 AM on 13 May 2010CO2 was higher in the late Ordovician
A 2005 study shows that the late Ordovician glaciation actually occurred 10 million years before. This ice age did not occur when CO2 was at it's peak. Rather it began at a time when the concentration was between 180 and 200 ppm. http://geology.gsapubs.org/content/33/2/109.short -
Dikran Marsupial at 03:23 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
e says: "Long term processes such as rock weathering eventually start to remove CO2 from the atmosphere." I think the 200 year adjustment time is based on transfer of CO2 from the surface waters to the deep ocean, rather than chemical weathering, which acts on even longer time scales. -
Dikran Marsupial at 03:19 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
johnd says: "If CO2 has been calculated as having a long residency time, what is the residency time of water vapour." CO2 has a short residence time (4-5 years) but a long adjustment time (50-200 years). CO2 needs modeling rather differently to other GHGs due to the large annual exchange flux. "Even though there is a high turnover of individual molecules, water vapour as a gas has residency time beyond measurement, a permanent presence that will exist whilst warmth from any source rises from the earth's surface. " Water vapour doesn't have a residence time beyond measurement, IIRC it is a couple of weeks. As I understand it warm air holds more water vapour than cold air, so if CO2 radiative forcing falls, and air temperature with it, then water vapour will precipitate out and there will be less radiative forcing from water vapour as well. It is a feedback in both directions. CO2 is a permanent presence in the atmosphere in exactly the same sense that water vapour is. -
Doug Bostrom at 03:13 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
RSVP, you've got to make a stronger effort here. If by adding C02 to the atmosphere we cause it to be a more effective insulator, if we then remove C02 from the atmosphere we can expect it be a less effective insulator. In terms of net effect, this is simply insulation we're talking about. Do you live where it's necessary to have blankets on your bed? What happens when your blanket slips off? It's that simple. Please try a little harder. -
Estimating climate sensitivity from 3 million years ago
RSVP, Long term processes such as rock weathering eventually start to remove CO2 from the atmosphere. As CO2 decreases the equilibrium temperature gets pushed down and the earth cools. -
Doug Bostrom at 03:05 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
Ring-a-ding! Teachable moment. What I said: Surface insolation for Earth taking into account angle of incidence, atmospheric attenuation, diurnal cycle etc. is roughly 250MW/km2. The surface of the Earth is about 510,000,000 km2. So, about 127,500TW of total insolation. What RSVP perceived and concluded: doug_bostrom "surface of the Earth is about 510,000,000 km2. So, about 127,500TW of total insolation" You are taking the total surface area. Only one side of the Earth gets Sun at any given time, so you will need to at least half that result for starters and reduce some more to account for albedo. If we take the time to read a little more carefully and integrate new information, more progress in understanding becomes possible. -
RSVP at 02:57 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
John Why isnt waste heat in the list of skeptical arguments?Moderator Response: Not enough time to have written pages for all the arguments. The Links contain more. (Click the "Links" button in the horizontal bar at the top of the page.) -
RSVP at 02:54 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
Ned And aside from the question of what is causing global warming, you remark that the effects of CO2 will linger for 200 years even if CO2 levels were to stabilize. Assuming that the Earth's temperature were to actually increase 4 degrees 200 years from now. And assuming GHG did return to "normal" (say 250 ppm). What exactly should cause the Earth's temperature to come back to "normal", assuming all else being equal? Shouldnt it remain higher if equilibrium is maintained? -
Ned at 02:41 AM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
Right, IPCC always gives figures for warming by the end of the century (or 2095, in this case from AR4) but the warming won't stop there. 2095 is actually not that far away. Go back the same amount of time and you're in 1925 ... approximately when my parents-in-law were born. The average girl born in Japan this year will still be alive in 2095, the end point for the IPCC AR4 projections. That's pretty amazing when you think about it. -
Alexandre at 02:17 AM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
Ned #28 I find it important to stress that those ranges in your bottom box is just the projection for the end of the century. The warming (particularly the slow albedo feedback) is projected to go beyond that. -
michael sweet at 02:11 AM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
James Wright, It was pointed out earlier in the thread that this was a worst case analysis. The temperature change required depends on what you consider bad. If you are only worried about large areas of Earth being completely uninhabitable it requires 7C. On the other hand, CB Dunkerson at #5 pointed out that several thousand people have died already in heat waves throughout Europe. If climate sensitivity is really 6C per doubling (long term) we have currently committed the Earth to substantial warming. How bad does it have to be to be considered bad? -
Ned at 01:40 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
johnd, now you're talking about feedbacks, all of which apply to both the radiative forcing from CO2 and the (much smaller) forcing from waste heat. There's the water vapor feedback, the ice albedo feedback, the tundra/forest albedo feedback, etc. All of which will be very small for a very small forcing (waste heat) and much larger for a much larger forcing (absorption of IR by GHGs).Moderator Response: Indeed, the off topic of waste heat has been discussed enough on this thread. Further comments on that topic probably will be deleted from this thread. But please do suggest links to other treatments of that topic. -
Estimating climate sensitivity from 3 million years ago
johnd, Talking about water vapour just confuses the question. You can compare the relative significance of waste heat vs. CO2 by measuring both of their effects on temperature without any feedbacks. Taking feedbacks into account just multiplies both sides of the equation by the same number. The rate vs. increase of a rate thing has been explained in pretty much every way possible. If it is still unclear, please try and re-read and see if one of the explanations sinks in. I don't think much more can be said on this thread. -
johnd at 01:14 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
If the heat sink for waste heat is water vapour, and water vapour concentration is relative to temperature, would not the increased water vapour due to that waste heat in effect accumulate the waste heat even if it is relatively small. -
Ned at 00:48 AM on 13 May 2010Heat stress: setting an upper limit on what we can adapt to
James Wight has a good point. Unfortunately, the table at global warming impacts doesn't really have a handy way of breaking down impacts as a function of temperature increase. That would be a long-term project -- it's basically what Mark Lynas does in his book Six Degrees. There's a handy version of this kind of chart in the IPCC AR4 SPM:
Figure SPM.7. Examples of impacts associated with projected global average surface warming.
But it's entirely qualitative, unfortunately. I wonder if anyone ever tried to produce a similar graphic with quantitative metrics? That could get ugly fast, but it's an interesting information visualization challenge.
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Ned at 00:37 AM on 13 May 2010Estimating climate sensitivity from 3 million years ago
RSVP writes: "I understand the "theory"; however, there is no theory required to quantify waste heat. " There's no theory required to quantify the absorption of longwave radiation by CO2 either. You can measure it in the lab. Again, the complicated part is the feedbacks. You are verging onto "argument from incredulity". I really think you need to give this up. It's been explained over and over again (not just in this thread) that waste heat is quantitatively trivial compared to the radiative effects of greenhouse gases. At some point, continuing refusal to engage with the points that are made by so many other people crosses the boundary into trolling. -
Ned at 00:31 AM on 13 May 2010Earth's five mass extinction events
Mike Roddy writes: Thanks for this, fascinating stuff, especially Chris #45. I have a question for nobody in particular: Hansen says that burning all the coal and tar sands will lead to Venus. BAU projections call for 5-7C temps in 2100, which is deadly, but not Venus. Does this mean that feedbacks at 5-7C will subsequenstly overwhelm the planet, since the rise in CO2 has been so rapid? Good questions. First of all, note that this is Hansen's own opinion, and other scientists may not be convinced by this claim. That said, Hansen is talking about burning all the conventional oil, coal, heavy oil/tar sands (cf Canada, Venezuela) and I think oil shale as well. That's a long-term, multi-century process, not something that would happen by 2100. So even if temperatures rise 5-7 C by 2100, Hansen's not saying that in itself would trigger a runaway greenhouse effect (RGHE?) like on Venus. What he IS saying is that if we spend the next few centuries burning everything, with CO2 over 1000 ppm, various other feedbacks like clathrates etc. would kick in and lead to RGHE conditions. That's still a pretty extreme claim, and I would want to see a bunch of convincing model results before accepting that it's possible. All that said, there's a lot of room for "extreme misery" even if we don't actually trigger a Venus-style RGHE. Burning a large enough fraction of coal and/or tar sands would put us at 3XCO2 and probably lead to disastrous conditions for much of the world's population.
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