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David Horton at 18:22 PM on 9 July 2010Hotties vs Frosties?
John, with all due respect, do you seriously think this is a kind of academic dispute where people of goodwill are just arguing over interpretation of data? -
ian_nicolson at 18:20 PM on 9 July 2010Hotties vs Frosties?
Drat, a hottie got in first. Mind you, that's quite unusual in the blogosphere. . . Any way, to try to follow the mellow tone of John's post, which I take to be an expression of a kind of equivalent to the "what would a reasonable man understand?" position (coupled to a welcome appeal for collaborative effort to resolve a polarising issue that appears to be characterised by people taking a "whatever the other lot think means absolute doom and disaster therefore I am entitled to be as ploemic and unreasonable as possible" approach), can I suggest that the names for the camps might work better as "hotties versus "notties"? Rant over . . . ;-) -
Marcus at 17:47 PM on 9 July 2010Hotties vs Frosties?
Here's the problem though John-*context*. Whilst it might be true to say that the warming of the last 15 years is *not* statistically significant (show me anyone who claims otherwise), that represents a gross oversimplification. Anyone who is being honest knows that, over a 15 year time period, global temperatures are subject to a very high noise to signal ratio. That doesn't mean that the planet hasn't warmed in that time. For instance, if I take the temperature data of the last 15 years (1995 to 2009), I get a positive slope of +0.0149, & an R-squared value of 0.402 (where anything greater than a 0.5 is usually accepted as statistically significant). What makes this all the more damning though is that the last 5 years of that 15 year period have been dominated by a *deep solar minimum*-yet still the Frosties can provide no evidence of actual cooling. Why do the Frosties always insist on cherry-picking the dates which they *think* will give them the result they want (usually it fails, like their 1998-2008 cherry pick, which still gives a positive slope of +0.0106) instead of looking at the bigger picture? -
RSVP at 15:35 PM on 9 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
post 6 1) "On the contrary, most of the energy being stored from the increased greenhouse effect is going into the oceans:" Not "on the contrary". This is "also" true, and this energy storage in water is longer term. I was talking about the short-time energy storage captured in the atmosphere until this heat convects to the oceans. 2) "Doubling greenhouse gases causes more infrared radiation to return back to the Earth's surface." In electronics, when you double the width of a resistor, the resistance decreases by half. In other words you double the conductivity. If CO2 is absorbing energy from the ocean surface, it is taking it away, not returning it. (At some point one needs to make up their mind about which way the energy is going.) In any case, this surface heat reaches CO2 and warms the surrounding gases (N2 and O2) and thus has that "greenhouse" warming effect on the air. Yes, the rate of warming will increase with more CO2, but by "rate", I mean how "fast", not how "much". This also means that the rate of ocean cooling will also increase. So, the idea that more atmospheric CO2 warms the oceans (for me) does not pan out. 3) "The increased greenhouse effect has been directly observed by surface measurements and satellites." There seems to be a stretching of the definition of greenhouse effect. Initially it had to do with warming of the atmosphere, but here it seems to imply warming the ocean as well. -
mothincarnate at 13:34 PM on 9 July 2010Italian translation of A Scientific Guide to the 'Skeptics Handbook'
Sorry - I wasn't trying to advertise. But I hope you felt that I did your work justice.Response: Advertise away, your blog post was very relevant - I had to go searching around just to track it down so please post URLs next time :-)
I thought yours was a great post - I like how you took the very brief explanations (intentionally very brief) in the Scientific Guide and fleshed them out in further detail. -
mothincarnate at 13:06 PM on 9 July 2010Italian translation of A Scientific Guide to the 'Skeptics Handbook'
That's fair enough.. I also wrote about a post comparing both handbooks (point to point comparison) and elaborated to make it clear that she didn't survive another attack - your handbook sunk hers. :)Response: Here's a link to your blog post for those interested in a 3rd party comparison of the Skeptics Handbook vs A Scientific Guide to the Skeptics Handbook. Thanks for dropping by and letting us know about the post. -
billkerr at 12:51 PM on 9 July 2010A Scientific Guide to the 'Skeptics Handbook'
hi john, Roger Pielke snr has incorporate my comment 32 and your response into his blog post: feedback on my invitation on the three hypotheses of climate It's at the end, his blog summarises feedback received about his 3 hypotheses. He has promised to respond to the feedback in a follow up blog. -
mothincarnate at 11:57 AM on 9 July 2010Italian translation of A Scientific Guide to the 'Skeptics Handbook'
An yet Nova naively trumpets on her blog that the Scientific guide feel short. I suspect that she didn't even read it - merely saw the graph. Keep up the great work!Response: She definitely read it. I'll write a response to her response but it'll be a few days - several other tasks rank higher on the to-do list right now. -
scaddenp at 09:07 AM on 9 July 2010Tai Chi Temperature Reconstructions
Johnd. I agree. I'm all for understanding the divergence problem and what it might tell us about better selection for temperature proxies. However, whatever the answer is, the agreement of existing ring proxies with other proxies suggests that it is not going have effect on our understanding of past temperatures. Perhaps we will better proxies in the future and be able to refine existing proxies as a result of this understanding but I doubt very much if you will get a different paleoclimate. Every proxy has limitations and problems, but the concordance of them is a cause for believing that the paleoclimate record is reasonably well defined. Also, in the sense that the point of paleoclimate record is to validate climate models, having a record that has more certainties than our proxies for forcings is of limited value. The important result from paleoclimate work is that it does not invalid our current understanding of how climate works. -
johnd at 08:19 AM on 9 July 2010Tai Chi Temperature Reconstructions
scaddenp at 07:08 AM, only a quick response re "to pick trees where circumstances dictate that the growth rings will determined by primarily by temperature." If that is done, and all growth factors accounted for, then there shouldn't be such a thing as a "divergence problem" should there? -
CoalGeologist at 08:17 AM on 9 July 2010Tai Chi Temperature Reconstructions
In response to Ned @#42 You've highlighted here why it is important to separate as much as possible the discussions of four categories of issues: 1) Documentation of climate change, 2) Attribution of climate change, 3) Predictions of future climate change together with interpreted impact, and 4) Issues of response and remediation. In order to understand WHY it's so important to disengage #4 from the rest requires some understanding of the underlying factors responsible for the phenomenon of AGW Denialism. This discussion would be outside the scope of the present topic, but suffice it to say that AGW Denialism is rooted in issues related to #4, and the arguments related to #1, #2, and #3 are constructed in reverse to support a specific (often ideologically based) position. In other words, one's views related to #4 can introduce bias in how the other, ostensibly scientific, issues are treated. On the other hand, any reasonable approach regarding #4 (response and remediation) must entail probabilities, which requires some unbiased estimates of certainty regarding the first three. To the extent that contemporary climate seems to approximately resemble climate during the MWP (differences in the forcings notwithstanding), much hinges on the precision and accuracy of climate models regarding future climate change. It is exceedingly important, therefore, that climate scientists maintain credibility on this topic, which is one reason why the "hockey stick" debate has broader implications than just whether or not temperatures today are higher, lower, or the same as during the MWP. -
johnd at 08:03 AM on 9 July 2010Climate is chaotic and cannot be predicted
I should add to my post that the same principle applies when the anticipation is that negative growth will continue unabated as does also occur from time to time. OT a bit, but those who do accumulate the wealth transferred from others generally consider that it is made at the time the shares are bought, not at the time of selling. -
johnd at 07:56 AM on 9 July 2010Climate is chaotic and cannot be predicted
John Brookes at 18:35 PM, productivity growth is only an indirect driver. The direct driver is the overall consensus of the market sentiment which in turn is driven not what any individual component is valued at today, but what it is likely to be valued at at some point in the future, ie the anticipation that positive growth will continue unabated. Of course overall consensus can create a situation that often results in the market diverging from the underlying fundamental drivers until a correction takes place that catches by surprise all those who were of consensus, but not those who had been examining those relevant indicators that had been ignored by all bar a few. Generally it is those few who accumulate a disproportionate amount of the wealth over time. -
scaddenp at 07:12 AM on 9 July 2010Tai Chi Temperature Reconstructions
Whoops "It doesn't change the picture though." -
scaddenp at 07:08 AM on 9 July 2010Tai Chi Temperature Reconstructions
johnd, you dont expect a single paper to cover all the aspects in using tree rings for temperature determination. That tree rings respond to factors others than temperature is hardly news to anyone working in the field. That is the critical part of selection of trees for use in this work - to pick trees where circumstances dictate that the growth rings will determined by primarily by temperature. The fact that tree ring proxies match well with other completely independent proxies suggests to me that they that they havent got the temperature that wrong. If you think tree rings are flawed, then look at proxy reconstructions that dont use any tree ring data. It change the picture though. -
johnd at 04:41 AM on 9 July 2010Tai Chi Temperature Reconstructions
Peter Hogarth at 18:58 PM, I followed up your links regarding the divergence problem. I don't know if you have read them or not, I have only had time to read the Buntgen 2008. Buntgen 2008 is of limited use. I feel that they have gotten the whole process back to front, and that there is very little understanding of plant biology amongst those who compiled the report. Tree growth, as with all plants, is the result of a combination of complex inputs. To draw any worthwhile conclusions, not only must all those factors be understood, but must be accounted for. Once they have been accounted for, only then can any of them, including to temperature, be correlated to growth. Thus any study relating growth rings to temperature should basically be a study of tree growth, and any conclusions drawn about temperature basically a byproduct. Buntgen 2008 does virtually nothing to understand tree growth, all it basically confirms is that there is a divirgence problem by examining data, but perhaps with limited understanding of what the data represents. There is nothing about soil nutrient levels, nor about tree density. These are two major factors that affect tree growth and change over time. There was nothing about how changing CO2 levels are accounted for, it is not even referred to at all. However the most glaring omission, is that of sulphur dioxide. There is not a single mention in the entire study, yet here is perhaps the most relevant factor of all, particularly if the trees being studied are anywhere in Europe. It is this omission that would cause me to discard any such study as a useful reference. Irrespective if you have read Buntgen 2008 or not, I would recommend that you read some literature that addresses ALL the factors that affect tree growth, particularly those concerning sulphur dioxide. This may be a place to start, it is a couple of decades old but very relevant Sulfur dioxide and vegetation: physiology, ecology, and policy issues by William E. Winner, Harold A. Mooney, Robert A. Goldstein It is not enough to know that there is a divergence problem, we need to know why in order to input into any modelling that is done to reconstruct historic data. -
muoncounter at 04:08 AM on 9 July 2010Archibald’s take on world temperatures
31, 32: "highest global temperatures have been recorded during a low period in the solar cycle." "solar activity has been low for the past 40 years but is now showing signs of increasing." Are you speaking of some long-term solar cycle or the more familiar sunspot cycle? John has written on other threads that TSI is decreasing. This TSI graph from PMOD's 'Solar Constant' page supports that point.
The 11-12 year period is clearly shown; the '79 peak value seems the highest of the lot.
TSI is well-correlated with sunspot number, which has a much longer observation history. However, these short-term cycles are hardly a match for the global temperature trends, as shown below, from wikipedia.
While one can certainly see the early 20th-century temperature low in the long-term sunspot graph, the flat section (1950-1970's) in the temperature graph is a puzzler. I would love to see if a study including solar activity, atmospheric CO2 and another independent factor like atmospheric albedo (via sulphate/particulate emissions) sheds some light on that question. For example, if particulate levels rose between WW2 and the mid 70's, would that be enough to temporarily suppress the long term temperature trend?
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Tai Chi Temperature Reconstructions
johnd at 03:23, The only way to evaluate the accuracy of a particular proxy is to compare it to other established proxies or to recent temperature measurements. The fact that all these proxies independently show the same trends and that they line up well with modern temperatures establishes that they are likely accurate representations of temperatures. -
KR at 03:40 AM on 9 July 2010Tai Chi Temperature Reconstructions
Well, johnd, I would suggest you then find additional proxy data, or re-evaluate the data currently collected, and present your findings. Write it up and publish! This is the best evidence we have, and the best conclusions that can be drawn from them. There is no solid evidence for any other conclusion than these reconstructions of temperature over the last 2000 years. I would love to see more data, in particular more proxies for the Southern hemisphere, but lacking that, and lacking any model that predicts major hemispheric differences (other than "more oceans, slower to respond", which doesn't really change the overall results), that doesn't seem to be a major problem. Hypothetical data (that which might exist) is not evidence, and hypothetical analysis errors such as you mention here are not a disproof. Or, for that matter, any reason to doubt the current conclusions. -
johnd at 03:23 AM on 9 July 2010Tai Chi Temperature Reconstructions
KR at 22:54 PM, the reconstruction is most likely an accurate representation of the proxy DATA available. It is the basically the same data available to anyone who wants to do a reconstruction. Whether or not that data is representative, or accurate has not been assessed and requires a different analysis rather than a compilation. -
MarkR at 03:10 AM on 9 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
#1: they do comment that seasonal effects will only catch 'fast' feedbacks like quick albedo changes from snow & clouds. The seasonal cycle has a wonderful advantage in that we're pretty confident about what causes it and can quantify it, whereas longer time periods (e.g. the last century) may have uncertain inputs since we don't know things like aerosol or ground albedo radiative forcings from 80 years ago. On the other hand, they do caution that regional changes are a problem and they're absolutely clear that they have to make some assumptions to get this result. However, it's the best method I can think of for teasing a figure out of the seasonal cycle. -
MarkR at 03:05 AM on 9 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
#10: I think it's in the subtext from 'Both types of clouds are part of the throttle control, reducing incoming energy'. Albedo changes are pretty efficient at controlling incoming heat. 'However, this would imply a gradual decrease in GHG forcing which exactly matched the incremental billion-year increase in solar forcing to the present value.' Demonstrates that perhaps Willis hasn't read up about the carbonate-silicate cycle, which also neatly explains why Venus is now a hothouse despite evidence for there originally being water there. If Willis' hypothesis was true for 'any' planet with water like he suggests, then Venus should be temperate today... it isn't. -
IanP at 02:00 AM on 9 July 2010How Jo Nova doesn't get past climate change
In a recent post Jo Nova thinks consensus and empirical evidence are mutually exclusive. I made the mistake of suggesting that consensus arises from the empirical evidence in the comments section. I then had "argument from authority" thrown at me when I mentioned the 97% consensus figure. Garrh the stupid, it burns! -
KR at 22:54 PM on 8 July 2010Tai Chi Temperature Reconstructions
So, johnd - you agree that the reconstructions are accurate representations of temperature variations over the last 2000 years? That the "hockey stick" shape is correct? And you're shifting the discussion over to why these changes occurred? That's good; there still seem to be lots of folks who feel that the Earth isn't warming, or that the MWP was hotter than things are now. Those are the people I would like to get to read Peter's analysis. -
philipm at 21:42 PM on 8 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
#8 MarkR: you presume wrong. Willis complete ignores albedo and in the comments on the article argues he need not consider it at all. Mind you, he also claims peer review is a modern concept and I had to look up the definition of the modern era to realise it started before the 17th century, so he probably knows some other things I don't. I like the way a totally implausible piece on another site has turned into a useful way of understanding the science here. What a pity most of the people who read the other site won't be reading this. -
Berényi Péter at 21:31 PM on 8 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
Murphy 2009 [...]includes ocean heat down to 3000 metres - the NODC OHC graph you've shown is upper ocean heat You mean between 1977 and 1990 more than 1023 J went below 700 m without increasing OHC above this level. Then it suddenly stopped going down for the next 14 years but accumulated in the upper layer. Any hint of physics behind this weird behavior? I can't see a significant change of global ocean overturning rate around that time in Marsch 2000 Fig. 12. (a).
Journal of Climate 2000; 13: 3239-3260
Volume 13, Issue 18 (September 2000)
Recent Variability of the North Atlantic Thermohaline Circulation Inferred from Surface Heat and Freshwater Fluxes
Robert Marsh
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Ned at 21:23 PM on 8 July 2010Tai Chi Temperature Reconstructions
johnd writes: Peter's reconstruction is a determination of how temperature has changed over time, and not about why it may have varied. Thus the basic outcome was predetermined, ie the planet has and is in a warming trend. Yes, I agree that the planet is warming and that Peter's work just provides an additional demonstration of that rather than directly addressing the question of why it's warming. In an ideal world that kind of demonstration wouldn't be necessary, but most of us recognize that there are a lot of people out there who still harbor the mistaken impression that the world is cooling or that it was warmer during the MWP. So, if you are comfortable with the fact that the world has warmed rapidly over the past half-century, to a temperature that is probably higher than any in the past 2000 years, then great. You can safely ignore this thread. Others, however, might benefit from it. William Connelley has a recent post over at Stoat that explicates how he sees the situation with global warming. There are four main points that most informed people would agree on: (1) The earth is getting warmer. (2) Humans are causing most of this warming, through greenhouse gas emissions and land use. (3) If we don't cut back on emissions, the warming will continue and in fact accelerate. (4) This will be a problem and we have to do something about it. Connolley says (and I agree) that those points are listed in approximately the order of certainty, with (1), (2), and (3) being essentially undisputable but with much less agreement about (4). Given that, it would be nice if we could just take the first three points for granted and focus all our energy on resolving the questions surrounding (4). Unfortunately, even people who ought to know better keep going back to revisit the first three points. Thus, post like Peter's here, and in fact all of John Cook's work on this site, are regrettably necessary. -
MarkR at 19:36 PM on 8 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
#2: Willis' method uses hemispheres, so summer/winter is applicable. I'll rephrase the article when I get back later. #4: That was the name of the WUWT piece :P #6: I was trying to keep it as short as possible but I've clearly failed to get across my point! I'll look at rewriting it. With climate sensitivity you have 3 extra heat flows to look at. First, heat lost to space from Earth warming up (this is the temperature change), heat flow into the oceans and atmosphere (showing how close you are to equilibrium) and extra heat reflected or allowed to escape (feedbacks which can be positive or negative). These 3 must add up to the change in heating or radiative forcing you applied and they change with time. Immediately after you add heating, you have very little extra from the Earth having warmed up and lots of heat going into the atmosphere and oceans. You're nowhere near getting climate sensitivity. If you leave it for ages, eventually you'll get near equilibrium and heat in = heat out. There's very little going into the atmosphere and oceans and almost all the extra heat will be 'cancelled out' by the sum of feedbacks which control heat flow to space PLUS the extra heat being radiated because temperatures have risen. I assume Willis' argument is largely albedo based, but he's looking at too short a time and looking at regional heating probably leads to incorrect feedbacks too (e.g. there are data showing increased cloudiness in summer, but global circulation is slightly different to what you'd get with a global heating so that could once again be a regional change) -
Berényi Péter at 18:56 PM on 8 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
most of the energy being stored from the increased greenhouse effect is going into the oceans Or it's not stored at all, just goes to space. After all that's the coldest heat reservoir around (2.7 K). Where did you get the image from? It's inconsistent with NODC OHC history reconstruction.
Response: The image comes from An observationally based energy balance for the Earth since 1950 (Murphy 2009) (Dan Murphy was gracious enough to email me his data) and includes ocean heat down to 3000 metres - the NODC OHC graph you've shown is upper ocean heat (something like the top 700 metres off the top of my head). -
John Brookes at 18:35 PM on 8 July 2010Climate is chaotic and cannot be predicted
I'm particularly taken with DaveU (2) and his mention of share prices. Share price movement is quite unpredictable for an individual share over days. Indeed, even over long periods an individual company might go broke. However, when you take the whole share market, and look at it over any 30 year period, it goes up. It goes up because there is an underlying driver (productivity growth) always pushing in one direction - up. So yes, the share price index bounces around, sometimes making no gains over a 10 year period (just like global temps?), but in the long term it goes up and up and up..... Chaotic, but predictable. -
RSVP at 17:21 PM on 8 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
The article does not explain in what way thunderstorms cancel out energy. Wind, lightening, rain, clouds?? It is one thing to "dissipate" energy, and quite another to "cancel it out". That point aside, it's nice to see the discussion turn towards questions of energy storage, which is what global warming is all about. By definition, non greenhouse gases (those that make up 97% of the atmosphere) is where the energy is being "stored". And doubling greenhouse gases will not cause more energy to be stored... it will only cause it to be stored (or released) faster.Response: "non greenhouse gases (those that make up 97% of the atmosphere) is where the energy is being 'stored'. And doubling greenhouse gases will not cause more energy to be stored"
On the contrary, most of the energy being stored from the increased greenhouse effect is going into the oceans:
Doubling greenhouse gases causes more infrared radiation to return back to the Earth's surface. This isn't just theory or climate modelling. The increased greenhouse effect has been directly observed by surface measurements and satellites. -
Is Willis wrong at WUWT? or Sensitivity and Sensibility II
MattJ, the southern hemisphere has significantly more ocean, so it shouldn't be too surprising that the rate of heat transfer isn't perfectly symmetrical from summer to winter. The summer and winter referred to in this post are from the northern hemiphere's perspective. -
Tom_the_Bomb at 13:27 PM on 8 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
A better name for this series would probably have been "Sense and Sensitivity". =) Just sayin'. -
scaddenp at 11:40 AM on 8 July 2010Tai Chi Temperature Reconstructions
Johnd, you have lost me. How do the methodologies "predetermine" that they will find a warming trend? If the world was actually cooling, are you implying that the measurements methods would still claim it was warming? If you are looking for regional scale examination of the temperature proxies (and the pattern which any model for climate must be able to reproduce), then surely this was the point of Mann 09? -
Jeff T at 10:43 AM on 8 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Following on from my previous comment: Select two days (perhaps, one in April and one in October) that have equal average temperatures at some latitude. Divide the temperature difference (zero) by the insolation difference (not zero). By Eschenbach's method, the sensitivity is zero at that latitude. By choosing dates carefully, you can get any sensitivity you want with Eschenbach's method. -
Rob Honeycutt at 10:02 AM on 8 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
MattJ... I believe that is what fig. 2 is about. -
MattJ at 09:51 AM on 8 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
How can the Earth "store heat in summer, losing it in winter", when half the Earth is in winter when the other half is in summer??? -
Tony O at 09:48 AM on 8 July 2010Is Willis wrong at WUWT? or Sensitivity and Sensibility II
I take it Knutti's figure is for the fast feedbacks not the slow feedbacks. Has anyone calculated an estimated sensitivity implied by the orbital cycles (ie including the really slow feedbacks)? -
Jeff T at 08:57 AM on 8 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Select a day in March and a day in September that have equal solar insolation. The temperature difference is particularly large at high latitudes. Divide the temperature difference (not zero) by the insolation difference (zero). By Eschenbach's method, the sensitivity is infinite. -
johnd at 08:53 AM on 8 July 2010Tai Chi Temperature Reconstructions
Peter's reconstruction is a determination of how temperature has changed over time, and not about why it may have varied. Thus the basic outcome was predetermined, ie the planet has and is in a warming trend. The data utilised is subject to the same limitations as most other proxy data, biased representation of NH over SH, error ranges, so it is reasonable to expect that the results will resemble most other reconstructions. All that could have changed is the timing of any changes, and the magnitude of any short term changes, however the long term trend is built in. It does not allow for what factors may have resulted in any change in trends within the overall longterm trend. That is a different issue and the one that is really relevant. Perhaps then, adjustments can be made to the reconstructions just as adjustments are made to the instrumental temperature records to account for changes in circumstances. I earlier used the example of testing blood and urine samples and skywatcher suggested collecting and testing multiple samples. That actually helps make my point. Collect samples from the entire population and have them all analysed by every laboratory, the results should all come out the same, because the chemical analysis is already predetermined by the biological functions of the human body. There will be variations within individual samples, and perhaps groups of samples, and they generally will fit with the "normal" range or within the error bars, but nothing is going to change the final outcome. Irrespective of where any researchers take the samples to study, as long as the samples are representative of the general population, the results should be the same. If they differ then either the samples are not representative, of the laboratory methodology was wrong. Perhaps studying human growth may be a better example. Humans are measured from the moment they are born, perhaps even earlier, and then through their entire lives. Weight and height are recorded throughout. Any study that examines human growth patterns is going to come to the same conclusion, weight and height increase during the growing period and then declines. There will be exceptions amongst individuals and groups of individuals, but it is predetermined that growth occurs. Examining the reasons why it may vary, increasing in trend, or decreasing, even halting, are completely different issues. -
witsendnj at 07:58 AM on 8 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
I have always likened that "CO2 is good for plants" notion to the idea that extra calories are good in the human diet. How about those diabetes and heart attack epidemics? It might be good in the short term to pack on extra weight, but in the long run, it's deadly. -
Philippe Chantreau at 06:38 AM on 8 July 2010Tai Chi Temperature Reconstructions
Plevy asks "How many practising academics (mathematicians or otherwise) were involved in assessing subprime mortgages?" A number of them and many did not see anything wrong, because they didn't want to. However, Nassim Nicholas Taleb and Benoit Mandelbrot (his teacher) looked at these financial models and didn't like them one bit, especially after 1987. http://www.pbs.org/newshour/bb/business/july-dec08/psolman_10-21.html -
KR at 04:46 AM on 8 July 2010Tai Chi Temperature Reconstructions
Looking at my previous post I realized I had left something out - using exponential fitting to align different trees into a single record looks like it might wipe out absolute differences. You get (as I understand it) absolute growth differences by comparing the thickness of equivalent rings (say, the 15-year ring) on trees of different eras, and by scaling the entire record according to lifespan overlaps and relative thicknesses at those overlaps. -
Phila at 03:51 AM on 8 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
#8 philipm if there is a serious case that the science is flawed...why do they entertain this sort of drivel? I think you just answered your own question. This is all they've got. -
Alden Griffith at 03:50 AM on 8 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
RE #17: Berényi Péter at 01:45 AM on 8 July, 2010 It depends on how much "forcing" comes from CO2, which in turn depends on the sign and strength of water vapor + cloud feedback. It seems that Eschenbach is assuming 'interchangeable' forcings in terms of Wm-2 values - he's assuming net effects with feedbacks included (although he seems to only believe in negative feedbacks anyhow...). Case in point: he uses a strictly solar forcing to estimate a strictly CO2 forcing. Using this net forcings approach, one can simply convert the CO2 sensitivity to its degrees C / Wm-2 value (0.014). Hence the whopping forcing required to come out of an ice age. -
Alden Griffith at 03:38 AM on 8 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Earth Sciences 101 – Final Exam QUESTION: Willis Eschenbach recently estimated the Earth’s climate sensitivity by examining winter vs. summer temperature and insolation at different latitudes: “My insight was that I could compare the winter insolation with the summer insolation. From that I could calculate how much the solar forcing increased from winter to summer. Then I could compare that with the change in temperature from winter to summer, and that would give me the climate sensitivity for each latitude band.” From this estimate of climate sensitivity, Eschenbach concludes that the climate sensitivity to a doubling of atmospheric carbon dioxide is approximately 0.05 degrees C. This is in contrast to the IPCC climate sensitivity range of 2 to 4.5 degrees C. Explain why this is NOT an informative way to estimate climate sensitivity. ANSWER: The main flaw in Eschenbach’s analysis is that the time period over which sensitivity is calculated (6 months) is too short. Thus, there is not nearly enough time to reach equilibrium (this is especially important given that the IPCC presents sensitivity at equilibrium). The heat capacity of the Earth is far too great to allow much of a temperature response over such a brief period. In contrast, if the Earth stopped orbiting the sun and the seasons remained fixed, then there would eventually be enough time to assess the equilibrium temperature response to such a large solar forcing. The equilibrium response would likely be very large indeed, yielding a much greater sensitivity value. However, this would still underestimate the true sensitivity because of teleconnections in the climate system, i.e. the Northern and Southern hemispheres are not isolated from each other in terms of energy flows. Energy from the summer hemisphere flows to the winter hemisphere and would reduce the apparent climate sensitivity. A comparison with the planet Mercury is useful. On Mercury, there is very little heat capacity (e.g. no oceans, no atmosphere) and virtually no teleconnections (e.g. no oceans, no atmosphere). Thus we would expect its temperature to respond far more rapidly to changes in solar insolation (as it does). Eschenbach’s analysis of climate sensitivity based on seasonality might work for Mercury, but it is fundamentally inappropriate for Earth. Beyond examining the assumptions of Eschenbach’s analysis, it is also worth examining its implications. A sensitivity of 0.05 degrees C to a doubling of CO2 is equivalent to 0.014 degrees C / Wm-2. This value suggests that the ~7 degree C change between glaciations would require a forcing of 518 Wm-2. This is greater than the average solar insolation of the entire planet (342 Wm-2)! This simple examination reveals that Eschenbach’s sensitivity is far too low to make any sense – the result of the extremely short time period over which it was calculated and the unaccounted for heat exchanges between hemispheres. In short: Eschenbach takes an extremely large forcing (summer versus winter insolation), assesses the response over an extremely short period of time (summer to winter), and comes up with an extremely low sensitivity. What you put in is what you get out. Tada!A+ -
Berényi Péter at 01:45 AM on 8 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
#1 Icarus at 09:12 AM on 7 July, 2010 Wow indeed. According to Willis's value for climate sensitivity, the ~7°C rise in global average temperature at the end of the last glaciation must have been caused by a whopping 560W/m² change in forcing. It depends on how much "forcing" comes from CO2, which in turn depends on the sign and strength of water vapor + cloud feedback. As the water cycle is pretty fast (average residence time of water in troposphere is ~9 days, in stratosphere less than a month), the parameters of the water feedback can be determined from short term studies. Neither 30+ year "climatologies" nor computational climate models are needed. Proper measurement of atmospheric water response to seasonal changes of insolation (& SST) should be sufficient. NH continental glaciation is a different matter. In that case most of the positive feedback comes from mid-latitude surface albedo changes, which is a slow process, on the order of millennia. -
chris at 00:39 AM on 8 July 2010Astronomical cycles
Ken Lambert at 23:43 PM on 7 July, 2010 I deal with highly non-linear larde deflection FEA analyses every day. Many engineering relationships are non-linear, much of nature is non-linear - so what is this big deal about statistical linearity? We can fit the sea level data how one wishes. The extant fact is that the satellite data fits closely to a linear trend (somewhere around 3.4 mm.yr-1 over the whole period). We can fit the data to a quadratic. If one does this the quadratic fit is essentially the same as the linear fit. The reason is that the third term of the quadratic is as close to zero as makes no difference. The reason a linear fit is appropriate is that it allows one to address a very simple and pertinent question namely: ” Given the variability in the data is the sea level rise consistent with a linear progression in time, or is it accelerating or decelerating?” Cutting through all the flak, I think we've established that the sea level data conform rather closely to a linear fit (or a quadratic with an essentially zero "acceleration term"!), that there is no justification in the data to infer that the rate of sea level rise is slowing down or speeding up, and that there is no basis in the data for insinuating "offsets" in the merging of sea level data. So some progress I would say! -
KR at 00:31 AM on 8 July 2010Tai Chi Temperature Reconstructions
thingadota - Seriously, that's quite the laundry list of "maybe/coulda/might have" issues with dating analysis. Every scientist in every field looks at their calibration issues - whether it's O2 isotope analysis, tree rings, core sample microbe prevalence, boreholes, etc. A random list of possible mistakes just indicates that you haven't dated the samples you're complaining about. And metamorphic rock changes are hardly an issue when examining proxies for the last 2000 years! For those who are interested, I previously posted something on tree ring analysis on the Kung Fu Climate thread. There are some very straightforward ways of correctly overlapping tree ring datings to extend the timeline past an individual tree lifespan, and given some knowledge about how the studied species responds to temperature, sufficient data to average out/correct for variations in water levels, insolation, etc., you can examine the temperature effects over time on tree growth. -
Paul Daniel Ash at 00:15 AM on 8 July 2010Is Willis Wrong at WUWT? or Sensitivity and Sensibility I
Ignoring it is not working. Fighting mere credulousness with rational argument is a bit like fighting fire with oatmeal, but until anyone has a better idea, what can be done must be done.
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